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Publications of year 2010

Books and proceedings

  1. Othmar Frey. Synthetic Aperture Radar Imaging in the Time Domain for Nonlinear Sensor Trajectories and SAR Tomography, PhD Thesis. Remote Sensing Series, vol. 59, Remote Sensing Laboratories, University of Zurich, Zurich, Switzerland. 2010. Keyword(s): SAR Processing, SAR Tomography, Tomography, Focusing, Time-Domain Back-Projection, TDBP, Corridor Mapping, Curvilinear SAR, Nonlinear Flight Tracks, Synthetic Aperture Radar (SAR), Remote Sensing, Airborne SAR, Forestry, L-Band, P-Band, Interferometry, InSAR, SAR Interferometry, Polarimetry, PolInSAR, Polarimetric SAR Tomography, Array signal processing, Extended Chirp Scaling, ECS, Mosaicking, Geocoding, Integrated Focusing and Geocoding, Georeferencing, mapping, E-SAR, digital elevation model, Capon, Capon beamformer, beamforming, Focusing, multibaseline, multiple signal classification, MUSIC, three-dimensional imaging, 3-D imaging, Vegetation.
    @Book{frey2010PhDThesis,
    title = {Synthetic Aperture Radar Imaging in the Time Domain for Nonlinear Sensor Trajectories and SAR Tomography},
    year = {2010},
    author = {Othmar Frey},
    series = {PhD Thesis. Remote Sensing Series, vol. 59, Remote Sensing Laboratories, University of Zurich, Zurich, Switzerland},
    isbn = {978-3-03703-025-7},
    file = {:frey2010PhDThesis.pdf:PDF},
    keywords = {SAR Processing, SAR Tomography, Tomography, Focusing, Time-Domain Back-Projection, TDBP, Corridor Mapping, Curvilinear SAR, Nonlinear Flight Tracks, Synthetic Aperture Radar (SAR), Remote Sensing, Airborne SAR, Forestry, L-Band, P-Band, Interferometry, InSAR, SAR Interferometry, Polarimetry, PolInSAR, Polarimetric SAR Tomography, Array signal processing, Extended Chirp Scaling, ECS, Mosaicking, Geocoding, Integrated Focusing and Geocoding, Georeferencing, mapping, E-SAR, digital elevation model, Capon, Capon beamformer,beamforming, Focusing, multibaseline, multiple signal classification, MUSIC, three-dimensional imaging, 3-D imaging, Vegetation},
    owner = {ofrey},
    pdf = {http://opac.nebis.ch/ediss/20111072.pdf},
    url = {http://opac.nebis.ch:80/F/?local_base=NEBIS&con_lng=GER&func=find-b&find_code=SYS&request=006410622},
    
    }
    


Thesis

  1. Evan C. Zaugg. Generalized Image Formation for Pulsed and LFM-CW Synthetic Aperture Radar. PhD thesis, 2010. Keyword(s): SAR Processing, LFM-CW, LFM-CW SAR, FMCW, MoComp, motion compensation, CSA, ECS, Chirp Scaling, Extended Chirp Scaling, FSA, Frequency Scaling Algorithm, Range-Doppler Algorithm, synthetic aperture radar, Brigham Young University, muSAR system, LFM-CW signal model, SAR image quality, aircraft, atmospheric turbulence, high-resolution synthetic aperture radar systems, linear frequency-modulated continuous-wave signal, motion compensation, motion correction algorithms, unmanned aerial vehicle, Airborne SAR, geophysical techniques.
    Abstract: Approximations made in the traditional signal model for synthetic aperture radar (SAR) processing cause defocusing of the radar images when the system operates under conditions where the approximations lose validity. This dissertation investigates a number of these approximations and presents algorithmic improvements based on generalizations of the approxmations of the SAR signal model. These improvements result in better focused imagery from SAR systems with varied designs and parameters. Among the advancements presented is the development of a generalized chirp-scaling algorithm and a generalized frequency scaling algorithm to address the problems caused by approximations based on a Taylor series expansion of the SAR signal for both pulsed SAR and linear frequency modulated continuous wave (LFM-CW) SAR systems. These generalized algorithms extend the ability of frequency-domain algorithms to process SAR data from systems with a low frequency, a wide beamwidth, and a large bandwidth. Image formation algorithms are developed that account for the continuous platform motion and compensate for translational position errors due to the continuous non-ideal motion of real-world LFM-CW SAR systems, including a backprojection algorithm that does not rely upon the traditional stop-and-go approximation for platform motion.

    @PhdThesis{phDThesisEvanZaugg2010Generalized_Image_Formation_for_Pulsed_and_LFMCW_Synthetic_Aperture_Radar,
    Title = {Generalized Image Formation for Pulsed and {LFM-CW} Synthetic Aperture Radar},
    Author = {Evan C. Zaugg},
    Date = {April 2010},
    Institution = {Brigham Young University},
    Url = {http://scholarsarchive.byu.edu/etd/2489/},
    Year = {2010},
    Abstract = {Approximations made in the traditional signal model for synthetic aperture radar (SAR) processing cause defocusing of the radar images when the system operates under conditions where the approximations lose validity. This dissertation investigates a number of these approximations and presents algorithmic improvements based on generalizations of the approxmations of the SAR signal model. These improvements result in better focused imagery from SAR systems with varied designs and parameters. Among the advancements presented is the development of a generalized chirp-scaling algorithm and a generalized frequency scaling algorithm to address the problems caused by approximations based on a Taylor series expansion of the SAR signal for both pulsed SAR and linear frequency modulated continuous wave (LFM-CW) SAR systems. These generalized algorithms extend the ability of frequency-domain algorithms to process SAR data from systems with a low frequency, a wide beamwidth, and a large bandwidth. Image formation algorithms are developed that account for the continuous platform motion and compensate for translational position errors due to the continuous non-ideal motion of real-world LFM-CW SAR systems, including a backprojection algorithm that does not rely upon the traditional stop-and-go approximation for platform motion.},
    Keywords = {SAR Processing, LFM-CW, LFM-CW SAR, FMCW, MoComp, motion compensation, CSA, ECS, Chirp Scaling, Extended Chirp Scaling, FSA, Frequency Scaling Algorithm, Range-Doppler Algorithm, synthetic aperture radar, Brigham Young University, muSAR system, LFM-CW signal model, SAR image quality, aircraft, atmospheric turbulence, high-resolution synthetic aperture radar systems, linear frequency-modulated continuous-wave signal, motion compensation, motion correction algorithms, unmanned aerial vehicle, Airborne SAR, geophysical techniques},
    Owner = {ofrey},
    Pdf = {../../../docs/phDThesisEvanZaugg2010Generalized_Image_Formation_for_Pulsed_and_LFMCW_Synthetic_Aperture_Radar.pdf} 
    }
    


Articles in journal or book chapters

  1. Stefano Tebaldini and Andrea Monti Guarnieri. Methods and Performances for Multi-Pass SAR Interferometry, chapter 18, pages 329-356. InTech, 2010. Keyword(s): SAR Processing, Modelling Interferogram Stacks, PSI, Persistent Scatterer Interferometry, Differential SAR Interferometry, D-InSAR, InSAR, SAR Interferometry, Interferometry, Decorrelation, Temporal Decorrelation, C-band measurement, DInSAR, ERS-1 data, Italy, Rome, agricultural areas, differential interferometric SAR, distributed targets, geometrical decorrelation, interferogram stack modeling, permanent scatterers, progressive ground motion, progressively decorrelating targets, sinusoidal ground motion, synthetic aperture radar interferometry, temporal decorrelation, radiowave interferometry, remote sensing by radar, synthetic aperture radar, vegetation mapping;.
    Abstract: Thanks to the several space missions accomplished since ERS-1, the scientific community has been provided with a huge amount of data suitable for interferometric processing. The innovation was the availability of multiple compatible images of the same areas. Such images, achieved by looking from slightly different point of view different orbits, and/or by different frequencies, and/or at different times, has largely extended the capabilities of InSAR with respect to the traditional dual image case. The advantage granted by the possibility to form multiple interferograms, instead than just one, is two folded. On the one hand, the estimation of the parameters of interest, be them related to the DEM or the terrain deformations, is driven by a larger data set, resulting in more accurate estimates. On the other hand, new parameters may be added to the set of the unknowns, allowing to study complex phenomena, such as the temporal evolution of the atmospheric and deformation fields. A major issue with multi-image InSAR is that targets are, in general, affected by temporal and spatial decorrelation phenomena, which hinders the exploitation of large spatial and/or temporal baselines. For this reason, most of literature about multi-image InSAR has focused mainly on targets that stay coherent in all the acquisitions, which has resulted in a substantial lack of a systemic approach to deal with decorrelating targets in the field of InSAR. The aim of this chapter is to propose a general approach to exploit all the available information, that is the stack of interferometric SAR images, and that formally accounts for the impact of target decorrelation. This approach is based on the optimal estimate of the data in a statistical sense. The basic idea is to split the estimation process into two steps. In the first step, a maximum likelihood (ML) estimator is used that jointly exploits all the N x (N-1)/2 interferograms available with N acquisitions, in order to yield the best estimates of the N-1 phases that correspond to the optical path differences between the target and the sensors. Target decorrelation is accounted for by properly weighting each interferogram in dependence on the target statistics. The estimated phases will be referred to as Linked Phases, to remind that these terms are the result of the joint processing of all the N(N-1)/2 interferograms. Once the first estimation step has yielded the estimates of the interferometric phases, the second step is required to separate the contributions of the APSs and the decorrelation noise from the parameters of interest, such as the Line of Sight Deformation Field (LDF) and the topography.

    @InBook{tebaldiniMontiGuarnieriInBook2010MethodsPerformancesMultiPassSARInterferometry,
    chapter = {18},
    pages = {329-356},
    title = {Methods and Performances for Multi-Pass SAR Interferometry},
    publisher = {InTech},
    year = {2010},
    author = {Tebaldini, Stefano and Monti Guarnieri, Andrea},
    editor = {Pasquale Imperatore and Daniele Riccio},
    isbn = {978-953-7619-97-8},
    abstract = {Thanks to the several space missions accomplished since ERS-1, the scientific community has been provided with a huge amount of data suitable for interferometric processing. The innovation was the availability of multiple compatible images of the same areas. Such images, achieved by looking from slightly different point of view different orbits, and/or by different frequencies, and/or at different times, has largely extended the capabilities of InSAR with respect to the traditional dual image case. The advantage granted by the possibility to form multiple interferograms, instead than just one, is two folded. On the one hand, the estimation of the parameters of interest, be them related to the DEM or the terrain deformations, is driven by a larger data set, resulting in more accurate estimates. On the other hand, new parameters may be added to the set of the unknowns, allowing to study complex phenomena, such as the temporal evolution of the atmospheric and deformation fields. A major issue with multi-image InSAR is that targets are, in general, affected by temporal and spatial decorrelation phenomena, which hinders the exploitation of large spatial and/or temporal baselines. For this reason, most of literature about multi-image InSAR has focused mainly on targets that stay coherent in all the acquisitions, which has resulted in a substantial lack of a systemic approach to deal with decorrelating targets in the field of InSAR. The aim of this chapter is to propose a general approach to exploit all the available information, that is the stack of interferometric SAR images, and that formally accounts for the impact of target decorrelation. This approach is based on the optimal estimate of the data in a statistical sense. The basic idea is to split the estimation process into two steps. In the first step, a maximum likelihood (ML) estimator is used that jointly exploits all the N x (N-1)/2 interferograms available with N acquisitions, in order to yield the best estimates of the N-1 phases that correspond to the optical path differences between the target and the sensors. Target decorrelation is accounted for by properly weighting each interferogram in dependence on the target statistics. The estimated phases will be referred to as Linked Phases, to remind that these terms are the result of the joint processing of all the N(N-1)/2 interferograms. Once the first estimation step has yielded the estimates of the interferometric phases, the second step is required to separate the contributions of the APSs and the decorrelation noise from the parameters of interest, such as the Line of Sight Deformation Field (LDF) and the topography.},
    booktitle = {Geoscience and Remote Sensing: New Achievements},
    doi = {10.5772/9112},
    file = {:tebaldiniMontiGuarnieriInBook2010MethodsPerformancesMultiPassSARInterferometry.pdf:PDF},
    keywords = {SAR Processing, Modelling Interferogram Stacks, PSI, Persistent Scatterer Interferometry, Differential SAR Interferometry, D-InSAR, InSAR, SAR Interferometry, Interferometry, Decorrelation, Temporal Decorrelation, C-band measurement;DInSAR;ERS-1 data;Italy;Rome;agricultural areas;differential interferometric SAR;distributed targets;geometrical decorrelation;interferogram stack modeling;permanent scatterers;progressive ground motion;progressively decorrelating targets;sinusoidal ground motion;synthetic aperture radar interferometry;temporal decorrelation;radiowave interferometry;remote sensing by radar;synthetic aperture radar;vegetation mapping;},
    owner = {ofrey},
    pdf = {../../../docs/tebaldiniMontiGuarnieriInBook2010MethodsPerformancesMultiPassSARInterferometry.pdf},
    url = {https://www.intechopen.com/books/geoscience-and-remote-sensing-new-achievements/methods-and-performances-for-multi-pass-sar-interferometry},
    
    }
    


  2. Joong-Sun Won Chang-Wook Lee, Zhong Lu, Hyung-Sup Jung and Daniel Dzurisin. Surface Deformation of Augustine Volcano, 1992?2005, from Multiple-Interferogram Processing Using a Refined Small Baseline Subset (SBAS) Interferometric Synthetic Aperture Radar (InSAR) Approach. In J.A. Power, M.L. Coombs, and J.T. Freymueller, editors, The 2006 Eruption of Augustine Volcano, Alaska, number 1769, chapter 18. U.S. Geological Survey, 2010. Keyword(s): SAR Processing, PSI, Persistent Scatterer Interferometry, Interferometry, SAR Interferometry, InSAR, Differential SAR Interferometry, DInSAR, SBAS, Small Baseline Subset, Volcano Monitoring, Surface Deformation, Deformation Monitoring, Geology.
    Abstract: Augustine Volcano is an active stratovolcano located in southwestern Cook Inlet, about 280 kilometers southwest of Anchorage, Alaska. The volcano produced six significant explosive eruptions between 1812 and 1986. Augustine eruptions typically have an explosive onset followed by dome building. The most recent eruption began on January 11, 2006. We applied the small baseline subset (SBAS) interferometric synthetic aperture radar (InSAR) technique to measure ground surface deformation during 1992?2005 with the use of European Remote Sensing Satellites 1 and 2 (ERS?1 and ERS?2) radar imagery. Through a multiple-interferogram approach, atmospheric delay artifacts, which hinder conventional InSAR measurements, are significantly reduced by spatial and temporal filtering. This allows us to retrieve time-series deformation over coherent points at millimeter-scale accuracy. The deformation results from two independent satellite tracks agree with each other, suggesting 2 to 8 cm wholesale uplift of Augustine Volcano from 1992 to 2005. Global Positioning System (GPS) data acquired in September 2004 and October 2005 confirm the SBAS InSAR results. A preliminary model consisting of a contracting source at 2 to 4 km depth and an inflating source at 7 to 12 km depth fits the observed deformation reasonably well. We interpret the deeper source as a long-term magma storage zone and the shallower source as a subsidiary reservoir that was tapped during the 2006 eruption. The shallow source corresponds approximately to the location of the volcano-tectonic earthquakes that preceded and followed the 1976 and 2006 eruptions, respectively.

    @InCollection{leeLuJungWonDzurisin2010_SBAS_PSI_p1769_chapter18,
    author = {Chang-Wook Lee, Zhong Lu, Hyung-Sup Jung, Joong-Sun Won, and Daniel Dzurisin},
    title = {Surface Deformation of Augustine Volcano, 1992?2005, from Multiple-Interferogram Processing Using a Refined Small Baseline Subset (SBAS) Interferometric Synthetic Aperture Radar (InSAR) Approach},
    booktitle = {The 2006 Eruption of Augustine Volcano, Alaska},
    publisher = {U.S. Geological Survey},
    year = {2010},
    editor = {Power, J.A. and Coombs, M.L. and Freymueller, J.T.},
    number = {1769},
    chapter = {18},
    abstract = {Augustine Volcano is an active stratovolcano located in southwestern Cook Inlet, about 280 kilometers southwest of Anchorage, Alaska. The volcano produced six significant explosive eruptions between 1812 and 1986. Augustine eruptions typically have an explosive onset followed by dome building. The most recent eruption began on January 11, 2006. We applied the small baseline subset (SBAS) interferometric synthetic aperture radar (InSAR) technique to measure ground surface deformation during 1992?2005 with the use of European Remote Sensing Satellites 1 and 2 (ERS?1 and ERS?2) radar imagery. Through a multiple-interferogram approach, atmospheric delay artifacts, which hinder conventional InSAR measurements, are significantly reduced by spatial and temporal filtering. This allows us to retrieve time-series deformation over coherent points at millimeter-scale accuracy. The deformation results from two independent satellite tracks agree with each other, suggesting 2 to 8 cm wholesale uplift of Augustine Volcano from 1992 to 2005. Global Positioning System (GPS) data acquired in September 2004 and October 2005 confirm the SBAS InSAR results. A preliminary model consisting of a contracting source at 2 to 4 km depth and an inflating source at 7 to 12 km depth fits the observed deformation reasonably well. We interpret the deeper source as a long-term magma storage zone and the shallower source as a subsidiary reservoir that was tapped during the 2006 eruption. The shallow source corresponds approximately to the location of the volcano-tectonic earthquakes that preceded and followed the 1976 and 2006 eruptions, respectively.},
    file = {:leeLuJungWonDzurisin2010_SBAS_PSI_p1769_chapter18.pdf:PDF},
    keywords = {SAR Processing, PSI, Persistent Scatterer Interferometry, Interferometry, SAR Interferometry, InSAR, Differential SAR Interferometry, DInSAR, SBAS, Small Baseline Subset, Volcano Monitoring, Surface Deformation, Deformation Monitoring, Geology},
    owner = {ofrey},
    pdf = {../../../docs/leeLuJungWonDzurisin2010_SBAS_PSI_p1769_chapter18.pdf},
    url = {http://pubs.usgs.gov/pp/1769/chapters/p1769_chapter18.pdf},
    
    }
    


  3. R.G. Baraniuk, E. Candes, M. Elad, and Yi Ma. Applications of Sparse Representation and Compressive Sensing [Scanning the Issue]. Proceedings of the IEEE, 98(6):906-909, june 2010. Keyword(s): NP-hard, compressive sensing, convex optimization, greedy methods, high-dimensional data, linear combination, overcomplete dictionary, sparse representation, computational complexity, signal processing, sparse matrices;.
    Abstract: Sparse representation and compressive sensing establishes a more rigorous mathematical framework for studying high-dimensional data and ways to uncover the structures of the data, giving rise to a large repertoire of efficient algorithms. A sparse signal is a signal that can be represented as a linear combination of relatively few base elements in a basis or an overcomplete dictionary. A sufficiently sparse linear representation can be correctly and efficiently computed by greedy methods and convex optimization (i.e., the l1-l0 equivalence), even though this problem is extremely difficult-NP-hard in the general case.

    @Article{5466604,
    author = {Baraniuk, R.G. and Candes, E. and Elad, M. and Yi Ma},
    journal = {Proceedings of the IEEE},
    title = {Applications of Sparse Representation and Compressive Sensing [Scanning the Issue]},
    year = {2010},
    issn = {0018-9219},
    month = {june},
    number = {6},
    pages = {906-909},
    volume = {98},
    abstract = {Sparse representation and compressive sensing establishes a more rigorous mathematical framework for studying high-dimensional data and ways to uncover the structures of the data, giving rise to a large repertoire of efficient algorithms. A sparse signal is a signal that can be represented as a linear combination of relatively few base elements in a basis or an overcomplete dictionary. A sufficiently sparse linear representation can be correctly and efficiently computed by greedy methods and convex optimization (i.e., the l1-l0 equivalence), even though this problem is extremely difficult-NP-hard in the general case.},
    doi = {10.1109/JPROC.2010.2047424},
    keywords = {NP-hard;compressive sensing;convex optimization;greedy methods;high-dimensional data;linear combination;overcomplete dictionary;sparse representation;computational complexity;signal processing;sparse matrices;},
    
    }
    


  4. B. Brautigam, J.H. Gonzalez, M. Schwerdt, and M. Bachmann. TerraSAR-X Instrument Calibration Results and Extension for TanDEM-X. IEEE Transactions on Geoscience and Remote Sensing, 48(2):702-715, February 2010. Keyword(s): TerraSAR-X, TanDEM-X, Earth observation, German TerraSAR-X system, TanDEM-X, TerraSAR-X image products, TerraSAR-X instrument calibration results, active phased array X-band antenna, antenna performance control, bistatic calibration techniques, electronic beam steering, radar images, radiometric stability, satellite flying formation, spaceborne remote sensing, synthetic aperture radar, antenna phased arrays, calibration, phased array radar, radar antennas, radar imaging, remote sensing by radar, spaceborne radar, synthetic aperture radar.
    Abstract: Spaceborne remote sensing with synthetic aperture radar (SAR) has become an essential source of high-resolution and continuous Earth observation. Modern satellites like the German TerraSAR-X system provide state-of-the-art radar images with respect to operating flexibility and imaging quality. The outstanding performance of TerraSAR-X image products is achieved by an innovative calibration approach that minimizes systematic antenna and instrument characteristics. The active phased array X-band antenna is fed by 384 transmit/receive modules for electronic beam steering and shaping in the azimuth and elevation direction. The flexible radar instrument hosts an internal calibration system which guarantees the high radiometric stability of all SAR products. New techniques for antenna performance control have been successfully implemented, setting a high standard for next-generation SAR missions. This paper summarizes all essential calibration results of TerraSAR-X that cover internal instrument behavior. Furthermore, we give an outlook on the required bistatic calibration techniques for the future TanDEM-X mission that faces additional performance challenges when calibrating two TerraSAR-X satellites flying in close formation.

    @Article{brautigamGonzalesSchwerdtBachmann2010,
    author = {Brautigam, B. and Gonzalez, J.H. and Schwerdt, M. and Bachmann, M.},
    title = {{TerraSAR-X} Instrument Calibration Results and Extension for {TanDEM-X}},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    year = {2010},
    volume = {48},
    number = {2},
    pages = {702-715},
    month = feb,
    issn = {0196-2892},
    abstract = {Spaceborne remote sensing with synthetic aperture radar (SAR) has become an essential source of high-resolution and continuous Earth observation. Modern satellites like the German TerraSAR-X system provide state-of-the-art radar images with respect to operating flexibility and imaging quality. The outstanding performance of TerraSAR-X image products is achieved by an innovative calibration approach that minimizes systematic antenna and instrument characteristics. The active phased array X-band antenna is fed by 384 transmit/receive modules for electronic beam steering and shaping in the azimuth and elevation direction. The flexible radar instrument hosts an internal calibration system which guarantees the high radiometric stability of all SAR products. New techniques for antenna performance control have been successfully implemented, setting a high standard for next-generation SAR missions. This paper summarizes all essential calibration results of TerraSAR-X that cover internal instrument behavior. Furthermore, we give an outlook on the required bistatic calibration techniques for the future TanDEM-X mission that faces additional performance challenges when calibrating two TerraSAR-X satellites flying in close formation.},
    doi = {10.1109/TGRS.2009.2030673},
    file = {:brautigamGonzalesSchwerdtBachmann2010.pdf:PDF},
    keywords = {TerraSAR-X, TanDEM-X, Earth observation;German TerraSAR-X system;TanDEM-X;TerraSAR-X image products;TerraSAR-X instrument calibration results;active phased array X-band antenna;antenna performance control;bistatic calibration techniques;electronic beam steering;radar images;radiometric stability;satellite flying formation;spaceborne remote sensing;synthetic aperture radar;antenna phased arrays;calibration;phased array radar;radar antennas;radar imaging;remote sensing by radar;spaceborne radar;synthetic aperture radar},
    owner = {ofrey},
    pdf = {../../../docs/brautigamGonzalesSchwerdtBachmann2010.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5299143},
    
    }
    


  5. E.J. Candes and Y. Plan. Matrix Completion With Noise. Proceedings of the IEEE, 98(6):925-936, june 2010. Keyword(s): compressed sensing, convex optimization problem, data constraints, low rank matrices, matrix completion, nuclear norm minimization, data integrity, matrix algebra, minimisation, noise, signal sampling;.
    Abstract: On the heels of compressed sensing, a new field has very recently emerged. This field addresses a broad range of problems of significant practical interest, namely, the recovery of a data matrix from what appears to be incomplete, and perhaps even corrupted, information. In its simplest form, the problem is to recover a matrix from a small sample of its entries. It comes up in many areas of science and engineering, including collaborative filtering, machine learning, control, remote sensing, and computer vision, to name a few. This paper surveys the novel literature on matrix completion, which shows that under some suitable conditions, one can recover an unknown low-rank matrix from a nearly minimal set of entries by solving a simple convex optimization problem, namely, nuclear-norm minimization subject to data constraints. Further, this paper introduces novel results showing that matrix completion is provably accurate even when the few observed entries are corrupted with a small amount of noise. A typical result is that one can recover an unknown matrix of low rank from just about log noisy samples with an error that is proportional to the noise level. We present numerical results that complement our quantitative analysis and show that, in practice, nuclear-norm minimization accurately fills in the many missing entries of large low-rank matrices from just a few noisy samples. Some analogies between matrix completion and compressed sensing are discussed throughout.

    @Article{5454406,
    author = {Candes, E.J. and Plan, Y.},
    journal = {Proceedings of the IEEE},
    title = {Matrix Completion With Noise},
    year = {2010},
    issn = {0018-9219},
    month = {june},
    number = {6},
    pages = {925-936},
    volume = {98},
    abstract = {On the heels of compressed sensing, a new field has very recently emerged. This field addresses a broad range of problems of significant practical interest, namely, the recovery of a data matrix from what appears to be incomplete, and perhaps even corrupted, information. In its simplest form, the problem is to recover a matrix from a small sample of its entries. It comes up in many areas of science and engineering, including collaborative filtering, machine learning, control, remote sensing, and computer vision, to name a few. This paper surveys the novel literature on matrix completion, which shows that under some suitable conditions, one can recover an unknown low-rank matrix from a nearly minimal set of entries by solving a simple convex optimization problem, namely, nuclear-norm minimization subject to data constraints. Further, this paper introduces novel results showing that matrix completion is provably accurate even when the few observed entries are corrupted with a small amount of noise. A typical result is that one can recover an unknown matrix of low rank from just about log noisy samples with an error that is proportional to the noise level. We present numerical results that complement our quantitative analysis and show that, in practice, nuclear-norm minimization accurately fills in the many missing entries of large low-rank matrices from just a few noisy samples. Some analogies between matrix completion and compressed sensing are discussed throughout.},
    doi = {10.1109/JPROC.2009.2035722},
    keywords = {compressed sensing;convex optimization problem;data constraints;low rank matrices;matrix completion;nuclear norm minimization;data integrity;matrix algebra;minimisation;noise;signal sampling;},
    
    }
    


  6. E.J. Candes and T. Tao. The Power of Convex Relaxation: Near-Optimal Matrix Completion. IEEE Transactions on Information Theory, 56(5):2053-2080, May 2010. Keyword(s): collaborative filtering, convex relaxation, free probability, information theoretic limit, matrix completion problem, near-optimal matrix completion, nuclear norm minimization, random matrices, random matrix theory, semidefinite programming, convex programming, information theory, random processes;.
    Abstract: This paper is concerned with the problem of recovering an unknown matrix from a small fraction of its entries. This is known as the matrix completion problem, and comes up in a great number of applications, including the famous Netflix Prize and other similar questions in collaborative filtering. In general, accurate recovery of a matrix from a small number of entries is impossible, but the knowledge that the unknown matrix has low rank radically changes this premise, making the search for solutions meaningful. This paper presents optimality results quantifying the minimum number of entries needed to recover a matrix of rank r exactly by any method whatsoever (the information theoretic limit). More importantly, the paper shows that, under certain incoherence assumptions on the singular vectors of the matrix, recovery is possible by solving a convenient convex program as soon as the number of entries is on the order of the information theoretic limit (up to logarithmic factors). This convex program simply finds, among all matrices consistent with the observed entries, that with minimum nuclear norm. As an example, we show that on the order of nr log(n) samples are needed to recover a random n x n matrix of rank r by any method, and to be sure, nuclear norm minimization succeeds as soon as the number of entries is of the form nr polylog(n).

    @Article{5452187,
    Title = {The Power of Convex Relaxation: Near-Optimal Matrix Completion},
    Author = {Candes, E.J. and Tao, T.},
    Doi = {10.1109/TIT.2010.2044061},
    ISSN = {0018-9448},
    Month = may,
    Number = {5},
    Pages = {2053-2080},
    Volume = {56},
    Year = {2010},
    Abstract = {This paper is concerned with the problem of recovering an unknown matrix from a small fraction of its entries. This is known as the matrix completion problem, and comes up in a great number of applications, including the famous Netflix Prize and other similar questions in collaborative filtering. In general, accurate recovery of a matrix from a small number of entries is impossible, but the knowledge that the unknown matrix has low rank radically changes this premise, making the search for solutions meaningful. This paper presents optimality results quantifying the minimum number of entries needed to recover a matrix of rank r exactly by any method whatsoever (the information theoretic limit). More importantly, the paper shows that, under certain incoherence assumptions on the singular vectors of the matrix, recovery is possible by solving a convenient convex program as soon as the number of entries is on the order of the information theoretic limit (up to logarithmic factors). This convex program simply finds, among all matrices consistent with the observed entries, that with minimum nuclear norm. As an example, we show that on the order of nr log(n) samples are needed to recover a random n x n matrix of rank r by any method, and to be sure, nuclear norm minimization succeeds as soon as the number of entries is of the form nr polylog(n).},
    Journal = {IEEE Transactions on Information Theory},
    Keywords = {collaborative filtering;convex relaxation;free probability;information theoretic limit;matrix completion problem;near-optimal matrix completion;nuclear norm minimization;random matrices;random matrix theory;semidefinite programming;convex programming;information theory;random processes;} 
    }
    


  7. M. Crosetto, O. Monserrat, R. Iglesias, and B. Crippa. Persistent Scatterer Interferometry: potential, limits and initial C- and X-band comparison. Photogrammetric Engineering and Remote Sensing, 76(9):1061-1069, 2010. Keyword(s): SAR Processing, PSI, Persistent Scatterer Interferometry, Interferometry, SAR Interferometry, InSAR, Differential SAR Interferometry, ground deformation time series, DInSAR, remote sensing.
    Abstract: This paper is focused on Persistent Scatterer Interferometry (PSI), a powerful remote sensing technique used to measure and monitor deformation phenomena. It only refers to satellite-based PSI techniques, focusing in particular on the most important sources of C-band SAR data: ERS-1/2 and Envisat. In addition, it compares C- and X-band results, considering data from the high resolution TerraSAR-X sensor. The paper begins with a concise description of the main characteristics of PSI. It then discusses the most important PSI products and their performances, analysing in detail their spatial sampling, the so-called residual topographic error and PSI geocoding, the average displacement rates and the deformation time series. As C-band products are concerned, the paper reports some relevant PSI validation results, which come from the ESA- funded Terrafirma Validation Project. Regarding the X-band, it describes the results obtained over the city of Barcelona by processing 13 StripMap TerraSAR-X images. The last part of the paper discusses the main limits of PSI.

    @Article{crosettoMoserratIglesiasCrippaPSI2010,
    author = {Crosetto, M. and Monserrat, O. and Iglesias, R. and Crippa, B.},
    title = {Persistent Scatterer Interferometry: potential, limits and initial {C-} and {X-}band comparison},
    journal = {Photogrammetric Engineering and Remote Sensing},
    year = {2010},
    volume = {76},
    number = {9},
    pages = {1061-1069},
    abstract = {This paper is focused on Persistent Scatterer Interferometry (PSI), a powerful remote sensing technique used to measure and monitor deformation phenomena. It only refers to satellite-based PSI techniques, focusing in particular on the most important sources of C-band SAR data: ERS-1/2 and Envisat. In addition, it compares C- and X-band results, considering data from the high resolution TerraSAR-X sensor. The paper begins with a concise description of the main characteristics of PSI. It then discusses the most important PSI products and their performances, analysing in detail their spatial sampling, the so-called residual topographic error and PSI geocoding, the average displacement rates and the deformation time series. As C-band products are concerned, the paper reports some relevant PSI validation results, which come from the ESA- funded Terrafirma Validation Project. Regarding the X-band, it describes the results obtained over the city of Barcelona by processing 13 StripMap TerraSAR-X images. The last part of the paper discusses the main limits of PSI.},
    file = {:crosettoMoserratIglesiasCrippaPSI2010.pdf:PDF},
    keywords = {SAR Processing, PSI, Persistent Scatterer Interferometry, Interferometry, SAR Interferometry, InSAR, Differential SAR Interferometry, ground deformation time series, DInSAR, remote sensing},
    owner = {ofrey},
    pdf = {../../../docs/crosettoMoserratIglesiasCrippaPSI2010.pdf},
    url = {http://digital.ipcprintservices.com/publication/?i=45474&p=&l=&m=&ver=&pp=},
    
    }
    


  8. D. D'Aria, A. Ferretti, A.M. Guarnieri, and S. Tebaldini. SAR Calibration Aided by Permanent Scatterers. IEEE Trans. Geosci. Remote Sens., 48(4):2076-2086, April 2010. Keyword(s): SAR Processing, PSI, Persistent Scatterer Interferometry, Differential SAR Interferometry, C band spaceborne SAR, Ku band ground based SAR, PS based normalisation, SAR calibration, absolute calibrated devices, corner reflectors, interferometric SAR image stack, iterative maximum likelihood method, permanent scatterers, radiometric stability, repeated SAR acquisitions, stable targets, synthetic aperture radar, calibration, electromagnetic wave scattering, iterative methods, maximum likelihood estimation, radar interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar.
    Abstract: We propose a calibration method suitable for a set of repeated synthetic aperture radar (SAR) acquisitions that uses both absolute calibrated devices (such as corner reflectors) and stable targets identified in the scene [the permanent scatterers (PSs)]. Precisely, the role of the PS is to extend the initial calibration sequence by monitoring the radiometric stability of the system throughout the whole mission life span. At a first step, this paper approaches the problem of PS-based normalization by an iterative maximum-likelihood method that exploits the stack of complex interferometric SAR images. Two solutions are given based on different assumptions on the PS phases. As a second step, the merging of these estimates with the available calibration information is discussed. Results achieved by experimental acquisitions are shown in two different SAR systems: 1) a C-band spaceborne SAR and 2) a Ku-band ground-based SAR.

    @Article{dAriaFerrettiMontiGuarnieriTebaldini2010CalibPSI,
    author = {D'Aria, D. and Ferretti, A. and Guarnieri, A.M. and Tebaldini, S.},
    title = {SAR Calibration Aided by Permanent Scatterers},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {4},
    pages = {2076-2086},
    month = apr,
    issn = {0196-2892},
    abstract = {We propose a calibration method suitable for a set of repeated synthetic aperture radar (SAR) acquisitions that uses both absolute calibrated devices (such as corner reflectors) and stable targets identified in the scene [the permanent scatterers (PSs)]. Precisely, the role of the PS is to extend the initial calibration sequence by monitoring the radiometric stability of the system throughout the whole mission life span. At a first step, this paper approaches the problem of PS-based normalization by an iterative maximum-likelihood method that exploits the stack of complex interferometric SAR images. Two solutions are given based on different assumptions on the PS phases. As a second step, the merging of these estimates with the available calibration information is discussed. Results achieved by experimental acquisitions are shown in two different SAR systems: 1) a C-band spaceborne SAR and 2) a Ku-band ground-based SAR.},
    doi = {10.1109/TGRS.2009.2033672},
    file = {:dAriaFerrettiMontiGuarnieriTebaldini2010CalibPSI.pdf:PDF},
    keywords = {SAR Processing, PSI, Persistent Scatterer Interferometry, Differential SAR Interferometry, C band spaceborne SAR; Ku band ground based SAR;PS based normalisation;SAR calibration;absolute calibrated devices;corner reflectors;interferometric SAR image stack;iterative maximum likelihood method;permanent scatterers;radiometric stability;repeated SAR acquisitions;stable targets;synthetic aperture radar;calibration;electromagnetic wave scattering;iterative methods;maximum likelihood estimation;radar interferometry;remote sensing by radar;spaceborne radar;synthetic aperture radar},
    
    }
    


  9. Lin Du, Jian Li, and Petre Stoica. Fully Automatic Computation of Diagonal Loading Levels for Robust Adaptive Beamforming. IEEE Transactions on Aerospace and Electronic Systems, 46(1):449-458, January 2010. Keyword(s): Capon, array signal processing, covariance matrices, fully automatic computation, diagonal loading levels, robust adaptive beamforming, covariance matrix estimate, Capon beamforming formulation, Robustness, Array signal processing, Covariance matrix, Degradation, Councils, Uncertainty, Guidelines, Spatial filters, Signal to noise ratio, Calibration.
    Abstract: The main drawback of the conventional diagonal loading (DL) approaches is that there is no clear guideline on how to choose the DL level reliably or how to select user parameters appropriately. An algorithm that can be used to compute the DL level completely automatically from the given data without the need of specifying any user parameter is considered. In this algorithm an enhanced covariance matrix estimate obtained via a shrinkage method, instead of the sample covariance matrix, is used in the standard Capon beamforming formulation. The performance of the resulting beamformer is illustrated via numerical examples, and it is compared with several other adaptive beamformers.

    @Article{duLiStoicaTAES2010FullyAutomaticDiagonalLoadingForRobustCAPONBeamforming,
    author = {Lin Du and Jian Li and Petre Stoica},
    title = {Fully Automatic Computation of Diagonal Loading Levels for Robust Adaptive Beamforming},
    journal = {IEEE Transactions on Aerospace and Electronic Systems},
    year = {2010},
    volume = {46},
    number = {1},
    pages = {449-458},
    month = {Jan},
    issn = {2371-9877},
    abstract = {The main drawback of the conventional diagonal loading (DL) approaches is that there is no clear guideline on how to choose the DL level reliably or how to select user parameters appropriately. An algorithm that can be used to compute the DL level completely automatically from the given data without the need of specifying any user parameter is considered. In this algorithm an enhanced covariance matrix estimate obtained via a shrinkage method, instead of the sample covariance matrix, is used in the standard Capon beamforming formulation. The performance of the resulting beamformer is illustrated via numerical examples, and it is compared with several other adaptive beamformers.},
    doi = {10.1109/TAES.2010.5417174},
    file = {:duLiStoicaTAES2010FullyAutomaticDiagonalLoadingForRobustCAPONBeamforming.pdf:PDF},
    keywords = {Capon, array signal processing;covariance matrices;fully automatic computation;diagonal loading levels;robust adaptive beamforming;covariance matrix estimate;Capon beamforming formulation;Robustness;Array signal processing;Covariance matrix;Degradation;Councils;Uncertainty;Guidelines;Spatial filters;Signal to noise ratio;Calibration},
    owner = {ofrey},
    
    }
    


  10. A. Elsherbini and K. Sarabandi. Mapping of Sand Layer Thickness in Deserts Using SAR Interferometry. IEEE_J_GRS, 48(9):3550-3559, September 2010. Keyword(s): electromagnetic wave scattering, geophysical image processing, geophysical techniques, radar interferometry, remote sensing by radar, sand, synthetic aperture radar, terrain mapping, topography (Earth), Ka InSAR, SAR interferometry, Saudi Arabia, aperture radar system, bedrock topography, desert area, groundwater exploration, inversion algorithm, oil field, radar imaging, sand layer thickness, sand topography, sensitivity analysis, subsurface imaging, terrain mapping, Costs, Explosives, Laser radar, Light scattering, Optical scattering, Petroleum, Radar scattering, Seismic waves, Surfaces, Synthetic aperture radar interferometry, Interferometric synthetic aperture radar (InSAR), radar imaging, subsurface imaging, terrain mapping.
    @Article{Elsherbini2010a,
    author = {A. Elsherbini and K. Sarabandi},
    title = {Mapping of Sand Layer Thickness in Deserts Using {SAR} Interferometry},
    journal = IEEE_J_GRS,
    year = {2010},
    volume = {48},
    number = {9},
    month = sep,
    pages = {3550--3559},
    issn = {0196-2892},
    doi = {10.1109/TGRS.2010.2047110},
    keywords = {electromagnetic wave scattering, geophysical image processing, geophysical techniques, radar interferometry, remote sensing by radar, sand, synthetic aperture radar, terrain mapping, topography (Earth), Ka InSAR, SAR interferometry, Saudi Arabia, aperture radar system, bedrock topography, desert area, groundwater exploration, inversion algorithm, oil field, radar imaging, sand layer thickness, sand topography, sensitivity analysis, subsurface imaging, terrain mapping, Costs, Explosives, Laser radar, Light scattering, Optical scattering, Petroleum, Radar scattering, Seismic waves, Surfaces, Synthetic aperture radar interferometry, Interferometric synthetic aperture radar (InSAR), radar imaging, subsurface imaging, terrain mapping},
    owner = {ofrey},
    
    }
    


  11. Joachim H.G. Ender. On compressive sensing applied to radar. Signal Processing, 90(5):1402 - 1414, 2010. Note: Special Section on Statistical Signal and Array Processing. Keyword(s): Compressive Sensing, Compressed Sensing, Radar, Sparse arrays, Pulse compression, Radar imaging, ISAR, Airspace surveillance, DOA estimation.
    Abstract: Compressive sensing (CS) techniques offer a framework for the detection and allocation of sparse signals with a reduced number of samples. Today, modern radar systems operate with high bandwidth demanding high sample rates according to the Shannon-Nyquist theorem and a huge number of single elements for phased array antennas. Often only a small amount of target parameters is the final output, arising the question, if CS could not be a good mean to reduce data size, complexity, weight, power consumption and costs of radar systems. There is only a small number of publications addressing the application of CS to radar, leaving several open questions. This paper addresses some aspects as a further step to CS-radar by presenting generic system architectures and implementation considerations. It is not the aim of this paper to investigate numerically efficient algorithms but to point to promising applications as well as arising problems. Three possible applications are considered: pulse compression, radar imaging, and air space surveillance with array antennas. Some simulation results are presented and enriched by the evaluation of real data acquired by an experimental radar system of Fraunhofer FHR.

    @Article{Ender2010CompressiveSensing,
    Title = {On compressive sensing applied to radar},
    Author = {Joachim H.G. Ender},
    Doi = {10.1016/j.sigpro.2009.11.009},
    ISSN = {0165-1684},
    Note = {Special Section on Statistical Signal and Array Processing},
    Number = {5},
    Pages = {1402 - 1414},
    Url = {http://www.sciencedirect.com/science/article/pii/S0165168409004721},
    Volume = {90},
    Year = {2010},
    Abstract = {Compressive sensing (CS) techniques offer a framework for the detection and allocation of sparse signals with a reduced number of samples. Today, modern radar systems operate with high bandwidth demanding high sample rates according to the Shannon-Nyquist theorem and a huge number of single elements for phased array antennas. Often only a small amount of target parameters is the final output, arising the question, if CS could not be a good mean to reduce data size, complexity, weight, power consumption and costs of radar systems. There is only a small number of publications addressing the application of CS to radar, leaving several open questions. This paper addresses some aspects as a further step to CS-radar by presenting generic system architectures and implementation considerations. It is not the aim of this paper to investigate numerically efficient algorithms but to point to promising applications as well as arising problems. Three possible applications are considered: pulse compression, radar imaging, and air space surveillance with array antennas. Some simulation results are presented and enriched by the evaluation of real data acquired by an experimental radar system of Fraunhofer FHR.},
    Journal = {Signal Processing},
    Keywords = {Compressive Sensing, Compressed Sensing,Radar, Sparse arrays, Pulse compression, Radar imaging, ISAR, Airspace surveillance, DOA estimation} 
    }
    


  12. G. Fornaro, G. Franceschetti, F. Lombardini, A. Mori, and M. Calamia. Potentials and Limitations of Moon-Borne SAR Imaging. IEEE Transactions on Geoscience and Remote Sensing, 48(7):3009-3019, July 2010. Keyword(s): SAR Processing, Earth observation, Moon-borne SAR imaging, artificial Earth orbit satellites, interferometry, natural Earth satellite, synthetic aperture radar system, Moon, artificial satellites, radar interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar.
    Abstract: Moon exploitation is among the next space mission priorities. Earth observation (EO), which is traditionally implemented on artificial lower Earth orbit satellites, can be, in principle, extended to the platform constituted by the natural Earth satellite. With this regard, we investigate the features related to the EO by a possible Moon-borne synthetic aperture radar system in terms of imaging characteristics and potential applications, as well as of expected limitations.

    @Article{5443570,
    Title = {Potentials and Limitations of Moon-Borne {SAR} Imaging},
    Author = {Fornaro, G. and Franceschetti, G. and Lombardini, F. and Mori, A. and Calamia, M.},
    Doi = {10.1109/TGRS.2010.2041463},
    ISSN = {0196-2892},
    Month = jul,
    Number = {7},
    Pages = {3009-3019},
    Volume = {48},
    Year = {2010},
    Abstract = {Moon exploitation is among the next space mission priorities. Earth observation (EO), which is traditionally implemented on artificial lower Earth orbit satellites, can be, in principle, extended to the platform constituted by the natural Earth satellite. With this regard, we investigate the features related to the EO by a possible Moon-borne synthetic aperture radar system in terms of imaging characteristics and potential applications, as well as of expected limitations.},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {SAR Processing, Earth observation;Moon-borne SAR imaging;artificial Earth orbit satellites;interferometry;natural Earth satellite;synthetic aperture radar system;Moon;artificial satellites;radar interferometry;remote sensing by radar;spaceborne radar;synthetic aperture radar} 
    }
    


  13. G. Fornaro, F. Serafino, and D. Reale. 4-D SAR Imaging: The Case Study of Rome. IEEE Geoscience and Remote Sensing Letters, 7(2):236 -240, April 2010. Keyword(s): SAR Processing, SAR Tomography, 4-D SAR imaging, Italy, Rome, differential SAR tomography, differential interferometric SAR processing, ground-scatterer monitoring, multibaseline SAR processing, multitemporal SAR processing, permanent-scatterer interferometry, spaceborne data, geophysical image processing, geophysical techniques, radar interferometry, synthetic aperture radar.
    Abstract: Four-dimensional synthetic aperture radar (SAR) imaging, also known as differential SAR tomography, is a new research topic in the framework of coherent multitemporal/multibaseline SAR processing that extends the interferometry concept. Four-dimensional SAR imaging-based processing could improve the capability of ground-scatterer monitoring with respect to classical differential interferometric SAR processing. The first results on the applicability of such an advanced tomographic SAR processing to real spaceborne data were recently discussed in the literature. In this letter, we present the results of an experiment with a data set that demonstrates the potentialities of this new technique for monitoring complex targets, such as infrastructures.

    @Article{fornaroSerafinoRealeTGRS2010,
    Title = {{4-D} {SAR} Imaging: The Case Study of {Rome}},
    Author = {Fornaro, G. and Serafino, F. and Reale, D.},
    Doi = {10.1109/LGRS.2009.2032133},
    ISSN = {1545-598X},
    Month = apr,
    Number = {2},
    Pages = {236 -240},
    Volume = {7},
    Year = {2010},
    Abstract = {Four-dimensional synthetic aperture radar (SAR) imaging, also known as differential SAR tomography, is a new research topic in the framework of coherent multitemporal/multibaseline SAR processing that extends the interferometry concept. Four-dimensional SAR imaging-based processing could improve the capability of ground-scatterer monitoring with respect to classical differential interferometric SAR processing. The first results on the applicability of such an advanced tomographic SAR processing to real spaceborne data were recently discussed in the literature. In this letter, we present the results of an experiment with a data set that demonstrates the potentialities of this new technique for monitoring complex targets, such as infrastructures.},
    Journal = {IEEE Geoscience and Remote Sensing Letters},
    Keywords = {SAR Processing, SAR Tomography, 4-D SAR imaging;Italy;Rome;differential SAR tomography;differential interferometric SAR processing;ground-scatterer monitoring;multibaseline SAR processing;multitemporal SAR processing;permanent-scatterer interferometry;spaceborne data;geophysical image processing;geophysical techniques;radar interferometry;synthetic aperture radar} 
    }
    


  14. Martina Gabele, Benjamin Brautigam, Daniel Schulze, Ulrich Steinbrecher, Nuria Tous-Ramon, and Marvan Younis. Fore and Aft Channel Reconstruction in the TerraSAR-X Dual Receive Antenna Mode. IEEE Trans. Geosci. Remote Sens., 48(2):795-806, February 2010. Keyword(s): TerraSAR-X, Quad-Pol, TerraSAR-X dual receive antenna mode, TerraSAR-X satellite, aft channel reconstruction, along-track direction, along-track interferometric data, antenna splitting, fore channel reconstruction, ground moving target indication, hardware transformation matrix estimation, internal calibration pulses, redundant receiver unit, sum and difference channel data, synthetic aperture radar, geophysical techniques, radar antennas, radar target recognition, synthetic aperture radar.
    Abstract: The TerraSAR-X satellite is a high-resolution synthetic aperture radar (SAR) system launched in June 2007 which provides the option to split the antenna in along-track direction and sample two physical channels separately. Modern SARs are equipped with active phased array antennas and multiple channels. In order to keep costs low, TerraSAR-X uses the redundant receiver unit for the second channel such that fore and aft channel signals are combined by a hybrid coupler to form sum and difference channel data. The dual receive antenna (DRA) mode can either be used to acquire along-track interferometric data or to acquire signals with different polarizations at the same time (Quad-Pol). Fore and aft channel reconstruction is necessary if ground moving target indication (GMTI) algorithms such as the displaced phase center antenna technique or along-track interferometry shall be applied, and in order to separate the horizontally and vertically polarized received signal components. The proposed approach uses internal calibration pulses from different calibration beams in order to estimate and compensate the hardware impact. The theoretical framework together with the results from the experimental data evaluation for the fore and aft channel reconstruction of the TerraSAR-X DRA mode are presented. The impact of the receive hardware transformation matrix estimation accuracy on errors in the reconstructed fore and aft channel image data is studied, and first examples on the GMTI capability of the TerraSAR-X DRA mode are given.

    @Article{gabeleBrautigamSchulzeSteinbrecherTousRamonYounis2010,
    author = {Gabele, Martina and Brautigam, Benjamin and Schulze, Daniel and Steinbrecher, Ulrich and Tous-Ramon, Nuria and Younis, Marvan},
    title = {Fore and Aft Channel Reconstruction in the {TerraSAR-X} Dual Receive Antenna Mode},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {2},
    pages = {795-806},
    month = feb,
    issn = {0196-2892},
    abstract = {The TerraSAR-X satellite is a high-resolution synthetic aperture radar (SAR) system launched in June 2007 which provides the option to split the antenna in along-track direction and sample two physical channels separately. Modern SARs are equipped with active phased array antennas and multiple channels. In order to keep costs low, TerraSAR-X uses the redundant receiver unit for the second channel such that fore and aft channel signals are combined by a hybrid coupler to form sum and difference channel data. The dual receive antenna (DRA) mode can either be used to acquire along-track interferometric data or to acquire signals with different polarizations at the same time (Quad-Pol). Fore and aft channel reconstruction is necessary if ground moving target indication (GMTI) algorithms such as the displaced phase center antenna technique or along-track interferometry shall be applied, and in order to separate the horizontally and vertically polarized received signal components. The proposed approach uses internal calibration pulses from different calibration beams in order to estimate and compensate the hardware impact. The theoretical framework together with the results from the experimental data evaluation for the fore and aft channel reconstruction of the TerraSAR-X DRA mode are presented. The impact of the receive hardware transformation matrix estimation accuracy on errors in the reconstructed fore and aft channel image data is studied, and first examples on the GMTI capability of the TerraSAR-X DRA mode are given.},
    doi = {10.1109/TGRS.2009.2032920},
    file = {:gabeleBrautigamSchulzeSteinbrecherTousRamonYounis2010.pdf:PDF},
    keywords = {TerraSAR-X,Quad-Pol;TerraSAR-X dual receive antenna mode;TerraSAR-X satellite;aft channel reconstruction;along-track direction;along-track interferometric data;antenna splitting;fore channel reconstruction;ground moving target indication;hardware transformation matrix estimation;internal calibration pulses;redundant receiver unit;sum and difference channel data;synthetic aperture radar;geophysical techniques;radar antennas;radar target recognition;synthetic aperture radar},
    owner = {ofrey},
    pdf = {../../../docs/gabeleBrautigamSchulzeSteinbrecherTousRamonYounis2010.pdf},
    
    }
    


  15. Nicolas Gebert, Gerhard Krieger, and Alberto Moreira. Multichannel Azimuth Processing in ScanSAR and TOPS Mode Operation. IEEE Trans. Geosci. Remote Sens., 48(7):2994-3008, July 2010. Keyword(s): SAR Processing, TOPS, Terrain Observation by Progressive Scans, geophysical signal processing, geophysical techniques, synthetic aperture radar, SAR missions, SAR signal processing, TOPS mode operation, Terrain Observation by Progressive Scans system, azimuth antenna length, conventional synthetic aperture radar, digital beamforming algorithms, digital signal processing network, geometric resolution, high-resolution wide-swath SAR imaging, multichannel ScanSAR systems, multichannel azimuth processing, multichannel burst-mode operation, multichannel stripmap mode, multiple azimuth channels, multiple receive channels, staircase multichannel processing, stripmap operation, ultrawide-swath imaging, ultrawide-swath synthetic aperture radar imaging, High-resolution ultrawide-swath synthetic aperture radar (SAR) imaging, ScanSAR, TOPS, multichannel azimuth processing, multichannel burst-mode operation.
    Abstract: Due to a system-inherent limitation, conventional synthetic aperture radar (SAR) is incapable of imaging a wide swath with high geometric resolution. This restriction can be overcome by systems with multiple receive channels in combination with an additional digital signal processing network. So far, the application of such digital beamforming algorithms for high-resolution wide-swath SAR imaging has been restricted to multichannel systems in stripmap operation. However, in stripmap mode, the overall azimuth antenna length restricts the achievable swath width, thus preventing very wide swaths as requested by future SAR missions. Consequently, new concepts for ultrawide-swath imaging are needed. A promising candidate is a SAR system with multiple azimuth channels being operated in burst mode. This paper analyzes innovative ScanSAR and Terrain Observation by Progressive Scans (TOPS) system concepts with regard to multichannel azimuth processing. For this, the theoretical analyses, performance figures, and SAR signal processing, which had previously been derived for multichannel stripmap mode, are extended to systems operating in burst modes. The investigations reveal that multichannel ScanSAR systems enable the imaging of ultrawide swaths with high azimuth resolution and compact antenna lengths. These considerations are embedded in a multichannel ScanSAR system design example to demonstrate its capability to image an ultrawide swath of 400 km with a high geometric resolution of 5 m. In a next step, this system is adapted to TOPS mode operation, including an innovative staircase multichannel processing approach optimized for TOPS.

    @Article{gebertKriegerMoreiraTGRS2010TOPSmultichannel,
    author = {Gebert, Nicolas and Krieger, Gerhard and Moreira, Alberto},
    title = {Multichannel Azimuth Processing in {ScanSAR} and {TOPS} Mode Operation},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {7},
    pages = {2994-3008},
    month = {July},
    issn = {0196-2892},
    abstract = {Due to a system-inherent limitation, conventional synthetic aperture radar (SAR) is incapable of imaging a wide swath with high geometric resolution. This restriction can be overcome by systems with multiple receive channels in combination with an additional digital signal processing network. So far, the application of such digital beamforming algorithms for high-resolution wide-swath SAR imaging has been restricted to multichannel systems in stripmap operation. However, in stripmap mode, the overall azimuth antenna length restricts the achievable swath width, thus preventing very wide swaths as requested by future SAR missions. Consequently, new concepts for ultrawide-swath imaging are needed. A promising candidate is a SAR system with multiple azimuth channels being operated in burst mode. This paper analyzes innovative ScanSAR and Terrain Observation by Progressive Scans (TOPS) system concepts with regard to multichannel azimuth processing. For this, the theoretical analyses, performance figures, and SAR signal processing, which had previously been derived for multichannel stripmap mode, are extended to systems operating in burst modes. The investigations reveal that multichannel ScanSAR systems enable the imaging of ultrawide swaths with high azimuth resolution and compact antenna lengths. These considerations are embedded in a multichannel ScanSAR system design example to demonstrate its capability to image an ultrawide swath of 400 km with a high geometric resolution of 5 m. In a next step, this system is adapted to TOPS mode operation, including an innovative staircase multichannel processing approach optimized for TOPS.},
    doi = {10.1109/TGRS.2010.2041356},
    file = {:gebertKriegerMoreiraTGRS2010TOPSmultichannel.pdf:PDF},
    keywords = {SAR Processing, TOPS, Terrain Observation by Progressive Scans,geophysical signal processing;geophysical techniques;synthetic aperture radar;SAR missions;SAR signal processing;TOPS mode operation;Terrain Observation by Progressive Scans system;azimuth antenna length;conventional synthetic aperture radar;digital beamforming algorithms;digital signal processing network;geometric resolution;high-resolution wide-swath SAR imaging;multichannel ScanSAR systems;multichannel azimuth processing;multichannel burst-mode operation;multichannel stripmap mode;multiple azimuth channels;multiple receive channels;staircase multichannel processing;stripmap operation;ultrawide-swath imaging;ultrawide-swath synthetic aperture radar imaging;High-resolution ultrawide-swath synthetic aperture radar (SAR) imaging;ScanSAR;TOPS;multichannel azimuth processing;multichannel burst-mode operation},
    pdf = {../../../docs/gebertKriegerMoreiraTGRS2010TOPSmultichannel.pdf},
    
    }
    


  16. Stefan Gernhardt, Nico Adam, Michael Eineder, and Richard Bamler. Potential of very high resolution SAR for persistent scatterer interferometry in urban areas. Annals of GIS, 16(2):103-111, 2010.
    @Article{gernhardtAdamEinederBamler2010PSIUrban,
    author = {Gernhardt, Stefan and Adam, Nico and Eineder, Michael and Bamler, Richard},
    title = {Potential of very high resolution {SAR} for persistent scatterer interferometry in urban areas},
    year = {2010},
    volume = {16},
    number = {2},
    pages = {103-111},
    journal = {Annals of GIS},
    owner = {ofrey},
    publisher = {Taylor \& Francis},
    
    }
    


  17. J.H. Gonzalez, M. Bachmann, G. Krieger, and H. Fiedler. Development of the TanDEM-X Calibration Concept: Analysis of Systematic Errors. IEEE Transactions on Geoscience and Remote Sensing, 48(2):716-726, February 2010. Keyword(s): TerraSAR-X, TanDEM-X, Astrium GmbH, DEM calibration, DEM height error, DLR, German Aerospace Center, HRTI level 3 accuracy, High-Resolution Terrain Information, TanDEM-X calibration concept, TerraSAR-X, bistatic satellite synthetic aperture radar mission, height accuracy requirements, helix formation, high-precision global digital elevation model, residual-error sources, spaceborne radar remote sensing, systematic error analysis, calibration, digital elevation models, measurement errors, radar altimetry, remote sensing by radar, spaceborne radar, synthetic aperture radar.
    Abstract: The TanDEM-X mission, result of the partnership between the German Aerospace Center (DLR) and Astrium GmbH, opens a new era in spaceborne radar remote sensing. The first bistatic satellite synthetic aperture radar mission is formed by flying TanDEM-X and TerraSAR-X in a closely controlled helix formation. The primary mission goal is the derivation of a high-precision global digital elevation model (DEM) according to High-Resolution Terrain Information (HRTI) level 3 accuracy. The finite precision of the baseline knowledge and uncompensated radar instrument drifts introduce errors that may compromise the height accuracy requirements. By means of a DEM calibration, which uses absolute height references, and the information provided by adjacent interferogram overlaps, these height errors can be minimized. This paper summarizes the exhaustive studies of the nature of the residual-error sources that have been carried out during the development of the DEM calibration concept. Models for these errors are set up and simulations of the resulting DEM height error for different scenarios provide the basis for the development of a successful DEM calibration strategy for the TanDEM-X mission.

    @Article{5353668,
    Title = {Development of the TanDEM-X Calibration Concept: Analysis of Systematic Errors},
    Author = {Gonzalez, J.H. and Bachmann, M. and Krieger, G. and Fiedler, H.},
    Doi = {10.1109/TGRS.2009.2034980},
    ISSN = {0196-2892},
    Month = feb,
    Number = {2},
    Pages = {716-726},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5353668},
    Volume = {48},
    Year = {2010},
    Abstract = {The TanDEM-X mission, result of the partnership between the German Aerospace Center (DLR) and Astrium GmbH, opens a new era in spaceborne radar remote sensing. The first bistatic satellite synthetic aperture radar mission is formed by flying TanDEM-X and TerraSAR-X in a closely controlled helix formation. The primary mission goal is the derivation of a high-precision global digital elevation model (DEM) according to High-Resolution Terrain Information (HRTI) level 3 accuracy. The finite precision of the baseline knowledge and uncompensated radar instrument drifts introduce errors that may compromise the height accuracy requirements. By means of a DEM calibration, which uses absolute height references, and the information provided by adjacent interferogram overlaps, these height errors can be minimized. This paper summarizes the exhaustive studies of the nature of the residual-error sources that have been carried out during the development of the DEM calibration concept. Models for these errors are set up and simulations of the resulting DEM height error for different scenarios provide the basis for the development of a successful DEM calibration strategy for the TanDEM-X mission.},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {TerraSAR-X, TanDEM-X, Astrium GmbH;DEM calibration;DEM height error;DLR;German Aerospace Center;HRTI level 3 accuracy;High-Resolution Terrain Information;TanDEM-X calibration concept;TerraSAR-X;bistatic satellite synthetic aperture radar mission;height accuracy requirements;helix formation;high-precision global digital elevation model;residual-error sources;spaceborne radar remote sensing;systematic error analysis;calibration;digital elevation models;measurement errors;radar altimetry;remote sensing by radar;spaceborne radar;synthetic aperture radar},
    Owner = {ofrey},
    Pdf = {../../../docs/gonzalesBachmannKriegerFiedler2010.pdf} 
    }
    


  18. G. Herrera, R. Tomás, F. Vicente, J. M. Lopez-Sanchez, Jordi J. Mallorquì, and J. Mulas. Mapping ground movements in open pit mining areas using differential SAR interferometry. International Journal of Rock Mechanics and Mining Sciences, 47(7):1114-1125, 2010.
    @Article{herreraTomasVicenteLopezSanchezMallorquiMulas2010,
    author = {Herrera, G. and Tom{\'a}s, R. and Vicente, F. and Lopez-Sanchez, J. M. and Mallorqu{\'\i}, Jordi J. and Mulas, J.},
    title = {Mapping ground movements in open pit mining areas using differential {SAR} interferometry},
    journal = {International Journal of Rock Mechanics and Mining Sciences},
    year = {2010},
    volume = {47},
    number = {7},
    pages = {1114-1125},
    owner = {ofrey},
    publisher = {Elsevier},
    
    }
    


  19. Michael Jehle, Othmar Frey, David Small, and Erich Meier. Measurement of Ionospheric TEC in Spaceborne SAR Data. IEEE Trans. Geosci. Remote Sens., 48(6):2460-2468, June 2010. Keyword(s): SAR Processing, Total Electron Content Estimation, TEC Estimation, Ionospheric TEC, Faraday Rotation, Path Delay, Autofocus, TEC Autofocus, Spaceborne SAR, L-Band, ALOS, Phased Array L-band SAR, PALSAR, P-Pand, Simulation, Calibration.
    Abstract: The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. At high states of solar activity, Faraday rotation (FR) and signal path delays disturb radar polarimetry and reduce resolution in range and azimuth. While these effects are negligible at X-band, FR and the frequency-dependent path delays can become seriously problematic starting at L-band. For quality assurance and calibration purposes, existing L-band or potential spaceborne P-band missions require the estimation of the ionospheric state before or during the data take. This paper introduces two approaches for measuring the ionospheric total electron content (TEC) from single-polarized spaceborne SAR data. The two methods are demonstrated using simulations. Both methods leverage knowledge of the frequency-dependent path delay through the ionosphere: The first estimates TEC from the phase error of the filter mismatch, while the second gauges path-delay differences between up and down chirps. FR, mean (direct current) offsets, and noise contributions are also considered in the simulations. Finally, possibilities for further methodological improvements are discussed.

    @Article{jehleFreySmallMeier2010:IonTECfromSAR,
    author = {Jehle, Michael and Frey, Othmar and Small, David and Meier, Erich},
    title = {Measurement of Ionospheric {TEC} in Spaceborne {SAR} Data},
    journal = {{IEEE} Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {6},
    pages = {2460-2468},
    month = jun,
    issn = {0196-2892},
    abstract = {The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. At high states of solar activity, Faraday rotation (FR) and signal path delays disturb radar polarimetry and reduce resolution in range and azimuth. While these effects are negligible at X-band, FR and the frequency-dependent path delays can become seriously problematic starting at L-band. For quality assurance and calibration purposes, existing L-band or potential spaceborne P-band missions require the estimation of the ionospheric state before or during the data take. This paper introduces two approaches for measuring the ionospheric total electron content (TEC) from single-polarized spaceborne SAR data. The two methods are demonstrated using simulations. Both methods leverage knowledge of the frequency-dependent path delay through the ionosphere: The first estimates TEC from the phase error of the filter mismatch, while the second gauges path-delay differences between up and down chirps. FR, mean (direct current) offsets, and noise contributions are also considered in the simulations. Finally, possibilities for further methodological improvements are discussed.},
    doi = {10.1109/TGRS.2010.2040621},
    file = {:jehleFreySmallMeier2010.pdf:PDF},
    keywords = {SAR Processing, Total Electron Content Estimation, TEC Estimation, Ionospheric TEC, Faraday Rotation, Path Delay, Autofocus, TEC Autofocus, Spaceborne SAR, L-Band, ALOS, Phased Array L-band SAR,PALSAR, P-Pand, Simulation, Calibration},
    owner = {ofrey},
    pdf = {http://www.ifu-sar.ethz.ch/otfrey/SARbibliography/myPapers/jehleFreySmallMeier2010.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5427043},
    
    }
    


  20. S. Jun, Z. Xiaoling, Y. Jianyu, and W. Chen. APC Trajectory Design for One-Active Linear-Array Three-Dimensional Imaging SAR. IEEE Transactions on Geoscience and Remote Sensing, 48(3):1470-1486, March 2010. Keyword(s): SAR Processing, W-Band, antenna phased arrays, geophysical signal processing, geophysical techniques, image resolution, radar imaging, stereo image processing, synthetic aperture radar, 3D ambiguity function, 3D spatial resolution, Lagrange multiplier method, W-band wave carrier, along-track resolution, antenna phase center function, antenna phase center trajectory design, cross-track resolution, millimeter wave carrier, minimum variance criterion, one-active linear-array 3D imaging SAR, parabolic distribution, switching mode, one-active linear-array 3-D imaging SAR (LASAR), 3-D imaging SAR, Antenna phase center trajectory (APCT) design, Lagrange multiplier method, synthetic aperture radar (SAR).
    Abstract: This paper discusses the antenna phase center trajectory (APCT) design for the "one-active" linear-array 3D imaging SAR (LASAR). First, we discuss the principle of the one-active LASAR and demonstrate its feasibility by experiment. To describe the 3D spatial resolution of the one-active LASAR, the relationship between the 3D ambiguity function (AF) of the one-active LASAR and the system parameters is discussed in detail. Based on the analysis, we divide the APCT design into three topics: the direction of the linear array, the length of the linear array, and the switching mode of the active element [named as antenna phase center function (APCF)]. On the first topic, we conclude that, when the range, along-track, and cross-track directions are orthogonal to each other, the ambiguity region of the one-active LASAR attains minimum, and the 3D spatial resolution can be separated into the range, along-track, and cross-track resolutions. On the second topic, we find that the cross-track resolution is determined by the length of the linear array and the frequency of the carrier. To ensure that the length of the linear array is acceptable, the carrier should be W-band wave or millimeter wave. On the third topic, the effect of APCF is researched, and we find that both the periodic APCF and the pseudorandom APCF can produce 3D resolution, except for the periodic rectangle APCF. For the pseudorandom APCF and the periodic APCF with short period, the cross-range 2D AF is or can be approximated as the product of two 1D AFs in the along- and cross-track directions. Finally, the distribution of the pseudorandom APCF is optimized by the Lagrange multiplier method under the minimum variance criterion, and we find that, when the pseudorandom APCF obeys the parabolic distribution, the cross-range 2D AF is optimal.

    @ARTICLE{junXiaolingJianyuChenTGARS2010WBANDRadar,
    author={S. Jun and Z. Xiaoling and Y. Jianyu and W. Chen},
    journal={IEEE Transactions on Geoscience and Remote Sensing},
    title={APC Trajectory Design for One-Active Linear-Array Three-Dimensional Imaging SAR},
    year={2010},
    volume={48},
    number={3},
    pages={1470-1486},
    abstract={This paper discusses the antenna phase center trajectory (APCT) design for the "one-active" linear-array 3D imaging SAR (LASAR). First, we discuss the principle of the one-active LASAR and demonstrate its feasibility by experiment. To describe the 3D spatial resolution of the one-active LASAR, the relationship between the 3D ambiguity function (AF) of the one-active LASAR and the system parameters is discussed in detail. Based on the analysis, we divide the APCT design into three topics: the direction of the linear array, the length of the linear array, and the switching mode of the active element [named as antenna phase center function (APCF)]. On the first topic, we conclude that, when the range, along-track, and cross-track directions are orthogonal to each other, the ambiguity region of the one-active LASAR attains minimum, and the 3D spatial resolution can be separated into the range, along-track, and cross-track resolutions. On the second topic, we find that the cross-track resolution is determined by the length of the linear array and the frequency of the carrier. To ensure that the length of the linear array is acceptable, the carrier should be W-band wave or millimeter wave. On the third topic, the effect of APCF is researched, and we find that both the periodic APCF and the pseudorandom APCF can produce 3D resolution, except for the periodic rectangle APCF. For the pseudorandom APCF and the periodic APCF with short period, the cross-range 2D AF is or can be approximated as the product of two 1D AFs in the along- and cross-track directions. Finally, the distribution of the pseudorandom APCF is optimized by the Lagrange multiplier method under the minimum variance criterion, and we find that, when the pseudorandom APCF obeys the parabolic distribution, the cross-range 2D AF is optimal.},
    keywords={SAR Processing, W-Band,antenna phased arrays;geophysical signal processing;geophysical techniques;image resolution;radar imaging;stereo image processing;synthetic aperture radar;3D ambiguity function;3D spatial resolution;Lagrange multiplier method;W-band wave carrier;along-track resolution;antenna phase center function;antenna phase center trajectory design;cross-track resolution;millimeter wave carrier;minimum variance criterion;one-active linear-array 3D imaging SAR;parabolic distribution;switching mode; one-active linear-array 3-D imaging SAR (LASAR);3-D imaging SAR;Antenna phase center trajectory (APCT) design;Lagrange multiplier method;synthetic aperture radar (SAR)},
    doi={10.1109/TGRS.2009.2031430},
    ISSN={0196-2892},
    month=mar,
    owner = {ofrey},
    
    }
    


  21. G. Krieger, Irena Hajnsek, Konstantinos P. Papathanassiou, M. Younis, and A. Moreira. Interferometric Synthetic Aperture Radar (SAR) Missions Employing Formation Flying. Proceedings of the IEEE, 98(5):816-843, May 2010. Keyword(s): SAR Processing, Tandem-L, Tandem-X, Formation Flying, Spaceborne SAR, SAR Tomography, Tomography.
    Abstract: This paper presents an overview of single-pass interferometric Synthetic Aperture Radar (SAR) missions employing two or more satellites flying in a close formation. The simultaneous reception of the scattered radar echoes from different viewing directions by multiple spatially distributed antennas enables the acquisition of unique Earth observation products for environmental and climate monitoring. After a short introduction to the basic principles and applications of SAR interferometry, designs for the twin satellite missions TanDEM-X and Tandem-L are presented. The primary objective of TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the generation of a global Digital Elevation Model (DEM) with unprecedented accuracy as the basis for a wide range of scientific research as well as for commercial DEM production. This goal is achieved by enhancing the TerraSAR-X mission with a second TerraSAR-X like satellite that will be launched in spring 2010. Both satellites act then as a large single-pass SAR interferometer with the opportunity for flexible baseline selection. Building upon the experience gathered with the TanDEM-X mission design, the fully polarimetric L-band twin satellite formation Tandem-L is proposed. Important objectives of this highly capable interferometric SAR mission are the global acquisition of three-dimensional forest structure and biomass inventories, large-scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The sophisticated mission concept and the high data-acquisition capacity of Tandem-L will moreover provide a unique data source to systematically observe, analyze, and quantify the dynamics of a wide range of additional processes in the bio-, litho-, hydro-, and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics. Enabling technologies and techniques are described in detail. An ou- tlook on future interferometric and tomographic concepts and developments, including multistatic SAR systems with multiple receivers, is provided.

    @Article{KriegerHajnsekPapathanassiouYounisMoreira2010:FormationFlyingSpaceborneMissions,
    author = {Krieger, G. and Hajnsek, Irena and Papathanassiou, Konstantinos P. and Younis, M. and Moreira, A.},
    title = {Interferometric Synthetic Aperture Radar ({SAR}) Missions Employing Formation Flying},
    journal = {Proceedings of the IEEE},
    year = {2010},
    volume = {98},
    number = {5},
    pages = {816-843},
    month = may,
    issn = {0018-9219},
    abstract = {This paper presents an overview of single-pass interferometric Synthetic Aperture Radar (SAR) missions employing two or more satellites flying in a close formation. The simultaneous reception of the scattered radar echoes from different viewing directions by multiple spatially distributed antennas enables the acquisition of unique Earth observation products for environmental and climate monitoring. After a short introduction to the basic principles and applications of SAR interferometry, designs for the twin satellite missions TanDEM-X and Tandem-L are presented. The primary objective of TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the generation of a global Digital Elevation Model (DEM) with unprecedented accuracy as the basis for a wide range of scientific research as well as for commercial DEM production. This goal is achieved by enhancing the TerraSAR-X mission with a second TerraSAR-X like satellite that will be launched in spring 2010. Both satellites act then as a large single-pass SAR interferometer with the opportunity for flexible baseline selection. Building upon the experience gathered with the TanDEM-X mission design, the fully polarimetric L-band twin satellite formation Tandem-L is proposed. Important objectives of this highly capable interferometric SAR mission are the global acquisition of three-dimensional forest structure and biomass inventories, large-scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The sophisticated mission concept and the high data-acquisition capacity of Tandem-L will moreover provide a unique data source to systematically observe, analyze, and quantify the dynamics of a wide range of additional processes in the bio-, litho-, hydro-, and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics. Enabling technologies and techniques are described in detail. An ou- tlook on future interferometric and tomographic concepts and developments, including multistatic SAR systems with multiple receivers, is provided.},
    doi = {10.1109/JPROC.2009.2038948},
    keywords = {SAR Processing, Tandem-L, Tandem-X, Formation Flying, Spaceborne SAR, SAR Tomography, Tomography},
    
    }
    


  22. Dawei Liu, Guoqing Sun, Zhifeng Guo, K.J. Ranson, and Yang Du. Three-Dimensional Coherent Radar Backscatter Model and Simulations of Scattering Phase Center of Forest Canopies. IEEE Trans. Geosci. Remote Sens., 48(1):349-357, January 2010. Keyword(s): 3D coherent radar backscatter model, InSAR signals, SAR interferometric data, canopy height, canopy spatial structure, forest canopies, forest stand, forest structural parameters, ground surface backscattering, interferometric SAR, scattering phase center simulations, synthetic aperture radar, time delay, backscatter, geophysical signal processing, radar interferometry, remote sensing by radar, synthetic aperture radar, vegetation;.
    Abstract: A 3-D coherent radar backscatter model for forest canopies was developed and used to improve the understanding of synthetic aperture radar (SAR) interferometric data. The model was based on a realistic 3-D spatial structure of a forest stand, in which every scatterer has its deterministic location. A backscattering signal from a scatterer was mapped into a pixel according to its range or signal time delay. The range or the time delay also determines the phase of the scattered field. All scattering matrices within a pixel were coherently added to yield the total backscattering field of the pixel. The coherent radar backscatter model takes into account not only the scattering contribution from the scatterers in the forest canopy but also the direct backscattering of the ground surface. Forest stands with three different spatial structures were simulated using L-system and field measurements. The number and sizes of trees in these forest stands were identical, but the 2-D arrangements of the trees were different. The interferometric SAR (InSAR) signals of these scenes were simulated using the 3-D coherent SAR model, and the heights of scattering phase centers were estimated from the simulated InSAR data. The results reported in this paper show that the spatial structures of vegetation play an important role in the location of the scattering phase center. The height of scattering phase center depends on canopy height, attenuation of canopy, and the gaps within the canopy. This paper shows that the spatial structure needs to be considered when the InSAR data are used for the estimation of forest structural parameters.

    @Article{liuSunGuoRansonDu2010,
    Title = {Three-Dimensional Coherent Radar Backscatter Model and Simulations of Scattering Phase Center of Forest Canopies},
    Author = {Dawei Liu and Guoqing Sun and Zhifeng Guo and Ranson, K.J. and Yang Du},
    Doi = {10.1109/TGRS.2009.2024301},
    ISSN = {0196-2892},
    Month = jan,
    Number = {1},
    Pages = {349-357},
    Volume = {48},
    Year = {2010},
    Abstract = {A 3-D coherent radar backscatter model for forest canopies was developed and used to improve the understanding of synthetic aperture radar (SAR) interferometric data. The model was based on a realistic 3-D spatial structure of a forest stand, in which every scatterer has its deterministic location. A backscattering signal from a scatterer was mapped into a pixel according to its range or signal time delay. The range or the time delay also determines the phase of the scattered field. All scattering matrices within a pixel were coherently added to yield the total backscattering field of the pixel. The coherent radar backscatter model takes into account not only the scattering contribution from the scatterers in the forest canopy but also the direct backscattering of the ground surface. Forest stands with three different spatial structures were simulated using L-system and field measurements. The number and sizes of trees in these forest stands were identical, but the 2-D arrangements of the trees were different. The interferometric SAR (InSAR) signals of these scenes were simulated using the 3-D coherent SAR model, and the heights of scattering phase centers were estimated from the simulated InSAR data. The results reported in this paper show that the spatial structures of vegetation play an important role in the location of the scattering phase center. The height of scattering phase center depends on canopy height, attenuation of canopy, and the gaps within the canopy. This paper shows that the spatial structure needs to be considered when the InSAR data are used for the estimation of forest structural parameters.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {3D coherent radar backscatter model;InSAR signals;SAR interferometric data;canopy height;canopy spatial structure;forest canopies;forest stand;forest structural parameters;ground surface backscattering;interferometric SAR;scattering phase center simulations;synthetic aperture radar;time delay;backscatter;geophysical signal processing;radar interferometry;remote sensing by radar;synthetic aperture radar;vegetation;} 
    }
    


  23. Paco Lopez-Dekker and Jordi. J. Mallorqui. Capon- and APES-Based SAR Processing: Performance and Practical Considerations. IEEE Transactions on Geoscience and Remote Sensing, 48(5):2388-2402, May 2010. Keyword(s): SAR Processing, APES, Amplitude and Phase EStimation, Capon, minimum variance distortionless response, MVDR, Capon Beamforming, Beamforming, geophysical techniques, spectral analysis, synthetic aperture radar, minimum variance method, APES-based SAR processing, spectral-estimation algorithms, synthetic aperture radar, Capon processing chain, chip-image size, resampling factor, diagonal loading, joint-processing approach, Monte Carlo simulations, RADARSAT-2 quad-polarization data, Barcelona, adaptive processing, 2D spectral analysis, Spain, Azimuth, Backpropagation algorithms, Focusing, Covariance matrix, Phase estimation, Tomography, Remote sensing, Laboratories, Microwave communication, Array signal processing, Adaptive processing, synthetic aperture radar, 2-D spectral analysis.
    Abstract: This paper discusses the use of Capon's minimum-variance method (MVM) and Amplitude and Phase EStimation (APES) spectral-estimation algorithms to synthetic aperture radar range-azimuth focusing. The rationale of the algorithms is discussed. An implementation of a Capon or APES processing chain is explained, and processing parameters such as chip-image size, resampling factor, and diagonal loading are discussed. For multichannel cases, a joint-processing approach is presented. A set of Monte Carlo simulations are described and used to benchmark Capon- and APES-based processing against conventional matched-filter-based approaches. Both methods improve the resolution and reduce sidelobes. APES yields generally better estimates of amplitude and phase than Capon but with worse resolution. Results with RADARSAT-2 quad-polarization data over Barcelona are used to qualitatively study the real-life performance of these algorithms.

    @Article{lopezDekkerMallorqui2010CaponAndAPESbasedSARProcessing,
    author = {Lopez-Dekker, Paco and Mallorqui, Jordi. J.},
    title = {{Capon}- and {APES}-Based {SAR} Processing: Performance and Practical Considerations},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    year = {2010},
    volume = {48},
    number = {5},
    pages = {2388-2402},
    month = {May},
    issn = {1558-0644},
    abstract = {This paper discusses the use of Capon's minimum-variance method (MVM) and Amplitude and Phase EStimation (APES) spectral-estimation algorithms to synthetic aperture radar range-azimuth focusing. The rationale of the algorithms is discussed. An implementation of a Capon or APES processing chain is explained, and processing parameters such as chip-image size, resampling factor, and diagonal loading are discussed. For multichannel cases, a joint-processing approach is presented. A set of Monte Carlo simulations are described and used to benchmark Capon- and APES-based processing against conventional matched-filter-based approaches. Both methods improve the resolution and reduce sidelobes. APES yields generally better estimates of amplitude and phase than Capon but with worse resolution. Results with RADARSAT-2 quad-polarization data over Barcelona are used to qualitatively study the real-life performance of these algorithms.},
    doi = {10.1109/TGRS.2009.2038902},
    file = {:lopezDekkerMallorqui2010CaponAndAPESbasedSARProcessing.pdf:PDF},
    keywords = {SAR Processing, APES, Amplitude and Phase EStimation, Capon, minimum variance distortionless response, MVDR, Capon Beamforming, Beamforming, geophysical techniques;spectral analysis;synthetic aperture radar;minimum variance method;APES-based SAR processing;spectral-estimation algorithms;synthetic aperture radar;Capon processing chain;chip-image size;resampling factor;diagonal loading;joint-processing approach;Monte Carlo simulations;RADARSAT-2 quad-polarization data;Barcelona;adaptive processing;2D spectral analysis;Spain;Azimuth;Backpropagation algorithms;Focusing;Covariance matrix;Phase estimation;Tomography;Remote sensing;Laboratories;Microwave communication;Array signal processing;Adaptive processing;synthetic aperture radar;2-D spectral analysis},
    owner = {ofrey},
    
    }
    


  24. G. Margarit, J. J. Mallorqui, and L. Pipia. Polarimetric Characterization and Temporal Stability Analysis of Urban Target Scattering. IEEE_J_GRS, 48(4):2038-2048, April 2010. Keyword(s): geophysical image processing, radar polarimetry, synthetic aperture radar, vegetation mapping, GRaphical Electromagnetic Computing SAR data, RADARSAT-2, TerraSAR-X, geometrical configuration, geometry-scattering, high resolution images, land classification, nonprobabilistic models, polarimetric capabilities, polarimetric characterization, polarimetric-dispersion properties, quasideterministic scattering behavior, synthetic aperture radar images, temporal stability analysis, urban target scattering, urban-image postprocessing, Analytical models, Computational modeling, Electromagnetic modeling, Electromagnetic scattering, Geometry, Image analysis, Radar scattering, Solid modeling, Stability analysis, Synthetic aperture radar, Polarimetry, synthetic aperture radar (SAR) simulation, urban scattering.
    @Article{Margarit2010,
    author = {G. Margarit and J. J. Mallorqui and L. Pipia},
    title = {Polarimetric Characterization and Temporal Stability Analysis of Urban Target Scattering},
    journal = IEEE_J_GRS,
    year = {2010},
    volume = {48},
    number = {4},
    month = apr,
    pages = {2038--2048},
    issn = {0196-2892},
    doi = {10.1109/TGRS.2009.2035052},
    keywords = {geophysical image processing, radar polarimetry, synthetic aperture radar, vegetation mapping, GRaphical Electromagnetic Computing SAR data, RADARSAT-2, TerraSAR-X, geometrical configuration, geometry-scattering, high resolution images, land classification, nonprobabilistic models, polarimetric capabilities, polarimetric characterization, polarimetric-dispersion properties, quasideterministic scattering behavior, synthetic aperture radar images, temporal stability analysis, urban target scattering, urban-image postprocessing, Analytical models, Computational modeling, Electromagnetic modeling, Electromagnetic scattering, Geometry, Image analysis, Radar scattering, Solid modeling, Stability analysis, Synthetic aperture radar, Polarimetry, synthetic aperture radar (SAR) simulation, urban scattering},
    owner = {ofrey},
    
    }
    


  25. Adriano Meta, Joseph Mittermayer, Pau Prats, Rolf Scheiber, and Ulrich Steinbrecher. TOPS Imaging With TerraSAR-X: Mode Design and Performance Analysis. IEEE Trans. Geosci. Remote Sens., 48(2):759-769, February 2010. Keyword(s): SAR Processing, TOPS, geophysical techniques, radar antennas, radar imaging, radar interferometry, synthetic aperture radar, DTAR deterioration, ScanSAR modes, TOPS imaging, TSX, TerraSAR-X, Terrain Observation by Progressive Scan, antenna steering, burst acquisition, complete azimuth antenna pattern, imaging mode design, interferometry, performance analysis, squinted angles, wide-swath TOPS, ScanSAR, synthetic aperture radar (SAR), terrain observation by progressive scan (TOPS), wide-swath SAR.
    @Article{metaMittermayerPratsScheiberSteinbrecherTGARS2010TOPS,
    author = {Meta, Adriano and Mittermayer, Joseph and Prats, Pau and Scheiber, Rolf and Steinbrecher, Ulrich},
    title = {{TOPS} Imaging With {TerraSAR-X}: Mode Design and Performance Analysis},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {2},
    pages = {759-769},
    month = {Feb},
    issn = {0196-2892},
    doi = {10.1109/TGRS.2009.2026743},
    file = {:metaMittermayerPratsScheiberSteinbrecherTGARS2010TOPS.pdf:PDF},
    keywords = {SAR Processing, TOPS, geophysical techniques;radar antennas;radar imaging;radar interferometry;synthetic aperture radar;DTAR deterioration;ScanSAR modes;TOPS imaging;TSX;TerraSAR-X;Terrain Observation by Progressive Scan;antenna steering;burst acquisition;complete azimuth antenna pattern;imaging mode design;interferometry;performance analysis;squinted angles;wide-swath TOPS;ScanSAR;synthetic aperture radar (SAR);terrain observation by progressive scan (TOPS);wide-swath SAR},
    pdf = {../../../docs/metaMittermayerPratsScheiberSteinbrecherTGARS2010TOPS.pdf},
    
    }
    


  26. J. Mittermayer, Marwan Younis, R. Metzig, S. Wollstadt, J. Marquez Martinez, and Adriano Meta. TerraSAR-X System Performance Characterization and Verification. IEEE Transactions on Geoscience and Remote Sensing, 48(2):660-676, February 2010. Keyword(s): calibration, geophysical techniques, optimisation, remote sensing by radar, spaceborne radar, synthetic aperture radar, ScanSAR, Spotlight, TerraSAR-X system, acquisition geometry, ambiguities, block adaptive quantization setting, commissioning phase, elevation beam definition, impulse-response function, noise, optimization, performance characterization, radiometric resolution, range timing, receiving gain, synthetic aperture radar, systems verification, Commissioning phase, SAR system performance, TerraSAR-X (TS-X), synthetic aperture radar (SAR).
    Abstract: This paper presents results from the synthetic aperture radar (SAR) system performance characterization, optimization, and verification as carried out during the TerraSAR-X commissioning phase. Starting from the acquisition geometry and instrument performance, fundamental acquisition parameters such as elevation beam definition, range timing, receiving gain, and block adaptive quantization setting are presented. The verification of the key performance parameters-ambiguities, impulse-response function, noise, and radiometric resolution-is discussed. ScanSAR and Spotlight particularities are described.

    @Article{mittermayerYounisMetzigWollstadtMarquezMartinezMetaTGRS2010TerraSARXSystemPerformance,
    author = {J. Mittermayer and Marwan Younis and R. Metzig and S. Wollstadt and J. Marquez Martinez and Adriano Meta},
    title = {{TerraSAR-X} System Performance Characterization and Verification},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    year = {2010},
    volume = {48},
    number = {2},
    month = feb,
    pages = {660-676},
    issn = {0196-2892},
    doi = {10.1109/TGRS.2009.2026742},
    abstract = {This paper presents results from the synthetic aperture radar (SAR) system performance characterization, optimization, and verification as carried out during the TerraSAR-X commissioning phase. Starting from the acquisition geometry and instrument performance, fundamental acquisition parameters such as elevation beam definition, range timing, receiving gain, and block adaptive quantization setting are presented. The verification of the key performance parameters-ambiguities, impulse-response function, noise, and radiometric resolution-is discussed. ScanSAR and Spotlight particularities are described.},
    keywords = {calibration;geophysical techniques;optimisation;remote sensing by radar;spaceborne radar;synthetic aperture radar;ScanSAR;Spotlight;TerraSAR-X system;acquisition geometry;ambiguities;block adaptive quantization setting;commissioning phase;elevation beam definition;impulse-response function;noise;optimization;performance characterization;radiometric resolution;range timing;receiving gain;synthetic aperture radar;systems verification;Commissioning phase;SAR system performance;TerraSAR-X (TS-X);synthetic aperture radar (SAR)},
    owner = {ofrey},
    pdf = {../../../docs/mittermayerYounisMetzigWollstadtMarquezMartinezMetaTGRS2010TerraSARXSystemPerformance.pdf},
    
    }
    


  27. Andrea Monti Guarnieri and Silvia Scirpoli. Efficient Wavenumber Domain Focusing for Ground-Based SAR. IEEE Geoscience and Remote Sensing Letters, 7(1):161-165, January 2010. Keyword(s): SAR Processing, omega-k, Wavenumver Domain Algorithm, Range Migration Algorithm, GB-SAR, SAR Focusing, Azimuth Focusing, computational complexity, focusing, geophysical signal processing, geophysical techniques, radar signal processing, remote sensing by radar, synthetic aperture radar, computational complexity, efficient wavenumber domain focusing, ground-based SAR, kernel nonseparability, modified Stolt interpolation, polar formatting algorithm, range-angular domain, space-varying resampling, synthetic aperture radar, Focusing, ground-based (GB) synthetic aperture radar (SAR), wavenumber domain algorithm.
    Abstract: We present an efficient focusing algorithm for synthetic aperture radar (SAR) data acquired in short bursts by a geometry with a large range spread, i.e., the case of ground-based (GB) SAR. The usual approach for focusing GB SAR data is the polar formatting algorithm, whose computational complexity, however, is quite relevant due to the nonseparability of the kernel. In this letter, we introduce a different format for the focused data, namely, the range-angular domain. Such format keeps the benefit of the polar format that samples data close to the resolution, but allows for the design of a separable kernel in the wavenumber domain. The proposed kernel exploits a modified Stolt interpolation and an efficient space-varying resampling. Results of processing on both simulated and real data are presented.

    @Article{montiGuarnieriScirpoliGRSL2010EfficientOmegaKFocusingGBSAR,
    author = {Monti Guarnieri, Andrea and Scirpoli, Silvia},
    title = {Efficient Wavenumber Domain Focusing for Ground-Based SAR},
    journal = {IEEE Geoscience and Remote Sensing Letters},
    year = {2010},
    volume = {7},
    number = {1},
    pages = {161-165},
    month = {Jan},
    issn = {1545-598X},
    abstract = {We present an efficient focusing algorithm for synthetic aperture radar (SAR) data acquired in short bursts by a geometry with a large range spread, i.e., the case of ground-based (GB) SAR. The usual approach for focusing GB SAR data is the polar formatting algorithm, whose computational complexity, however, is quite relevant due to the nonseparability of the kernel. In this letter, we introduce a different format for the focused data, namely, the range-angular domain. Such format keeps the benefit of the polar format that samples data close to the resolution, but allows for the design of a separable kernel in the wavenumber domain. The proposed kernel exploits a modified Stolt interpolation and an efficient space-varying resampling. Results of processing on both simulated and real data are presented.},
    doi = {10.1109/LGRS.2009.2029245},
    file = {:montiGuarnieriScirpoliGRSL2010EfficientOmegaKFocusingGBSAR.pdf:PDF},
    keywords = {SAR Processing, omega-k, Wavenumver Domain Algorithm, Range Migration Algorithm, GB-SAR, SAR Focusing, Azimuth Focusing, computational complexity;focusing;geophysical signal processing;geophysical techniques;radar signal processing;remote sensing by radar;synthetic aperture radar;computational complexity;efficient wavenumber domain focusing;ground-based SAR;kernel nonseparability;modified Stolt interpolation;polar formatting algorithm;range-angular domain;space-varying resampling;synthetic aperture radar;Focusing;ground-based (GB) synthetic aperture radar (SAR);wavenumber domain algorithm},
    owner = {ofrey},
    pdf = {../../../docs/montiGuarnieriScirpoliGRSL2010EfficientOmegaKFocusingGBSAR.pdf},
    
    }
    


  28. Andrea Monti-Guarnieri and Stefano Tebaldini. ML-Based Fringe-Frequency Estimation for InSAR. IEEE Geoscience and Remote Sensing Letters, 7(1):136-140, January 2010. Keyword(s): SAR Processing, InSAR, SAR Interferometry, ENVISAR, ASAR.
    Abstract: This letter focuses on estimating the local fringe frequency of the interferometric phase, under the hypothesis of superficial scattering. Starting from the formulation of the maximum-likelihood estimator, a new simplified estimator is derived. Due to computational efficiency and robustness versus model errors, the resulting estimator is suited for large data processing in the presence of model uncertainty. Furthermore, such an estimator can be straightforwardly extended to the multibaseline case, resulting in the possibility to estimate the terrain slope with great accuracy. An application to real data is presented, based on a multibaseline ENVISAT data set.

    @Article{montiGuarnieriTebaldiniGRSL2010:InSARFringeFreqEstim,
    Title = {ML-Based Fringe-Frequency Estimation for InSAR},
    Author = {Monti-Guarnieri, Andrea and Tebaldini, Stefano},
    Doi = {10.1109/LGRS.2009.2028661},
    ISSN = {1545-598X},
    Month = {jan},
    Number = {1},
    Pages = {136-140},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5238604&isnumber=5379155},
    Volume = {7},
    Year = {2010},
    Abstract = {This letter focuses on estimating the local fringe frequency of the interferometric phase, under the hypothesis of superficial scattering. Starting from the formulation of the maximum-likelihood estimator, a new simplified estimator is derived. Due to computational efficiency and robustness versus model errors, the resulting estimator is suited for large data processing in the presence of model uncertainty. Furthermore, such an estimator can be straightforwardly extended to the multibaseline case, resulting in the possibility to estimate the terrain slope with great accuracy. An application to real data is presented, based on a multibaseline ENVISAT data set.},
    Journal = {IEEE Geoscience and Remote Sensing Letters},
    Keywords = {SAR Processing, InSAR, SAR Interferometry, ENVISAR, ASAR},
    Owner = {ofrey},
    Pdf = {../../../docs/montiGuarnieriTebaldiniGRSL2010.pdf} 
    }
    


  29. V. D. Navarro-Sanchez, J. M. Lopez-Sanchez, and F. Vicente-Guijalba. A Contribution of Polarimetry to Satellite Differential SAR Interferometry: Increasing the Number of Pixel Candidates. IEEE Geosci. Remote Sens. Lett., 7(2):276-280, April 2010. Keyword(s): geophysical techniques, radar interferometry, radar polarimetry, synthetic aperture radar, TerraSAR-X, advanced differential SAR interferometry, amplitude dispersion index, amplitude dispersion selection, average coherence, copolar linear channels, dual-pol images, interferograms, pixel candidates, polarimetric information, satellite sensors, single-pol data, urban area, Differential synthetic aperture radar (SAR) interferometry, polarimetry.
    Abstract: This letter presents a general method for increasing the number of pixel candidates, those selected for processing in advanced differential SAR interferometry, by means of the exploitation of the polarimetric information provided by new satellite sensors. The algorithm is formulated for two different criteria of selection: the average coherence over the stack of interferograms and the amplitude dispersion index of the stack of images. Experimental results obtained with dual-pol images of TerraSAR-X over an urban area have demonstrated the expected improvement. The number of pixel candidates for an arbitrary threshold is 60% higher than that for single-pol data when using the average coherence and three times higher when using the dispersion index. The approach has also been compared to a selection based on a set of conventional channels (the copolar linear channels and the first two Pauli ones), showing a slight improvement for coherence selection and an important one for amplitude dispersion selection.

    @Article{navarroSanchezLopezSanchezVicenteGuijalbaGRSL2010PolarimetrySatelliteDInSAR,
    author = {V. D. Navarro-Sanchez and J. M. Lopez-Sanchez and F. Vicente-Guijalba},
    title = {A Contribution of Polarimetry to Satellite Differential {SAR} Interferometry: Increasing the Number of Pixel Candidates},
    journal = {IEEE Geosci. Remote Sens. Lett.},
    year = {2010},
    volume = {7},
    number = {2},
    pages = {276-280},
    month = apr,
    issn = {1545-598X},
    abstract = {This letter presents a general method for increasing the number of pixel candidates, those selected for processing in advanced differential SAR interferometry, by means of the exploitation of the polarimetric information provided by new satellite sensors. The algorithm is formulated for two different criteria of selection: the average coherence over the stack of interferograms and the amplitude dispersion index of the stack of images. Experimental results obtained with dual-pol images of TerraSAR-X over an urban area have demonstrated the expected improvement. The number of pixel candidates for an arbitrary threshold is 60% higher than that for single-pol data when using the average coherence and three times higher when using the dispersion index. The approach has also been compared to a selection based on a set of conventional channels (the copolar linear channels and the first two Pauli ones), showing a slight improvement for coherence selection and an important one for amplitude dispersion selection.},
    doi = {10.1109/LGRS.2009.2033013},
    keywords = {geophysical techniques;radar interferometry;radar polarimetry;synthetic aperture radar;TerraSAR-X;advanced differential SAR interferometry;amplitude dispersion index;amplitude dispersion selection;average coherence;copolar linear channels;dual-pol images;interferograms;pixel candidates;polarimetric information;satellite sensors;single-pol data;urban area;Differential synthetic aperture radar (SAR) interferometry;polarimetry},
    owner = {ofrey},
    
    }
    


  30. Maxim Neumann, Laurent Ferro-Famil, and Andreas Reigber. Estimation of Forest Structure, Ground, and Canopy Layer Characteristics From Multibaseline Polarimetric Interferometric SAR Data. IEEE Trans. Geosci. Remote Sens., 48(3):1086-1104, March 2010. Keyword(s): SAR Processing, Multibaseline SAR, Germany, PolInSAR, RVoG, vertical structure, Traunstein test site, airborne SAR, L-band, angular distribution, canopy layer heights, differential extinction, double-bounce ground-trunk interactions, forest layer heights, forest parameter retrieval, forest structure estimation, forest vegetation, ground topography, ground-to-volume ratio, ground-truth measurements, interferometric coherence, particle scattering anisotropy, polarimetric Synthetic Aperture Radar interferometry, polarimetric decomposition, polarimetric scattering media model, polarization orientation randomness, random-volume-over-ground PolInSAR parameter inversion, repeat-pass configuration, root-mean-square error, surface scattering, temporal decorrelation, tree morphology, volume coherency matrices, volumetric canopy, volumetric understory scattering, wave attenuation, radar interferometry, radar polarimetry, remote sensing by radar, synthetic aperture radar, vegetation mapping;.
    Abstract: This paper concerns forest parameter retrieval from polarimetric interferometric synthetic aperture radar (PolInSAR) data considering two layers, one for the ground under the vegetation and one for the volumetric canopy. A model is designed to combine a physical model-based polarimetric decomposition with the random-volume-over-ground (RVoG) PolInSAR parameter inversion approach. The combination of a polarimetric scattering media model with a PolInSAR RVoG vertical structure model provides the possibility to separate the ground and the volume coherency matrices based on polarimetric signatures and interferometric coherence diversity. The proposed polarimetric decomposition characterizes volumetric media by the degree of polarization orientation randomness and by the particle scattering anisotropy. Using the full model enhances the estimation of the vertical forest structure parameters by enabling us to estimate the ground-to-volume ratio, the temporal decorrelation, and the differential extinction. For forest vegetation observed at L-band, this model accounts for the ground topography, forest and canopy layer heights, wave attenuation in the canopy, tree morphology in the form of the angular distribution and the effective shapes of the branches, and the contributions from the ground level consisting of surface scattering and double-bounce ground-trunk interactions, as well as volumetric understory scattering. The parameter estimation performance is evaluated on real airborne L-band SAR data of the Traunstein test site, acquired by the German Aerospace Center (DLR)'s E-SAR sensor in 2003, in both single- and multibaseline configurations. The retrieved forest height is compared with the ground-truth measurements, revealing, for the given test site, an average root-mean-square error (rmse) of about 5 m in the repeat-pass configuration. This implies an improvement in rmse by over 2 m in comparison to the pure coherence-based RVoG PolInSAR parameter inversion.

    @Article{neumannFerroFamilReigber2010:ForestPolInSAR,
    Title = {Estimation of Forest Structure, Ground, and Canopy Layer Characteristics From Multibaseline Polarimetric Interferometric {SAR} Data},
    Author = {Neumann, Maxim and Ferro-Famil, Laurent and Reigber, Andreas},
    Doi = {10.1109/TGRS.2009.2031101},
    ISSN = {0196-2892},
    Month = mar,
    Number = {3},
    Pages = {1086-1104},
    Volume = {48},
    Year = {2010},
    Abstract = {This paper concerns forest parameter retrieval from polarimetric interferometric synthetic aperture radar (PolInSAR) data considering two layers, one for the ground under the vegetation and one for the volumetric canopy. A model is designed to combine a physical model-based polarimetric decomposition with the random-volume-over-ground (RVoG) PolInSAR parameter inversion approach. The combination of a polarimetric scattering media model with a PolInSAR RVoG vertical structure model provides the possibility to separate the ground and the volume coherency matrices based on polarimetric signatures and interferometric coherence diversity. The proposed polarimetric decomposition characterizes volumetric media by the degree of polarization orientation randomness and by the particle scattering anisotropy. Using the full model enhances the estimation of the vertical forest structure parameters by enabling us to estimate the ground-to-volume ratio, the temporal decorrelation, and the differential extinction. For forest vegetation observed at L-band, this model accounts for the ground topography, forest and canopy layer heights, wave attenuation in the canopy, tree morphology in the form of the angular distribution and the effective shapes of the branches, and the contributions from the ground level consisting of surface scattering and double-bounce ground-trunk interactions, as well as volumetric understory scattering. The parameter estimation performance is evaluated on real airborne L-band SAR data of the Traunstein test site, acquired by the German Aerospace Center (DLR)'s E-SAR sensor in 2003, in both single- and multibaseline configurations. The retrieved forest height is compared with the ground-truth measurements, revealing, for the given test site, an average root-mean-square error (rmse) of about 5 m in the repeat-pass configuration. This implies an improvement in rmse by over 2 m in comparison to the pure coherence-based RVoG PolInSAR parameter inversion.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, Multibaseline SAR;Germany;PolInSAR, RVoG, vertical structure;Traunstein test site;airborne SAR, L-band; angular distribution;canopy layer heights;differential extinction;double-bounce ground-trunk interactions;forest layer heights; forest parameter retrieval;forest structure estimation;forest vegetation;ground topography;ground-to-volume ratio;ground-truth measurements; interferometric coherence;particle scattering anisotropy;polarimetric Synthetic Aperture Radar interferometry; polarimetric decomposition;polarimetric scattering media model;polarization orientation randomness; random-volume-over-ground PolInSAR parameter inversion;repeat-pass configuration;root-mean-square error; surface scattering;temporal decorrelation;tree morphology;volume coherency matrices;volumetric canopy; volumetric understory scattering;wave attenuation;radar interferometry;radar polarimetry;remote sensing by radar; synthetic aperture radar;vegetation mapping;} 
    }
    


  31. Pau Prats, Rolf Scheiber, Josef Mittermayer, Adriano Meta, and Alberto Moreira. Processing of Sliding Spotlight and TOPS SAR Data Using Baseband Azimuth Scaling. IEEE Trans. Geosci. Remote Sens., 48(2):770-780, February 2010. Keyword(s): data acquisition, geophysical image processing, radar imaging, synthetic aperture radar, Doppler centroid, SAR processing, ScanSAR mode, TOPS SAR Data, TerraSAR-X, azimuth processing, baseband azimuth scaling, data focusing, phase preserving processor, sliding spotlight, synthetic aperture radar, terrain observation, Azimuth scaling, SAR processing, ScanSAR, Terrain Observation by Progressive Scans (TOPS), spotlight, synthetic aperture radar (SAR).
    Abstract: This paper presents an efficient phase preserving processor for the focusing of data acquired in sliding spotlight and Terrain Observation by Progressive Scans (TOPS) imaging modes. They share in common a linear variation of the Doppler centroid along the azimuth dimension, which is due to a steering of the antenna (either mechanically or electronically) throughout the data take. Existing approaches for the azimuth processing can become inefficient due to the additional processing to overcome the folding in the focused domain. In this paper, a new azimuth scaling approach is presented to perform the azimuth processing, whose kernel is exactly the same for sliding spotlight and TOPS modes. The possibility to use the proposed approach to process data acquired in the ScanSAR mode, as well as a discussion concerning staring spotlight, is also included. Simulations with point targets and real data acquired by TerraSAR-X in sliding spotlight and TOPS modes are used to validate the developed algorithm.

    @Article{pratsScheiberMittermayerMetaMoreiraTGARS2010TOPS,
    author = {Prats, Pau and Scheiber, Rolf and Mittermayer, Josef and Meta, Adriano and Moreira, Alberto},
    title = {Processing of Sliding Spotlight and {TOPS} {SAR} Data Using Baseband Azimuth Scaling},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {2},
    pages = {770-780},
    month = {Feb},
    issn = {0196-2892},
    abstract = {This paper presents an efficient phase preserving processor for the focusing of data acquired in sliding spotlight and Terrain Observation by Progressive Scans (TOPS) imaging modes. They share in common a linear variation of the Doppler centroid along the azimuth dimension, which is due to a steering of the antenna (either mechanically or electronically) throughout the data take. Existing approaches for the azimuth processing can become inefficient due to the additional processing to overcome the folding in the focused domain. In this paper, a new azimuth scaling approach is presented to perform the azimuth processing, whose kernel is exactly the same for sliding spotlight and TOPS modes. The possibility to use the proposed approach to process data acquired in the ScanSAR mode, as well as a discussion concerning staring spotlight, is also included. Simulations with point targets and real data acquired by TerraSAR-X in sliding spotlight and TOPS modes are used to validate the developed algorithm.},
    doi = {10.1109/TGRS.2009.2027701},
    file = {:pratsScheiberMittermayerMetaMoreiraTGARS2010TOPS.pdf:PDF},
    keywords = {data acquisition;geophysical image processing;radar imaging;synthetic aperture radar;Doppler centroid;SAR processing;ScanSAR mode;TOPS SAR Data;TerraSAR-X;azimuth processing;baseband azimuth scaling;data focusing;phase preserving processor;sliding spotlight;synthetic aperture radar;terrain observation;Azimuth scaling;SAR processing;ScanSAR;Terrain Observation by Progressive Scans (TOPS);spotlight;synthetic aperture radar (SAR)},
    pdf = {../../../docs/pratsScheiberMittermayerMetaMoreiraTGARS2010TOPS.pdf},
    
    }
    


  32. B. Rabus, H. Wehn, and M. Nolan. The Importance of Soil Moisture and Soil Structure for InSAR Phase and Backscatter, as Determined by FDTD Modeling. IEEE_J_GRS, 48(5):2421-2429, May 2010. Keyword(s): backscatter, geophysical techniques, radar interferometry, soil, spaceborne radar, surface roughness, synthetic aperture radar, FDTD Modeling, SAR phase, air-filled-void content, backscatter data, backscatter inversions, backscatter responses, bulk moisture content, correlation length, finite-difference time domain, finite-difference time-domain simulator, interferometric phase, mean bulk moisture, microwave backscatter, near-surface soil-structure parameters, phase changes, phase differences, soil structures, spaceborne InSAR techniques, spaceborne interferometric synthetic aperture radar, surface roughness, uniform soil-moisture distributions, vertical moisture gradient, Finite-difference time domain (FDTD), interferometric synthetic aperture radar (InSAR), microwave backscatter, soil moisture, synthetic aperture radar (SAR).
    @Article{Rabus2010,
    author = {B. Rabus and H. Wehn and M. Nolan},
    title = {The Importance of Soil Moisture and Soil Structure for {InSAR} Phase and Backscatter, as Determined by {FDTD} Modeling},
    year = {2010},
    volume = {48},
    number = {5},
    month = may,
    pages = {2421--2429},
    issn = {0196-2892},
    doi = {10.1109/TGRS.2009.2039353},
    journal = IEEE_J_GRS,
    keywords = {backscatter, geophysical techniques, radar interferometry, soil, spaceborne radar, surface roughness, synthetic aperture radar, FDTD Modeling, SAR phase, air-filled-void content, backscatter data, backscatter inversions, backscatter responses, bulk moisture content, correlation length, finite-difference time domain, finite-difference time-domain simulator, interferometric phase, mean bulk moisture, microwave backscatter, near-surface soil-structure parameters, phase changes, phase differences, soil structures, spaceborne InSAR techniques, spaceborne interferometric synthetic aperture radar, surface roughness, uniform soil-moisture distributions, vertical moisture gradient, Finite-difference time domain (FDTD), interferometric synthetic aperture radar (InSAR), microwave backscatter, soil moisture, synthetic aperture radar (SAR)},
    owner = {ofrey},
    
    }
    


  33. M. Rodriguez-Cassola, S.V. Baumgartner, G. Krieger, and A. Moreira. Bistatic TerraSAR-X/F-SAR Spaceborne-Airborne SAR Experiment: Description, Data Processing, and Results. IEEE Trans. Geosci. Remote Sens., 48(2):781-794, February 2010. Keyword(s): SAR Processing, Bistatic SAR, Time-Domain Back-Projection, TDBP, Doppler information, German Aerospace Center, TerraSAR-X/F-SAR bistatic data, backscatter, bistatic back-projection algorithm, bistatic synthetic aperture radar, calibration, data processing, first X-band spaceborne-airborne SAR, nonstationary bistatic acquisitions, phase-preserving bistatic focusing, synchronization algorithm, airborne radar, backscatter, calibration, data acquisition, geophysical signal processing, radar signal processing, remote sensing by radar, spaceborne radar, synchronisation, synthetic aperture radar.
    Abstract: We report about the first X-band spaceborne-airborne bistatic synthetic aperture radar (SAR) experiment, conducted early November 2007, using the German satellite TerraSAR-X as transmitter and the German Aerospace Center's (DLR) new airborne radar system F-SAR as receiver. The importance of the experiment resides in both its pioneering character and its potential to serve as a test bed for the validation of nonstationary bistatic acquisitions, novel calibration and synchronization algorithms, and advanced imaging techniques. Due to the independent operation of the transmitter and receiver, an accurate synchronization procedure was needed during processing to make high-resolution imaging feasible. Precise phase-preserving bistatic focusing can only be achieved if time and phase synchronization exist. The synchronization approach, based on the evaluation of the range histories of several reference targets, was verified through a separate analysis of the range and Doppler contributions. After successful synchronization, nonstationary focusing was performed using a bistatic backprojection algorithm. During the campaign, stand-alone TerraSAR-X monostatic as well as interoperated TerraSAR-X/F-SAR bistatic data sets were recorded. As expected, the bistatic image shows a space-variant behavior in spatial resolution and in signal-to-noise ratio. Due to the selected configuration, the bistatic image outperforms its monostatic counterpart in almost the complete imaged scene. A detailed comparison between monostatic and bistatic images is given, illustrating the complementarity of both measurements in terms of backscatter and Doppler information. The results are of fundamental importance for the development of future nonsynchronized bistatic SAR systems.

    @Article{RodriguezCassolaBaumgartnerKriegerMoreira2007:BiStaticBackProjection,
    Title = {Bistatic {TerraSAR-X/F-SAR} Spaceborne-Airborne {SAR} Experiment: Description, Data Processing, and Results},
    Author = {Rodriguez-Cassola, M. and Baumgartner, S.V. and Krieger, G. and Moreira, A.},
    Doi = {10.1109/TGRS.2009.2029984},
    ISSN = {0196-2892},
    Month = feb,
    Number = {2},
    Pages = {781-794},
    Volume = {48},
    Year = {2010},
    Abstract = {We report about the first X-band spaceborne-airborne bistatic synthetic aperture radar (SAR) experiment, conducted early November 2007, using the German satellite TerraSAR-X as transmitter and the German Aerospace Center's (DLR) new airborne radar system F-SAR as receiver. The importance of the experiment resides in both its pioneering character and its potential to serve as a test bed for the validation of nonstationary bistatic acquisitions, novel calibration and synchronization algorithms, and advanced imaging techniques. Due to the independent operation of the transmitter and receiver, an accurate synchronization procedure was needed during processing to make high-resolution imaging feasible. Precise phase-preserving bistatic focusing can only be achieved if time and phase synchronization exist. The synchronization approach, based on the evaluation of the range histories of several reference targets, was verified through a separate analysis of the range and Doppler contributions. After successful synchronization, nonstationary focusing was performed using a bistatic backprojection algorithm. During the campaign, stand-alone TerraSAR-X monostatic as well as interoperated TerraSAR-X/F-SAR bistatic data sets were recorded. As expected, the bistatic image shows a space-variant behavior in spatial resolution and in signal-to-noise ratio. Due to the selected configuration, the bistatic image outperforms its monostatic counterpart in almost the complete imaged scene. A detailed comparison between monostatic and bistatic images is given, illustrating the complementarity of both measurements in terms of backscatter and Doppler information. The results are of fundamental importance for the development of future nonsynchronized bistatic SAR systems.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, Bistatic SAR, Time-Domain Back-Projection, TDBP, Doppler information;German Aerospace Center;TerraSAR-X/F-SAR bistatic data;backscatter;bistatic back-projection algorithm;bistatic synthetic aperture radar;calibration;data processing;first X-band spaceborne-airborne SAR;nonstationary bistatic acquisitions;phase-preserving bistatic focusing;synchronization algorithm;airborne radar;backscatter;calibration;data acquisition;geophysical signal processing;radar signal processing;remote sensing by radar;spaceborne radar;synchronisation;synthetic aperture radar} 
    }
    


  34. Helmut Rott, Simon H. Yueh, Donlad W. Cline, Claude Duguay, Richard Essery, Christian Haas, Florence Heliere, Michael Kern, Giovanni Macelloni, Eirik Malnes, Thomas Nagler, Jouni Pulliainen, H. Rebhan, and A. Thompson. Cold Regions Hydrology High-Resolution Observatory for Snow and Cold Land Processes. Proceedings of the IEEE, 98(5):752-765, May 2010. Keyword(s): glaciology, ice, remote sensing by radar, sea ice, snow, synthetic aperture radar, water, climate models, cold land processes, cold regions hydrology high-resolution observatory satellite mission, cryosphere, frequency 17.2 GHz, frequency 9.6 GHz, glaciers, global snow observations, global water cycle, lake ice, land snow, scattering signal decomposition, sea ice, synthetic aperture radar, water cycle variability prediction, Hydrology, Ice surface, Lakes, Land surface, Observatories, Satellites, Sea ice, Sea surface, Snow, Water resources, Climate research, earth observation satellite, glaciers, snow cover, synthetic aperture radar, water resources.
    Abstract: Snow is a critical component of the global water cycle and climate system, and a major source of water supply in many parts of the world. There is a lack of spatially distributed information on the accumulation of snow on land surfaces, glaciers, lake ice, and sea ice. Satellite missions for systematic and global snow observations will be essential to improve the representation of the cryosphere in climate models and to advance the knowledge and prediction of the water cycle variability and changes that depend on snow and ice resources. This paper describes the scientific drivers and technical approach of the proposed Cold Regions Hydrology High-Resolution Observatory (CoReH2O) satellite mission for snow and cold land processes. The sensor is a synthetic aperture radar operating at 17.2 and 9.6 GHz, VV and VH polarizations. The dual-frequency and dual-polarization design enables the decomposition of the scattering signal for retrieving snow mass and other physical properties of snow and ice.

    @Article{rottEtAlProcIEEE2010CoReH20,
    author = {Rott, Helmut and Yueh, Simon H. and Cline, Donlad W. and Duguay, Claude and Essery, Richard and Haas, Christian and Heliere, Florence and Kern, Michael and Macelloni, Giovanni and Malnes, Eirik and Nagler, Thomas and Pulliainen, Jouni and Rebhan, H. and Thompson, A.},
    title = {Cold Regions Hydrology High-Resolution Observatory for Snow and Cold Land Processes},
    journal = {Proceedings of the IEEE},
    year = {2010},
    volume = {98},
    number = {5},
    pages = {752-765},
    month = may,
    issn = {0018-9219},
    abstract = {Snow is a critical component of the global water cycle and climate system, and a major source of water supply in many parts of the world. There is a lack of spatially distributed information on the accumulation of snow on land surfaces, glaciers, lake ice, and sea ice. Satellite missions for systematic and global snow observations will be essential to improve the representation of the cryosphere in climate models and to advance the knowledge and prediction of the water cycle variability and changes that depend on snow and ice resources. This paper describes the scientific drivers and technical approach of the proposed Cold Regions Hydrology High-Resolution Observatory (CoReH2O) satellite mission for snow and cold land processes. The sensor is a synthetic aperture radar operating at 17.2 and 9.6 GHz, VV and VH polarizations. The dual-frequency and dual-polarization design enables the decomposition of the scattering signal for retrieving snow mass and other physical properties of snow and ice.},
    doi = {10.1109/JPROC.2009.2038947},
    file = {:rottEtAlProcIEEE2010CoReH20.pdf:PDF},
    keywords = {glaciology;ice;remote sensing by radar;sea ice;snow;synthetic aperture radar;water;climate models;cold land processes;cold regions hydrology high-resolution observatory satellite mission;cryosphere;frequency 17.2 GHz;frequency 9.6 GHz;glaciers;global snow observations;global water cycle;lake ice;land snow;scattering signal decomposition;sea ice;synthetic aperture radar;water cycle variability prediction;Hydrology;Ice surface;Lakes;Land surface;Observatories;Satellites;Sea ice;Sea surface;Snow;Water resources;Climate research;earth observation satellite;glaciers;snow cover;synthetic aperture radar;water resources},
    owner = {ofrey},
    pdf = {../../../docs/rottEtAlProcIEEE2010CoReH20.pdf},
    
    }
    


  35. Sabine Rödelsperger, Gwendolyn Läufer, Carl Gerstenecker, and Matthias Becker. Monitoring of displacements with ground-based microwave interferometry: IBIS-S and IBIS-L. Journal of Applied Geodesy, 4(1):41 - 54, 2010.
    @Article{roedelspergerEtAl2010DisplacementWithGBInSARIBISSandIBISL,
    author = {Sabine R\"odelsperger and Gwendolyn L\"aufer and Carl Gerstenecker and Matthias Becker},
    journal = {Journal of Applied Geodesy},
    title = {Monitoring of displacements with ground-based microwave interferometry: {IBIS-S} and {IBIS-L}},
    year = {2010},
    number = {1},
    pages = {41 - 54},
    volume = {4},
    address = {Berlin, Boston},
    doi = {https://doi.org/10.1515/jag.2010.005},
    owner = {ofrey},
    publisher = {De Gruyter},
    url = {https://www.degruyter.com/view/journals/jag/4/1/article-p41.xml},
    
    }
    


  36. P. Samczynski and K.S. Kulpa. Coherent MapDrift Technique. IEEE Trans. Geosci. Remote Sens., 48(3):1505-1517, 2010. Keyword(s): SAR Processing, Autofocus, SAR Autofocus, MoComp, Motion Compensation, Map-Drift Autofocus, Coherent Map-Drift Autofocus, geophysical signal processing, radar signal processing, remote sensing by radar, synthetic aperture radar, target tracking, Earth imaging, MapDrift principles, coherent MapDrift technique, flight parameter estimation, moving target indication, parametric autofocus technique, real time processing, strip mode SAR systems, synthetic aperture radar, Autofocus, MD, coherent MapDrift (CMD), moving-target indication (MTI), multilook, subaperture, synthetic aperture radar (SAR).
    Abstract: A new parametric autofocus technique with a high accuracy of flight-parameter estimation dedicated to strip-mode synthetic aperture radar (SAR) systems is presented. Most of the known autofocus techniques require high-reflectivity targets (man-made targets) to obtain a properly focused SAR image. The technique proposed in this paper allows flight parameters to be estimated effectively, even for a low-contrast scene (e.g., forests, fields, small paths, etc.). The autofocus technique is based on well-known MapDrift (MD) principles. The presented technique is a coherent one, which allows flight parameters to be estimated more precisely than in the other well-known parametric technique referred to as classical MD. The presented technique allows flight parameters to be estimated with accuracy that is independent of the initial velocity error. It can be used for real-time processing for both Earth imaging and moving-target indication.

    @Article{samczynskiKulpaTGRS2010,
    author = {Samczynski, P. and Kulpa, K.S.},
    title = {Coherent MapDrift Technique},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {3},
    pages = {1505-1517},
    issn = {0196-2892},
    abstract = {A new parametric autofocus technique with a high accuracy of flight-parameter estimation dedicated to strip-mode synthetic aperture radar (SAR) systems is presented. Most of the known autofocus techniques require high-reflectivity targets (man-made targets) to obtain a properly focused SAR image. The technique proposed in this paper allows flight parameters to be estimated effectively, even for a low-contrast scene (e.g., forests, fields, small paths, etc.). The autofocus technique is based on well-known MapDrift (MD) principles. The presented technique is a coherent one, which allows flight parameters to be estimated more precisely than in the other well-known parametric technique referred to as classical MD. The presented technique allows flight parameters to be estimated with accuracy that is independent of the initial velocity error. It can be used for real-time processing for both Earth imaging and moving-target indication.},
    doi = {10.1109/TGRS.2009.2032241},
    file = {:samczynskiKulpaTGRS2010.pdf:PDF},
    keywords = {SAR Processing, Autofocus, SAR Autofocus, MoComp, Motion Compensation,Map-Drift Autofocus, Coherent Map-Drift Autofocus, geophysical signal processing;radar signal processing;remote sensing by radar;synthetic aperture radar;target tracking;Earth imaging;MapDrift principles;coherent MapDrift technique;flight parameter estimation;moving target indication;parametric autofocus technique;real time processing;strip mode SAR systems;synthetic aperture radar;Autofocus;MD;coherent MapDrift (CMD);moving-target indication (MTI);multilook;subaperture;synthetic aperture radar (SAR)},
    pdf = {../../../docs/samczynskiKulpaTGRS2010.pdf},
    
    }
    


  37. E. Sansosti, F. Casu, M. Manzo, and R. Lanari. Space-borne radar interferometry techniques for the generation of deformation time series: An advanced tool for Earth's surface displacement analysis. Geophys. Res. Lett., 37(20):L20305, October 2010. Keyword(s): SAR Processing, PSI, Persistent Scatterer Interferometry, Interferometry, SAR Interferometry, InSAR, Differential SAR Interferometry, ground deformation time series, DInSAR, remote sensing, Mathematical Geophysics, Time series analysis, Remote sensing, Satellite geodesy.
    Abstract: This work is focused on advanced differential SAR interferometry (DInSAR) techniques for the generation of deformation time series from sequences of SAR images. We first present the basic rationale of these techniques providing some details of the most well known algorithms. Subsequently, through the analysis of selected case studies focused on the available C-band SAR data archives, we show the relevance of the retrieved spatially dense deformation time series for the comprehension of several geophysical phenomena. We finally introduce, again via a real case study, the advances brought in by the new generation X-band space-borne SAR sensors, highlighting new investigation possibilities for fast varying deformation phenomena.

    @Article{sansostiCasuManzoLanari2010PSI,
    author = {Sansosti, E. and Casu, F. and Manzo, M. and Lanari, R.},
    title = {Space-borne radar interferometry techniques for the generation of deformation time series: An advanced tool for Earth's surface displacement analysis},
    journal = {Geophys. Res. Lett.},
    year = {2010},
    volume = {37},
    number = {20},
    pages = {L20305},
    month = oct,
    issn = {0094-8276},
    abstract = {This work is focused on advanced differential SAR interferometry (DInSAR) techniques for the generation of deformation time series from sequences of SAR images. We first present the basic rationale of these techniques providing some details of the most well known algorithms. Subsequently, through the analysis of selected case studies focused on the available C-band SAR data archives, we show the relevance of the retrieved spatially dense deformation time series for the comprehension of several geophysical phenomena. We finally introduce, again via a real case study, the advances brought in by the new generation X-band space-borne SAR sensors, highlighting new investigation possibilities for fast varying deformation phenomena.},
    file = {:sansostiCasuManzoLanari2010PSI.pdf:PDF},
    keywords = {SAR Processing, PSI, Persistent Scatterer Interferometry, Interferometry, SAR Interferometry, InSAR, Differential SAR Interferometry, ground deformation time series, DInSAR, remote sensing, Mathematical Geophysics, Time series analysis, Remote sensing, Satellite geodesy},
    owner = {ofrey},
    pdf = {../../../docs/sansostiCasuManzoLanari2010PSI.pdf},
    publisher = {AGU},
    url = {http://dx.doi.org/10.1029/2010GL044379},
    
    }
    


  38. Piyush Shanker Agram and Howard Zebker. Edgelist phase unwrapping algorithm for time series InSAR analysis. J. Opt. Soc. Am. A, 27(3):605-612, March 2010. Keyword(s): SAR Processing, Three-dimensional image processing, Interferometry, InSAR, SAR Interferometry, Synthetic aperture radar, Phase, Phase unwrapping.
    Abstract: We present here a new integer programming formulation for phase unwrapping of multidimensional data. Phase unwrapping is a key problem in many coherent imaging systems, including time series synthetic aperture radar interferometry (InSAR), with two spatial and one temporal data dimensions. The minimum cost flow (MCF) [IEEE Trans. Geosci. Remote Sens. 36, 813 (1998)] phase unwrapping algorithm describes a global cost minimization problem involving flow between phase residues computed over closed loops. Here we replace closed loops by reliable edges as the basic construct, thus leading to the name ``edgelist.'' Our algorithm has several advantages over current methods---it simplifies the representation of multidimensional phase unwrapping, it incorporates data from external sources, such as GPS, where available to better constrain the unwrapped solution, and it treats regularly sampled or sparsely sampled data alike. It thus is particularly applicable to time series InSAR, where data are often irregularly spaced in time and individual interferograms can be corrupted with large decorrelated regions. We show that, similar to the MCF network problem, the edgelist formulation also exhibits total unimodularity, which enables us to solve the integer program problem by using efficient linear programming tools. We apply our method to a persistent scatterer-InSAR data set from the creeping section of the Central San Andreas Fault and find that the average creep rate of 22 mm/Yr is constant within 3 mm/Yr over 1992-2004 but varies systematically with ground location, with a slightly higher rate in 1992-1998 than in 1999-2003.

    @Article{shankerAgramZebkerJOSAA2010:PhaseUnwrapping,
    Title = {Edgelist phase unwrapping algorithm for time series {InSAR} analysis},
    Author = {Shanker Agram, Piyush and Howard Zebker},
    Doi = {10.1364/JOSAA.27.000605},
    Month = mar,
    Number = {3},
    Pages = {605--612},
    Url = {http://josaa.osa.org/abstract.cfm?URI=josaa-27-3-605},
    Volume = {27},
    Year = {2010},
    Abstract = {We present here a new integer programming formulation for phase unwrapping of multidimensional data. Phase unwrapping is a key problem in many coherent imaging systems, including time series synthetic aperture radar interferometry (InSAR), with two spatial and one temporal data dimensions. The minimum cost flow (MCF) [IEEE Trans. Geosci. Remote Sens. 36, 813 (1998)] phase unwrapping algorithm describes a global cost minimization problem involving flow between phase residues computed over closed loops. Here we replace closed loops by reliable edges as the basic construct, thus leading to the name ``edgelist.'' Our algorithm has several advantages over current methods---it simplifies the representation of multidimensional phase unwrapping, it incorporates data from external sources, such as GPS, where available to better constrain the unwrapped solution, and it treats regularly sampled or sparsely sampled data alike. It thus is particularly applicable to time series InSAR, where data are often irregularly spaced in time and individual interferograms can be corrupted with large decorrelated regions. We show that, similar to the MCF network problem, the edgelist formulation also exhibits total unimodularity, which enables us to solve the integer program problem by using efficient linear programming tools. We apply our method to a persistent scatterer-InSAR data set from the creeping section of the Central San Andreas Fault and find that the average creep rate of 22 mm/Yr is constant within 3 mm/Yr over 1992-2004 but varies systematically with ground location, with a slightly higher rate in 1992-1998 than in 1999-2003.},
    Journal = {J. Opt. Soc. Am. A},
    Keywords = {SAR Processing, Three-dimensional image processing; Interferometry; InSAR, SAR Interferometry, Synthetic aperture radar; Phase; Phase unwrapping},
    Owner = {ofrey},
    Pdf = {../../../docs/shankerAgramZebkerJOSAA2010.pdf},
    Publisher = {OSA} 
    }
    


  39. Manoochehr Shirzaei and TR Walter. Time-dependent volcano source monitoring using interferometric synthetic aperture radar time series: A combined genetic algorithm and Kalman filter approach. Journal of Geophysical Research: Solid Earth, 115(B10), 2010. Keyword(s): SAR Processing, Deformation, Deformation Monitoring, DInSAR, SAR Interferometry, Differential Interferometry, Kalman Filter.
    Abstract: Modern geodetic methods allow continuous monitoring of deformation fields of volcanoes. The acquired data contribute significantly to the study of the dynamics of magmatic sources prior to, during and after eruptions and intrusions. In addition to advancing the monitoring techniques, it is important to develop suitable approaches to deal with deformation time series. Here, we present, test and apply a new approach for time-dependent, nonlinear inversion using a combination of a genetic algorithm (GA) and a Kalman filter (KF). The GA is used in the form presented by Shirzaei and Walter (2009), and the KF implementation now allows for the treatment of monitoring data as a full time series rather than as single time steps. This approach provides a flexible tool for assessing unevenly sampled and heterogeneous time series data and explains the deformation field using time-consistent dislocation sources. Following synthetic tests, we demonstrate the merits of time-consistent source modeling for interferometric synthetic aperture radar (InSAR) data available between 1992 and 2008 from the Campi Flegrei volcano in Italy. We obtained multiple episodes of linear velocity for the reservoir pressure change associated with a parabolic surface deformation on the volcano. These data may be interpreted via differential equations as a linear flux to the shallow reservoir that provides new insight into how both the shallow and deep reservoirs communicate beneath Campi Flegrei. The synthetic test and case study demonstrate the robustness of our approach and the ability to track and monitor the source of systems with complex dynamics. It is applicable to time-dependent optimization problems in volcanic and tectonic environments in other tectonic environments in other areas and allows understanding of the spatiotemporal extent of a physical process in quantitative manner.

    @Article{Shirzaei2010,
    author = {Shirzaei, Manoochehr and Walter, TR},
    title = {Time-dependent volcano source monitoring using interferometric synthetic aperture radar time series: A combined genetic algorithm and Kalman filter approach},
    year = {2010},
    volume = {115},
    number = {B10},
    doi = {10.1029/2010JB007476},
    abstract = {Modern geodetic methods allow continuous monitoring of deformation fields of volcanoes. The acquired data contribute significantly to the study of the dynamics of magmatic sources prior to, during and after eruptions and intrusions. In addition to advancing the monitoring techniques, it is important to develop suitable approaches to deal with deformation time series. Here, we present, test and apply a new approach for time-dependent, nonlinear inversion using a combination of a genetic algorithm (GA) and a Kalman filter (KF). The GA is used in the form presented by Shirzaei and Walter (2009), and the KF implementation now allows for the treatment of monitoring data as a full time series rather than as single time steps. This approach provides a flexible tool for assessing unevenly sampled and heterogeneous time series data and explains the deformation field using time-consistent dislocation sources. Following synthetic tests, we demonstrate the merits of time-consistent source modeling for interferometric synthetic aperture radar (InSAR) data available between 1992 and 2008 from the Campi Flegrei volcano in Italy. We obtained multiple episodes of linear velocity for the reservoir pressure change associated with a parabolic surface deformation on the volcano. These data may be interpreted via differential equations as a linear flux to the shallow reservoir that provides new insight into how both the shallow and deep reservoirs communicate beneath Campi Flegrei. The synthetic test and case study demonstrate the robustness of our approach and the ability to track and monitor the source of systems with complex dynamics. It is applicable to time-dependent optimization problems in volcanic and tectonic environments in other tectonic environments in other areas and allows understanding of the spatiotemporal extent of a physical process in quantitative manner.},
    journal = {Journal of Geophysical Research: Solid Earth},
    keywords = {SAR Processing, Deformation, Deformation Monitoring, DInSAR, SAR Interferometry, Differential Interferometry, Kalman Filter},
    owner = {ofrey},
    publisher = {Wiley Online Library},
    
    }
    


  40. Stefano Tebaldini. Single and Multipolarimetric SAR Tomography of Forested Areas: A Parametric Approach. IEEE Trans. Geosci. Remote Sens., 48(5):2375-2387, May 2010. Keyword(s): SAR Processing, SAR Tomography, Tomography, Forest, Forestry, Fourier spectrum, Remningstorp, Sweden, backscattered powers, covariance matching estimation technique, effective scattering centers, forested areas, multibaseline data, multiple synthetic aperture radar observations, multipolarimetric SAR tomography, multipolarimetric acquisition, parameter estimation, polarimetric data set, radar signal processing, real P-band multibaseline, resolution cell, geophysical signal processing, geophysical techniques, optical tomography, radar polarimetry, synthetic aperture radar;.
    Abstract: In this paper, a technique is described for the tomographic characterization of forested areas through multiple synthetic aperture radar (SAR) observations, based on either single or multipolarimetric acquisitions. This technique is based on the idea of characterizing the Fourier spectrum of the multibaseline data as being constituted by two effective scattering centers displaced along the vertical direction, plus the associated decorrelation terms. As a result, SAR tomography will be formulated as the problem of detecting the number of scattering centers within the resolution cell, estimating the parameters that describe their spatial structure, and evaluating the associated backscattered powers. Parameter estimation is carried out through the covariance matching estimation technique, which provides an asymptotically optimal solution. The results of an experiment performed on a real P-band multibaseline fully polarimetric data set relative to the forested site of Remningstorp, Sweden, are reported.

    @Article{tebaldiniTGRS2010:TOMOFOREST,
    Title = {Single and Multipolarimetric {SAR} Tomography of Forested Areas: A Parametric Approach},
    Author = {Tebaldini, Stefano},
    Doi = {10.1109/TGRS.2009.2037748},
    ISSN = {0196-2892},
    Month = may,
    Number = {5},
    Pages = {2375-2387},
    Volume = {48},
    Year = {2010},
    Abstract = {In this paper, a technique is described for the tomographic characterization of forested areas through multiple synthetic aperture radar (SAR) observations, based on either single or multipolarimetric acquisitions. This technique is based on the idea of characterizing the Fourier spectrum of the multibaseline data as being constituted by two effective scattering centers displaced along the vertical direction, plus the associated decorrelation terms. As a result, SAR tomography will be formulated as the problem of detecting the number of scattering centers within the resolution cell, estimating the parameters that describe their spatial structure, and evaluating the associated backscattered powers. Parameter estimation is carried out through the covariance matching estimation technique, which provides an asymptotically optimal solution. The results of an experiment performed on a real P-band multibaseline fully polarimetric data set relative to the forested site of Remningstorp, Sweden, are reported.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Forest, Forestry, Fourier spectrum;Remningstorp;Sweden;backscattered powers;covariance matching estimation technique;effective scattering centers;forested areas;multibaseline data;multiple synthetic aperture radar observations;multipolarimetric SAR tomography;multipolarimetric acquisition;parameter estimation;polarimetric data set;radar signal processing;real P-band multibaseline;resolution cell;geophysical signal processing;geophysical techniques;optical tomography;radar polarimetry;synthetic aperture radar;} 
    }
    


  41. Stefano Tebaldini and Andrea Monti-Guarnieri. On the Role of Phase Stability in SAR Multibaseline Applications. IEEE Transactions on Geoscience and Remote Sensing, 48(7):2953-2966, July 2010. Keyword(s): SAR Processing, InSAR, Interferometry, SAR Interferometry, Monte Carlo simulations, Neyman-Pearson theory, P-band, Remningstorp, SAR multibaseline applications, Sweden, atmospheric disturbances, multibaseline synthetic aperture radar interferometry, phase calibration, phase stability, propagation disturbances, residual platform motion, signal-to-noise ratio, statistical analysis, SAR Tomography, Tomography, Monte Carlo methods, geophysical techniques, radar interferometry, remote sensing by radar, statistical analysis, synthetic aperture radar;.
    Abstract: This paper is meant to present a statistical analysis of the role of propagation disturbances (PDs), such as those due to atmospheric disturbances or to residual platform motion, in multibaseline synthetic aperture radar (SAR) interferometry (InSAR) and tomography (T-SAR) applications. The analysis will consider both pointlike and distributed targets in such a way as to cover all the cases that are relevant in the applications. In order to provide a tool for the evaluation of the impact of PDs on the analysis of an arbitrary scenario, a definition of signal-to-noise ratio (SNR) will be introduced that accounts for both the presence of PDs and the characteristics of the imaged scene. In the case of pointlike targets, it will be shown that such definition of SNR allows reusing well known results following after the Neyman-Pearson theory, thus providing a straightforward tool to asses phase-stability requirements for the detection and localization of multiple pointlike targets. In the case of distributed targets, instead, it will be provided a detailed analysis of the random fluctuations of the reconstructed scene as a function of the extent of the PDs, of the vertical structure of the imaged scene, and of the number of looks that are employed. Results from Monte Carlo simulations will be presented that fully support the theoretical developments within this paper. The most relevant conclusion of this paper is that the impact of PDs is more severe in the case where the imaged scene is characterized by a complex vertical structure or when multiple pointlike targets are present. As a consequence, it follows that the T-SAR analyses require either a higher phase stability or a more accurate phase calibration with respect to InSAR analyses. Finally, an example of phase-stability analysis and phase calibration of a real data set will be shown, based on a P-band data set relative to the forest site of Remningstorp, Sweden.

    @Article{tebaldiniMontiGuarnieri2010TomoPhaseStab,
    Title = {On the Role of Phase Stability in {SAR} Multibaseline Applications},
    Author = {Tebaldini, Stefano and Monti-Guarnieri, Andrea},
    Doi = {10.1109/TGRS.2010.2043738},
    ISSN = {0196-2892},
    Month = jul,
    Number = {7},
    Pages = {2953-2966},
    Volume = {48},
    Year = {2010},
    Abstract = {This paper is meant to present a statistical analysis of the role of propagation disturbances (PDs), such as those due to atmospheric disturbances or to residual platform motion, in multibaseline synthetic aperture radar (SAR) interferometry (InSAR) and tomography (T-SAR) applications. The analysis will consider both pointlike and distributed targets in such a way as to cover all the cases that are relevant in the applications. In order to provide a tool for the evaluation of the impact of PDs on the analysis of an arbitrary scenario, a definition of signal-to-noise ratio (SNR) will be introduced that accounts for both the presence of PDs and the characteristics of the imaged scene. In the case of pointlike targets, it will be shown that such definition of SNR allows reusing well known results following after the Neyman-Pearson theory, thus providing a straightforward tool to asses phase-stability requirements for the detection and localization of multiple pointlike targets. In the case of distributed targets, instead, it will be provided a detailed analysis of the random fluctuations of the reconstructed scene as a function of the extent of the PDs, of the vertical structure of the imaged scene, and of the number of looks that are employed. Results from Monte Carlo simulations will be presented that fully support the theoretical developments within this paper. The most relevant conclusion of this paper is that the impact of PDs is more severe in the case where the imaged scene is characterized by a complex vertical structure or when multiple pointlike targets are present. As a consequence, it follows that the T-SAR analyses require either a higher phase stability or a more accurate phase calibration with respect to InSAR analyses. Finally, an example of phase-stability analysis and phase calibration of a real data set will be shown, based on a P-band data set relative to the forest site of Remningstorp, Sweden.},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {SAR Processing, InSAR; Interferometry, SAR Interferometry, Monte Carlo simulations;Neyman-Pearson theory;P-band;Remningstorp;SAR multibaseline applications;Sweden;atmospheric disturbances;multibaseline synthetic aperture radar interferometry;phase calibration;phase stability;propagation disturbances;residual platform motion;signal-to-noise ratio;statistical analysis;SAR Tomography; Tomography, Monte Carlo methods;geophysical techniques;radar interferometry;remote sensing by radar;statistical analysis;synthetic aperture radar;} 
    }
    


  42. R Tomás, G Herrera, J Delgado, Juan Manuel Lopez-Sanchez, JJ Mallorquì, and J Mulas. A ground subsidence study based on DInSAR data: calibration of soil parameters and subsidence prediction in Murcia City (Spain). Engineering geology, 111(1):19-30, 2010.
    @Article{tomasHerreraDelgadoLopezSanchezMallorquiMulasEnginGeology2010SubsidenceDInSAR,
    author = {Tom{\'a}s, R and Herrera, G and Delgado, J and Lopez-Sanchez, Juan Manuel and Mallorqu{\'\i}, JJ and Mulas, J},
    title = {A ground subsidence study based on {DInSAR} data: calibration of soil parameters and subsidence prediction in {Murcia} City ({Spain})},
    journal = {Engineering geology},
    year = {2010},
    volume = {111},
    number = {1},
    pages = {19-30},
    owner = {ofrey},
    publisher = {Elsevier},
    
    }
    


  43. G. Vilardo, R. Isaia, G. Ventura, P. De Martino, and C. Terranova. InSAR Permanent Scatterer analysis reveals fault re-activation during inflation and deflation episodes at Campi Flegrei caldera. Remote Sensing of Environment, 114(10):2373-2383, 2010.
    @Article{vilardoIsaiaVenturaDeMartinoTerranovaRSE2010,
    author = {Vilardo, G. and Isaia, R. and Ventura, G. and De Martino, P. and Terranova, C.},
    title = {{InSAR} Permanent Scatterer analysis reveals fault re-activation during inflation and deflation episodes at {Campi Flegrei} caldera},
    year = {2010},
    volume = {114},
    number = {10},
    pages = {2373--2383},
    journal = {Remote Sensing of Environment},
    owner = {ofrey},
    publisher = {Elsevier},
    
    }
    


  44. Viet Thuy Vu, Thomas K. Sjogren, and Mats I. Pettersson. Ultrawideband Chirp Scaling Algorithm. IEEE Geoscience and Remote Sensing Letters, 7(2):281-285, April 2010. Keyword(s): SAR Processing, Chirp Scaling, Chirp Scaling Algorithm, CSA, UCS, Azimuth Focusing, Focusing Algorithm, CARABAS-II, LORA, UWB SAR, UWB, antenna beamwidth, fractional bandwidth, ground-moving-target-indication SAR systems, high pulse repetition frequency, integration angle, synthetic aperture radar imaging algorithms, ultrawideband chirp scaling algorithm, geophysical image processing, geophysical techniques, synthetic aperture radar;.
    Abstract: A new version of chirp scaling (CS), the so-called ultrawideband (UWB) CS (UCS), is proposed in this letter. UCS aims at UWB synthetic aperture radar (SAR) systems utilizing large fractional bandwidth and wide antenna beamwidth associated with a wide integration angle. Furthermore, it is also valid for SAR systems with special characteristics such as ground-moving-target-indication SAR systems with a very high pulse repetition frequency.

    @Article{vuSjogrenPettersson2010UWCSA,
    Title = {Ultrawideband Chirp Scaling Algorithm},
    Author = {Viet Thuy Vu and Sjogren, Thomas K. and Pettersson, Mats I.},
    Doi = {10.1109/LGRS.2009.2033316},
    ISSN = {1545-598X},
    Month = apr,
    Number = {2},
    Pages = {281-285},
    Volume = {7},
    Year = {2010},
    Abstract = {A new version of chirp scaling (CS), the so-called ultrawideband (UWB) CS (UCS), is proposed in this letter. UCS aims at UWB synthetic aperture radar (SAR) systems utilizing large fractional bandwidth and wide antenna beamwidth associated with a wide integration angle. Furthermore, it is also valid for SAR systems with special characteristics such as ground-moving-target-indication SAR systems with a very high pulse repetition frequency.},
    Journal = {IEEE Geoscience and Remote Sensing Letters},
    Keywords = {SAR Processing, Chirp Scaling, Chirp Scaling Algorithm, CSA, UCS, Azimuth Focusing, Focusing Algorithm, CARABAS-II;LORA;UWB SAR; UWB, antenna beamwidth;fractional bandwidth;ground-moving-target-indication SAR systems;high pulse repetition frequency;integration angle;synthetic aperture radar imaging algorithms;ultrawideband chirp scaling algorithm;geophysical image processing;geophysical techniques;synthetic aperture radar;},
    Owner = {ofrey} 
    }
    


  45. Viet Thuy Vu, Thomas K. Sjogren, M.I. Pettersson, A. Gustavsson, and Lars M.H. Ulander. Detection of Moving Targets by Focusing in UWB SAR: Theory and Experimental Results. IEEE Trans. Geosci. Remote Sens., 48(10):3799 -3815, October 2010. Keyword(s): SAR Processing, UWB SAR, azimuth focusing, moving target detection, multichannel SAR data, reference system, reliable detection, signal-to-clutter noise ratio, single-channel SAR data, ultrawideband synthetic aperture radar, object detection, synthetic aperture radar, target tracking, ultra wideband radar;.
    Abstract: Moving-target detection in ultrawideband (UWB) synthetic aperture radar (SAR) is associated with long integration time and must accommodate azimuth focusing for reliable detection. This paper presents the theory on detection of moving targets by focusing and experimental results on single-channel SAR data aimed at evaluating the detection performance. The results with respect to both simulated and real data show that the ability to detect moving targets increases significantly when applying the proposed detection technique. The improvement in signal-to-clutter noise ratio, which is a basic requisite for evaluating the performance, reaches approximately 20 dB, using only single-channel SAR data. This gain will be preserved for the case of multichannel SAR data. The reference system for this study is the airborne UWB low-frequency SAR Coherent All RAdio BAnd Sensing II.

    @Article{vuSjogrenPetterssonGustavssonUlander2010,
    Title = {Detection of Moving Targets by Focusing in {UWB} {SAR}: Theory and Experimental Results},
    Author = {Viet Thuy Vu and Sjogren, Thomas K. and Pettersson, M.I. and Gustavsson, A. and Ulander, Lars M.H.},
    Doi = {10.1109/TGRS.2010.2048572},
    ISSN = {0196-2892},
    Month = oct,
    Number = {10},
    Pages = {3799 -3815},
    Volume = {48},
    Year = {2010},
    Abstract = {Moving-target detection in ultrawideband (UWB) synthetic aperture radar (SAR) is associated with long integration time and must accommodate azimuth focusing for reliable detection. This paper presents the theory on detection of moving targets by focusing and experimental results on single-channel SAR data aimed at evaluating the detection performance. The results with respect to both simulated and real data show that the ability to detect moving targets increases significantly when applying the proposed detection technique. The improvement in signal-to-clutter noise ratio, which is a basic requisite for evaluating the performance, reaches approximately 20 dB, using only single-channel SAR data. This gain will be preserved for the case of multichannel SAR data. The reference system for this study is the airborne UWB low-frequency SAR Coherent All RAdio BAnd Sensing II.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, UWB SAR;azimuth focusing;moving target detection;multichannel SAR data;reference system;reliable detection;signal-to-clutter noise ratio;single-channel SAR data;ultrawideband synthetic aperture radar;object detection;synthetic aperture radar;target tracking;ultra wideband radar;},
    Owner = {ofrey} 
    }
    


  46. Viet Thuy Vu, Thomas K. Sjogren, Mats I. Pettersson, L. Hakansson, A. Gustavsson, and Lars M. H. Ulander. RFI Suppression in Ultrawideband SAR Using an Adaptive Line Enhancer. IEEE Geosci. Remote Sens. Lett., 7(4):694-698, October 2010. Keyword(s): SAR Processing, RFI, radio frequency interference, RFI mitigation, interference suppression, least mean squares methods, radiofrequency interference, synthetic aperture radar, ultra wideband radar, RFI suppression, UWB low-frequency SAR data, adaptive line enhancer, least mean square algorithm, radiofrequency interference, ultrawideband low-frequency synthetic aperture radar, Adaptive control, Interference suppression, Least mean square algorithms, Line enhancers, Programmable control, Proposals, Radio frequency, Radiofrequency interference, Synthetic aperture radar, Ultra wideband technology, Adaptive line enhancer (ALE), CARABAS-II, normalized least mean square (LMS) (NLMS), radio-frequency interference (RFI), synthetic aperture radar (SAR), ultrawideband (UWB).
    Abstract: In this letter, we propose an approach to suppress radio-frequency interference (RFI) in ultrawideband (UWB) low-frequency synthetic aperture radar (SAR). According to the proposal, RFI is suppressed by using an adaptive line enhancer controlled by the normalized least mean square algorithm. The approach is tested successfully on real UWB low-frequency SAR data. In order to keep the computational burden down, possible ways to integrate the RFI suppression approach into SAR imaging algorithms are also suggested.

    @Article{vuSjogrenPetterssonHakanssonGustavssonUlander2010RFI,
    Title = {{RFI} Suppression in Ultrawideband {SAR} Using an Adaptive Line Enhancer},
    Author = {Vu, Viet Thuy and Sjogren, Thomas K. and Pettersson, Mats I. and Hakansson, L. and Gustavsson, A. and Ulander, Lars M. H.},
    Doi = {10.1109/LGRS.2010.2045633},
    ISSN = {1545-598X},
    Month = oct,
    Number = {4},
    Pages = {694-698},
    Volume = {7},
    Year = {2010},
    Abstract = {In this letter, we propose an approach to suppress radio-frequency interference (RFI) in ultrawideband (UWB) low-frequency synthetic aperture radar (SAR). According to the proposal, RFI is suppressed by using an adaptive line enhancer controlled by the normalized least mean square algorithm. The approach is tested successfully on real UWB low-frequency SAR data. In order to keep the computational burden down, possible ways to integrate the RFI suppression approach into SAR imaging algorithms are also suggested.},
    Journal = {IEEE Geosci. Remote Sens. Lett.},
    Keywords = {SAR Processing, RFI, radio frequency interference, RFI mitigation, interference suppression;least mean squares methods;radiofrequency interference;synthetic aperture radar;ultra wideband radar;RFI suppression;UWB low-frequency SAR data;adaptive line enhancer;least mean square algorithm;radiofrequency interference;ultrawideband low-frequency synthetic aperture radar;Adaptive control;Interference suppression;Least mean square algorithms;Line enhancers;Programmable control;Proposals;Radio frequency;Radiofrequency interference;Synthetic aperture radar;Ultra wideband technology;Adaptive line enhancer (ALE);CARABAS-II;normalized least mean square (LMS) (NLMS);radio-frequency interference (RFI);synthetic aperture radar (SAR);ultrawideband (UWB)} 
    }
    


  47. Viet Thuy Vu, Thomas K. Sjogren, Mats I. Pettersson, and H. Hellsten. An Impulse Response Function for Evaluation of UWB SAR Imaging. IEEE Transactions on Signal Processing, 58(7):3927-3932, July 2010. Keyword(s): SAR Processing, impulse response function evaluation, Resolution, Range Resolution, Azimuth Resolution, IRF, UWB, object detection, radar imaging, synthetic aperture radar, transient response, ultra wideband radar, IRF-SAR, UWB SAR imaging, image quality measurement, impulse response function, narrowband-narrowbeam SAR systems, point target, spatial resolution estimation, two-dimensional sine function, Impulse response function in SAR imaging (IRF-SAR), Sinc, impulse response function in UWB SAR imaging (IRF-USAR), synthetic aperture radar (SAR), ultrawideband-ultrawidebeam (UWB).
    Abstract: Based on analysis of a point target imaged by different synthetic aperture radar (SAR) systems, the commonly used impulse response function in SAR Imaging (IRF-SAR)-a two-dimensional (2-D) sinc function-is shown to be inappropriate for ultrawideband-ultrawidebeam (UWB) SAR systems utilizing a large fractional signal bandwidth and a wide antenna beamwidth. As a consequence, the applications of the 2-D sinc function such as image quality measurements and spatial resolution estimations are limited to narrowband-narrowbeam (NB) SAR systems exploiting a small fractional signal bandwidth and a narrow antenna beamwidth. In this paper, a more general IRF-SAR, which aims at UWB SAR systems, is derived with an assumption of flat two-dimensional (2-D) Fourier transform (FT) of a SAR image and called IRF-USAR. However, the derived IRF-USAR is also valid for NB SAR systems.

    @Article{vuSjogrenPetterssonHellsten2010IRFEvaluationUWBSAR,
    Title = {An Impulse Response Function for Evaluation of {UWB} {SAR} Imaging},
    Author = {Vu, Viet Thuy and Sjogren, Thomas K. and Pettersson, Mats I. and Hellsten, H.},
    Doi = {10.1109/TSP.2010.2047503},
    ISSN = {1053-587X},
    Month = jul,
    Number = {7},
    Pages = {3927-3932},
    Volume = {58},
    Year = {2010},
    Abstract = {Based on analysis of a point target imaged by different synthetic aperture radar (SAR) systems, the commonly used impulse response function in SAR Imaging (IRF-SAR)-a two-dimensional (2-D) sinc function-is shown to be inappropriate for ultrawideband-ultrawidebeam (UWB) SAR systems utilizing a large fractional signal bandwidth and a wide antenna beamwidth. As a consequence, the applications of the 2-D sinc function such as image quality measurements and spatial resolution estimations are limited to narrowband-narrowbeam (NB) SAR systems exploiting a small fractional signal bandwidth and a narrow antenna beamwidth. In this paper, a more general IRF-SAR, which aims at UWB SAR systems, is derived with an assumption of flat two-dimensional (2-D) Fourier transform (FT) of a SAR image and called IRF-USAR. However, the derived IRF-USAR is also valid for NB SAR systems.},
    Journal = {IEEE Transactions on Signal Processing},
    Keywords = {SAR Processing, impulse response function evaluation, Resolution, Range Resolution, Azimuth Resolution, IRF, UWB, object detection;radar imaging;synthetic aperture radar;transient response;ultra wideband radar;IRF-SAR;UWB SAR imaging;image quality measurement;impulse response function;narrowband-narrowbeam SAR systems;point target;spatial resolution estimation;two-dimensional sine function;Impulse response function in SAR imaging (IRF-SAR);Sinc;impulse response function in UWB SAR imaging (IRF-USAR);synthetic aperture radar (SAR);ultrawideband-ultrawidebeam (UWB)} 
    }
    


  48. Teng Wang, Mingsheng Liao, and Daniele Perissin. InSAR Coherence-Decomposition Analysis. IEEE Geosci. Remote Sens. Lett., 7(1):156-160, January 2010. Keyword(s): SAR Processing, geophysical signal processing, radar interferometry, radar signal processing, radar theory, remote sensing by radar, spaceborne radar, synthetic aperture radar, terrain mapping, topography (Earth), Badong, China, European Remote Sensing satellite tandem data, InSAR coherence decomposition analysis, acquisition geometry, classification algorithms, distributed target, geometrical coherence, geometrical decorrelation, mountain areas, phase coherence, pointlike target identification, sensor acquisition parameters, synthetic aperture radar interferometry, temporal coherence estimation, temporal decorrelation, terrain temporal changes, topographic model, Coherence estimation, synthetic aperture radar interferometry (InSAR);.
    Abstract: The phase coherence in synthetic aperture radar interferometry is often used in classification algorithms to detect possible temporal changes of the imaged terrain. However, in mountain areas, the interferometric coherence is also sensitive to the slight variations of the acquisition geometry. In this letter, we propose a very simple but effective method to separate the temporal decorrelation from the geometrical one. Assuming the imaged terrain can be modeled as a distributed target, the geometrical coherence can be estimated by exploiting a topographic model and the sensor acquisition parameters. The discrepancy between the geometrical coherence and the observed one can then be ascribed to temporal changes. Moreover, in presence of pointlike targets, the hypothesis of distributed terrain is no longer valid, and higher values of the observed coherence with respect to the synthetic geometrical one can be used to detect such targets. The proposed approach allows then in mountain areas the following conditions: (1) a simple and very fast rough estimation of the temporal coherence, and (2) the identification of pointlike targets using just two images. The method has been applied and tested in the Badong (China) site using European Remote Sensing satellite tandem data.

    @Article{wangLiaoPerissinGRSL2010,
    author = {Teng Wang and Mingsheng Liao and Perissin, Daniele},
    title = {{InSAR} Coherence-Decomposition Analysis},
    journal = {IEEE Geosci. Remote Sens. Lett.},
    year = {2010},
    volume = {7},
    number = {1},
    pages = {156-160},
    month = jan,
    issn = {1545-598X},
    abstract = {The phase coherence in synthetic aperture radar interferometry is often used in classification algorithms to detect possible temporal changes of the imaged terrain. However, in mountain areas, the interferometric coherence is also sensitive to the slight variations of the acquisition geometry. In this letter, we propose a very simple but effective method to separate the temporal decorrelation from the geometrical one. Assuming the imaged terrain can be modeled as a distributed target, the geometrical coherence can be estimated by exploiting a topographic model and the sensor acquisition parameters. The discrepancy between the geometrical coherence and the observed one can then be ascribed to temporal changes. Moreover, in presence of pointlike targets, the hypothesis of distributed terrain is no longer valid, and higher values of the observed coherence with respect to the synthetic geometrical one can be used to detect such targets. The proposed approach allows then in mountain areas the following conditions: (1) a simple and very fast rough estimation of the temporal coherence, and (2) the identification of pointlike targets using just two images. The method has been applied and tested in the Badong (China) site using European Remote Sensing satellite tandem data.},
    doi = {10.1109/LGRS.2009.2029126},
    file = {:wangLiaoPerissinGRSL2010.pdf:PDF},
    keywords = {SAR Processing, geophysical signal processing;radar interferometry;radar signal processing;radar theory;remote sensing by radar;spaceborne radar;synthetic aperture radar;terrain mapping;topography (Earth);Badong;China;European Remote Sensing satellite tandem data;InSAR coherence decomposition analysis;acquisition geometry;classification algorithms;distributed target;geometrical coherence;geometrical decorrelation;mountain areas;phase coherence;pointlike target identification;sensor acquisition parameters;synthetic aperture radar interferometry;temporal coherence estimation;temporal decorrelation;terrain temporal changes;topographic model;Coherence estimation;synthetic aperture radar interferometry (InSAR);},
    pdf = {../../../docs/wangLiaoPerissinGRSL2010.pdf},
    
    }
    


  49. R. Wang, O. Loffeld, Y.L. Neo, H. Nies, I. Walterscheid, T. Espeter, J. Klare, and J. Ender. Focusing Bistatic SAR Data in Airborne/Stationary Configuration. IEEE Trans. Geosci. Remote Sens., 48(1):452-465, January 2010. Keyword(s): SAR Processing, Bistatic SAR, BiSAR data, Forschungsgesellschaft fur Angewandte Naturwissenschaften, PAMIR, Transall C-160, airborne SAR system, azimuth modulation, bistatic SAR airborne-stationary configuration, bistatic SAR data, bistatic point-target reference spectrum, frequency domain based focusing algorithm, interpolation free wavenumber domain algorithm, range offset, range variant interpolation, stationary X-band transmitter, synthetic aperture radar, target azimuth position, target range migration trajectory, airborne radar, geophysical signal processing, interpolation, radar signal processing, remote sensing by radar, synthetic aperture radar.
    Abstract: This paper presents a frequency-domain-based focusing algorithm for the bistatic synthetic aperture radar (BiSAR) data in airborne/stationary configuration. In this bistatic configuration, only the moving platform contributes to the azimuth modulation, whereas the stationary platform introduces a range offset (RO) to the range migration trajectories of targets at the same range. The offset is determined by the azimuth position of different targets with respect to the stationary platform. Since the RO is position dependent, monostatic SAR imaging algorithms are not able to focus the bistatic data collected in this configuration. In this paper, an analytical bistatic point-target reference spectrum is derived, and then, a frequency-domain-based algorithm is developed to focus the bistatic data. It uses an interpolation-free wavenumber-domain algorithm as a basis and performs a range-variant interpolation to correct the position-dependent RO in the image domain after coarse focusing. The proposed algorithm is validated by the simulated data and the real BiSAR data acquired by the Forschungsgesellschaft f{\"u}r Angewandte Naturwissenschaften's airborne SAR system, PAMIR, in December 2007. In this BiSAR experiment, an X-band transmitter was stationary operated on a hill with PAMIR as the receiver mounted on a Transall C-160.

    @Article{WangLoffeldNeoNiesWalterscheidEspeterKlareEnder2010:BiStatic,
    Title = {Focusing Bistatic {SAR} Data in Airborne/Stationary Configuration},
    Author = {Wang, R. and Loffeld, O. and Neo, Y.L. and Nies, H. and Walterscheid, I. and Espeter, T. and Klare, J. and Ender, J.},
    Doi = {10.1109/TGRS.2009.2027700},
    ISSN = {0196-2892},
    Month = jan,
    Number = {1},
    Pages = {452-465},
    Volume = {48},
    Year = {2010},
    Abstract = {This paper presents a frequency-domain-based focusing algorithm for the bistatic synthetic aperture radar (BiSAR) data in airborne/stationary configuration. In this bistatic configuration, only the moving platform contributes to the azimuth modulation, whereas the stationary platform introduces a range offset (RO) to the range migration trajectories of targets at the same range. The offset is determined by the azimuth position of different targets with respect to the stationary platform. Since the RO is position dependent, monostatic SAR imaging algorithms are not able to focus the bistatic data collected in this configuration. In this paper, an analytical bistatic point-target reference spectrum is derived, and then, a frequency-domain-based algorithm is developed to focus the bistatic data. It uses an interpolation-free wavenumber-domain algorithm as a basis and performs a range-variant interpolation to correct the position-dependent RO in the image domain after coarse focusing. The proposed algorithm is validated by the simulated data and the real BiSAR data acquired by the Forschungsgesellschaft f{\"u}r Angewandte Naturwissenschaften's airborne SAR system, PAMIR, in December 2007. In this BiSAR experiment, an X-band transmitter was stationary operated on a hill with PAMIR as the receiver mounted on a Transall C-160.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing,Bistatic SAR,BiSAR data;Forschungsgesellschaft fur Angewandte Naturwissenschaften;PAMIR;Transall C-160;airborne SAR system;azimuth modulation;bistatic SAR airborne-stationary configuration;bistatic SAR data;bistatic point-target reference spectrum;frequency domain based focusing algorithm;interpolation free wavenumber domain algorithm;range offset;range variant interpolation;stationary X-band transmitter;synthetic aperture radar;target azimuth position;target range migration trajectory;airborne radar;geophysical signal processing;interpolation;radar signal processing;remote sensing by radar;synthetic aperture radar} 
    }
    


  50. U. Wegmuller, D. Walter, V. Spreckels, and Charles L. Werner. Nonuniform Ground Motion Monitoring With TerraSAR-X Persistent Scatterer Interferometry. IEEE Trans. Geosci. Remote Sens., 48(2):895 -904, February 2010. Keyword(s): mining, radar interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar, PSI, TerraSAR-X persistent scatterer interferometry, deep-level mining, nonuniform ground motion monitoring, Differential SAR interferometry (DINSAR), TerraSAR-X, land deformation, mining, persistent scatterer interferometry (PSI);.
    Abstract: In the past, the application of Persistent Scatterer Interferometry (PSI) was primarily possible in the case of slow (less than a few centimeters per year) uniform movements. In this paper, we show how PSI permits the monitoring of relatively fast (including rates up to gt; 50 cm/year) and nonuniform movements using TerraSAR-X repeat observations over deep-level mining. To enable this, parts of the PSI methodology were adapted to the special characteristics of the example studied. Apart from a description of the methodology used and the result achieved, error considerations and a validation of the result with in situ measurements are included.

    @Article{wegmullerWalterSpreckelsWernerTGRS2010NonuniformDefPSI,
    author = {Wegmuller, U. and Walter, D. and Spreckels, V. and Werner, Charles L.},
    title = {Nonuniform Ground Motion Monitoring With {TerraSAR-X} Persistent Scatterer Interferometry},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {2},
    pages = {895 -904},
    month = feb,
    issn = {0196-2892},
    abstract = {In the past, the application of Persistent Scatterer Interferometry (PSI) was primarily possible in the case of slow (less than a few centimeters per year) uniform movements. In this paper, we show how PSI permits the monitoring of relatively fast (including rates up to gt; 50 cm/year) and nonuniform movements using TerraSAR-X repeat observations over deep-level mining. To enable this, parts of the PSI methodology were adapted to the special characteristics of the example studied. Apart from a description of the methodology used and the result achieved, error considerations and a validation of the result with in situ measurements are included.},
    doi = {10.1109/TGRS.2009.2030792},
    file = {:wegmullerWalterSpreckelsWernerTGRS2010NonuniformDefPSI.pdf:PDF},
    keywords = {mining;radar interferometry;remote sensing by radar;spaceborne radar;synthetic aperture radar;PSI;TerraSAR-X persistent scatterer interferometry;deep-level mining;nonuniform ground motion monitoring;Differential SAR interferometry (DINSAR);TerraSAR-X;land deformation;mining;persistent scatterer interferometry (PSI);},
    pdf = {../../../docs/wegmullerWalterSpreckelsWernerTGRS2010NonuniformDefPSI.pdf},
    
    }
    


  51. Meng Wei and David T. Sandwell. Decorrelation of L-Band and C-Band Interferometry Over Vegetated Areas in California. IEEE Trans. Geosci. Remote Sens., 48(7):2942-2952, July 2010. Keyword(s): SAR Processing, Decorrelation, Temporal Decorrelation, Earth crust, faulting, geomorphology, radar interferometry, remote sensing by radar, synthetic aperture radar, vegetation mapping, C-band European Remote Sensing Satellite interferograms, Coast Range area, ERS interferogram, Imperial Valley, L-band Advanced Land Observation Satellite interferograms, Northern California forests, Parkfleld, San Andreas Fault system, Southern California, crustal deformation, decorrelation behavior, decorrelation time, fault creep, interferometric synthetic aperture radar, interseismic deformation, local uplifting signal, near-fault interseismic deformation, sandy surfaces, seasonal acquisitions, signal-to-noise ratio, spatial baseline, spatial baseline lost correlation, temporal baseline, temporal baseline lost correlation, vegetated areas, Correlation, crustal deformation, interferometry, synthetic aperture radar (SAR).
    Abstract: Temporal decorrelation is one of the main limitations for recovering interseismic deformation along the San Andreas Fault system using interferometric synthetic aperture radar. To assess the improved correlation properties of L-band with respect to C-band, we analyzed L-band Advanced Land Observation Satellite (ALOS) interferograms with a range of temporal and spatial baselines over three vegetated areas in California and compared them with corresponding C-band European Remote Sensing Satellite (ERS) interferograms. Over the highly vegetated Northern California forests in the Coast Range area, ALOS remains remarkably well correlated over a 2-year period, whereas an ERS interferogram with a similar temporal and spatial baseline lost correlation. In Central California near Parkfield, we found a similar pattern in decorrelation behavior, which enabled the recovery of a fault creep and a local uplifting signal at L-band that was not apparent at C-band. In the Imperial Valley in Southern California, both ALOS and ERS have low correlation over farmlands. ALOS has lower correlation over some sandy surfaces than ERS, probably due to low signal-to-noise ratio. In general, L-band interferograms with similar seasonal acquisitions have higher correlation than those with dissimilar season. For both L- and C-band, correlation over vegetated areas decreases with time for intervals less than 1 year and then remains relatively constant at longer time intervals. The decorrelation time for L-band is more than 2 years in the forest in California whereas that for C-band is less than 6 months. Overall, these results suggest that L-band interferograms will reveal near-fault interseismic deformation once sufficient data become available.

    @Article{weiSandwellTGRS2010TempDecorrelationLBandCBand,
    author = {Meng Wei and Sandwell, David T.},
    title = {Decorrelation of {L-}Band and {C-}Band Interferometry Over Vegetated Areas in {C}alifornia},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {7},
    pages = {2942-2952},
    month = jul,
    issn = {0196-2892},
    abstract = {Temporal decorrelation is one of the main limitations for recovering interseismic deformation along the San Andreas Fault system using interferometric synthetic aperture radar. To assess the improved correlation properties of L-band with respect to C-band, we analyzed L-band Advanced Land Observation Satellite (ALOS) interferograms with a range of temporal and spatial baselines over three vegetated areas in California and compared them with corresponding C-band European Remote Sensing Satellite (ERS) interferograms. Over the highly vegetated Northern California forests in the Coast Range area, ALOS remains remarkably well correlated over a 2-year period, whereas an ERS interferogram with a similar temporal and spatial baseline lost correlation. In Central California near Parkfield, we found a similar pattern in decorrelation behavior, which enabled the recovery of a fault creep and a local uplifting signal at L-band that was not apparent at C-band. In the Imperial Valley in Southern California, both ALOS and ERS have low correlation over farmlands. ALOS has lower correlation over some sandy surfaces than ERS, probably due to low signal-to-noise ratio. In general, L-band interferograms with similar seasonal acquisitions have higher correlation than those with dissimilar season. For both L- and C-band, correlation over vegetated areas decreases with time for intervals less than 1 year and then remains relatively constant at longer time intervals. The decorrelation time for L-band is more than 2 years in the forest in California whereas that for C-band is less than 6 months. Overall, these results suggest that L-band interferograms will reveal near-fault interseismic deformation once sufficient data become available.},
    doi = {10.1109/TGRS.2010.2043442},
    file = {:weiSandwellTGRS2010TempDecorrelationLBandCBand.pdf:PDF},
    keywords = {SAR Processing, Decorrelation, Temporal Decorrelation, Earth crust;faulting;geomorphology;radar interferometry;remote sensing by radar;synthetic aperture radar;vegetation mapping;C-band European Remote Sensing Satellite interferograms;Coast Range area;ERS interferogram;Imperial Valley;L-band Advanced Land Observation Satellite interferograms;Northern California forests;Parkfleld;San Andreas Fault system;Southern California;crustal deformation;decorrelation behavior;decorrelation time;fault creep;interferometric synthetic aperture radar;interseismic deformation;local uplifting signal;near-fault interseismic deformation;sandy surfaces;seasonal acquisitions;signal-to-noise ratio;spatial baseline;spatial baseline lost correlation;temporal baseline;temporal baseline lost correlation;vegetated areas;Correlation;crustal deformation;interferometry;synthetic aperture radar (SAR)},
    pdf = {../../../docs/weiSandwellTGRS2010TempDecorrelationLBandCBand.pdf},
    
    }
    


  52. Howard A. Zebker, Scott Hensley, Piyush Shanker Agram, and C. Wortham. Geodetically Accurate InSAR Data Processor. IEEE Trans. Geosci. Remote Sens., 48(12):4309-4321, December 2010. Keyword(s): SAR Processing, InSAR data processor, focus correction phase terms, image distortion, interferometric synthetic aperture radar, motion-compensation techniques, orbit tracking, radar echoes, radar interferometry, topography-corrected interferograms, motion compensation, radar interferometry, synthetic aperture radar;.
    Abstract: We present a new interferometric synthetic aperture radar (InSAR) processing approach that capitalizes on the precise orbit tracking that is available with modern radar satellites. Our method uses an accurate orbit information along with motion-compensation techniques to propagate the radar echoes to positions along a noninertial virtual orbit frame in which the location and focusing equations are particularly simple, so that images are focused without requiring autofocus techniques and are computed efficiently. Motion compensation requires two additional focus correction phase terms that are implemented in the frequency domain. If the images from an interferometric pair or stack are all computed along the same reference orbit, flat-Earth topographic correction is not needed, and image coregistration is simplified, obviating many difficulties that are often encountered in InSAR processing. We process several data sets collected by the ALOS PALSAR instrument and find that the geodetic accuracy of the radar images is 10-20 m, with up to 20 m of additional image distortion needed to align 100 km #x00D7; 100 km scenes with reference digital elevation models. We validated the accuracy by using both known radar corner reflector locations and by the registration of the interferograms with digital maps. The topography-corrected interferograms are free from all geometric phase terms, and they clearly show the geophysical observables of crustal deformation, atmospheric phase, and ionospheric phase.

    @Article{zebkerHensleyShankerAgramWortham2010:GeodeticallyAccurateInSARProc,
    author = {Zebker, Howard A. and Hensley, Scott and Shanker Agram, Piyush and Wortham, C.},
    title = {Geodetically Accurate {InSAR} Data Processor},
    journal = {{IEEE} Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {12},
    pages = {4309-4321},
    month = dec,
    issn = {0196-2892},
    abstract = {We present a new interferometric synthetic aperture radar (InSAR) processing approach that capitalizes on the precise orbit tracking that is available with modern radar satellites. Our method uses an accurate orbit information along with motion-compensation techniques to propagate the radar echoes to positions along a noninertial virtual orbit frame in which the location and focusing equations are particularly simple, so that images are focused without requiring autofocus techniques and are computed efficiently. Motion compensation requires two additional focus correction phase terms that are implemented in the frequency domain. If the images from an interferometric pair or stack are all computed along the same reference orbit, flat-Earth topographic correction is not needed, and image coregistration is simplified, obviating many difficulties that are often encountered in InSAR processing. We process several data sets collected by the ALOS PALSAR instrument and find that the geodetic accuracy of the radar images is 10-20 m, with up to 20 m of additional image distortion needed to align 100 km #x00D7; 100 km scenes with reference digital elevation models. We validated the accuracy by using both known radar corner reflector locations and by the registration of the interferograms with digital maps. The topography-corrected interferograms are free from all geometric phase terms, and they clearly show the geophysical observables of crustal deformation, atmospheric phase, and ionospheric phase.},
    doi = {10.1109/TGRS.2010.2051333},
    file = {:zebkerHensleyShankerAgramWortham2010.pdf:PDF},
    keywords = {SAR Processing, InSAR data processor;focus correction phase terms;image distortion;interferometric synthetic aperture radar;motion-compensation techniques;orbit tracking;radar echoes;radar interferometry;topography-corrected interferograms;motion compensation;radar interferometry;synthetic aperture radar;},
    owner = {ofrey},
    pdf = {../../../docs/zebkerHensleyShankerAgramWortham2010.pdf},
    
    }
    


  53. Xiao Xiang Zhu and Richard Bamler. Tomographic SAR Inversion by $L_1$-Norm Regularization --- The Compressive Sensing Approach. IEEE Trans. Geosci. Remote Sens., 48(10):3839-3846, 2010. Keyword(s): SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry, Anisotropic magnetoresistance, Azimuth, Control systems, Image reconstruction, Radar tracking, Reconstruction algorithms, Signal resolution, Spaceborne radar, Synthetic aperture radar, Tomography, image reconstruction, image resolution, radar imaging, radar resolution, remote sensing by radar, spaceborne radar, synthetic aperture radar, 3D imaging, 3D tomographic resolution element, L1-norm regularization, azimuth-range cell, compressive sensing, elevation direction, point localization, spaceborne SAR systems, super-resolution reconstruction algorithm, synthetic aperture radar, tomographic SAR inversion, tomographic elevation resolution, Compressive sensing (CS), TerraSAR-X, differential synthetic aperture radar tomography (D-TomoSAR), urban mapping.
    Abstract: Synthetic aperture radar (SAR) tomography (TomoSAR) extends the synthetic aperture principle into the elevation direction for 3-D imaging. The resolution in the elevation direction depends on the size of the elevation aperture, i.e., on the spread of orbit tracks. Since the orbits of modern meter-resolution spaceborne SAR systems, like TerraSAR-X, are tightly controlled, the tomographic elevation resolution is at least an order of magnitude lower than in range and azimuth. Hence, super-resolution reconstruction algorithms are desired. The high anisotropy of the 3-D tomographic resolution element renders the signals sparse in the elevation direction; only a few pointlike reflections are expected per azimuth-range cell. This property suggests using compressive sensing (CS) methods for tomographic reconstruction. This paper presents the theory of 4-D (differential, i.e., space-time) CS TomoSAR and compares it with parametric (nonlinear least squares) and nonparametric (singular value decomposition) reconstruction methods. Super-resolution properties and point localization accuracies are demonstrated using simulations and real data. A CS reconstruction of a building complex from TerraSAR-X spotlight data is presented.

    @Article{zhuBamlerTGRS2010L1NormCS,
    author = {Xiao Xiang Zhu and Richard Bamler},
    title = {Tomographic {SAR} Inversion by {$L_1$}-Norm Regularization --- The Compressive Sensing Approach},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {10},
    pages = {3839-3846},
    abstract = {Synthetic aperture radar (SAR) tomography (TomoSAR) extends the synthetic aperture principle into the elevation direction for 3-D imaging. The resolution in the elevation direction depends on the size of the elevation aperture, i.e., on the spread of orbit tracks. Since the orbits of modern meter-resolution spaceborne SAR systems, like TerraSAR-X, are tightly controlled, the tomographic elevation resolution is at least an order of magnitude lower than in range and azimuth. Hence, super-resolution reconstruction algorithms are desired. The high anisotropy of the 3-D tomographic resolution element renders the signals sparse in the elevation direction; only a few pointlike reflections are expected per azimuth-range cell. This property suggests using compressive sensing (CS) methods for tomographic reconstruction. This paper presents the theory of 4-D (differential, i.e., space-time) CS TomoSAR and compares it with parametric (nonlinear least squares) and nonparametric (singular value decomposition) reconstruction methods. Super-resolution properties and point localization accuracies are demonstrated using simulations and real data. A CS reconstruction of a building complex from TerraSAR-X spotlight data is presented.},
    doi = {10.1109/TGRS.2010.2048117},
    file = {:zhuBamlerTGRS2010L1NormCS.pdf:PDF},
    keywords = {SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry, Anisotropic magnetoresistance;Azimuth;Control systems; Image reconstruction;Radar tracking;Reconstruction algorithms;Signal resolution;Spaceborne radar; Synthetic aperture radar;Tomography;image reconstruction;image resolution;radar imaging;radar resolution; remote sensing by radar;spaceborne radar;synthetic aperture radar;3D imaging;3D tomographic resolution element; L1-norm regularization;azimuth-range cell;compressive sensing;elevation direction;point localization; spaceborne SAR systems;super-resolution reconstruction algorithm;synthetic aperture radar; tomographic SAR inversion;tomographic elevation resolution;Compressive sensing (CS);TerraSAR-X; differential synthetic aperture radar tomography (D-TomoSAR);urban mapping},
    owner = {ofrey},
    pdf = {../../../docs/zhuBamlerTGRS2010L1NormCS.pdf},
    
    }
    


  54. Xiao Xiang Zhu and Richard Bamler. Very High Resolution Spaceborne SAR Tomography in Urban Environment. IEEE Trans. Geosci. Remote Sens., 48(12):4296-4308, December 2010. Keyword(s): SAR Processing, SAR Tomography, Tomography, Singular Value Decomposition, SVD, InSAR, SAR Interferometry, Interferometry, Apertures, Floors, High-resolution imaging, Image reconstruction, Radar scattering, Reflectivity, Spaceborne radar, Spectral analysis, Tomography, Urban areas, parameter estimation, radar imaging, singular value decomposition, spaceborne SAR, spectral analysis, synthetic aperture radar, tomography, 3D imaging, COSMO-Skymed, TerraSAR-X, TomoSAR, Wiener-type regularization, azimuth-range pixel, elevation direction, maximum a posteriori estimator, meter-resolution spaceborne SAR systems, parametric estimation algorithms, radar reflectivity, reconstructions, singular-value decomposition method, spaceborne SAR data, spectral analysis, synthetic aperture principle, synthetic aperture radar tomography, tomographic reconstruction, urban environment, very high resolution spaceborne SAR tomography, Differential synthetic aperture radar tomography (D-TomoSAR), TerraSAR-X, spotlight SAR, urban mapping;.
    Abstract: Synthetic aperture radar tomography (TomoSAR) extends the synthetic aperture principle into the elevation direction for 3-D imaging. It uses stacks of several acquisitions from slightly different viewing angles (the elevation aperture) to reconstruct the reflectivity function along the elevation direction by means of spectral analysis for every azimuth-range pixel. The new class of meter-resolution spaceborne SAR systems (TerraSAR-X and COSMO-Skymed) offers a tremendous improvement in tomographic reconstruction of urban areas and man-made infrastructure. The high resolution fits well to the inherent scale of buildings (floor height, distance of windows, etc.). This paper demonstrates the tomographic potential of these SARs and the achievable quality on the basis of TerraSAR-X spotlight data of urban environment. A new Wiener-type regularization to the singular-value decomposition method-equivalent to a maximum a posteriori estimator-for TomoSAR is introduced and is extended to the differential case (4-D, i.e., space-time). Different model selection schemes for the estimation of the number of scatterers in a resolution cell are compared and proven to be applicable in practice. Two parametric estimation algorithms of the scatterers' elevation and their velocities are evaluated. First 3-D and 4-D reconstructions of an entire building complex (including its radar reflectivity) with very high level of detail from spaceborne SAR data by pixelwise TomoSAR are presented.

    @Article{zhuBamlerTGRS2010a,
    author = {Xiao Xiang Zhu and Richard Bamler},
    title = {Very High Resolution Spaceborne {SAR} Tomography in Urban Environment},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    year = {2010},
    volume = {48},
    number = {12},
    pages = {4296-4308},
    month = dec,
    issn = {0196-2892},
    abstract = {Synthetic aperture radar tomography (TomoSAR) extends the synthetic aperture principle into the elevation direction for 3-D imaging. It uses stacks of several acquisitions from slightly different viewing angles (the elevation aperture) to reconstruct the reflectivity function along the elevation direction by means of spectral analysis for every azimuth-range pixel. The new class of meter-resolution spaceborne SAR systems (TerraSAR-X and COSMO-Skymed) offers a tremendous improvement in tomographic reconstruction of urban areas and man-made infrastructure. The high resolution fits well to the inherent scale of buildings (floor height, distance of windows, etc.). This paper demonstrates the tomographic potential of these SARs and the achievable quality on the basis of TerraSAR-X spotlight data of urban environment. A new Wiener-type regularization to the singular-value decomposition method-equivalent to a maximum a posteriori estimator-for TomoSAR is introduced and is extended to the differential case (4-D, i.e., space-time). Different model selection schemes for the estimation of the number of scatterers in a resolution cell are compared and proven to be applicable in practice. Two parametric estimation algorithms of the scatterers' elevation and their velocities are evaluated. First 3-D and 4-D reconstructions of an entire building complex (including its radar reflectivity) with very high level of detail from spaceborne SAR data by pixelwise TomoSAR are presented.},
    doi = {10.1109/TGRS.2010.2050487},
    file = {:zhuBamlerTGRS2010a.pdf:PDF},
    keywords = {SAR Processing, SAR Tomography, Tomography, Singular Value Decomposition, SVD, InSAR, SAR Interferometry, Interferometry, Apertures;Floors;High-resolution imaging;Image reconstruction;Radar scattering;Reflectivity; Spaceborne radar;Spectral analysis;Tomography;Urban areas;parameter estimation;radar imaging;singular value decomposition;spaceborne SAR;spectral analysis;synthetic aperture radar;tomography;3D imaging; COSMO-Skymed;TerraSAR-X;TomoSAR;Wiener-type regularization;azimuth-range pixel;elevation direction; maximum a posteriori estimator;meter-resolution spaceborne SAR systems;parametric estimation algorithms; radar reflectivity;reconstructions;singular-value decomposition method;spaceborne SAR data; spectral analysis;synthetic aperture principle;synthetic aperture radar tomography; tomographic reconstruction;urban environment;very high resolution spaceborne SAR tomography; Differential synthetic aperture radar tomography (D-TomoSAR);TerraSAR-X;spotlight SAR;urban mapping;},
    owner = {ofrey},
    pdf = {../../../docs/zhuBamlerTGRS2010a.pdf},
    
    }
    


  55. A. Zymnis, S. Boyd, and E. Candes. Compressed Sensing With Quantized Measurements. IEEE Signal Processing Letters, 17(2):149-152, February 2010. Keyword(s): Gaussian noise, compressed sensing, convex function, first order method, numerical simulation, quantized measurement, sparse signal estimation, Gaussian noise, quantisation (signal), signal processing;.
    Abstract: We consider the problem of estimating a sparse signal from a set of quantized, Gaussian noise corrupted measurements, where each measurement corresponds to an interval of values. We give two methods for (approximately) solving this problem, each based on minimizing a differentiable convex function plus an l 1 regularization term. Using a first order method developed by Hale et al, we demonstrate the performance of the methods through numerical simulation. We find that, using these methods, compressed sensing can be carried out even when the quantization is very coarse, e.g., 1 or 2 bits per measurement.

    @Article{5306135,
    Title = {Compressed Sensing With Quantized Measurements},
    Author = {Zymnis, A. and Boyd, S. and Candes, E.},
    Doi = {10.1109/LSP.2009.2035667},
    ISSN = {1070-9908},
    Month = feb,
    Number = {2},
    Pages = {149-152},
    Volume = {17},
    Year = {2010},
    Abstract = {We consider the problem of estimating a sparse signal from a set of quantized, Gaussian noise corrupted measurements, where each measurement corresponds to an interval of values. We give two methods for (approximately) solving this problem, each based on minimizing a differentiable convex function plus an l 1 regularization term. Using a first order method developed by Hale et al, we demonstrate the performance of the methods through numerical simulation. We find that, using these methods, compressed sensing can be carried out even when the quantization is very coarse, e.g., 1 or 2 bits per measurement.},
    Journal = {IEEE Signal Processing Letters},
    Keywords = {Gaussian noise;compressed sensing;convex function;first order method;numerical simulation;quantized measurement;sparse signal estimation;Gaussian noise;quantisation (signal);signal processing;} 
    }
    


Conference articles

  1. R. Brcic, A. Parizzi, M. Eineder, R. Bamler, and F. Meyer. Estimation and compensation of ionospheric delay for SAR interferometry. In Proc. IEEE Int. Geosci. Remote Sens. Symp., pages 2908-2911, July 2010. Keyword(s): compensation, data acquisition, ionospheric electromagnetic wave propagation, radar interferometry, radiowave propagation, remote sensing by radar, spaceborne radar, synthetic aperture radar, L-band ALOS-PALSAR acquisition, L-band system, SAR interferometry, SAR signal propagation, X-band frequency, dispersive effect, ionospheric delay compensation, ionospheric delay estimation, phase error, spaceborne SAR system, synthetic aperture rada, Azimuth, Bandwidth, Delay, Estimation, Frequency estimation, Ionosphere, L-band, delta-k, ionosphere, split-spectrum, wideband interferometry.
    Abstract: For spaceborne SAR (Synthetic Aperture Radar) systems, the dispersive effects of the ionosphere on the propagation of the SAR signal can be a significant source of phase error. While at X-band frequencies the effects are small, current and future L-band systems would benefit from ionospheric compensation. We consider two ways to estimate the ionospheric delay in SAR signals and evaluate them on L-band ALOS-PALSAR acquisitions.

    @InProceedings{brcicParizziEinederBamlerMeyerIGARSS2010IonoDelayInSAR,
    author = {R. Brcic and A. Parizzi and M. Eineder and R. Bamler and F. Meyer},
    title = {Estimation and compensation of ionospheric delay for {SAR} interferometry},
    booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    year = {2010},
    pages = {2908--2911},
    month = jul,
    abstract = {For spaceborne SAR (Synthetic Aperture Radar) systems, the dispersive effects of the ionosphere on the propagation of the SAR signal can be a significant source of phase error. While at X-band frequencies the effects are small, current and future L-band systems would benefit from ionospheric compensation. We consider two ways to estimate the ionospheric delay in SAR signals and evaluate them on L-band ALOS-PALSAR acquisitions.},
    doi = {10.1109/IGARSS.2010.5652231},
    file = {:brcicParizziEinederBamlerMeyerIGARSS2010IonoDelayInSAR.pdf:PDF},
    issn = {2153-6996},
    keywords = {compensation, data acquisition, ionospheric electromagnetic wave propagation, radar interferometry, radiowave propagation, remote sensing by radar, spaceborne radar, synthetic aperture radar, L-band ALOS-PALSAR acquisition, L-band system, SAR interferometry, SAR signal propagation, X-band frequency, dispersive effect, ionospheric delay compensation, ionospheric delay estimation, phase error, spaceborne SAR system, synthetic aperture rada, Azimuth, Bandwidth, Delay, Estimation, Frequency estimation, Ionosphere, L-band, delta-k, ionosphere, split-spectrum, wideband interferometry},
    owner = {ofrey},
    
    }
    


  2. E. Candes, Xiaodong Li, Yi Ma, and J. Wright. Robust principal component analysis?: Recovering low-rank matrices from sparse errors. In Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop, pages 201-204, October 2010. Keyword(s): bioinformatics, computer vision, low rank data matrix, nonvanishing fraction, nuclear norm, positive fraction, robust principal component analysis, simple convex program, weighted combination, matrix algebra, principal component analysis;.
    Abstract: The problem of recovering a low-rank data matrix from corrupted observations arises in many application areas, including computer vision, system identification, and bioinformatics. Recently it was shown that low-rank matrices satisfying an appropriate incoherence condition can be exactly recovered from non-vanishing fractions of errors by solving a simple convex program, Principal Component Pursuit, which minimizes a weighted combination of the nuclear norm and the #x2113;1 norm of the corruption. Our methodology and results suggest a principled approach to robust principal component analysis, since they show that one can efficiently and exactly recover the principal components of a low-rank data matrix even when a positive fraction of the entries are corrupted. These results extend to the case where a fraction of entries are missing as well.

    @InProceedings{5606734,
    Title = {Robust principal component analysis?: Recovering low-rank matrices from sparse errors},
    Author = {Candes, E. and Xiaodong Li and Yi Ma and Wright, J.},
    Booktitle = {Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop},
    Doi = {10.1109/SAM.2010.5606734},
    Month = oct,
    Pages = {201-204},
    Year = {2010},
    Abstract = {The problem of recovering a low-rank data matrix from corrupted observations arises in many application areas, including computer vision, system identification, and bioinformatics. Recently it was shown that low-rank matrices satisfying an appropriate incoherence condition can be exactly recovered from non-vanishing fractions of errors by solving a simple convex program, Principal Component Pursuit, which minimizes a weighted combination of the nuclear norm and the #x2113;1 norm of the corruption. Our methodology and results suggest a principled approach to robust principal component analysis, since they show that one can efficiently and exactly recover the principal components of a low-rank data matrix even when a positive fraction of the entries are corrupted. These results extend to the case where a fraction of entries are missing as well.},
    ISSN = {1551-2282},
    Keywords = {bioinformatics;computer vision;low rank data matrix;nonvanishing fraction;nuclear norm;positive fraction;robust principal component analysis;simple convex program;weighted combination;matrix algebra;principal component analysis;} 
    }
    


  3. N. Chamberlain, H. Ghaemi, L. Giersch, L. Harcke, R. Hodges, J. Hoffman, W. Johnson, R. Jordan, B. Khayatian, P. Rosen, G. Sadowy, S. Shaffer, Y. Shen, L. Veilleux, and P. Wu. The DESDynI synthetic aperture radar array-fed reflector antenna. In Proc. IEEE Int. Symposium on Phased Array Systems and Technology (ARRAY), pages 381-386, October 2010. Keyword(s): DESDynl, Earth-orbit remote sensing, NASA, SweepSAR, active switched array, array-fed reflector antenna, lidar instruments, patch antenna, radar imaging, synthetic aperture radar antenna, active antenna arrays, aperture antennas, microstrip antenna arrays, radar antennas, reflector antenna feeds, synthetic aperture radar.
    Abstract: DESDynI is a mission being developed by NASA with radar and lidar instruments for Earth-orbit remote sensing. This paper focuses on the design of a large-aperture antenna for the radar instrument. The antenna comprises a deployable reflector antenna and an active switched array of patch elements fed by transmit / receive modules. The antenna and radar architecture facilitates a new mode of synthetic aperture radar imaging called `SweepSAR'. A system-level description of the antenna is provided, along with predictions of antenna performance.

    @InProceedings{chamberlainGhaemiGierschHarckeEtAl2010DESDynI,
    author = {Chamberlain, N. and Ghaemi, H. and Giersch, L. and Harcke, L. and Hodges, R. and Hoffman, J. and Johnson, W. and Jordan, R. and Khayatian, B. and Rosen, P. and Sadowy, G. and Shaffer, S. and Shen, Y. and Veilleux, L. and Wu, P.},
    title = {The {DESDynI} synthetic aperture radar array-fed reflector antenna},
    booktitle = {Proc. IEEE Int. Symposium on Phased Array Systems and Technology (ARRAY)},
    year = {2010},
    pages = {381-386},
    month = oct,
    abstract = {DESDynI is a mission being developed by NASA with radar and lidar instruments for Earth-orbit remote sensing. This paper focuses on the design of a large-aperture antenna for the radar instrument. The antenna comprises a deployable reflector antenna and an active switched array of patch elements fed by transmit / receive modules. The antenna and radar architecture facilitates a new mode of synthetic aperture radar imaging called `SweepSAR'. A system-level description of the antenna is provided, along with predictions of antenna performance.},
    doi = {10.1109/ARRAY.2010.5613339},
    file = {:chamberlainGhaemiGierschHarckeEtAl2010DESDynI.pdf:PDF},
    keywords = {DESDynl;Earth-orbit remote sensing;NASA;SweepSAR;active switched array;array-fed reflector antenna;lidar instruments;patch antenna;radar imaging;synthetic aperture radar antenna;active antenna arrays;aperture antennas;microstrip antenna arrays;radar antennas;reflector antenna feeds;synthetic aperture radar},
    pdf = {../../../docs/chamberlainGhaemiGierschHarckeEtAl2010DESDynI.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5613339},
    
    }
    


  4. G. C. Eastland, T. M. Marston, and P. L. Marston. Evolution of acoustic feature timing and imaging for different cylinder exposures and applications of reversible SAS filtering. In Proc. OCEANS 2010 MTS/IEEE SEATTLE, pages 1-4, September 2010. Keyword(s): acoustic wave scattering, filtering theory, sonar imaging, synthetic aperture sonar, acoustic feature imaging, acoustic feature timing, acoustic paths, acoustic scattering, cylinder exposures, reversible SAS filtering, synthetic aperture sonar, timing slope, Geometry, Imaging, Receivers, Scattering, Synthetic aperture sonar, Timing, Transducers.
    @InProceedings{Eastland2010,
    author = {G. C. Eastland and T. M. Marston and P. L. Marston},
    title = {Evolution of acoustic feature timing and imaging for different cylinder exposures and applications of reversible SAS filtering},
    booktitle = {Proc. OCEANS 2010 MTS/IEEE SEATTLE},
    year = {2010},
    month = sep,
    pages = {1--4},
    doi = {10.1109/OCEANS.2010.5664581},
    issn = {0197-7385},
    keywords = {acoustic wave scattering, filtering theory, sonar imaging, synthetic aperture sonar, acoustic feature imaging, acoustic feature timing, acoustic paths, acoustic scattering, cylinder exposures, reversible SAS filtering, synthetic aperture sonar, timing slope, Geometry, Imaging, Receivers, Scattering, Synthetic aperture sonar, Timing, Transducers},
    owner = {ofrey},
    
    }
    


  5. A. L. Espana, K. L. Williams, S. G. Kargl, M. Zampolli, T. M. Marston, and P. L. Marston. Measurements and modeling of the acoustic scattering from an aluminum pipe in the free field and in contact with a sand sediment. In Proc. OCEANS 2010 MTS/IEEE SEATTLE, pages 1-5, September 2010. Keyword(s): acoustic wave scattering, finite element analysis, sediments, sonar imaging, spatial filters, synthetic aperture sonar, FE calculation, SAS images, acoustic scattering measurement, acoustic scattering modeling, aluminum pipe, elastic contribution, elastic response, finite element model, flattened sand sediment, free field, fresh water pond, monostatic scattering, spatial filter boundary, specular response, synthetic aperture sonar techniques, target strength, Aluminum, Arrays, Finite element methods, Rails, Scattering, Sediments, Synthetic aperture sonar.
    @InProceedings{Espana2010,
    author = {A. L. Espana and K. L. Williams and S. G. Kargl and M. Zampolli and T. M. Marston and P. L. Marston},
    title = {Measurements and modeling of the acoustic scattering from an aluminum pipe in the free field and in contact with a sand sediment},
    booktitle = {Proc. OCEANS 2010 MTS/IEEE SEATTLE},
    year = {2010},
    month = sep,
    pages = {1--5},
    doi = {10.1109/OCEANS.2010.5664603},
    issn = {0197-7385},
    keywords = {acoustic wave scattering, finite element analysis, sediments, sonar imaging, spatial filters, synthetic aperture sonar, FE calculation, SAS images, acoustic scattering measurement, acoustic scattering modeling, aluminum pipe, elastic contribution, elastic response, finite element model, flattened sand sediment, free field, fresh water pond, monostatic scattering, spatial filter boundary, specular response, synthetic aperture sonar techniques, target strength, Aluminum, Arrays, Finite element methods, Rails, Scattering, Sediments, Synthetic aperture sonar},
    owner = {ofrey},
    
    }
    


  6. Othmar Frey. SAR Imaging in the Time-Domain for Nonlinear Sensor Trajectories and SAR Tomography. In Proc. CEOS SAR Calibration and Validation Workshop, Zurich, Switzerland, August 2010. Note: Abstract.
    @InProceedings{freyCEOSAbstract2010:Tomo,
    Title = {SAR Imaging in the Time-Domain for Nonlinear Sensor Trajectories and SAR Tomography},
    Author = {Othmar Frey},
    Booktitle = {Proc. CEOS SAR Calibration and Validation Workshop},
    Month = aug,
    Note = {Abstract.},
    Year = {2010},
    Address = {Zurich, Switzerland},
    Owner = {ofrey} 
    }
    


  7. Othmar Frey and Erich Meier. 3D SAR Imaging of a Forest Using Airborne MB-SAR Data at L- and P-Band: Data Processing and Analysis. In Proc. EUSAR 2010 - 8th European Conference on Synthetic Aperture Radar, pages 166-169, 2010. Keyword(s): Airborne radar, Array signal processing, Capon, Capon beamformer, L-band, P-band, SAR processing, SAR tomography, beamforming, Focusing, forestry, interferometry, InSAR, multibaseline, multiple signal classification, MUSIC, polarimetry, Remote Sensing, synthetic aperture radar, SAR, three-dimensional imaging, 3-D imaging, time-domain back-projection, TDBP, tomography, Vegetation.
    Abstract: Using a time-domain back-projection based focusing algorithm in combination with three tomographic focusing techniques (multilook standard beamforming, robust Capon beamforming, and MUSIC) a 3D volume containing a forested area has been tomographically imaged at L- and P-band. In this paper, we present further results and insights obtained by processing and analyzing these data sets with respect to the localization of the scattering sources using the three different focusing techniques, as well as for both, the two frequency bands and the different polarimetric channels.

    @InProceedings{freyMeierEUSAR2010:Tomo,
    author = {Othmar Frey and Erich Meier},
    title = {{3D} {SAR} Imaging of a Forest Using Airborne {MB-SAR} Data at {L-} and {P-}Band: Data Processing and Analysis},
    booktitle = {Proc. EUSAR 2010 - 8th European Conference on Synthetic Aperture Radar},
    year = {2010},
    pages = {166-169},
    abstract = {Using a time-domain back-projection based focusing algorithm in combination with three tomographic focusing techniques (multilook standard beamforming, robust Capon beamforming, and MUSIC) a 3D volume containing a forested area has been tomographically imaged at L- and P-band. In this paper, we present further results and insights obtained by processing and analyzing these data sets with respect to the localization of the scattering sources using the three different focusing techniques, as well as for both, the two frequency bands and the different polarimetric channels.},
    file = {:freyMeierEUSAR2010.pdf:PDF},
    keywords = {Airborne radar, Array signal processing, Capon, Capon beamformer, L-band, P-band, SAR processing, SAR tomography, beamforming, Focusing, forestry, interferometry, InSAR, multibaseline, multiple signal classification, MUSIC, polarimetry, Remote Sensing, synthetic aperture radar, SAR, three-dimensional imaging, 3-D imaging, time-domain back-projection, TDBP, tomography, Vegetation},
    pdf = {http://www.ifu-sar.ethz.ch/otfrey/SARbibliography/myPapers/freyMeierEUSAR2010.pdf},
    
    }
    


  8. Othmar Frey and Erich Meier. Analyzing Tomographic SAR Data of a Forest With Respect to Frequency, Polarization, and Focusing Techniques. In Proc. IEEE Int. Geosci. Remote Sens. Symp., pages 150-153, July 2010. Note: Invited Paper. Keyword(s): Airborne radar, Array signal processing, Capon, Capon beamformer, L-band, P-band, SAR processing, SAR tomography, beamforming, Focusing, forestry, interferometry, InSAR, multibaseline, multiple signal classification, MUSIC, polarimetry, Remote Sensing, synthetic aperture radar, SAR, three-dimensional imaging, 3-D imaging, time-domain back-projection, TDBP, tomography, Vegetation.
    Abstract: In this paper, two fully-polarimetric tomographic SAR data sets of a forested area, at L-band and P-band, are analyzed with respect to the localization of scattering sources and scattering mechanisms. In particular, the 3D SAR data is examined regarding the performance of three different tomographic focusing techniques multilook standard beamforming, robust Capon beamforming, and MUSIC, as well as for both, the two frequency bands and the different polarimetric channels.

    @InProceedings{freyMeier2010Igarss:Tomo,
    author = {Othmar Frey and Erich Meier},
    title = {Analyzing Tomographic {SAR} Data of a Forest With Respect to Frequency, Polarization, and Focusing Techniques},
    booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    year = {2010},
    pages = {150-153},
    month = jul,
    note = {Invited Paper},
    abstract = {In this paper, two fully-polarimetric tomographic SAR data sets of a forested area, at L-band and P-band, are analyzed with respect to the localization of scattering sources and scattering mechanisms. In particular, the 3D SAR data is examined regarding the performance of three different tomographic focusing techniques multilook standard beamforming, robust Capon beamforming, and MUSIC, as well as for both, the two frequency bands and the different polarimetric channels.},
    file = {:freyMeierIGARSS2010.pdf:PDF},
    keywords = {Airborne radar, Array signal processing, Capon, Capon beamformer, L-band, P-band, SAR processing, SAR tomography, beamforming, Focusing, forestry, interferometry, InSAR, multibaseline, multiple signal classification, MUSIC, polarimetry, Remote Sensing, synthetic aperture radar, SAR, three-dimensional imaging, 3-D imaging, time-domain back-projection, TDBP, tomography, Vegetation},
    pdf = {http://www.ifu-sar.ethz.ch/otfrey/SARbibliography/myPapers/freyMeierIGARSS2010.pdf},
    url = {http://ieeexplore.ieee.org/iel5/5639672/5648802/05654438.pdf},
    
    }
    


  9. LeRoy A. Gorham and Brian D. Rigling. Dual format algorithm for monostatic SAR. In Edmund G. Zelnio and Frederick D. Garber, editors, , volume 7699, pages 769905, 2010. SPIE. Keyword(s): SAR Processing, Dual Format Algorithm, DFA, Polar Format Algorithm, PFA, Spotlight SAR, Spotlight-mode data.
    @Conference{gorhamRiglingDualFormatAlgorithm2010,
    author = {LeRoy A. Gorham and Brian D. Rigling},
    title = {Dual format algorithm for monostatic SAR},
    year = {2010},
    editor = {Edmund G. Zelnio and Frederick D. Garber},
    volume = {7699},
    number = {1},
    pages = {769905},
    publisher = {SPIE},
    doi = {10.1117/12.855374},
    eid = {769905},
    file = {:gorhamRiglingDualFormatAlgorithm2010.pdf:PDF},
    journal = {Algorithms for Synthetic Aperture Radar Imagery XVII},
    keywords = {SAR Processing, Dual Format Algorithm, DFA, Polar Format Algorithm, PFA, Spotlight SAR, Spotlight-mode data},
    location = {Orlando, Florida, USA},
    numpages = {6},
    owner = {ofrey},
    pdf = {../../../docs/jakowatzWahlYockyBrayBowRichardsSpotlightComparisonOfAlgorithms2004.pdf},
    url = {http://link.aip.org/link/?PSI/7699/769905/1},
    
    }
    


  10. S. Hantscher, S. Lang, M. Hägelen, and H. Essen. 94 GHz person scanner with circular aperture as part of a new sensor concept on airports. In International Radar Symposium, pages 1-4, June 2010. Keyword(s): SAR Processing, W-Band, Fraunhofer, Airports, Apertures, Radar imaging, Radar tracking, Security, Synthetic aperture radar, Airport security, Radar, Synthetic Aperture Radar.
    Abstract: In the following paper, a new concept for increasing the aiport security is proposed. As a part of this innovative system, a W-band person scanner with a circular aperture for 360 deg scans has been built up. The usage of the Synthetic Aperture Radar (SAR) principle allows the detection of concealed objects with a resolution of 3mm in azimuth and 3 cm in range direction.

    @INPROCEEDINGS{hantscherLangHaegelenEssenIRS2010WBANDPersonScanner,
    author={S. Hantscher and S. Lang and M. H\"agelen and H. Essen},
    booktitle={International Radar Symposium},
    title={94 GHz person scanner with circular aperture as part of a new sensor concept on airports},
    year={2010},
    volume={},
    number={},
    pages={1-4},
    abstract={In the following paper, a new concept for increasing the aiport security is proposed. As a part of this innovative system, a W-band person scanner with a circular aperture for 360 deg scans has been built up. The usage of the Synthetic Aperture Radar (SAR) principle allows the detection of concealed objects with a resolution of 3mm in azimuth and 3 cm in range direction.},
    keywords={SAR Processing, W-Band, Fraunhofer,Airports;Apertures;Radar imaging;Radar tracking;Security;Synthetic aperture radar;Airport security;Radar;Synthetic Aperture Radar},
    doi={},
    ISSN={2155-5745},
    month=jun,
    owner = {ofrey},
    
    }
    


  11. Leif Harcke, L. Weintraub, Sang-Ho Yun, R. Dickinson, E. Gurrola, Scott Hensley, and N. Marechal. Spotlight-mode synthetic aperture radar processing for high-resolution lunar mapping. In Proc. IEEE Radar Conference, pages 1260-1264, May 2010. Keyword(s): AD 2008 to 2009, Goldstone Solar System Radar, NASA LCROSS mission impact site, autofocus technique, time-domain back-projection, bistatic time-domain backprojection technique, bistatic SAR, change detection techniques, fast-time Doppler removal, focus-plane motion, geolocation, high-resolution lunar mapping, local topography, lunar poles, phase errors, polar format algorithm, preprocessing system, radar interferometry, radar mapping, resolution cells, spotlight imaging techniques, spotlight-mode synthetic aperture radar processing, topographic mapping, geophysical equipment, radar interferometry, remote sensing by radar, synthetic aperture radar.
    Abstract: During the 2008-2009 year, the Goldstone Solar System Radar was upgraded to support radar mapping of the lunar poles at 4 m resolution. The finer resolution of the new system and the accompanying migration through resolution cells called for spotlight, rather than delay-Doppler, imaging techniques. A new pre-processing system supports fast-time Doppler removal and motion compensation to a point. Two spotlight imaging techniques which compensate for phase errors due to (i) out of focus-plane motion of the radar and (ii) local topography, have been implemented and tested. One is based on the polar format algorithm followed by a unique autofocus technique, the other is a full bistatic time-domain backprojection technique. The processing system yields imagery of the specified resolution. Products enabled by this new system include topographic mapping through radar interferometry, and change detection techniques (amplitude and coherent change) for geolocation of the NASA LCROSS mission impact site.

    @InProceedings{harckeWeintraubYunDickinsonGurrolaHensleyMarechal2010,
    author = {Harcke, Leif and Weintraub, L. and Sang-Ho Yun and Dickinson, R. and Gurrola, E. and Hensley, Scott and Marechal, N.},
    title = {Spotlight-mode synthetic aperture radar processing for high-resolution lunar mapping},
    booktitle = {Proc. IEEE Radar Conference},
    year = {2010},
    pages = {1260-1264},
    month = may,
    abstract = {During the 2008-2009 year, the Goldstone Solar System Radar was upgraded to support radar mapping of the lunar poles at 4 m resolution. The finer resolution of the new system and the accompanying migration through resolution cells called for spotlight, rather than delay-Doppler, imaging techniques. A new pre-processing system supports fast-time Doppler removal and motion compensation to a point. Two spotlight imaging techniques which compensate for phase errors due to (i) out of focus-plane motion of the radar and (ii) local topography, have been implemented and tested. One is based on the polar format algorithm followed by a unique autofocus technique, the other is a full bistatic time-domain backprojection technique. The processing system yields imagery of the specified resolution. Products enabled by this new system include topographic mapping through radar interferometry, and change detection techniques (amplitude and coherent change) for geolocation of the NASA LCROSS mission impact site.},
    doi = {10.1109/RADAR.2010.5494426},
    file = {:harckeWeintraubYunDickinsonGurrolaHensleyMarechal2010.pdf:PDF},
    issn = {1097-5659},
    keywords = {AD 2008 to 2009;Goldstone Solar System Radar;NASA LCROSS mission impact site;autofocus technique;time-domain back-projection, bistatic time-domain backprojection technique; bistatic SAR, change detection techniques;fast-time Doppler removal;focus-plane motion;geolocation;high-resolution lunar mapping;local topography;lunar poles;phase errors;polar format algorithm;preprocessing system;radar interferometry;radar mapping;resolution cells;spotlight imaging techniques;spotlight-mode synthetic aperture radar processing;topographic mapping;geophysical equipment;radar interferometry;remote sensing by radar;synthetic aperture radar},
    pdf = {../../../docs/harckeWeintraubYunDickinsonGurrolaHensleyMarechal2010.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5494426},
    
    }
    


  12. Hans Hellsten, Patrick Dammert, and Anders Ahlander. Autofocus in fast factorized backprojection for processing of SAR images when geometry parameters are unknown. In Proc. IEEE Radar Conf., pages 603-608, May 2010. Keyword(s): SAR Processing, Autofocus, Time-Domain Back-Projection, TDBP, FFBP, SAR image processing, antenna path parameters, autofocus, fast factorized backprojection, radar imaging, synthetic aperture radar.
    Abstract: This paper introduces a new autofocus method for high-resolution SAR systems. The new method relies on varying antenna path parameters, i.e. the cause of the focusing problem. The variation and determination of antenna path parameters is computed and structured by incorporating the method into the framework of fast factorized backprojection, and thus also blending deterministic focus and autofocus into one method. The new autofocus has been tested with wavelength-resolution SAR data with good results.

    @InProceedings{hellstenDammertAhlander2010AutofocusFFBP,
    author = {Hellsten, Hans and Dammert, Patrick and Ahlander, Anders},
    title = {Autofocus in fast factorized backprojection for processing of {SAR} images when geometry parameters are unknown},
    booktitle = {Proc. IEEE Radar Conf.},
    year = {2010},
    pages = {603-608},
    month = may,
    abstract = {This paper introduces a new autofocus method for high-resolution SAR systems. The new method relies on varying antenna path parameters, i.e. the cause of the focusing problem. The variation and determination of antenna path parameters is computed and structured by incorporating the method into the framework of fast factorized backprojection, and thus also blending deterministic focus and autofocus into one method. The new autofocus has been tested with wavelength-resolution SAR data with good results.},
    doi = {10.1109/RADAR.2010.5494549},
    file = {:hellstenDammertAhlander2010AutofocusFFBP.pdf:PDF},
    issn = {1097-5659},
    keywords = {SAR Processing, Autofocus, Time-Domain Back-Projection, TDBP, FFBP, SAR image processing;antenna path parameters;autofocus;fast factorized backprojection;radar imaging;synthetic aperture radar},
    pdf = {../../../docs/hellstenDammertAhlander2010AutofocusFFBP.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5494549},
    
    }
    


  13. Scott Hensley, E. Gurrola, Leif Harcke, M. Slade, K. Quirk, M. Srinivasan, C. Lee, Sang-Ho Yun, J. Jao, B. Wilson, E. De Jong, N. Marechal, L. Weintraub, R. Dickinson, R. Bloom, G. Karamyan, and A. Lilje. Lunar topographic mapping using a new high resolution mode for the GSSR radar. In Proc. IEEE Radar Conference, pages 464-469, May 2010. Keyword(s): Doppler image formation technique, Earth based radar interferometric measurement, Goldstone Solar System Radar, Moon topography mapping, autofocusing method, bandwidth 40 MHz, geodetic control, high resolution mode, interferograms, lidar topography maps, lunar topographic mapping, lunar topographic maps, range image formation technique, spotlight mode processing, Doppler radar, Moon, astronomical image processing, image resolution, optical radar, radar imaging, radar interferometry, radar resolution.
    Abstract: Mapping the Moon's topography using Earth based radar interferometric measurements by the Goldstone Solar System Radar (GSSR) has been done several times since the mid 1990s. In 2008 we reported at this conference the generation of lunar topographic maps having approximately 4 m height accuracy at a horizontal posting of 40 m. Since then GSSR radar has been improved to allow 40 MHz bandwidth imaging and consequently obtained images and interferograms with a resolution of about 4 m in range by 5 m in azimuth. The long synthetic aperture times of approximately 90 minutes in duration necessitated a migration from range/Doppler image formation techniques to spotlight mode processing and autofocusing methods. The improved resolution imagery should permit the generation of topographic maps with a factor of two better spatial resolution with about same height accuracy. Coupled the with the recent availability of new lidar topography maps of the lunar surface made by orbiting satellites of Japan and the United States the geodetic control of the radar generated maps products can be improved dramatically. This paper will discuss the hardware and software improvements made to the GSSR and present some of the new high resolution products.

    @InProceedings{hensleyGurrolaHarckeSladeEtAl2010LunarTopoMapping,
    author = {Hensley, Scott and Gurrola, E. and Harcke, Leif and Slade, M. and Quirk, K. and Srinivasan, M. and Lee, C. and Sang-Ho Yun and Jao, J. and Wilson, B. and De Jong, E. and Marechal, N. and Weintraub, L. and Dickinson, R. and Bloom, R. and Karamyan, G. and Lilje, A.},
    title = {Lunar topographic mapping using a new high resolution mode for the {GSSR} radar},
    booktitle = {Proc. IEEE Radar Conference},
    year = {2010},
    pages = {464-469},
    month = may,
    abstract = {Mapping the Moon's topography using Earth based radar interferometric measurements by the Goldstone Solar System Radar (GSSR) has been done several times since the mid 1990s. In 2008 we reported at this conference the generation of lunar topographic maps having approximately 4 m height accuracy at a horizontal posting of 40 m. Since then GSSR radar has been improved to allow 40 MHz bandwidth imaging and consequently obtained images and interferograms with a resolution of about 4 m in range by 5 m in azimuth. The long synthetic aperture times of approximately 90 minutes in duration necessitated a migration from range/Doppler image formation techniques to spotlight mode processing and autofocusing methods. The improved resolution imagery should permit the generation of topographic maps with a factor of two better spatial resolution with about same height accuracy. Coupled the with the recent availability of new lidar topography maps of the lunar surface made by orbiting satellites of Japan and the United States the geodetic control of the radar generated maps products can be improved dramatically. This paper will discuss the hardware and software improvements made to the GSSR and present some of the new high resolution products.},
    doi = {10.1109/RADAR.2010.5494575},
    file = {:hensleyGurrolaHarckeSladeEtAl2010LunarTopoMapping.pdf:PDF},
    issn = {1097-5659},
    keywords = {Doppler image formation technique;Earth based radar interferometric measurement;Goldstone Solar System Radar;Moon topography mapping;autofocusing method;bandwidth 40 MHz;geodetic control;high resolution mode;interferograms;lidar topography maps;lunar topographic mapping;lunar topographic maps;range image formation technique;spotlight mode processing;Doppler radar;Moon;astronomical image processing;image resolution;optical radar;radar imaging;radar interferometry;radar resolution},
    pdf = {../../../docs/hensleyGurrolaHarckeSladeEtAl2010LunarTopoMapping.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5494575},
    
    }
    


  14. Yue Huang, Laurent Ferro-Famil, and Andreas Reigber. Under foliage object imaging using SAR tomography and polarimetric spectral estimators. In Proc. EUSAR, pages 1-4, June 2010. Keyword(s): SAR Processing, SAR Tomography, Forestry, FOPEN, Tomography.
    Abstract: This paper addresses the imaging of objects located under a forest cover using Polarimetric SAR Tomography (POLTOM-SAR) at L band. High-Resolution (HR) spectral estimators, able to accurately separate multiple scattering centers in the vertical direction, are used to separate the response of objects and vehicles embedded in a volumetric background. Polarimetric spectral analysis techniques are introduced, and are shown to both improve the estimation accuracy of the vertical position of artificial scatterers and natural environments and provide optimal polarimetric features that may be used to further characterize the media under analysis. The effectiveness of the proposed approaches is demonstrated using tomograms derived from fully polarimetric L-band airborne data acquired by DLR's E-SAR system over the test site of Dornstetten, Germany.

    @InProceedings{huangFerroFamilReigberEUSAR2010:Tomo,
    Title = {Under foliage object imaging using {SAR} tomography and polarimetric spectral estimators},
    Author = {Huang, Yue and Ferro-Famil, Laurent and Reigber, Andreas},
    Booktitle = {Proc. EUSAR},
    Month = jun,
    Pages = {1-4},
    Year = {2010},
    Abstract = {This paper addresses the imaging of objects located under a forest cover using Polarimetric SAR Tomography (POLTOM-SAR) at L band. High-Resolution (HR) spectral estimators, able to accurately separate multiple scattering centers in the vertical direction, are used to separate the response of objects and vehicles embedded in a volumetric background. Polarimetric spectral analysis techniques are introduced, and are shown to both improve the estimation accuracy of the vertical position of artificial scatterers and natural environments and provide optimal polarimetric features that may be used to further characterize the media under analysis. The effectiveness of the proposed approaches is demonstrated using tomograms derived from fully polarimetric L-band airborne data acquired by DLR's E-SAR system over the test site of Dornstetten, Germany.},
    Keywords = {SAR Processing, SAR Tomography, Forestry, FOPEN, Tomography} 
    }
    


  15. Charles V. Jakowatz, Daniel E. Wahl, and David A. Yocky. A beamforming algorithm for bistatic SAR image formation. In Edmund G. Zelnio and Frederick D. Garber, editors, , volume 7699, pages 769902, 2010. SPIE. Keyword(s): SAR Processing, Bistatic SAR, Bistatic Spotlight-mode SAR, Autofocus, Autofocus in the TDBP Framework, Back-projection, Time-Domain Back-Projection, TDBP, Fast Back-projection, Fast Factorized Back-Projection, FFBP, Spotlight SAR, Spotlight-mode data, Beamforming.
    @Conference{jakowatzWahlYockyBeamformingBistatic2010,
    author = {Charles V. Jakowatz and Daniel E. Wahl and David A. Yocky},
    title = {A beamforming algorithm for bistatic SAR image formation},
    year = {2010},
    editor = {Edmund G. Zelnio and Frederick D. Garber},
    volume = {7699},
    number = {1},
    pages = {769902},
    publisher = {SPIE},
    doi = {10.1117/12.851871},
    eid = {769902},
    file = {:jakowatzWahlYockyBeamformingBistatic2010.pdf:PDF},
    journal = {Algorithms for Synthetic Aperture Radar Imagery XVII},
    keywords = {SAR Processing, Bistatic SAR, Bistatic Spotlight-mode SAR, Autofocus, Autofocus in the TDBP Framework, Back-projection, Time-Domain Back-Projection, TDBP, Fast Back-projection, Fast Factorized Back-Projection, FFBP, Spotlight SAR, Spotlight-mode data, Beamforming},
    location = {Orlando, Florida, USA},
    numpages = {6},
    owner = {ofrey},
    pdf = {../../../docs/jakowatzWahlYockyBeamformingBistatic2010.pdf},
    url = {http://link.aip.org/link/?PSI/7699/769902/1},
    
    }
    


  16. Fabrizio Lombardini, Francesco Cai, and Matteo Pardini. Tomographic Analyses of Non-stationary Volumetric Scattering. In Proc. EUSAR, pages 1-4, June 2010. Keyword(s): SAR Processing, SAR Tomography, Forestry, Tomography.
    Abstract: Much interest is continuing to grow in the advanced differential tomography framework which crosses differential SAR interferometry with 3D multibaseline tomography, producing `space-time' signatures of scattering dynamics in the SAR cell. In this paper, the important effect of temporal decorrelation during the repeat pass multibaseline acquisition is analyzed on superresolution (MUSIC) tomography. Moreover, a differential tomographic processor is proposed to get the new functionalities of forest volume tomography robust to temporal decorrelation, and of subcanopy ground subsidence monitoring. To this aim, a generalized MUSIC method matched to non line spectra is adapted to the 2-D domain. Simulated and first airborne real data results prove the concept.

    @InProceedings{lombardiniCaiPardiniEUSAR2010:Tomo,
    Title = {Tomographic Analyses of Non-stationary Volumetric Scattering},
    Author = {Lombardini, Fabrizio and Cai, Francesco and Pardini, Matteo},
    Booktitle = {Proc. EUSAR},
    Month = jun,
    Pages = {1-4},
    Year = {2010},
    Abstract = {Much interest is continuing to grow in the advanced differential tomography framework which crosses differential SAR interferometry with 3D multibaseline tomography, producing `space-time' signatures of scattering dynamics in the SAR cell. In this paper, the important effect of temporal decorrelation during the repeat pass multibaseline acquisition is analyzed on superresolution (MUSIC) tomography. Moreover, a differential tomographic processor is proposed to get the new functionalities of forest volume tomography robust to temporal decorrelation, and of subcanopy ground subsidence monitoring. To this aim, a generalized MUSIC method matched to non line spectra is adapted to the 2-D domain. Simulated and first airborne real data results prove the concept.},
    Keywords = {SAR Processing, SAR Tomography, Forestry, Tomography} 
    }
    


  17. T. M. Marston, P. L. Marston, and K. L. Williams. Scattering resonances, filtering with reversible SAS processing, and applications of quantitative ray theory. In Proc. OCEANS 2010 MTS/IEEE SEATTLE, pages 1-9, September 2010. Keyword(s): acoustic wave scattering, deconvolution, elasticity, feature extraction, geophysical image processing, image classification, sonar imaging, spatial filters, synthetic aperture sonar, SAS image processing, acoustic spectral content, deconvolution, elasticity, hybrid processing technique, image classification, quantitative ray theory, scattering resonance, spatial filter, spectral feature, structural resonance, synthetic aperture sonar, Aluminum, Approximation methods, Backscatter, Feature extraction, Scattering, Synthetic aperture sonar.
    @InProceedings{Marston2010,
    author = {T. M. Marston and P. L. Marston and K. L. Williams},
    title = {Scattering resonances, filtering with reversible SAS processing, and applications of quantitative ray theory},
    booktitle = {Proc. OCEANS 2010 MTS/IEEE SEATTLE},
    year = {2010},
    month = sep,
    pages = {1--9},
    doi = {10.1109/OCEANS.2010.5664606},
    issn = {0197-7385},
    keywords = {acoustic wave scattering, deconvolution, elasticity, feature extraction, geophysical image processing, image classification, sonar imaging, spatial filters, synthetic aperture sonar, SAS image processing, acoustic spectral content, deconvolution, elasticity, hybrid processing technique, image classification, quantitative ray theory, scattering resonance, spatial filter, spectral feature, structural resonance, synthetic aperture sonar, Aluminum, Approximation methods, Backscatter, Feature extraction, Scattering, Synthetic aperture sonar},
    owner = {ofrey},
    
    }
    


  18. Josef Mittermayer, Pau Prats, Davide D'Aria, Riccardo Piantanida, S. Sauer, Andrea Monti Guarnieri, Evert Attema, and Paul Snoeij. TOPS Sentinel-1 and TerraSAR-X Processor Comparison based on Simulated Data. In Synthetic Aperture Radar (EUSAR), 2010 8th European Conference on, pages 1-4, June 2010. Keyword(s): SAR Processing, TOPS, Terrain Observation by Progressive Scans, Antennas, Azimuth, Chirp, Floors, Image resolution, Noise, Remote sensing.
    Abstract: The paper reports about the comparison of the Sentinel-1 Prototype TOPS Processor with the Experimental TerraSAR-X TOPS processor. The comparison is based on simulated raw data generated from TerraSAR-X and Sentinel-1 parameter scenarios. Fundamental impulse response parameters were investigated in point target scenarios. Scenarios with point targets on top a noise floor allowed for comparison of burst images by means of a cross-interferogram. The comparison shows good accordance between the processing results from both processors.

    @InProceedings{mittermayerPratsdAriaPiantanidaSauerMontiGuarnieriAttemaSnoeijEUSAR2010TOPSSentinelVsTerraSARX,
    author = {Mittermayer, Josef and Prats, Pau and D'Aria, Davide and Piantanida, Riccardo and Sauer, S. and Guarnieri, Andrea Monti and Attema, Evert and Snoeij, Paul},
    title = {TOPS Sentinel-1 and TerraSAR-X Processor Comparison based on Simulated Data},
    booktitle = {Synthetic Aperture Radar (EUSAR), 2010 8th European Conference on},
    year = {2010},
    pages = {1-4},
    month = {June},
    abstract = {The paper reports about the comparison of the Sentinel-1 Prototype TOPS Processor with the Experimental TerraSAR-X TOPS processor. The comparison is based on simulated raw data generated from TerraSAR-X and Sentinel-1 parameter scenarios. Fundamental impulse response parameters were investigated in point target scenarios. Scenarios with point targets on top a noise floor allowed for comparison of burst images by means of a cross-interferogram. The comparison shows good accordance between the processing results from both processors.},
    file = {:mittermayerPratsdAriaPiantanidaSauerMontiGuarnieriAttemaSnoeijEUSAR2010TOPSSentinelVsTerraSARX.pdf:PDF},
    keywords = {SAR Processing, TOPS, Terrain Observation by Progressive Scans,Antennas;Azimuth;Chirp;Floors;Image resolution;Noise;Remote sensing},
    pdf = {../../../docs/mittermayerPratsdAriaPiantanidaSauerMontiGuarnieriAttemaSnoeijEUSAR2010TOPSSentinelVsTerraSARX.pdf},
    
    }
    


  19. D. Reale, G. Fornaro, A. Pauciullo, Xiao Xiang Zhu, N. Adam, and R. Bamler. Advanced techniques and new high resolution SAR sensors for monitoring urban areas. In Proc. IEEE Int. Geoscience and Remote Sensing Symp. (IGARSS), pages 1800-1803, 2010.
    @InProceedings{Reale2010,
    Title = {Advanced techniques and new high resolution SAR sensors for monitoring urban areas},
    Author = {Reale, D. and Fornaro, G. and Pauciullo, A. and Zhu, Xiao Xiang and Adam, N. and Bamler, R.},
    Booktitle = {Proc. IEEE Int. Geoscience and Remote Sensing Symp. (IGARSS)},
    Doi = {10.1109/IGARSS.2010.5652309},
    Pages = {1800--1803},
    Year = {2010},
    Owner = {ofrey} 
    }
    


  20. Paul A. Rosen, Scott Hensley, and Curtis Chen. Measurement and mitigation of the ionosphere in L-band Interferometric SAR data. In 2010 IEEE Radar Conference, pages 1459-1463, May 2010. Keyword(s): SAR Processing, cartography, image registration, ionosphere, ionospheric measuring apparatus, radar imaging, radar interferometry, synthetic aperture radar, ALOS PALSAR data, L-band InSAR data, PALSAR spectral band, bandwidth 28 MHz, deformation maps, differential TEC estimation, dispersive medium, earth changing surface, image registration, ionosphere measurement, ionosphere mitigation, multifrequency split-spectrum processing technique, nondispersive effects, pixel-by-pixel observation, radar waveform, relative phase change measurement, satellite-based repeat-pass interferometric synthetic aperture radar, split spectrum technique, subtle deformation signatures, synoptic high spatial resolution, Atmosphere, Atmospheric measurements, Delay effects, Dispersion, Earth, Ionosphere, L-band, Phase measurement, Spatial resolution, Synthetic aperture radar interferometry.
    Abstract: Satellite-based repeat-pass Interferometric Synthetic Aperture Radar (InSAR) provides a synoptic high spatial resolution perspective of Earth's changing surface, permitting one to view large areas quickly and efficiently. By measuring relative phase change from one observation to the next on a pixel-by-pixel basis, maps of deformation and change can be derived. Variability of the atmosphere and the ionosphere leads to phase/time delays that are present in the data that can mask many of the subtle deformation signatures of interest, so methods for mitigation of these effects are important. Many of these effects have been observed in existing ALOS PALSAR data, and studies are underway to characterize and mitigate the ionosphere using these data. Since the ionosphere is a dispersive medium, it is possible in principle distinguish the ionospheric signatures from the non-dispersive effects of deformation and the atmosphere. In this paper, we describe a method for mapping the ionosphere in InSAR data based on a multi-frequency split-spectrum processing technique. We examine a number of PALSAR data sets, including fully polarimetric and single-polarization 28 MHz bandwidth data, where anomalous effects in phase, amplitude and image registration have been observed. We demonstrate the estimation of the ionosphere by means of the split spectrum technique for estimating differential TEC, whereby a radar waveform is transmitted over the full PALSAR spectral band and widely separated portions of the receive spectrum are processed independently and compared for dispersive effects, and quantify its performance.

    @InProceedings{rosenHensleyChenIEEERadarCon2010IonosphereMitigationInSAR,
    author = {Paul A. Rosen and Scott Hensley and Curtis Chen},
    title = {Measurement and mitigation of the ionosphere in {L}-band Interferometric {SAR} data},
    booktitle = {2010 IEEE Radar Conference},
    year = {2010},
    pages = {1459-1463},
    month = may,
    abstract = {Satellite-based repeat-pass Interferometric Synthetic Aperture Radar (InSAR) provides a synoptic high spatial resolution perspective of Earth's changing surface, permitting one to view large areas quickly and efficiently. By measuring relative phase change from one observation to the next on a pixel-by-pixel basis, maps of deformation and change can be derived. Variability of the atmosphere and the ionosphere leads to phase/time delays that are present in the data that can mask many of the subtle deformation signatures of interest, so methods for mitigation of these effects are important. Many of these effects have been observed in existing ALOS PALSAR data, and studies are underway to characterize and mitigate the ionosphere using these data. Since the ionosphere is a dispersive medium, it is possible in principle distinguish the ionospheric signatures from the non-dispersive effects of deformation and the atmosphere. In this paper, we describe a method for mapping the ionosphere in InSAR data based on a multi-frequency split-spectrum processing technique. We examine a number of PALSAR data sets, including fully polarimetric and single-polarization 28 MHz bandwidth data, where anomalous effects in phase, amplitude and image registration have been observed. We demonstrate the estimation of the ionosphere by means of the split spectrum technique for estimating differential TEC, whereby a radar waveform is transmitted over the full PALSAR spectral band and widely separated portions of the receive spectrum are processed independently and compared for dispersive effects, and quantify its performance.},
    doi = {10.1109/RADAR.2010.5494385},
    file = {:rosenHensleyChenIEEERadarCon2010IonosphereMitigationInSAR.pdf:PDF},
    issn = {1097-5659},
    keywords = {SAR Processing, cartography;image registration;ionosphere;ionospheric measuring apparatus;radar imaging;radar interferometry;synthetic aperture radar;ALOS PALSAR data;L-band InSAR data;PALSAR spectral band;bandwidth 28 MHz;deformation maps;differential TEC estimation;dispersive medium;earth changing surface;image registration;ionosphere measurement;ionosphere mitigation;multifrequency split-spectrum processing technique;nondispersive effects;pixel-by-pixel observation;radar waveform;relative phase change measurement;satellite-based repeat-pass interferometric synthetic aperture radar;split spectrum technique;subtle deformation signatures;synoptic high spatial resolution;Atmosphere;Atmospheric measurements;Delay effects;Dispersion;Earth;Ionosphere;L-band;Phase measurement;Spatial resolution;Synthetic aperture radar interferometry},
    owner = {ofrey},
    
    }
    


  21. David Small, Nuno Miranda, Lukas Zuberbühler, Adrian Schubert, and Erich Meier. Terrain-corrected Gamma: Improved thematic land-cover retrieval for SAR with robust radiometric terrain correction. In Proc. ESA Living Planet Symp., ESA SP-686, Bergen, Norway, July 2010.
    @InProceedings{smallMirandaZuberbuehlerSchubertMeier2010:RadiometricNormalization,
    Title = {Terrain-corrected Gamma: Improved thematic land-cover retrieval for {SAR} with robust radiometric terrain correction},
    Author = {David Small and Nuno Miranda and Lukas Zuberb\"uhler and Adrian Schubert and Erich Meier},
    Booktitle = {Proc. ESA Living Planet Symp., ESA SP-686},
    Month = jul,
    Year = {2010},
    Address = {Bergen, Norway},
    Owner = {ofrey} 
    }
    


  22. Charles L. Werner, Andreas Wiesmann, Tazio Strozzi, Martin Schneebeli, and Christian Matzler. The SnowScat ground-based polarimetric scatterometer: Calibration and initial measurements from Davos Switzerland. In Proc. IEEE Int. Geosci. Remote Sens. Symp., pages 2363-2366, July 2010. Keyword(s): SnowScat, KuScat, calibration, geophysical equipment, radar polarimetry, snow, COld REgions Hydrology High-resolution Observatory Mission, Davos Switzerland, Ku-Band, SNOWSCAT ground-based polarimetric scatterometer, SnowScat, VH polarization, VV polarization, X-Band, calibration, dry snow, dual frequency radar, ground-based coherent polarimetric scatterometer, snow water equivalent retrieval algorithms, Antenna measurements, Antennas, Calibration, Frequency measurement, Instruments, Radar measurements, Snow.
    Abstract: The COld REgions Hydrology High-resolution Observatory (CoReH2O) Mission proposes a dual frequency radar operating at 9.6 and 17 GHz utilizing VV and VH polarization [1]. By combining Xand Ku-Band with both coand cross-polarization diversity it is possible to estimate the Snow Water Equivalent of dry snow. To support this proposed mission, ESA has sponsored the development of a ground-based coherent polarimetric scatterometer operating over the 9-18 GHz frequency range. ESA is supporting campaigns to acquire and process data using SnowScat for validation of Snow Water Equivalent (SWE) retrieval algorithms.

    @InProceedings{wernerWiesmannStrozziSchneebeliMatzlerIGARSS2010,
    author = {Werner, Charles L. and Wiesmann, Andreas and Strozzi, Tazio and Schneebeli, Martin and Matzler, Christian},
    title = {The {SnowScat} ground-based polarimetric scatterometer: Calibration and initial measurements from {Davos} {Switzerland}},
    booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    year = {2010},
    pages = {2363-2366},
    month = jul,
    abstract = {The COld REgions Hydrology High-resolution Observatory (CoReH2O) Mission proposes a dual frequency radar operating at 9.6 and 17 GHz utilizing VV and VH polarization [1]. By combining Xand Ku-Band with both coand cross-polarization diversity it is possible to estimate the Snow Water Equivalent of dry snow. To support this proposed mission, ESA has sponsored the development of a ground-based coherent polarimetric scatterometer operating over the 9-18 GHz frequency range. ESA is supporting campaigns to acquire and process data using SnowScat for validation of Snow Water Equivalent (SWE) retrieval algorithms.},
    doi = {10.1109/IGARSS.2010.5649015},
    file = {:wernerWiesmannStrozziSchneebeliMatzlerIGARSS2010.pdf:PDF},
    issn = {2153-6996},
    keywords = {SnowScat, KuScat, calibration;geophysical equipment;radar polarimetry;snow;COld REgions Hydrology High-resolution Observatory Mission;Davos Switzerland;Ku-Band;SNOWSCAT ground-based polarimetric scatterometer;SnowScat;VH polarization;VV polarization;X-Band;calibration;dry snow;dual frequency radar;ground-based coherent polarimetric scatterometer;snow water equivalent retrieval algorithms;Antenna measurements;Antennas;Calibration;Frequency measurement;Instruments;Radar measurements;Snow},
    
    }
    


  23. Andreas Wiesmann, Charles L. Werner, Tazio Strozzi, Christian Matzler, Thomas Nagler, Helmut Rott, Martin Schneebeli, and Urs Wegmuller. SnowScat, X- to Ku-Band Scatterometer Development. In Proc. ESA Living Planet Symposium, June 2010. Keyword(s): SnowScat, KuScat, backscatter, hydrological techniques, radiometry, remote sensing by radar, snow, spaceborne radar, C-band SAR satellite systems, ESA CoRe-H2O mission, Ku-band scatterometer, Swiss Alps, X-band scatterometer, backscatter information, backscattering signal, dry snow cover, dual frequency radar, frequency 18 GHz, frequency 9 GHz, mobile scatterometer, snow coverage, snow liquid water content, snow structure, spaceborne active microwave remote sensing, Backscatter, Frequency, Ground support, Radar measurements, Remote sensing, Satellites, Signal generators, Snow, Spaceborne radar, Water storage, Scatterometer, Snow, backscatter, snow grain.
    Abstract: The CoreH2O mission was selected, in May 2006, for pre-phase A and in 2009 for Phase-A mission feasibility study following a call for Earth Explorer Core mission ideas. Though various components of the cryosphere have been observed by non-dedicated satellite missions for years, and a dedicated European mission, CryoSat, is in preparation to observe fluctuations of the masses of ice sheets and sea ice, still large gaps in spatially detailed observation of key parameters and processes of global snow and ice masses and high latitude environment remain. The ESA CoRe-H2O mission aims at closing these gaps, providing high resolution data on extent, mass, and metamorphic state of snow and ice and on surface water extent at regular repeat intervals over extended areas. The CoRe-H2O mission objectives lead to a set of observational requirements for seasonal snow cover, glaciers and ice-sheets, fresh-water ice, sea ice and surface water. These requirements shall be achieved using a dual frequency X- (9.6 GHz), and Ku-band (17.2) SAR with two polarizations VV, VH, operated in ScanSAR mode. To some degree retrieval methods based on these frequencies have been demonstrated for the observation requirements. Recently, two parallel activities were undertaken for developing scattering and propagation models of snow-pack at Ku-band to improve the understanding of the scattering behavior of targets at this frequency. However, there is a lack of validation data to compare and validate these models. From field work and airborne campaigns many backscatter data sets of snow are available at X- band. In recent years measurements have also been acquired at Ku-band in the 14 to 15 GHz range. However, there is almost a complete lack of X- and Ku-band data over snow. Here we will present the work conducted within ESA/ESTEC project 20716/07/NL/EL whose purpose was to help close this important gap through the development of a ground-based scatterometer covering X and Ku-band, and test the instrument during a dedicated campaign to demonstrate the performance of the instrument in cold and harsh winter environment. The proposed and implemented solution was to build a coherent stepped frequency scatterometer covering 9 to 18 GHz. The instruments allows not only to cover the CoRe-H2O relevant channels but also the frequency band used for Cryosat. Another advantage of the wide bandwidth is that it allows to investigate the scattering behavior of the snowpack in detail by investigating the time domain data. The instrument has an embedded system controller and data storage, so that it runs autonomously also during communication link outages and can be controlled ober the Internet. The system was successfully tested during a dedicated field campaign at the high alpine test site Weissfluhjoch Davos in Switzerland. For 3 months the system was continuously operating from a 12m mast. To get comparable snow free measurements, the mesasurements were repeated at the same location during summer at snow free conditions. The instrument proved to withstand temperatures as low as 30 deg C, and wind up to 80 km/h. Detailed ground information complements the acquired radar data. To improve the data quality a campaign was conducted in the anechoic chamber at ESTEC. The campaign included detailed antenna measurements and calibration target measurements.

    @InProceedings{wiesmannEtAl2010SnowScat,
    author = {Wiesmann, Andreas and Werner, Charles L. and Strozzi, Tazio and Matzler, Christian and Nagler, Thomas and Rott, Helmut and Schneebeli, Martin and Wegmuller, Urs},
    booktitle = {Proc. ESA Living Planet Symposium},
    title = {{SnowScat}, {X-} to {Ku}-Band Scatterometer Development},
    year = {2010},
    month = jun,
    abstract = {The CoreH2O mission was selected, in May 2006, for pre-phase A and in 2009 for Phase-A mission feasibility study following a call for Earth Explorer Core mission ideas. Though various components of the cryosphere have been observed by non-dedicated satellite missions for years, and a dedicated European mission, CryoSat, is in preparation to observe fluctuations of the masses of ice sheets and sea ice, still large gaps in spatially detailed observation of key parameters and processes of global snow and ice masses and high latitude environment remain. The ESA CoRe-H2O mission aims at closing these gaps, providing high resolution data on extent, mass, and metamorphic state of snow and ice and on surface water extent at regular repeat intervals over extended areas. The CoRe-H2O mission objectives lead to a set of observational requirements for seasonal snow cover, glaciers and ice-sheets, fresh-water ice, sea ice and surface water. These requirements shall be achieved using a dual frequency X- (9.6 GHz), and Ku-band (17.2) SAR with two polarizations VV, VH, operated in ScanSAR mode. To some degree retrieval methods based on these frequencies have been demonstrated for the observation requirements. Recently, two parallel activities were undertaken for developing scattering and propagation models of snow-pack at Ku-band to improve the understanding of the scattering behavior of targets at this frequency. However, there is a lack of validation data to compare and validate these models. From field work and airborne campaigns many backscatter data sets of snow are available at X- band. In recent years measurements have also been acquired at Ku-band in the 14 to 15 GHz range. However, there is almost a complete lack of X- and Ku-band data over snow. Here we will present the work conducted within ESA/ESTEC project 20716/07/NL/EL whose purpose was to help close this important gap through the development of a ground-based scatterometer covering X and Ku-band, and test the instrument during a dedicated campaign to demonstrate the performance of the instrument in cold and harsh winter environment. The proposed and implemented solution was to build a coherent stepped frequency scatterometer covering 9 to 18 GHz. The instruments allows not only to cover the CoRe-H2O relevant channels but also the frequency band used for Cryosat. Another advantage of the wide bandwidth is that it allows to investigate the scattering behavior of the snowpack in detail by investigating the time domain data. The instrument has an embedded system controller and data storage, so that it runs autonomously also during communication link outages and can be controlled ober the Internet. The system was successfully tested during a dedicated field campaign at the high alpine test site Weissfluhjoch Davos in Switzerland. For 3 months the system was continuously operating from a 12m mast. To get comparable snow free measurements, the mesasurements were repeated at the same location during summer at snow free conditions. The instrument proved to withstand temperatures as low as 30 deg C, and wind up to 80 km/h. Detailed ground information complements the acquired radar data. To improve the data quality a campaign was conducted in the anechoic chamber at ESTEC. The campaign included detailed antenna measurements and calibration target measurements.},
    keywords = {SnowScat, KuScat, backscatter;hydrological techniques;radiometry;remote sensing by radar;snow;spaceborne radar;C-band SAR satellite systems;ESA CoRe-H2O mission;Ku-band scatterometer;Swiss Alps;X-band scatterometer;backscatter information;backscattering signal;dry snow cover;dual frequency radar;frequency 18 GHz;frequency 9 GHz;mobile scatterometer;snow coverage;snow liquid water content;snow structure;spaceborne active microwave remote sensing;Backscatter;Frequency;Ground support;Radar measurements;Remote sensing;Satellites;Signal generators;Snow;Spaceborne radar;Water storage;Scatterometer;Snow;backscatter;snow grain},
    
    }
    


  24. Xiao Xiang Zhu and Richard Bamler. Compressive sensing for high resolution differential SAR tomography - the SL1MMER algorithm. In Proc. IEEE Int. Geoscience and Remote Sensing Symp. (IGARSS), pages 17-20, 2010. Keyword(s): SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry.
    @InProceedings{Zhu2010c,
    Title = {Compressive sensing for high resolution differential SAR tomography - the SL1MMER algorithm},
    Author = {Xiao Xiang Zhu and Richard Bamler},
    Booktitle = {Proc. IEEE Int. Geoscience and Remote Sensing Symp. (IGARSS)},
    Doi = {10.1109/IGARSS.2010.5654021},
    Pages = {17--20},
    Year = {2010},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry},
    Owner = {ofrey} 
    }
    


Miscellaneous

  1. Xiao Xiang Zhu and Richard Bamler. Super-resolution for 4-D SAR Tomography via Compressive Sensing, 2010. Note: Synthetic Aperture Radar (EUSAR), 2010 8th European Conference on. Keyword(s): SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry.
    @Misc{Zhu2010,
    Title = {Super-resolution for {4-D} {SAR} Tomography via Compressive Sensing},
    Author = {Zhu, Xiao Xiang and Bamler, Richard},
    Note = {Synthetic Aperture Radar (EUSAR), 2010 8th European Conference on},
    Year = {2010},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry},
    Owner = {ofrey},
    Pages = {1--4} 
    }
    


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Last modified: Mon Feb 1 16:39:00 2021
Author: Othmar Frey, Earth Observation and Remote Sensing, Institute of Environmental Engineering, Swiss Federal Institute of Technology - ETH Zurich .


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