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Publications of year 2009

Books and proceedings

  1. Shane R. Cloude. Polarisation: Applications in Remote Sensing. Oxford Press, 2009. Keyword(s): SAR Processing, Polarisation, Interferometry, Polarimetric Interferometry, PolInSAR, InSAR, SAR Interferometry, Scattering, Remote Sensing, Radar, Radar Remote Sensing.
    @Book{cloudeBookPolarisation2009,
    title = {Polarisation: Applications in Remote Sensing},
    publisher = {Oxford Press},
    year = {2009},
    author = {Shane R. Cloude},
    isbn = {9780199569731},
    doi = {10.1093/acprof:oso/9780199569731.001.0001},
    keywords = {SAR Processing, Polarisation, Interferometry, Polarimetric Interferometry, PolInSAR, InSAR, SAR Interferometry, Scattering, Remote Sensing, Radar, Radar Remote Sensing},
    owner = {ofrey},
    pdf = {../cloudeBookPolarisation2009.pdf},
    url = {http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199569731.001.0001/acprof-9780199569731},
    
    }
    


  2. Peter J. Huber and Elvezio M. Ronchetti. Robust Statistics. John Wiley & Sons, Inc., Hoboken, New Jersey, 2nd edition, 2009. Keyword(s): Statistics, Robust Statistics, robust fit, curve fitting, robust least squares estimation.
    Abstract: When Wiley asked me to undertake a revision of Robust Statistics for a second edition, I was at first very reluctant to do so. My own interests had begun to shift toward data analysis in the late 1970s, and I had ceased to work in robustness shortly after the publication of the first edition. Not only was I now out of contact with the forefront of current work, but I also disagreed with some of the directions that the latter had taken and was not overly keen to enter into polemics. Back in the 1960s, robustness theory had been created to correct the instability problems of the "optimal" procedures of classical mathematical statistics. At that time, in order to make robustness acceptable within the paradigms then prevalent in statistics, it had been indispensable to create optimally robust (i.e., minimax) alternative procedures. Ironically, by the 1980s, "optimal" robustness began to run into analogous instability problems. In particular, while a high breakdown point clearly is desirable, the (still) fashionable strife for the highest possible breakdown point in my opinion is misguided: it is not only overly pessimistic, but, even worse, it disregards the central stability aspect of robustness. But an update clearly was necessary. After the closure date of the first edition, there had been important developments not only with regard to the breakdown point, on which I have added a chapter, but also in the areas of infinitesimal robustness, robust tests, and small sample asymptotics. In many places, it would suffice to update bibliographical references, so the manuscript of the second edition could be based on a re-keyed version of the first. Other aspects deserved a more extended discussion. I was fortunate to persuade Elvezio Ronchetti, who had been one of the prime researchers working in the two last mentioned areas (robust tests and small sample asymptotics), to collaborate and add the corresponding Chapters 13 and 14. Also, I extended the discussion of regression, and I decided to add a chapter on Bayesian robustness-even though, or perhaps because, I am not a Bayesian (or only rarely so). Among other minor changes, since most readers of the first edition had appreciated the General Remarks at the beginning of the chapters, I have expanded some of them and also elsewhere devoted more space to an informal discussion of motivations. The new edition still has no pretensions of being encyclopedic. Like the first, it is centered on a robustness concept based on minimax asymptotic variance and on M-estimation, complemented by some exact finite sample results. Much of the material of the first edition is just as valid as it was in 1980. Deliberately, such parts were left intact, except that bibliographical references had to be added. Also, I hope that my own perspective has improved with an increased temporal and professional distance. Although this improved perspective has not affected the mathematical facts, it has sometimes sharpened their interpretation. Special thanks go to Amy Hendrickson for her patient help with the Wiley LATEX- macros and the various quirks of TEX.

    @Book{bookHuberRonchetti2009RobustStatistics2ndEd,
    author = {Huber, Peter J. and Ronchetti, Elvezio M.},
    publisher = {John Wiley \& Sons, Inc.},
    title = {Robust Statistics},
    year = {2009},
    address = {Hoboken, New Jersey},
    edition = {2nd},
    isbn = {9780470434697},
    abstract = {When Wiley asked me to undertake a revision of Robust Statistics for a second edition, I was at first very reluctant to do so. My own interests had begun to shift toward data analysis in the late 1970s, and I had ceased to work in robustness shortly after the publication of the first edition. Not only was I now out of contact with the forefront of current work, but I also disagreed with some of the directions that the latter had taken and was not overly keen to enter into polemics. Back in the 1960s, robustness theory had been created to correct the instability problems of the "optimal" procedures of classical mathematical statistics. At that time, in order to make robustness acceptable within the paradigms then prevalent in statistics, it had been indispensable to create optimally robust (i.e., minimax) alternative procedures. Ironically, by the 1980s, "optimal" robustness began to run into analogous instability problems. In particular, while a high breakdown point clearly is desirable, the (still) fashionable strife for the highest possible breakdown point in my opinion is misguided: it is not only overly pessimistic, but, even worse, it disregards the central stability aspect of robustness. But an update clearly was necessary. After the closure date of the first edition, there had been important developments not only with regard to the breakdown point, on which I have added a chapter, but also in the areas of infinitesimal robustness, robust tests, and small sample asymptotics. In many places, it would suffice to update bibliographical references, so the manuscript of the second edition could be based on a re-keyed version of the first. Other aspects deserved a more extended discussion. I was fortunate to persuade Elvezio Ronchetti, who had been one of the prime researchers working in the two last mentioned areas (robust tests and small sample asymptotics), to collaborate and add the corresponding Chapters 13 and 14. Also, I extended the discussion of regression, and I decided to add a chapter on Bayesian robustness-even though, or perhaps because, I am not a Bayesian (or only rarely so). Among other minor changes, since most readers of the first edition had appreciated the General Remarks at the beginning of the chapters, I have expanded some of them and also elsewhere devoted more space to an informal discussion of motivations. The new edition still has no pretensions of being encyclopedic. Like the first, it is centered on a robustness concept based on minimax asymptotic variance and on M-estimation, complemented by some exact finite sample results. Much of the material of the first edition is just as valid as it was in 1980. Deliberately, such parts were left intact, except that bibliographical references had to be added. Also, I hope that my own perspective has improved with an increased temporal and professional distance. Although this improved perspective has not affected the mathematical facts, it has sometimes sharpened their interpretation. Special thanks go to Amy Hendrickson for her patient help with the Wiley LATEX- macros and the various quirks of TEX.},
    doi = {10.1002/9780470434697},
    file = {:bookHuberRonchetti2009RobustStatistics2ndEd.pdf:PDF},
    keywords = {Statistics, Robust Statistics, robust fit, curve fitting, robust least squares estimation},
    owner = {ofrey},
    
    }
    


  3. Jong-Sen Lee and Eric Pottier. Polarimetric radar imaging: from basics to applications. CRC Press, Taylor and Francis, 2009. Keyword(s): SAR Processing, Polarimetry, Polarimetric Decomposition.
    @Book{leePottier:PolarimetricRadarImagingBook2009,
    Title = {Polarimetric radar imaging: from basics to applications},
    Author = {Jong-Sen Lee and Eric Pottier},
    Publisher = {CRC Press, Taylor and Francis},
    Url = {http://www.techbooks.co.uk/artech/book310.htm},
    Year = {2009},
    Keywords = {SAR Processing, Polarimetry, Polarimetric Decomposition},
    Owner = {ofrey} 
    }
    


Articles in journal or book chapters

  1. Nico Adam, Alessandro Parizzi, Michael Eineder, and Michele Crosetto. Practical persistent scatterer processing validation in the course of the Terrafirma project. Journal of Applied Geophysics, 69(1):59-65, 2009.
    @Article{adamParizziEinederCrosetto2009,
    author = {Adam, Nico and Parizzi, Alessandro and Eineder, Michael and Crosetto, Michele},
    title = {Practical persistent scatterer processing validation in the course of the {Terrafirma} project},
    year = {2009},
    volume = {69},
    number = {1},
    pages = {59-65},
    journal = {Journal of Applied Geophysics},
    owner = {ofrey},
    publisher = {Elsevier},
    
    }
    


  2. Richard Bamler, Michael Eineder, Nico Adam, Xiaoxiang Zhu, and Stefan Gernhardt. Interferometric Potential of High Resolution Spaceborne SAR. Photogrammetrie - Fernerkundung - Geoinformation, 2009(5):407-419, 2009. Keyword(s): SAR Processing, SAR Interferometry, SAR Tomography, Tomography, Persistent Scatterer Interferometry, PSI, Spotlight SAR, TERRASAR-X, SAR TOMOGRAPHY.
    Abstract: The new class of high resolution spaceborne SAR systems, like TerraSAR-X and COSMO-Skymed opens new possibilities for SAR interferometry. The 1m resolution is particularly helpful when 2D, 2.5D, 3D, or 4D (space-time) imaging of buildings and urban infrastructure is required, where the non-interferometric interpretation of SAR imagery is difficult. Structure and deformation of individual buildings can be mapped, rather than only coarse deformation patterns of areas. The paper demonstrates several new developments in high resolution SAR interferometry using TerraSAR-X as an example. Of particular interest is the very high resolution spotlight mode, which requires some care in interferometric processing. Results from interferometry, Persistent Scatterer Interferometry (PSI), and tomographic SAR in urban environment are presented. The high resolution of TerraSAR-X also supports accurate speckle and feature tracking. An example of glacier monitoring is shown and discussed.

    @Article{bamlerEinederAdamZhuGernhardtPFG2009,
    author = {Bamler, Richard and Eineder, Michael and Adam, Nico and Zhu, Xiaoxiang and Gernhardt, Stefan},
    title = {Interferometric Potential of High Resolution Spaceborne {SAR}},
    journal = {Photogrammetrie - Fernerkundung - Geoinformation},
    year = {2009},
    volume = {2009},
    number = {5},
    pages = {407-419},
    abstract = {The new class of high resolution spaceborne SAR systems, like TerraSAR-X and COSMO-Skymed opens new possibilities for SAR interferometry. The 1m resolution is particularly helpful when 2D, 2.5D, 3D, or 4D (space-time) imaging of buildings and urban infrastructure is required, where the non-interferometric interpretation of SAR imagery is difficult. Structure and deformation of individual buildings can be mapped, rather than only coarse deformation patterns of areas. The paper demonstrates several new developments in high resolution SAR interferometry using TerraSAR-X as an example. Of particular interest is the very high resolution spotlight mode, which requires some care in interferometric processing. Results from interferometry, Persistent Scatterer Interferometry (PSI), and tomographic SAR in urban environment are presented. The high resolution of TerraSAR-X also supports accurate speckle and feature tracking. An example of glacier monitoring is shown and discussed.},
    doi = {10.1127/1432-8364/2009/0029},
    file = {:bamlerEinederAdamZhuGernhardtPFG2009.pdf:PDF},
    keywords = {SAR Processing, SAR Interferometry, SAR Tomography, Tomography, Persistent Scatterer Interferometry, PSI, Spotlight SAR, TERRASAR-X, SAR TOMOGRAPHY},
    pdf = {../../../docs/bamlerEinederAdamZhuGernhardtPFG2009.pdf},
    url = {http://www.ingentaconnect.com/content/schweiz/pfg/2009/00002009/00000005/art00004},
    
    }
    


  3. Antonio De Maio, Gianfranco Fornaro, and Antonio Pauciullo. Detection of Single Scatterers in Multidimensional SAR Imaging. IEEE Transactions on Geoscience and Remote Sensing, 47(7):2284-2297, July 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, radar imaging, radar interferometry, synthetic aperture radar, CFAR detection scheme, Rao test, SAR imaging, SAR interferometry, Wald test, constant false alarm rate, differential interferometry, generalized likelihood ratio test, multi-interferogram complex coherence, multidimensional synthetic aperture radar, scatterer interferometry, single scatterers detection, space deformation-velocity analysis.
    Abstract: Multidimensional synthetic aperture radar (SAR) imaging is a technique based on coherent SAR data combination for space (full 3-D) and space deformation-velocity (4-D) analysis. It is an extension of the concepts of SAR interferometry and differential interferometry SAR and offers new options for the analysis and monitoring of ground scenes. In this paper, we consider the problem of detecting single scatterers for localization and monitoring issues. To this end, we resort to a constant false alarm rate (CFAR) detection scheme which can be synthesized according to three different design criteria: generalized likelihood ratio test, Rao test, and Wald test. At the analysis stage, the performance of the aforementioned detector is compared to that of a previously proposed CFAR scheme, based on the multi-interferogram complex coherence and widely used in persistent scatterer interferometry. The analysis is conducted both on simulated and on real SAR data, acquired by ERS-1/2 satellites. Finally, Cramer-Rao lower bounds for the estimation of the scatterer elevation and velocity are provided.

    @Article{deMaioFornaroPauciullo2009,
    author = {De Maio, Antonio and Fornaro, Gianfranco and Pauciullo, Antonio},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Detection of Single Scatterers in Multidimensional SAR Imaging},
    year = {2009},
    issn = {0196-2892},
    month = jul,
    number = {7},
    pages = {2284-2297},
    volume = {47},
    abstract = {Multidimensional synthetic aperture radar (SAR) imaging is a technique based on coherent SAR data combination for space (full 3-D) and space deformation-velocity (4-D) analysis. It is an extension of the concepts of SAR interferometry and differential interferometry SAR and offers new options for the analysis and monitoring of ground scenes. In this paper, we consider the problem of detecting single scatterers for localization and monitoring issues. To this end, we resort to a constant false alarm rate (CFAR) detection scheme which can be synthesized according to three different design criteria: generalized likelihood ratio test, Rao test, and Wald test. At the analysis stage, the performance of the aforementioned detector is compared to that of a previously proposed CFAR scheme, based on the multi-interferogram complex coherence and widely used in persistent scatterer interferometry. The analysis is conducted both on simulated and on real SAR data, acquired by ERS-1/2 satellites. Finally, Cramer-Rao lower bounds for the estimation of the scatterer elevation and velocity are provided.},
    doi = {10.1109/TGRS.2008.2011632},
    file = {:deMaioFornaroPauciullo2009.pdf:PDF},
    keywords = {SAR Processing, SAR Tomography, Tomography, radar imaging, radar interferometry, synthetic aperture radar,CFAR detection scheme, Rao test, SAR imaging, SAR interferometry, Wald test, constant false alarm rate, differential interferometry, generalized likelihood ratio test, multi-interferogram complex coherence, multidimensional synthetic aperture radar, scatterer interferometry, single scatterers detection, space deformation-velocity analysis},
    pdf = {../../../docs/deMaioFornaroPauciullo2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4814567&isnumber=5075850},
    
    }
    


  4. Esra Erten, Andreas Reigber, Olaf Hellwich, and Pau Prats. Glacier Velocity Monitoring by Maximum Likelihood Texture Tracking. IEEE Transactions on Geoscience and Remote Sensing, 47(2):394-405, Feb. 2009. Keyword(s): SAR Processing, glaciology, hydrological techniques, image processing, maximum likelihood estimation, remote sensing by radar, spaceborne radar, synthetic aperture radar, Asia, ENVISAT-ASAR data acquisition, Inyltshik glacier, Kyrgyzstan, Maximum Likelihood Texture Tracking, alpine glacier systems, classical intensity tracking technique, glacier velocities measurement, glacier velocity monitoring, ice flows, intensity-based matching algorithm, melting, multiplicative speckle/noise model, remotely sensed data, signal-to-noise ratio, snowfall, spatial dynamics, speckle decorrelation, statistical description, synthetic aperture radar data, temporal dynamics, temporal speckle structure, tracking algorithm.
    Abstract: The performance of a tracking algorithm considering remotely sensed data strongly depends on a correct statistical description of the data, i.e., its noise model. The objective of this paper is to introduce a new intensity tracking algorithm for synthetic aperture radar (SAR) data, considering its multiplicative speckle/noise model. The proposed tracking algorithm is discussed regarding the measurement of glacier velocities. Glacier monitoring exhibits complex spatial and temporal dynamics including snowfall, melting, and ice flows at a variety of spatial and temporal scales. Due to these complex characteristics, most traditional methods based on SAR suffer from speckle decorrelation that results in a low signal-to-noise ratio. The proposed tracking technique improves the accuracy of the classical intensity tracking technique by making use of the temporal speckle structure. Even though a new intensity-based matching algorithm is proposed, particularly for incoherent data sets, the analysis of the proposed technique was also performed for correlated data sets. As it is demonstrated, the velocity monitoring can be continuously performed by using the maximum likelihood (ML) texture tracking without any assumption concerning the correlation of the data set. The ML texture tracking approach was tested on ENVISAT-ASAR data acquired during summer 2004 over the Inyltshik glacier in Kyrgyzstan, representing one of the largest alpine glacier systems of the world. It will be demonstrated that the proposed technique is capable of robustly and precisely detecting the surface velocity field and velocity changes in time.

    @Article{ertenReigberHellwichPrats2009:GlacierVelTextureTrack,
    author = {Erten, Esra and Reigber, Andreas and Hellwich, Olaf and Prats, Pau},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Glacier Velocity Monitoring by Maximum Likelihood Texture Tracking},
    year = {2009},
    issn = {0196-2892},
    month = {Feb.},
    number = {2},
    pages = {394-405},
    volume = {47},
    abstract = {The performance of a tracking algorithm considering remotely sensed data strongly depends on a correct statistical description of the data, i.e., its noise model. The objective of this paper is to introduce a new intensity tracking algorithm for synthetic aperture radar (SAR) data, considering its multiplicative speckle/noise model. The proposed tracking algorithm is discussed regarding the measurement of glacier velocities. Glacier monitoring exhibits complex spatial and temporal dynamics including snowfall, melting, and ice flows at a variety of spatial and temporal scales. Due to these complex characteristics, most traditional methods based on SAR suffer from speckle decorrelation that results in a low signal-to-noise ratio. The proposed tracking technique improves the accuracy of the classical intensity tracking technique by making use of the temporal speckle structure. Even though a new intensity-based matching algorithm is proposed, particularly for incoherent data sets, the analysis of the proposed technique was also performed for correlated data sets. As it is demonstrated, the velocity monitoring can be continuously performed by using the maximum likelihood (ML) texture tracking without any assumption concerning the correlation of the data set. The ML texture tracking approach was tested on ENVISAT-ASAR data acquired during summer 2004 over the Inyltshik glacier in Kyrgyzstan, representing one of the largest alpine glacier systems of the world. It will be demonstrated that the proposed technique is capable of robustly and precisely detecting the surface velocity field and velocity changes in time.},
    doi = {10.1109/TGRS.2008.2009932},
    keywords = {SAR Processing, glaciology, hydrological techniques, image processing, maximum likelihood estimation, remote sensing by radar, spaceborne radar, synthetic aperture radar, Asia, ENVISAT-ASAR data acquisition, Inyltshik glacier, Kyrgyzstan, Maximum Likelihood Texture Tracking, alpine glacier systems, classical intensity tracking technique, glacier velocities measurement, glacier velocity monitoring, ice flows, intensity-based matching algorithm, melting, multiplicative speckle/noise model, remotely sensed data, signal-to-noise ratio, snowfall, spatial dynamics, speckle decorrelation, statistical description, synthetic aperture radar data, temporal dynamics, temporal speckle structure, tracking algorithm},
    pdf = {../../../docs/ertenReigberHellwichPrats2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4768700&isnumber=4773457},
    
    }
    


  5. Gianfranco Fornaro and Antonio Pauciullo. LMMSE 3-D SAR Focusing. IEEE Trans. Geosci. Remote Sens., 47(1):214-223, January 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, data acquisition, remote sensing by radar, singular value decomposition, synthetic aperture radar, LMMSE, synthetic aperture radar imaging systems, antenna SAR sensor, atmospheric phase miscalibration, atmospheric residual miscalibration, beamforming, data correlation properties, data integration, linear minimum mean square error method, multistatic data acquisition, satellite technology, singular values decomposition inversion, stochastic process.
    Abstract: Three-dimensional synthetic aperture radar (SAR) imaging, a technique also known as SAR tomography, uses multiple views to extend the capability of SAR systems to 3-D imaging by achieving a profiling of the scattering power at different heights. Multiple views are obtained with the current satellite technology via successive passes of a single antenna SAR sensor over the same scene, but next-generation sensor formations are foreseen to acquire multistatic data. Conventional processing, such as the beamforming, or singular values decomposition inversion is based on geometrical derivations and, hence, assumes the accurate phase calibration and the absence of target decorrelation. This paper analyzes the effects of phase miscalibration due to residual uncompensated atmospheric contribution and temporal decorrelation and proposes a 3-D imaging technique based on a linear minimum mean square error approach. The resulting algorithm extends the possibilities of the conventional processing by carrying out an integration of data that accounts for the a priori data correlation properties. Hence, it allows handling of the presence of additional stochastic contributions such as: temporal coherence losses and atmospheric phase miscalibration. Moreover, with reference to future bistatic and multistatic systems, it permits an improved coherent integration of data acquired by simultaneous antenna in repeated passes.

    @Article{fornaroPauciullo2009:SARTOMO,
    Title = {{LMMSE} {3-D} {SAR} Focusing},
    Author = {Fornaro, Gianfranco and Pauciullo, Antonio},
    Doi = {10.1109/TGRS.2008.2000633},
    ISSN = {0196-2892},
    Month = jan,
    Number = {1},
    Pages = {214-223},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4689338&isnumber=4729687?tag=1},
    Volume = {47},
    Year = {2009},
    Abstract = {Three-dimensional synthetic aperture radar (SAR) imaging, a technique also known as SAR tomography, uses multiple views to extend the capability of SAR systems to 3-D imaging by achieving a profiling of the scattering power at different heights. Multiple views are obtained with the current satellite technology via successive passes of a single antenna SAR sensor over the same scene, but next-generation sensor formations are foreseen to acquire multistatic data. Conventional processing, such as the beamforming, or singular values decomposition inversion is based on geometrical derivations and, hence, assumes the accurate phase calibration and the absence of target decorrelation. This paper analyzes the effects of phase miscalibration due to residual uncompensated atmospheric contribution and temporal decorrelation and proposes a 3-D imaging technique based on a linear minimum mean square error approach. The resulting algorithm extends the possibilities of the conventional processing by carrying out an integration of data that accounts for the a priori data correlation properties. Hence, it allows handling of the presence of additional stochastic contributions such as: temporal coherence losses and atmospheric phase miscalibration. Moreover, with reference to future bistatic and multistatic systems, it permits an improved coherent integration of data acquired by simultaneous antenna in repeated passes.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, SAR Tomography, Tomography, data acquisition, remote sensing by radar, singular value decomposition, synthetic aperture radar, LMMSE, synthetic aperture radar imaging systems, antenna SAR sensor, atmospheric phase miscalibration, atmospheric residual miscalibration, beamforming, data correlation properties, data integration, linear minimum mean square error method, multistatic data acquisition, satellite technology, singular values decomposition inversion, stochastic process},
    Owner = {ofrey},
    Pdf = {../../../docs/fornaroPauciullo2009.pdf} 
    }
    


  6. G. Fornaro, D. Reale, and F. Serafino. Four-Dimensional SAR Imaging for Height Estimation and Monitoring of Single and Double Scatterers. IEEE Transactions on Geoscience and Remote Sensing, 47(1):224-237, January 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, geophysical signal processing, geophysical techniques, height measurement, radar signal processing, remote sensing by radar, synthetic aperture radar4D SAR imaging application, 4D space-velocity imaging, SAR signal postprocessing, differential SAR tomography, double scatterer monitoring, ground scatterers, height estimation, interfering target separation, mean deformation velocity, multipass SAR interferometry, nonlinear temporal deformations, single scatterer monitoring, slow deformation velocity, synthetic aperture radar, target contribution superposition.
    Abstract: The superposition of contributions from different stable targets within the same pixel is a phenomenon that may impair the imaging and monitoring of ground scatterers via the multipass synthetic aperture radar (SAR) interferometry technique. Three-dimensional SAR imaging, also known as SAR tomography, uses multiple views to profile the scattering power at different heights. This technique has been shown to be capable of separating interfering target responses on real data. Differential SAR tomography has been recently proposed as a technique that extends the potentialities of SAR tomography to the target deformation monitoring. It performs a 4-D space-velocity imaging that enables not only separating interfering targets in elevation but also distinguishing their single slow deformation velocities. This work addresses for the first time the application of 4-D SAR imaging to real data to determine the height and mean deformation velocity of single scatterers and double-scattering mechanisms interfering at high resolution in the same pixel. It also discusses the postprocessing steps required to identify the presence of stable single and double scatterers after elevation-velocity focusing. Moreover, it proposes a technique for the extraction of time series from interfering targets to measure possible nonlinear temporal deformations.

    @Article{fornaroRealeSerafino2009:SARTomo,
    Title = {Four-Dimensional SAR Imaging for Height Estimation and Monitoring of Single and Double Scatterers},
    Author = {Fornaro, G. and Reale, D. and Serafino, F.},
    Doi = {10.1109/TGRS.2008.2000837},
    ISSN = {0196-2892},
    Month = jan,
    Number = {1},
    Pages = {224-237},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4685869&isnumber=4729687},
    Volume = {47},
    Year = {2009},
    Abstract = {The superposition of contributions from different stable targets within the same pixel is a phenomenon that may impair the imaging and monitoring of ground scatterers via the multipass synthetic aperture radar (SAR) interferometry technique. Three-dimensional SAR imaging, also known as SAR tomography, uses multiple views to profile the scattering power at different heights. This technique has been shown to be capable of separating interfering target responses on real data. Differential SAR tomography has been recently proposed as a technique that extends the potentialities of SAR tomography to the target deformation monitoring. It performs a 4-D space-velocity imaging that enables not only separating interfering targets in elevation but also distinguishing their single slow deformation velocities. This work addresses for the first time the application of 4-D SAR imaging to real data to determine the height and mean deformation velocity of single scatterers and double-scattering mechanisms interfering at high resolution in the same pixel. It also discusses the postprocessing steps required to identify the presence of stable single and double scatterers after elevation-velocity focusing. Moreover, it proposes a technique for the extraction of time series from interfering targets to measure possible nonlinear temporal deformations.},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {SAR Processing, SAR Tomography, Tomography, geophysical signal processing, geophysical techniques, height measurement, radar signal processing, remote sensing by radar, synthetic aperture radar4D SAR imaging application, 4D space-velocity imaging, SAR signal postprocessing, differential SAR tomography, double scatterer monitoring, ground scatterers, height estimation, interfering target separation, mean deformation velocity, multipass SAR interferometry, nonlinear temporal deformations, single scatterer monitoring, slow deformation velocity, synthetic aperture radar, target contribution superposition},
    Pdf = {../../../docs/fornaroRealeSerafino2009.pdf} 
    }
    


  7. Joaquim Fortuny-Guasch. A Fast and Accurate Far-Field Pseudopolar Format Radar Imaging Algorithm. IEEE Transactions on Geoscience and Remote Sensing, 47(4):1187-1196, April 2009. Keyword(s): SAR Processing, GB-SAR, GB-SAR Focusing, Focusing, Azimuth Focusing, Terrestrial radar, Terrestrial SAR, CW radar, fast Fourier transforms, geophysical signal processing, radar imaging, remote sensing by radar, synthetic aperture radar, 2D fast Fourier transforms, frequency domain backscatter, frequency modulated CW radar, interpolation free series expansion, linear radar aperture, pseudopolar format radar imaging algorithm, stepped frequency continuous wave, synthetic aperture radar systems, ultrawideband radar, Antenna arrays, far field, radar data processing, radar imaging, synthetic aperture radar (SAR).
    Abstract: A novel imaging algorithm to be used under the condition of having an image scene in the far field of a linear radar aperture is presented. This is an application scenario that is drastically different from those of spaceborne and airborne synthetic aperture radar (SAR) systems, which has not been properly addressed to date. The technique is particularly tailored for a stepped-frequency continuous wave (CW) or frequency-modulated CW radar. The radar aperture must be linear and can be formed either with a physical or synthetic array. With the suggested method, the radar reflectivity of the image scene is obtained through an interpolation-free series expansion, where only 2-D fast Fourier transforms of the frequency-domain backscatter data are required. The resulting image is sampled on a polarlike or pseudopolar grid, which is introduced to simplify the formulation. The main advantages of this method are its extremely low computational cost and the high accuracy of the resulting imagery. The technique is extensively validated both with numerical simulations and two ground-based SAR data sets. Last but not least, numerical simulations show that this technique can be used with an ultrawideband radar of 1 GHz of bandwidth.

    @Article{fortunyGuaschTGRS2009GBSARPseudoPolarFocusing,
    author = {Fortuny-Guasch, Joaquim},
    title = {A Fast and Accurate Far-Field Pseudopolar Format Radar Imaging Algorithm},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    year = {2009},
    volume = {47},
    number = {4},
    pages = {1187-1196},
    month = apr,
    issn = {0196-2892},
    abstract = {A novel imaging algorithm to be used under the condition of having an image scene in the far field of a linear radar aperture is presented. This is an application scenario that is drastically different from those of spaceborne and airborne synthetic aperture radar (SAR) systems, which has not been properly addressed to date. The technique is particularly tailored for a stepped-frequency continuous wave (CW) or frequency-modulated CW radar. The radar aperture must be linear and can be formed either with a physical or synthetic array. With the suggested method, the radar reflectivity of the image scene is obtained through an interpolation-free series expansion, where only 2-D fast Fourier transforms of the frequency-domain backscatter data are required. The resulting image is sampled on a polarlike or pseudopolar grid, which is introduced to simplify the formulation. The main advantages of this method are its extremely low computational cost and the high accuracy of the resulting imagery. The technique is extensively validated both with numerical simulations and two ground-based SAR data sets. Last but not least, numerical simulations show that this technique can be used with an ultrawideband radar of 1 GHz of bandwidth.},
    doi = {10.1109/TGRS.2008.2007908},
    file = {:fortunyGuaschTGRS2009GBSARPseudoPolarFocusing.pdf:PDF},
    keywords = {SAR Processing, GB-SAR, GB-SAR Focusing, Focusing, Azimuth Focusing, Terrestrial radar, Terrestrial SAR, CW radar;fast Fourier transforms;geophysical signal processing;radar imaging;remote sensing by radar;synthetic aperture radar;2D fast Fourier transforms;frequency domain backscatter;frequency modulated CW radar;interpolation free series expansion;linear radar aperture;pseudopolar format radar imaging algorithm;stepped frequency continuous wave;synthetic aperture radar systems;ultrawideband radar;Antenna arrays;far field;radar data processing;radar imaging;synthetic aperture radar (SAR)},
    owner = {ofrey},
    pdf = {../../../docs/fortunyGuaschTGRS2009GBSARPseudoPolarFocusing.pdf},
    
    }
    


  8. Othmar Frey, Christophe Magnard, Maurice Rüegg, and Erich Meier. Focusing of Airborne Synthetic Aperture Radar Data from Highly Nonlinear Flight Tracks. IEEE Trans. Geosci. Remote Sens., 47(6):1844-1858, June 2009. Keyword(s): SAR Processing, Time-Domain Back-Projection, Back-Projection, TDBP, Non-Linear Flight Tracks, Curvilinear SAR, Extended Chirp Scaling, ECS, Mosaicking, Geocoding, Azimuth Focusing, Integrated Focusing and Geocoding, Georeferencing, mapping, corridor mapping, E-SAR, L-Band, digital elevation model, Airborne SAR.
    Abstract: Standard focusing of data from synthetic aperture radar (SAR) assumes a straight recording track of the sensor platform. Small non-linearities of airborne platform tracks are corrected for during a motion compensation step while maintaining the assumption of a linear flight path. This paper describes the processing of SAR data acquired from non-linear tracks, typical of sensors mounted on small aircraft or drones flying at low altitude. Such aircraft do not fly along straight tracks, but the trajectory depends on topography, influences of weather and wind, or the shape of areas of interest such as rivers or traffic routes. Two potential approaches for processing SAR data from such highly non-linear flight tracks are proposed: a patchwise frequency-domain processing and mosaicking technique, as well as a time-domain back-projection based technique. Both are evaluated with the help of experimental data featuring tracks with altitude changes, a double bend, a 90-degree curve and a linear flight track. In order to assess the quality of the focused data, close-ups of amplitude images are compared, impulse response functions of a point target are analyzed, and the coherence is evaluated. The experimental data was acquired by the German Aerospace Center's E-SAR L-band system.

    @Article{freyMagnardRueeggMeier08TGRS:Tracks,
    author = {Othmar Frey and Christophe Magnard and Maurice R{\"u}egg and Erich Meier},
    title = {Focusing of Airborne Synthetic Aperture Radar Data from Highly Nonlinear Flight Tracks},
    journal = {{IEEE} Trans. Geosci. Remote Sens.},
    year = {2009},
    volume = {47},
    number = {6},
    pages = {1844-1858},
    month = jun,
    abstract = {Standard focusing of data from synthetic aperture radar (SAR) assumes a straight recording track of the sensor platform. Small non-linearities of airborne platform tracks are corrected for during a motion compensation step while maintaining the assumption of a linear flight path. This paper describes the processing of SAR data acquired from non-linear tracks, typical of sensors mounted on small aircraft or drones flying at low altitude. Such aircraft do not fly along straight tracks, but the trajectory depends on topography, influences of weather and wind, or the shape of areas of interest such as rivers or traffic routes. Two potential approaches for processing SAR data from such highly non-linear flight tracks are proposed: a patchwise frequency-domain processing and mosaicking technique, as well as a time-domain back-projection based technique. Both are evaluated with the help of experimental data featuring tracks with altitude changes, a double bend, a 90-degree curve and a linear flight track. In order to assess the quality of the focused data, close-ups of amplitude images are compared, impulse response functions of a point target are analyzed, and the coherence is evaluated. The experimental data was acquired by the German Aerospace Center's E-SAR L-band system.},
    doi = {10.1109/TGRS.2008.2007591},
    file = {:freyMagnardRueeggMeier08TGRSTracks.pdf:PDF},
    keywords = {SAR Processing, Time-Domain Back-Projection, Back-Projection, TDBP, Non-Linear Flight Tracks, Curvilinear SAR, Extended Chirp Scaling, ECS, Mosaicking, Geocoding, Azimuth Focusing, Integrated Focusing and Geocoding, Georeferencing, mapping, corridor mapping, E-SAR, L-Band, digital elevation model, Airborne SAR},
    owner = {ofrey},
    pdf = {http://www.ifu-sar.ethz.ch/otfrey/SARbibliography/myPapers/freyMagnardRueeggMeier08TGRSTracks.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4812049},
    
    }
    


  9. Franck Garestier, Pascale C. Dubois-Fernandez, Dominique Guyon, and Thuy Le Toan. Forest Biophysical Parameter Estimation Using L- and P-Band Polarimetric SAR Data. IEEE Transactions on Geoscience and Remote Sensing, 47(10):3379-3388, October 2009. Keyword(s): SAR Processing, Biomass, Biophysical Parameters, Forst, L-Band, P-Band, PolSAR, SAR Polarimetry, Airborne SAR, RAMSES, ONERA.
    Abstract: L- and P-band airborne polarimetric synthetic aperture radar (SAR) data acquired by the RAMSES system over different height maritime pine (Pinus Pinaster Ait.) stands of the Nezer forest (Landes, France) have been evaluated for forest biophysical parameter estimation. A pseudolinear correlation has been brought to evidence at P-band between polarimetric anisotropy and mean tree height, which is also linked to other biophysical parameters in the Nezer forest, meaning that SAR polarimetry constitutes a promising tool for forest parameter retrieval at low frequency. The spatial conditions have been evaluated through the quantification of the impact of signal-to-noise ratio diminution and resolution degradation on the forest height inversion. It has been shown that the inversion accuracy remains acceptable for $NEsigma_{0}$, representing the noise level of the SAR image, which is lower than $-$15 dB, and for spatial resolution increasing up to 15 m.

    @Article{garestierDuboisGuyonLeToan2009:BioPhysPolSARLandPBand,
    author = {Garestier, Franck and Dubois-Fernandez, Pascale C. and Guyon, Dominique and Le Toan, Thuy},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Forest Biophysical Parameter Estimation Using L- and P-Band Polarimetric SAR Data},
    year = {2009},
    issn = {0196-2892},
    month = oct,
    number = {10},
    pages = {3379-3388},
    volume = {47},
    abstract = {L- and P-band airborne polarimetric synthetic aperture radar (SAR) data acquired by the RAMSES system over different height maritime pine (Pinus Pinaster Ait.) stands of the Nezer forest (Landes, France) have been evaluated for forest biophysical parameter estimation. A pseudolinear correlation has been brought to evidence at P-band between polarimetric anisotropy and mean tree height, which is also linked to other biophysical parameters in the Nezer forest, meaning that SAR polarimetry constitutes a promising tool for forest parameter retrieval at low frequency. The spatial conditions have been evaluated through the quantification of the impact of signal-to-noise ratio diminution and resolution degradation on the forest height inversion. It has been shown that the inversion accuracy remains acceptable for $NEsigma_{0}$, representing the noise level of the SAR image, which is lower than $-$15 dB, and for spatial resolution increasing up to 15 m.},
    doi = {10.1109/TGRS.2009.2022947},
    keywords = {SAR Processing, Biomass, Biophysical Parameters, Forst, L-Band, P-Band, PolSAR, SAR Polarimetry, Airborne SAR, RAMSES, ONERA},
    owner = {ofrey},
    pdf = {../../../docs/garestierDuboisGuyonLeToan2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5164921&isnumber=5257398},
    
    }
    


  10. Scott Goetz, Alessandro Baccini, Nadine Laporte, Tracy Johns, Wayne Walker, Josef Kellndorfer, Richard Houghton, and Mindy Sun. Mapping and monitoring carbon stocks with satellite observations: a comparison of methods. Carbon Balance and Management, 4(1):2, 2009. Keyword(s): Carbon Balance, Carbon stock, DESDynl mission, Biomass mission, biomass, ecosystem function, ecosystem structure, integrated L-band InSAR, Lidar, vegetation structure, optical, synthetic aperture radar, vegetation mapping.
    Abstract: Mapping and monitoring carbon stocks in forested regions of the world, particularly the tropics, has attracted a great deal of attention in recent years as deforestation and forest degradation account for up to 30 percent of anthropogenic carbon emissions, and are now included in climate change negotiations. We review the potential for satellites to measure carbon stocks, specifically aboveground biomass (AGB), and provide an overview of a range of approaches that have been developed and used to map AGB across a diverse set of conditions and geographic areas. We provide a summary of types of remote sensing measurements relevant to mapping AGB, and assess the relative merits and limitations of each. We then provide an overview of traditional techniques of mapping AGB based on ascribing field measurements to vegetation or land cover type classes, and describe the merits and limitations of those relative to recent data mining algorithms used in the context of an approach based on direct utilization of remote sensing measurements, whether optical or lidar reflectance, or radar backscatter. We conclude that while satellite remote sensing has often been discounted as inadequate for the task, attempts to map AGB without satellite imagery are insufficient. Moreover, the direct remote sensing approach provided more coherent maps of AGB relative to traditional approaches. We demonstrate this with a case study focused on continental Africa and discuss the work in the context of reducing uncertainty for carbon monitoring and markets.

    @Article{GoetzBacciniLaporteJohnsTracyWalkerKellndorferHoughtonSun2009,
    Title = {Mapping and monitoring carbon stocks with satellite observations: a comparison of methods},
    Author = {Goetz, Scott and Baccini, Alessandro and Laporte, Nadine and Johns, Tracy and Walker, Wayne and Kellndorfer, Josef and Houghton, Richard and Sun, Mindy},
    Doi = {10.1186/1750-0680-4-2},
    ISSN = {1750-0680},
    Number = {1},
    Pages = {2},
    Url = {http://www.cbmjournal.com/content/4/1/2},
    Volume = {4},
    Year = {2009},
    Abstract = {Mapping and monitoring carbon stocks in forested regions of the world, particularly the tropics, has attracted a great deal of attention in recent years as deforestation and forest degradation account for up to 30 percent of anthropogenic carbon emissions, and are now included in climate change negotiations. We review the potential for satellites to measure carbon stocks, specifically aboveground biomass (AGB), and provide an overview of a range of approaches that have been developed and used to map AGB across a diverse set of conditions and geographic areas. We provide a summary of types of remote sensing measurements relevant to mapping AGB, and assess the relative merits and limitations of each. We then provide an overview of traditional techniques of mapping AGB based on ascribing field measurements to vegetation or land cover type classes, and describe the merits and limitations of those relative to recent data mining algorithms used in the context of an approach based on direct utilization of remote sensing measurements, whether optical or lidar reflectance, or radar backscatter. We conclude that while satellite remote sensing has often been discounted as inadequate for the task, attempts to map AGB without satellite imagery are insufficient. Moreover, the direct remote sensing approach provided more coherent maps of AGB relative to traditional approaches. We demonstrate this with a case study focused on continental Africa and discuss the work in the context of reducing uncertainty for carbon monitoring and markets.},
    Journal = {Carbon Balance and Management},
    Keywords = {Carbon Balance, Carbon stock, DESDynl mission; Biomass mission, biomass,ecosystem function;ecosystem structure, integrated L-band InSAR;Lidar;vegetation structure;optical, synthetic aperture radar, vegetation mapping},
    Pubmedid = {19320965} 
    }
    


  11. J. Groen, Roy E. Hansen, H. J. Callow, J. C. Sabel, and T. O. Sabo. Shadow Enhancement in Synthetic Aperture Sonar Using Fixed Focusing. IEEE Journal of Oceanic Engineering, 34(3):269-284, July 2009. Keyword(s): Synthetic Aperture Sonar, SAS, image enhancement, sonar imaging, sonar target recognition, synthetic aperture sonar, HUGIN autonomous underwater vehicle, fixed focus shadow enhancement, shadow clarity, synthetic aperture sonar imaging, target recognition, widebeam synthetic aperture imaging systems, Acoustics, beamforming, focusing, imaging, shadow, synthetic aperture sonar (SAS).
    Abstract: A shadow cast by an object on the seafloor is important information for target recognition in synthetic aperture sonar (SAS) images. Synthetic aperture imaging causes a fundamental limitation to shadow clarity because the illuminator is moved during the data collection. This leads to a blend of echo and shadow, or geometrical fill-in in the shadow region. The fill-in is most dominant for widebeam synthetic aperture imaging systems. By treating the shadow as a moving target and compensating for the motion during the synthetic aperture imagery, we avoid the geometrical shadow fill-in. We show this to be equivalent to fixing the focus at the range of the shadow caster. This novel technique, referred to as fixed focus shadow enhancement (FFSE) can be used directly as an imaging method on hydrophone data or as a postprocessing technique on the complex SAS image. We demonstrate the FFSE technique on simulated data and on real data from a rail-based SAS, and on two different SAS systems operated on a HUGIN autonomous underwater vehicle.

    @Article{groenHansenCallowSabelSaboHOE2009ShadowEnhancementInSAS,
    author = {J. Groen and Roy E. Hansen and H. J. Callow and J. C. Sabel and T. O. Sabo},
    title = {Shadow Enhancement in Synthetic Aperture Sonar Using Fixed Focusing},
    journal = {IEEE Journal of Oceanic Engineering},
    year = {2009},
    volume = {34},
    number = {3},
    pages = {269-284},
    month = {July},
    issn = {0364-9059},
    abstract = {A shadow cast by an object on the seafloor is important information for target recognition in synthetic aperture sonar (SAS) images. Synthetic aperture imaging causes a fundamental limitation to shadow clarity because the illuminator is moved during the data collection. This leads to a blend of echo and shadow, or geometrical fill-in in the shadow region. The fill-in is most dominant for widebeam synthetic aperture imaging systems. By treating the shadow as a moving target and compensating for the motion during the synthetic aperture imagery, we avoid the geometrical shadow fill-in. We show this to be equivalent to fixing the focus at the range of the shadow caster. This novel technique, referred to as fixed focus shadow enhancement (FFSE) can be used directly as an imaging method on hydrophone data or as a postprocessing technique on the complex SAS image. We demonstrate the FFSE technique on simulated data and on real data from a rail-based SAS, and on two different SAS systems operated on a HUGIN autonomous underwater vehicle.},
    doi = {10.1109/JOE.2008.920996},
    file = {:groenHansenCallowSabelSaboHOE2009ShadowEnhancementInSAS.pdf:PDF},
    keywords = {Synthetic Aperture Sonar, SAS, image enhancement;sonar imaging;sonar target recognition;synthetic aperture sonar;HUGIN autonomous underwater vehicle;fixed focus shadow enhancement;shadow clarity;synthetic aperture sonar imaging;target recognition;widebeam synthetic aperture imaging systems;Acoustics;beamforming;focusing;imaging;shadow;synthetic aperture sonar (SAS)},
    
    }
    


  12. Irena Hajnsek, Thomas Jagdhuber, Helmut Schön, and Konstantinos P. Papathanassiou. Potential of Estimating Soil Moisture Under Vegetation Cover by Means of PolSAR. IEEE Transactions on Geoscience and Remote Sensing, 47(2):442-454, Feb. 2009. Keyword(s): SAR Processing, agriculture, crops, moisture, radar polarimetry, remote sensing by radar, soil, synthetic aperture radarAgriSAR campaign, L-band, PolSAR images, PolSAR, agricultural vegetation, canonical scattering components, crop types, dihedral components, polarimetric SAR acquisitions, scattering processes, soil moisture estimation, synthetic aperture radar, vegetation cover, ESAR, Airborne SAR.
    Abstract: In this paper, the potential of using polarimetric SAR (PolSAR) acquisitions for the estimation of volumetric soil moisture under agricultural vegetation is investigated. Soil-moisture estimation by means of SAR is a topic that is intensively investigated but yet not solved satisfactorily. The key problem is the presence of vegetation cover which biases soil-moisture estimates. In this paper, we discuss the problem of soil-moisture estimation in the presence of agricultural vegetation by means of L-band PolSAR images. SAR polarimetry allows the decomposition of the scattering signature into canonical scattering components and their quantification. We discuss simple canonical models for surface, dihedral, and vegetation scattering and use them to model and interpret scattering processes. The performance and modifications of the individual scattering components are discussed. The obtained surface and dihedral components are then used to retrieve surface soil moisture. The investigations cover, for the first time, the whole vegetation-growing period for three crop types using SAR data and ground measurements acquired in the frame of the AgriSAR campaign.

    @Article{hajnsekJagdhuberSchoenPapathanassiou2009:SoilMoisture,
    author = {Hajnsek, Irena and Jagdhuber, Thomas and Sch{\"o}n, Helmut and Papathanassiou, Konstantinos P.},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Potential of Estimating Soil Moisture Under Vegetation Cover by Means of PolSAR},
    year = {2009},
    issn = {0196-2892},
    month = {Feb.},
    number = {2},
    pages = {442-454},
    volume = {47},
    abstract = {In this paper, the potential of using polarimetric SAR (PolSAR) acquisitions for the estimation of volumetric soil moisture under agricultural vegetation is investigated. Soil-moisture estimation by means of SAR is a topic that is intensively investigated but yet not solved satisfactorily. The key problem is the presence of vegetation cover which biases soil-moisture estimates. In this paper, we discuss the problem of soil-moisture estimation in the presence of agricultural vegetation by means of L-band PolSAR images. SAR polarimetry allows the decomposition of the scattering signature into canonical scattering components and their quantification. We discuss simple canonical models for surface, dihedral, and vegetation scattering and use them to model and interpret scattering processes. The performance and modifications of the individual scattering components are discussed. The obtained surface and dihedral components are then used to retrieve surface soil moisture. The investigations cover, for the first time, the whole vegetation-growing period for three crop types using SAR data and ground measurements acquired in the frame of the AgriSAR campaign.},
    doi = {10.1109/TGRS.2008.2009642},
    keywords = {SAR Processing, agriculture, crops, moisture, radar polarimetry, remote sensing by radar, soil, synthetic aperture radarAgriSAR campaign, L-band, PolSAR images, PolSAR, agricultural vegetation, canonical scattering components, crop types, dihedral components, polarimetric SAR acquisitions, scattering processes, soil moisture estimation, synthetic aperture radar, vegetation cover, ESAR, Airborne SAR},
    pdf = {../../../docs/hajnsekJagdhuberSchoenPapathanassiou2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4773468&isnumber=4773457},
    
    }
    


  13. Michael Jehle, Maurice Rüegg, Lukas Zuberbühler, David Small, and Erich Meier. Measurement of Ionospheric Faraday Rotation in Simulated and Real Spaceborne SAR Data. IEEE Trans. Geosci. Remote Sens., 47(5):1512-1523, May 2009. Keyword(s): SAR Processing, Ionosphere, ALOS PALSAR, Advanced Land Observing Satellite, Earth's magnetic field, PALSAR data, Phased Array L-band Synthetic Aperture Radar, focused radar images, frequency-modulated electromagnetic wave traverse, ionospheric Faraday Rotation measurement, radar polarimetry, range-compressed, signal chirp bandwidth effects, signal path delays, spaceborne SAR data, spaceborne synthetic aperture radar, total electron content, TEC, Faraday effect, ionospheric electromagnetic wave propagation, radar polarimetry, radar signal processing, remote sensing by radar, synthetic aperture radar.
    Abstract: The influence of the atmosphere on a frequency-modulated electromagnetic wave traversing the ionosphere is becoming increasingly important for recent and upcoming low-frequency and wide-bandwidth spaceborne synthetic aperture radar (SAR) systems. The ionized ionosphere induces Faraday rotation (FR) at these frequencies that affects radar polarimetry and causes signal path delays resulting in a reduced range resolution. The work at hand introduces a simulation model of SAR signals passing through the atmosphere, including both frequency-dependent FR and path delays. Based on simulation results from this model [proven with real Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (PALSAR) data], estimation of FR in quad-polarized SAR data using the given approach is shown for raw, range-compressed, and focused radar images. Path delays and signal chirp bandwidth effects are considered. Investigations discuss the suitability of raw and compressed data versus combination of total electron content maps with the Earth's magnetic field for FR estimation and deduced from a large number of analyzed PALSAR data sets.

    @Article{JehleRueggZuberbuhlerSmallMeier2009:MeasurementofIonoFaradayRot,
    author = {Jehle, Michael and R{\"u}egg, Maurice and Zuberb{\"u}hler, Lukas and Small, David and Meier, Erich},
    title = {Measurement of Ionospheric {F}araday Rotation in Simulated and Real Spaceborne {SAR} Data},
    journal = {{IEEE} Trans. Geosci. Remote Sens.},
    year = {2009},
    volume = {47},
    number = {5},
    pages = {1512-1523},
    month = may,
    issn = {0196-2892},
    abstract = {The influence of the atmosphere on a frequency-modulated electromagnetic wave traversing the ionosphere is becoming increasingly important for recent and upcoming low-frequency and wide-bandwidth spaceborne synthetic aperture radar (SAR) systems. The ionized ionosphere induces Faraday rotation (FR) at these frequencies that affects radar polarimetry and causes signal path delays resulting in a reduced range resolution. The work at hand introduces a simulation model of SAR signals passing through the atmosphere, including both frequency-dependent FR and path delays. Based on simulation results from this model [proven with real Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (PALSAR) data], estimation of FR in quad-polarized SAR data using the given approach is shown for raw, range-compressed, and focused radar images. Path delays and signal chirp bandwidth effects are considered. Investigations discuss the suitability of raw and compressed data versus combination of total electron content maps with the Earth's magnetic field for FR estimation and deduced from a large number of analyzed PALSAR data sets.},
    doi = {10.1109/TGRS.2008.2004710},
    file = {:JehleRueggZuberbuhlerSmallMeier2009MeasurementofIonoFaradayRot.pdf:PDF},
    keywords = {SAR Processing, Ionosphere, ALOS PALSAR, Advanced Land Observing Satellite;Earth's magnetic field;PALSAR data;Phased Array L-band Synthetic Aperture Radar;focused radar images;frequency-modulated electromagnetic wave traverse;ionospheric Faraday Rotation measurement;radar polarimetry;range-compressed;signal chirp bandwidth effects;signal path delays;spaceborne SAR data;spaceborne synthetic aperture radar;total electron content; TEC, Faraday effect;ionospheric electromagnetic wave propagation;radar polarimetry; radar signal processing;remote sensing by radar;synthetic aperture radar},
    
    }
    


  14. Wang Jinfeng and Pi Yiming. SAR tomography imaging via higher-order spectrum analysis. Journal of Systems Engineering and Electronics, 20(4):748-754, August 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography.
    Abstract: To deal with the non-Gaussian noise in standard 2-D SAR images, the deramped signal in imaging plane, and the possible symmetric distribution of complex noise, the fourth-order cumulant of complex process is introduced into SAR tomography. With the estimated AR parameters of ARMA model of noise through Yule-Walker Walker equation, the signal series of height is pre-filtered. Then, through ESPRIT, the spectrum is obtained and the aperture in height direction is synthesized. Finally, the SAR tomography imaging of scene is achieved. The results of processing on signal with non-Gaussian noise demonstrate the robustness of the proposed method. The tomography imaging of the scenes shows that the higher-order spectrum analysis is feasible in the application.

    @Article{6074498,
    Title = {SAR tomography imaging via higher-order spectrum analysis},
    Author = {Jinfeng, Wang and Yiming, Pi},
    Month = aug,
    Number = {4},
    Pages = {748-754},
    Volume = {20},
    Year = {2009},
    Abstract = {To deal with the non-Gaussian noise in standard 2-D SAR images, the deramped signal in imaging plane, and the possible symmetric distribution of complex noise, the fourth-order cumulant of complex process is introduced into SAR tomography. With the estimated AR parameters of ARMA model of noise through Yule-Walker Walker equation, the signal series of height is pre-filtered. Then, through ESPRIT, the spectrum is obtained and the aperture in height direction is synthesized. Finally, the SAR tomography imaging of scene is achieved. The results of processing on signal with non-Gaussian noise demonstrate the robustness of the proposed method. The tomography imaging of the scenes shows that the higher-order spectrum analysis is feasible in the application.},
    Journal = {Journal of Systems Engineering and Electronics},
    Keywords = {SAR Processing, SAR Tomography, Tomography} 
    }
    


  15. Guoxiang Liu, Sean M. Buckley, Xiaoli Ding, Qiang Chen, and Xiaojun Luo. Estimating Spatiotemporal Ground Deformation With Improved Persistent-Scatterer Radar Interferometry. IEEE Trans. Geosci. Remote Sens., 47(9):3209-3219, September 2009. Keyword(s): AD 1992 to 2000, Arizona, C-band SAR images, EMD approach, European Remote Sensing 1-2 satellites, PS-InSAR technique, PS-neighborhood networking approach, Phoenix, USA, atmospheric artifacts, atmospheric signals, empirical mode decomposition approach, least squares method, linear deformation rates, nonlinear deformation, persistent-scatterer interferometric synthetic aperture radar technique, singular value decomposition, spatial-temporal decorrelation, subsidence, synthetic aperture radar images, temporally coherent radar targets, time series, topographic errors, geophysical techniques, radar interferometry, remote sensing by radar, synthetic aperture radar, topography (Earth);.
    Abstract: Synthetic aperture radar interferometry has been applied widely in recent years to ground deformation monitoring although difficulties are often encountered when applying the technology, among which the spatial and temporal decorrelation and atmospheric artifacts are the most prominent. The persistent-scatterer interferometric synthetic aperture radar (PS-InSAR) technique has overcome some of the difficulties by focusing only on the temporally coherent radar targets in a time series of synthetic aperture radar (SAR) images. This paper presents an improved PS-InSAR technique by introducing PS-neighborhood networking and empirical mode decomposition (EMD) approaches in the PS-InSAR solution. Linear deformation rates and topographic errors are estimated based on a least squares method, while the nonlinear deformation and atmospheric signals are computed by singular value decomposition and the EMD method. An area in Phoenix, AZ, is used as a test site to determine its historical subsidence with 39 C-band SAR images acquired by European Remote Sensing 1 and 2 satellites from 1992 to 2000.

    @Article{liuBuckleyDingChenLuo2009,
    Title = {Estimating Spatiotemporal Ground Deformation With Improved Persistent-Scatterer Radar Interferometry},
    Author = {Guoxiang Liu and Buckley, Sean M. and Xiaoli Ding and Qiang Chen and Xiaojun Luo},
    Doi = {10.1109/TGRS.2009.2028797},
    ISSN = {0196-2892},
    Month = sep,
    Number = {9},
    Pages = {3209-3219},
    Volume = {47},
    Year = {2009},
    Abstract = {Synthetic aperture radar interferometry has been applied widely in recent years to ground deformation monitoring although difficulties are often encountered when applying the technology, among which the spatial and temporal decorrelation and atmospheric artifacts are the most prominent. The persistent-scatterer interferometric synthetic aperture radar (PS-InSAR) technique has overcome some of the difficulties by focusing only on the temporally coherent radar targets in a time series of synthetic aperture radar (SAR) images. This paper presents an improved PS-InSAR technique by introducing PS-neighborhood networking and empirical mode decomposition (EMD) approaches in the PS-InSAR solution. Linear deformation rates and topographic errors are estimated based on a least squares method, while the nonlinear deformation and atmospheric signals are computed by singular value decomposition and the EMD method. An area in Phoenix, AZ, is used as a test site to determine its historical subsidence with 39 C-band SAR images acquired by European Remote Sensing 1 and 2 satellites from 1992 to 2000.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {AD 1992 to 2000;Arizona;C-band SAR images;EMD approach;European Remote Sensing 1-2 satellites;PS-InSAR technique;PS-neighborhood networking approach;Phoenix;USA;atmospheric artifacts;atmospheric signals;empirical mode decomposition approach;least squares method;linear deformation rates;nonlinear deformation;persistent-scatterer interferometric synthetic aperture radar technique;singular value decomposition;spatial-temporal decorrelation;subsidence;synthetic aperture radar images;temporally coherent radar targets;time series;topographic errors;geophysical techniques;radar interferometry;remote sensing by radar;synthetic aperture radar;topography (Earth);} 
    }
    


  16. F. Lombardini, M. Pardini, G. Fornaro, F. Serafino, L. Verrazzani, and M. Costantini. Linear and adaptive spaceborne threedimensional SAR tomography: a comparison on real data. IET Radar, Sonar Navigation, 3(4):424-436, August 2009. Keyword(s): ERS satellite urban data, SAR interferometry concept, adaptive beamforming, adaptive spaceborne three-dimensional SAR tomography, linear spaceborne three-dimensional SAR tomography, singular value decomposition, synthetic aperture radar imaging, array signal processing, geophysical signal processing, radar imaging, remote sensing by radar, singular value decomposition, spaceborne radar, synthetic aperture radar, tomography.
    Abstract: SAR Processing, SAR Tomography, Tomography, Three-dimensional (3-D) synthetic aperture radar (SAR) imaging is a recent technique, based on coherent SAR data combination, and aims to obtain a full 3-D analysis in space. It is a multibaseline extension of the SAR interferometry concept and offers new options for the analysis and monitoring of ground scenes by means of the capability of separating the scattering phenomena along the height dimension. In this work, the authors summarise and extend the results obtained by processing real ERS satellite urban data characterised by a long time span of acquisition and non-uniformly spaced satellite passes, comparing the performance in height focusing obtained with a singular value decomposition (SVD)-based method and adaptive beamforming.

    @Article{5210026,
    Title = {Linear and adaptive spaceborne threedimensional SAR tomography: a comparison on real data},
    Author = {Lombardini, F. and Pardini, M. and Fornaro, G. and Serafino, F. and Verrazzani, L. and Costantini, M.},
    Doi = {10.1049/iet-rsn.2008.0171},
    ISSN = {1751-8784},
    Month = aug,
    Number = {4},
    Pages = {424-436},
    Volume = {3},
    Year = {2009},
    Abstract = {SAR Processing, SAR Tomography, Tomography, Three-dimensional (3-D) synthetic aperture radar (SAR) imaging is a recent technique, based on coherent SAR data combination, and aims to obtain a full 3-D analysis in space. It is a multibaseline extension of the SAR interferometry concept and offers new options for the analysis and monitoring of ground scenes by means of the capability of separating the scattering phenomena along the height dimension. In this work, the authors summarise and extend the results obtained by processing real ERS satellite urban data characterised by a long time span of acquisition and non-uniformly spaced satellite passes, comparing the performance in height focusing obtained with a singular value decomposition (SVD)-based method and adaptive beamforming.},
    Journal = {IET Radar, Sonar Navigation},
    Keywords = {ERS satellite urban data;SAR interferometry concept;adaptive beamforming;adaptive spaceborne three-dimensional SAR tomography;linear spaceborne three-dimensional SAR tomography;singular value decomposition;synthetic aperture radar imaging;array signal processing;geophysical signal processing;radar imaging;remote sensing by radar;singular value decomposition;spaceborne radar;synthetic aperture radar;tomography} 
    }
    


  17. R. L. Morrison, M. N. Do, and D. C. Munson. MCA: A Multichannel Approach to SAR Autofocus. IEEE Transactions on Image Processing, 18(4):840-853, April 2009. Keyword(s): SAR Processing, Autofocus, SAR autofocus, defocusing operation, focused image, image restoration, linear algebraic formulation, multichannel autofocus, multichannel redundancy, sharpness metric optimization, synthetic aperture radar, vector-space formulation, image restoration, linear algebra, synthetic aperture radar;.
    Abstract: We present a new noniterative approach to synthetic aperture radar (SAR) autofocus, termed the multichannel autofocus (MCA) algorithm. The key in the approach is to exploit the multichannel redundancy of the defocusing operation to create a linear subspace, where the unknown perfectly focused image resides, expressed in terms of a known basis formed from the given defocused image. A unique solution for the perfectly focused image is then directly determined through a linear algebraic formulation by invoking an additional image support condition. The MCA approach is found to be computationally efficient and robust and does not require prior assumptions about the SAR scene used in existing methods. In addition, the vector-space formulation of MCA allows sharpness metric optimization to be easily incorporated within the restoration framework as a regularization term. We present experimental results characterizing the performance of MCA in comparison with conventional autofocus methods and discuss the practical implementation of the technique.

    @Article{morrisonDoMunsonMCA2009,
    author = {Morrison, R. L. and Do, M. N. and Munson, D. C.},
    title = {MCA: A Multichannel Approach to {SAR} Autofocus},
    journal = {IEEE Transactions on Image Processing},
    year = {2009},
    volume = {18},
    number = {4},
    pages = {840-853},
    month = apr,
    issn = {1057-7149},
    abstract = {We present a new noniterative approach to synthetic aperture radar (SAR) autofocus, termed the multichannel autofocus (MCA) algorithm. The key in the approach is to exploit the multichannel redundancy of the defocusing operation to create a linear subspace, where the unknown perfectly focused image resides, expressed in terms of a known basis formed from the given defocused image. A unique solution for the perfectly focused image is then directly determined through a linear algebraic formulation by invoking an additional image support condition. The MCA approach is found to be computationally efficient and robust and does not require prior assumptions about the SAR scene used in existing methods. In addition, the vector-space formulation of MCA allows sharpness metric optimization to be easily incorporated within the restoration framework as a regularization term. We present experimental results characterizing the performance of MCA in comparison with conventional autofocus methods and discuss the practical implementation of the technique.},
    doi = {10.1109/TIP.2009.2012883},
    file = {:morrisonDoMunsonMCA2009.pdf:PDF},
    keywords = {SAR Processing, Autofocus, SAR autofocus;defocusing operation;focused image;image restoration;linear algebraic formulation;multichannel autofocus;multichannel redundancy;sharpness metric optimization;synthetic aperture radar;vector-space formulation;image restoration;linear algebra;synthetic aperture radar;},
    pdf = {../../../docs/morrisonDoMunsonMCA2009.pdf},
    
    }
    


  18. Matteo Nannini, Rolf Scheiber, and Alberto Moreira. Estimation of the Minimum Number of Tracks for SAR Tomography. IEEE Trans. Geosci. Remote Sens., 47(2):531-543, February 2009. Keyword(s): SAR Processing, SAR Tomography, Capon, MUSIC, image reconstruction, airboren SAR, image representation, radar interferometry, synthetic aperture radar3D representation, German Aerospace Center, DLR, L-band, SAR interferometry, SARTom, data acquisition, equivalent targets, experimental SAR system, minimum tomographic aperture, spheroidal wave functions, subspace superresolution methods, synthetic aperture radar tomography, tracks minimum number determination, volumetric source, ESAR.
    Abstract: Synthetic aperture radar tomography (SARTom) is the natural extension of SAR interferometry to solve for multiple phase centers within a resolution cell and obtain the 3-D representation of a scene. This paper deals with the determination of the minimum number of tracks required to perform SARTom. Through the prolate spheroidal wave functions, the number of equivalent targets of a volumetric source is derived, and from it, the minimum number of observations required to apply subspace superresolution methods is computed. The minimum tomographic aperture length is also investigated. The results are validated on real data acquired in L-band by the experimental SAR system of the German Aerospace Center.

    @Article{nanniniScheiberMoreiraTGRS2009:SARTom,
    Title = {Estimation of the Minimum Number of Tracks for {SAR} Tomography},
    Author = {Nannini, Matteo and Scheiber, Rolf and Moreira, Alberto},
    Doi = {10.1109/TGRS.2008.2007846},
    ISSN = {0196-2892},
    Month = feb,
    Number = {2},
    Pages = {531-543},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4768718&isnumber=4773457},
    Volume = {47},
    Year = {2009},
    Abstract = {Synthetic aperture radar tomography (SARTom) is the natural extension of SAR interferometry to solve for multiple phase centers within a resolution cell and obtain the 3-D representation of a scene. This paper deals with the determination of the minimum number of tracks required to perform SARTom. Through the prolate spheroidal wave functions, the number of equivalent targets of a volumetric source is derived, and from it, the minimum number of observations required to apply subspace superresolution methods is computed. The minimum tomographic aperture length is also investigated. The results are validated on real data acquired in L-band by the experimental SAR system of the German Aerospace Center.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, SAR Tomography, Capon, MUSIC, image reconstruction, airboren SAR, image representation, radar interferometry, synthetic aperture radar3D representation, German Aerospace Center, DLR, L-band, SAR interferometry, SARTom, data acquisition, equivalent targets, experimental SAR system, minimum tomographic aperture, spheroidal wave functions, subspace superresolution methods, synthetic aperture radar tomography, tracks minimum number determination, volumetric source, ESAR},
    Owner = {ofrey},
    Pdf = {../../../docs/nanniniScheiberMoreiraTGRS2009.pdf} 
    }
    


  19. S. Ozsoy and A.A. Ergin. Pencil Back-Projection Method for SAR Imaging. IEEE Transactions on Image Processing, 18(3):573-581, March 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, SAR imaging, forward-backward total least squares bandpass matrix pencil method, pencil back-projection method, projected target reflectivity density function, synthetic aperture radar, tomographic image reconstruction, image reconstruction, least squares approximations, matrix algebra, radar imaging, synthetic aperture radar, Algorithms, Image Enhancement, Image Interpretation, Computer-Assisted, Imaging, Three-Dimensional, Radar, Reproducibility of Results, Sensitivity and Specificity, Tomography;.
    Abstract: We present a high-resolution method for spotlight mode SAR imaging that utilizes parametric modeling of projected target reflectivity density function and tomographic reconstruction. The method requires no polar-to-cartesian interpolation in spectral domain. Utilization of forward-backward total least squares bandpass matrix pencil method allows super resolution to be achieved in range for a single imaging angle. Hence, the quality of the image reconstructed by convolution back-projection is also improved. It is shown that the method is very resistant to noise and can generate images down to very low SNR values. Direct formulation in terms of physical quantities such as electric field and current density is another contribution of this paper.

    @Article{4770154,
    Title = {Pencil Back-Projection Method for SAR Imaging},
    Author = {Ozsoy, S. and Ergin, A.A.},
    Doi = {10.1109/TIP.2008.2010178},
    ISSN = {1057-7149},
    Month = mar,
    Number = {3},
    Pages = {573-581},
    Volume = {18},
    Year = {2009},
    Abstract = {We present a high-resolution method for spotlight mode SAR imaging that utilizes parametric modeling of projected target reflectivity density function and tomographic reconstruction. The method requires no polar-to-cartesian interpolation in spectral domain. Utilization of forward-backward total least squares bandpass matrix pencil method allows super resolution to be achieved in range for a single imaging angle. Hence, the quality of the image reconstructed by convolution back-projection is also improved. It is shown that the method is very resistant to noise and can generate images down to very low SNR values. Direct formulation in terms of physical quantities such as electric field and current density is another contribution of this paper.},
    Journal = {IEEE Transactions on Image Processing},
    Keywords = {SAR Processing, SAR Tomography, Tomography, SAR imaging;forward-backward total least squares bandpass matrix pencil method;pencil back-projection method;projected target reflectivity density function;synthetic aperture radar;tomographic image reconstruction;image reconstruction;least squares approximations;matrix algebra;radar imaging;synthetic aperture radar;Algorithms;Image Enhancement;Image Interpretation, Computer-Assisted;Imaging, Three-Dimensional;Radar;Reproducibility of Results;Sensitivity and Specificity;Tomography;} 
    }
    


  20. Luca Pipia, Xavier Fabregas, Albert Aguasca, Carlos Lopez-Martinez, Sergi Duque, Jordi J. Mallorqui, and Jordi Marturia. Polarimetric Differential SAR Interferometry: First Results With Ground-Based Measurements. IEEE Geosci. Remote Sens. Lett., 6(1):167-171, January 2009. Keyword(s): SAR Processing, GBSAR, Ground-based SAR, deformation monitoring, geomorphology, geophysical signal processing, radar interferometry, radar polarimetry, remote sensing by radar, synthetic aperture radar, topography (Earth), AD 2006 06 to 2007 03, PolSAR, Remote Sensing Laboratory, Sallent, Universitat Politecnica de Catalunya, coherent pixels technique, ground-based synthetic aperture radar sensor, high-quality deformation maps, northeastern Spain, polarimetric differential SAR interferometry, subsidence information, troposphere changes, zero-baseline polarimetric SAR, Ground-based synthetic aperture radar (GBSAR) sensor, SAR differential interferometry (DInSAR), SAR polarimetry.
    Abstract: The Remote Sensing Laboratory of the Universitat Politecnica de Catalunya carried out a one-year measuring campaign in the village of Sallent, northeastern Spain, using a polarimetric ground-based synthetic aperture radar (SAR) sensor. The objective was to study the subsidence phenomenon induced by the salt mining activity conducted in this area up to the middle of the last century. Zero-Baseline polarimetric SAR (PolSAR) data were gathered at X-band in nine different days, from June 2006 to March 2007. In this letter, the problem of extracting subsidence information from fully PolSAR acquisitions for the retrieval of high-quality deformation maps is addressed. After compensating for the atmospheric artifacts caused by troposphere changes, the linear component of the deformation process is estimated separately for each polarization channel with the Coherent Pixels Technique (CPT). Afterward, a novel polarimetric approach mixing the differential-phase information of each polarization channel is proposed. The results obtained in the two cases are quantitatively compared, and the advantages provided by the polarimetric acquisitions are finally stressed.

    @Article{pipiaFabregasAguascaLopezMartinezDuqueMallorquiMarturiaGRSL2009PolGBSAR,
    author = {Pipia, Luca and Fabregas, Xavier and Aguasca, Albert and Lopez-Martinez, Carlos and Duque, Sergi and Mallorqui, Jordi J. and Marturia, Jordi},
    title = {Polarimetric Differential {SAR} Interferometry: First Results With Ground-Based Measurements},
    journal = {IEEE Geosci. Remote Sens. Lett.},
    year = {2009},
    volume = {6},
    number = {1},
    pages = {167-171},
    month = jan,
    issn = {1545-598X},
    abstract = {The Remote Sensing Laboratory of the Universitat Politecnica de Catalunya carried out a one-year measuring campaign in the village of Sallent, northeastern Spain, using a polarimetric ground-based synthetic aperture radar (SAR) sensor. The objective was to study the subsidence phenomenon induced by the salt mining activity conducted in this area up to the middle of the last century. Zero-Baseline polarimetric SAR (PolSAR) data were gathered at X-band in nine different days, from June 2006 to March 2007. In this letter, the problem of extracting subsidence information from fully PolSAR acquisitions for the retrieval of high-quality deformation maps is addressed. After compensating for the atmospheric artifacts caused by troposphere changes, the linear component of the deformation process is estimated separately for each polarization channel with the Coherent Pixels Technique (CPT). Afterward, a novel polarimetric approach mixing the differential-phase information of each polarization channel is proposed. The results obtained in the two cases are quantitatively compared, and the advantages provided by the polarimetric acquisitions are finally stressed.},
    doi = {10.1109/LGRS.2008.2009007},
    file = {:pipiaFabregasAguascaLopezMartinezDuqueMallorquiMarturiaGRSL2009PolGBSAR.pdf:PDF},
    keywords = {SAR Processing, GBSAR, Ground-based SAR, deformation monitoring, geomorphology;geophysical signal processing;radar interferometry; radar polarimetry;remote sensing by radar;synthetic aperture radar;topography (Earth);AD 2006 06 to 2007 03;PolSAR; Remote Sensing Laboratory;Sallent;Universitat Politecnica de Catalunya;coherent pixels technique;ground-based synthetic aperture radar sensor; high-quality deformation maps;northeastern Spain;polarimetric differential SAR interferometry;subsidence information;troposphere changes; zero-baseline polarimetric SAR;Ground-based synthetic aperture radar (GBSAR) sensor;SAR differential interferometry (DInSAR);SAR polarimetry},
    
    }
    


  21. Pau Prats, Rolf Scheiber, Andreas Reigber, Christian Andres, and Ralf Horn. Estimation of the Surface Velocity Field of the Aletsch Glacier Using Multibaseline Airborne SAR Interferometry. IEEE Transactions on Geoscience and Remote Sensing, 47(2):419-430, Feb. 2009. Keyword(s): SAR Processing, InSAR, DInSAR, airborne SAR, glaciology, hydrological techniques, SAR Interferometry, Interferometry, remote sensing by radar, synthetic aperture radar, Aletsch Glacier, Alps, German Aerospace Center, L-band, airborne interferometric synthetic aperture radar, data acquisition, differential interferometry, experimental SAR system, line-of-sight displacement, multisquint approach, navigation system, residual motion errors, surface velocity field estimation, temperate glaciers, ESAR.
    Abstract: This paper presents a methodology to process airborne interferometric synthetic aperture radar (SAR) data to measure surface velocity fields (SVFs) of temperate glaciers, and applies it to data acquired over the Aletsch glacier. The first part of this paper deals with the main limitation in airborne interferometric SAR to retrieve reliable interferometric products, namely, the existence of the so-called residual motion errors - inaccuracies on the order of a few centimeters in the navigation system. An extended multisquint approach is proposed for their estimation in the case of nonstationary scenes. The second part of this paper expounds an efficient methodology to derive SVFs with airborne systems, where the line-of-sight displacement is estimated using differential interferometry and the along-track component by estimating the azimuth coregistration offsets. The necessary steps to finally obtain the 3-D SVF are also presented, as well as the possibility of combining different acquisition geometries. Airborne interferometric SAR data acquired by the Experimental SAR system of the German aerospace center over the Aletsch glacier, located in the Swiss Alps, are used to evaluate the performance of the proposed approach. The motion of the corner reflectors deployed in the scene is retrieved with an accuracy between 1 and 5 cm/day using L-band data.

    @Article{pratsScheiberReigberAndresHorn2009:DInSARAletsch,
    author = {Prats, Pau and Scheiber, Rolf and Reigber, Andreas and Andres, Christian and Horn, Ralf},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Estimation of the Surface Velocity Field of the {Aletsch} Glacier Using Multibaseline Airborne {SAR} Interferometry},
    year = {2009},
    issn = {0196-2892},
    month = {Feb.},
    number = {2},
    pages = {419-430},
    volume = {47},
    abstract = {This paper presents a methodology to process airborne interferometric synthetic aperture radar (SAR) data to measure surface velocity fields (SVFs) of temperate glaciers, and applies it to data acquired over the Aletsch glacier. The first part of this paper deals with the main limitation in airborne interferometric SAR to retrieve reliable interferometric products, namely, the existence of the so-called residual motion errors - inaccuracies on the order of a few centimeters in the navigation system. An extended multisquint approach is proposed for their estimation in the case of nonstationary scenes. The second part of this paper expounds an efficient methodology to derive SVFs with airborne systems, where the line-of-sight displacement is estimated using differential interferometry and the along-track component by estimating the azimuth coregistration offsets. The necessary steps to finally obtain the 3-D SVF are also presented, as well as the possibility of combining different acquisition geometries. Airborne interferometric SAR data acquired by the Experimental SAR system of the German aerospace center over the Aletsch glacier, located in the Swiss Alps, are used to evaluate the performance of the proposed approach. The motion of the corner reflectors deployed in the scene is retrieved with an accuracy between 1 and 5 cm/day using L-band data.},
    doi = {10.1109/TGRS.2008.2004277},
    keywords = {SAR Processing, InSAR, DInSAR, airborne SAR, glaciology, hydrological techniques, SAR Interferometry, Interferometry, remote sensing by radar, synthetic aperture radar, Aletsch Glacier, Alps, German Aerospace Center, L-band, airborne interferometric synthetic aperture radar, data acquisition, differential interferometry, experimental SAR system, line-of-sight displacement, multisquint approach, navigation system, residual motion errors, surface velocity field estimation, temperate glaciers, ESAR},
    owner = {ofrey},
    pdf = {../../../docs/pratsScheiberReigberAndresHorn2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4695999&isnumber=4773457},
    
    }
    


  22. S. Sauer, L. Ferro-Famil, A. Reigber, and E. Pottier. Polarimetric Dual-Baseline InSAR Building Height Estimation at L-Band. IEEE Geoscience and Remote Sensing Letters, 6(3):408-412, July 2009. Keyword(s): SAR Procerssing, PolInSAR, Polarimetry, InSAR, SAR Interferometry, Dual-Baseline, Multi-baseline SAR, SAR Tomography, Tomography, ESAR, Airborne SAR, Building Height.
    Abstract: This letter generalizes a multibaseline interferometric synthetic aperture radar (InSAR) signal model to the polarimetric scenario. Based on this formulation, two high-performance spectral analysis techniques are adapted to process multibaseline Pol-InSAR observations. These new methods enhance the height estimation of scatterers by calculating optimal polarization combinations and allow the determination of their physical characteristics. Applying the proposed algorithms to urban environments, the building layover problem is analyzed by means of polarimetric dual-baseline InSAR measurements: the ground and building height are estimated. The techniques are validated using dual-baseline Pol-InSAR data acquired by DLR's Experimental SAR (E-SAR) system over Dresden city.

    @Article{SauerFerroFamilReigberPottier2009:POlInSARBuildingHeight,
    author = {Sauer, S. and Ferro-Famil, L. and Reigber, A. and Pottier, E.},
    journal = {IEEE Geoscience and Remote Sensing Letters},
    title = {Polarimetric Dual-Baseline {InSAR} Building Height Estimation at {L}-Band},
    year = {2009},
    issn = {1545-598X},
    month = jul,
    number = {3},
    pages = {408-412},
    volume = {6},
    abstract = {This letter generalizes a multibaseline interferometric synthetic aperture radar (InSAR) signal model to the polarimetric scenario. Based on this formulation, two high-performance spectral analysis techniques are adapted to process multibaseline Pol-InSAR observations. These new methods enhance the height estimation of scatterers by calculating optimal polarization combinations and allow the determination of their physical characteristics. Applying the proposed algorithms to urban environments, the building layover problem is analyzed by means of polarimetric dual-baseline InSAR measurements: the ground and building height are estimated. The techniques are validated using dual-baseline Pol-InSAR data acquired by DLR's Experimental SAR (E-SAR) system over Dresden city.},
    doi = {10.1109/LGRS.2009.2014571},
    keywords = {SAR Procerssing, PolInSAR, Polarimetry, InSAR, SAR Interferometry, Dual-Baseline, Multi-baseline SAR, SAR Tomography, Tomography ,ESAR, Airborne SAR, Building Height},
    owner = {ofrey},
    pdf = {../../../docs/SauerFerroFamilReigberPottier2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4801686&isnumber=5153590},
    
    }
    


  23. Piyush Shanker Agram and Howard A. Zebker. Sparse Two-Dimensional Phase Unwrapping Using Regular Grid Methods. IEEE Geosci. Remote Sens. Lett., 6(3):519-522, July 2009. Keyword(s): SAR Processing, Delaunay triangulation, image reconstruction, interferometric synthetic aperture radar, nearest neighbor interpolation scheme, regular grid methods, sparse data, sparse two-dimensional phase unwrapping, image reconstruction, radar imaging, radar interferometry, synthetic aperture radar;.
    Abstract: Phase unwrapping is usually defined as the reconstruction of a function sampled on a spatial grid given its value modulo 2pi. Phase unwrapping is a key step in image reconstruction in many imaging techniques including interferometric synthetic aperture radar (InSAR). In recent years, many new methods have been developed to exploit the presence of coherent or persistent scattering points for extracting deformation signatures in regions where conventional InSAR fails. These techniques often yield measurements that are only poorly sampled spatially, yet these sparse data must still be unwrapped if we are to be able to extract useful geophysical information. The conventional well-sampled 2-D phase unwrapping problem based on phase residues is fairly well understood and many novel techniques involving geometry and network flow concepts have been implemented successfully to date. For sparse data, residues may be computed over the Delaunay triangulation of the data points, but published algorithms meet with limited success when the sparse data are unwrapped. The advantages of modern unwrapping methods applicable to well-sampled data are often lost when sparse data are analyzed. In this letter, we show that a nearest neighbor interpolation scheme allows powerful and existing 2-D solvers to be applied to sparse data. We present results using both simulated and real data sets to illustrate our method.

    @Article{shankerAgramZebkerGRSL2009:,
    Title = {Sparse Two-Dimensional Phase Unwrapping Using Regular Grid Methods},
    Author = {Shanker Agram, Piyush and Zebker, Howard A.},
    Doi = {10.1109/LGRS.2009.2020522},
    ISSN = {1545-598X},
    Month = jul,
    Number = {3},
    Pages = {519-522},
    Volume = {6},
    Year = {2009},
    Abstract = {Phase unwrapping is usually defined as the reconstruction of a function sampled on a spatial grid given its value modulo 2pi. Phase unwrapping is a key step in image reconstruction in many imaging techniques including interferometric synthetic aperture radar (InSAR). In recent years, many new methods have been developed to exploit the presence of coherent or persistent scattering points for extracting deformation signatures in regions where conventional InSAR fails. These techniques often yield measurements that are only poorly sampled spatially, yet these sparse data must still be unwrapped if we are to be able to extract useful geophysical information. The conventional well-sampled 2-D phase unwrapping problem based on phase residues is fairly well understood and many novel techniques involving geometry and network flow concepts have been implemented successfully to date. For sparse data, residues may be computed over the Delaunay triangulation of the data points, but published algorithms meet with limited success when the sparse data are unwrapped. The advantages of modern unwrapping methods applicable to well-sampled data are often lost when sparse data are analyzed. In this letter, we show that a nearest neighbor interpolation scheme allows powerful and existing 2-D solvers to be applied to sparse data. We present results using both simulated and real data sets to illustrate our method.},
    Journal = {{IEEE} Geosci. Remote Sens. Lett.},
    Keywords = {SAR Processing, Delaunay triangulation;image reconstruction;interferometric synthetic aperture radar; nearest neighbor interpolation scheme;regular grid methods;sparse data;sparse two-dimensional phase unwrapping; image reconstruction;radar imaging;radar interferometry;synthetic aperture radar;},
    Owner = {ofrey},
    Pdf = {../../../docs/shankerAgramZebkerGRSL2009.pdf} 
    }
    


  24. Manoochehr Shirzaei and TR Walter. Randomly iterated search and statistical competency as powerful inversion tools for deformation source modeling: Application to volcano interferometric synthetic aperture radar data. Journal of Geophysical Research: Solid Earth, 114(B10), 2009.
    @Article{Shirzaei2009,
    author = {Shirzaei, Manoochehr and Walter, TR},
    title = {Randomly iterated search and statistical competency as powerful inversion tools for deformation source modeling: Application to volcano interferometric synthetic aperture radar data},
    year = {2009},
    volume = {114},
    number = {B10},
    journal = {Journal of Geophysical Research: Solid Earth},
    owner = {ofrey},
    publisher = {Wiley Online Library},
    
    }
    


  25. Stefano Tebaldini. Algebraic Synthesis of Forest Scenarios From Multibaseline PolInSAR Data. IEEE Trans. Geosci. Remote Sens., 47(12):4132-4142, December 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, E-SAR, P-Band, algebra, geophysical techniques, radar polarimetry, remote sensing by radar, synthetic aperture radar, vegetationBioSAR, E-SAR airborne system, Kronecker products sum, P-band data set, Remningstorp, SAR surveys, Sweden, algebraic synthesis, forest scenarios, forested areas, least square solution, multibaseline PolInSAR data, multipolarimetric multibaseline synthetic aperture radar, single-baseline polarimetric SAR interferometry, statistical uncorrelation, temporal coherence losses, volumetric coherence losses.
    Abstract: In this paper, a new methodology is proposed for the analysis of forested areas basing on multipolarimetric multibaseline synthetic aperture radar (SAR) surveys. Such a methodology is based on three hypotheses: 1) statistical uncorrelation of the different scattering mechanisms (SMs), such as ground, volume, and ground-trunk scattering; 2) independence of volumetric and temporal coherence losses of each SM on the choice of the polarimetric channel; and 3) invariance (up to a scale factor) of the average polarimetric signature of each SM with respect to the choice of the track. Under these hypotheses, the data covariance matrix can be expressed as a Sum of Kronecker Products, after which it follows that K SMs are uniquely identified by K (K - 1) real numbers. This result provides the basis to perform SM separation by employing not only model-based approaches, generally retained in literature but also model-free and hybrid approaches, while yielding the best Least Square solution given the hypothesis of K SMs. It will be shown that this approach to SM separation is consistent with the inversion procedures usually exploited in single-baseline polarimetric SAR interferometry. Experimental validation of this methodology is provided on the basis of the P-band data set relative to the forest site of Remningstorp, Sweden, acquired by German Aerospace Center's E-SAR airborne system in the framework of the European Space Agency campaign BioSAR.

    @Article{tebaldiniTGRS2009:Tomo,
    Title = {Algebraic Synthesis of Forest Scenarios From Multibaseline {PolInSAR} Data},
    Author = {Tebaldini, Stefano},
    Doi = {10.1109/TGRS.2009.2023785},
    ISSN = {0196-2892},
    Month = dec,
    Number = {12},
    Pages = {4132-4142},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5226569&isnumber=5332061},
    Volume = {47},
    Year = {2009},
    Abstract = {In this paper, a new methodology is proposed for the analysis of forested areas basing on multipolarimetric multibaseline synthetic aperture radar (SAR) surveys. Such a methodology is based on three hypotheses: 1) statistical uncorrelation of the different scattering mechanisms (SMs), such as ground, volume, and ground-trunk scattering; 2) independence of volumetric and temporal coherence losses of each SM on the choice of the polarimetric channel; and 3) invariance (up to a scale factor) of the average polarimetric signature of each SM with respect to the choice of the track. Under these hypotheses, the data covariance matrix can be expressed as a Sum of Kronecker Products, after which it follows that K SMs are uniquely identified by K (K - 1) real numbers. This result provides the basis to perform SM separation by employing not only model-based approaches, generally retained in literature but also model-free and hybrid approaches, while yielding the best Least Square solution given the hypothesis of K SMs. It will be shown that this approach to SM separation is consistent with the inversion procedures usually exploited in single-baseline polarimetric SAR interferometry. Experimental validation of this methodology is provided on the basis of the P-band data set relative to the forest site of Remningstorp, Sweden, acquired by German Aerospace Center's E-SAR airborne system in the framework of the European Space Agency campaign BioSAR.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, SAR Tomography, Tomography, E-SAR, P-Band, algebra, geophysical techniques, radar polarimetry, remote sensing by radar, synthetic aperture radar, vegetationBioSAR, E-SAR airborne system, Kronecker products sum, P-band data set, Remningstorp, SAR surveys, Sweden, algebraic synthesis, forest scenarios, forested areas, least square solution, multibaseline PolInSAR data, multipolarimetric multibaseline synthetic aperture radar, single-baseline polarimetric SAR interferometry, statistical uncorrelation, temporal coherence losses, volumetric coherence losses},
    Owner = {ofrey},
    Pdf = {../../../docs/tebaldiniTGRS2009.pdf} 
    }
    


  26. R. N. Treuhaft, B. D. Chapman, J. R. dos Santos, F. G. Gonçalves, L. V. Dutra, P. M. L. A. Graça, and J. B. Drake. Vegetation profiles in tropical forests from multibaseline interferometric synthetic aperture radar, field, and lidar measurements. J. Geophys. Res., 114:1-16, December 2009. Keyword(s): SAR Processing, SAR Tomography, tropical forest structure, InSAR, interferometric SAR, lidar, Ecosystems, structure and dynamics, Remote sensing, Atmospheric Composition and Structure, Biosphere atmosphere interactions, Trace gases.
    Abstract: This paper addresses the estimation of vertical vegetation density profiles from multibaseline interferometric synthetic aperture radar (InSAR) data from the AirSAR aircraft at C band over primary, secondary, and abandoned-pasture stands at La Selva Biological Station, Costa Rica in 2004. Profiles were also estimated from field data taken in 2006 and lidar data taken with the LVIS, 25 m spot instrument in 2005. After motivating the study of tropical forest profiles based on their role in the global carbon cycle, ecosystem state, and biodiversity, this paper describes the InSAR, field, and lidar data acquisitions and analyses. Beyond qualitative agreement between profiles from the 3 measurement techniques, results show that InSAR and lidar profile-averaged mean height have RMS scatters about field-measured means of 3.4 m and 3.2 m, 16% and 15% of the average mean height, respectively. InSAR and lidar standard deviations of the vegetation distribution have RMS scatters about the field standard deviations of 1.9 m and 1.5 m, or 27% and 21%, respectively. Dominant errors in the profile-averaged mean height for each measurement technique were modeled. InSAR inaccuracies, dominated by ambiguities in finding the ground altitude and coherence calibration, together account for about 3 m of InSAR error in the mean height. The dominant, modeled error for the field measurements was the inaccuracy in modeling the trees as uniformly filled volumes of leaf area, inducing field errors in mean height of about 3 m. The dominant, modeled lidar error, also due to finding the ground, was 2 m.

    @Article{treuhaftChapmanDosSantosGoncalvesDutraGracaDrake2009:SARVegetationProfiles,
    Title = {Vegetation profiles in tropical forests from multibaseline interferometric synthetic aperture radar, field, and lidar measurements},
    Author = {Treuhaft, R. N. and Chapman, B. D. and dos Santos, J. R. and Gon\c{c}alves, F. G. and Dutra, L. V. and Gra\c{c}a, P. M. L. A. and Drake, J. B.},
    Month = dec,
    Pages = {1-16},
    Volume = {114},
    Year = {2009},
    Abstract = {This paper addresses the estimation of vertical vegetation density profiles from multibaseline interferometric synthetic aperture radar (InSAR) data from the AirSAR aircraft at C band over primary, secondary, and abandoned-pasture stands at La Selva Biological Station, Costa Rica in 2004. Profiles were also estimated from field data taken in 2006 and lidar data taken with the LVIS, 25 m spot instrument in 2005. After motivating the study of tropical forest profiles based on their role in the global carbon cycle, ecosystem state, and biodiversity, this paper describes the InSAR, field, and lidar data acquisitions and analyses. Beyond qualitative agreement between profiles from the 3 measurement techniques, results show that InSAR and lidar profile-averaged mean height have RMS scatters about field-measured means of 3.4 m and 3.2 m, 16% and 15% of the average mean height, respectively. InSAR and lidar standard deviations of the vegetation distribution have RMS scatters about the field standard deviations of 1.9 m and 1.5 m, or 27% and 21%, respectively. Dominant errors in the profile-averaged mean height for each measurement technique were modeled. InSAR inaccuracies, dominated by ambiguities in finding the ground altitude and coherence calibration, together account for about 3 m of InSAR error in the mean height. The dominant, modeled error for the field measurements was the inaccuracy in modeling the trees as uniformly filled volumes of leaf area, inducing field errors in mean height of about 3 m. The dominant, modeled lidar error, also due to finding the ground, was 2 m.},
    Journal = {J. Geophys. Res.},
    Keywords = {SAR Processing, SAR Tomography, tropical forest structure, InSAR, interferometric SAR, lidar, Ecosystems, structure and dynamics, Remote sensing, Atmospheric Composition and Structure, Biosphere atmosphere interactions, Trace gases},
    Owner = {ofrey},
    Pdf = {../../../docs/treuhaftChapmanDosSantosGoncalvesDutraGracaDrake2009.pdf},
    Publisher = {American Geophysical Union} 
    }
    


  27. R. Wang, O. Loffeld, H. Nies, and J. Ender. Focusing Spaceborne/Airborne Hybrid Bistatic SAR Data Using Wavenumber-Domain Algorithm. IEEE Trans. Geosci. Remote Sens., 47(7):2275-2283, July 2009. Keyword(s): SAR Processing, Bistatic SAR, SAR data processing, azimuth time-bandwidth product, azimuth-dependent range-cell-migration terms, azimuth-frequency dependence, bistatic formula, bistatic point-target reference spectrum, bistatic synthetic aperture radar, bistatic-deformation, hybrid spaceborne/airborne simulation experiment, inverse scaled Fourier transformation, inverse sliding-spotlight mode, sliding-spotlight mode, spaceborne/airborne hybrid bistatic configuration, total Doppler spectrum, wavenumber-domain algorithm, weighting factor, Fourier transforms, airborne radar, spaceborne radar, synthetic aperture radar.
    Abstract: This paper focuses on the bistatic synthetic aperture radar (SAR) data processing in a spaceborne/airborne hybrid bistatic configuration. Due to the extreme differences in platform velocities and slant ranges, the airborne system operates in the inverse sliding-spotlight mode, while the spaceborne system works in the sliding-spotlight mode to achieve a tradeoff between azimuth scene size and azimuth resolution. In this extreme bistatic configuration, our original bistatic formula shows a limitation of accurately describing the bistatic point-target reference spectrum, owing to the assumption of equal contributions of transmitter and receiver to the total Doppler spectrum. We extend our previous formula using the weighting operation where the weighting factor is the ratio of the azimuth time-bandwidth product (TBP) of the platform to the total azimuth TBP. In this paper, the bistatic-deformation and azimuth-dependent range-cell-migration terms were removed with phase multiplications performed blockwise in range-azimuth subsections. The remaining quasi-monostatic term shows the characteristic of the conventional monostatic SAR besides an additional azimuth-scaling term. For the monostatic characteristic, any precision monostatic SAR processing algorithms can handle. In this paper, we prefer the wavenumber-domain algorithm (also known as Omega-K), since it can accurately correct the range dependence of the range-azimuth coupling, as well as the azimuth-frequency dependence. For the azimuth-scaling term, an inverse scaled Fourier transformation is performed to correct it. Finally, a hybrid spaceborne/airborne simulation experiment is conducted to validate the proposed processing procedure.

    @Article{WangLoffeldNiesEnder2009:WavenumberDomainBistatic,
    Title = {Focusing Spaceborne/Airborne Hybrid Bistatic {SAR} Data Using Wavenumber-Domain Algorithm},
    Author = {Wang, R. and Loffeld, O. and Nies, H. and Ender, J.},
    Doi = {10.1109/TGRS.2008.2010852},
    ISSN = {0196-2892},
    Month = jul,
    Number = {7},
    Pages = {2275-2283},
    Volume = {47},
    Year = {2009},
    Abstract = {This paper focuses on the bistatic synthetic aperture radar (SAR) data processing in a spaceborne/airborne hybrid bistatic configuration. Due to the extreme differences in platform velocities and slant ranges, the airborne system operates in the inverse sliding-spotlight mode, while the spaceborne system works in the sliding-spotlight mode to achieve a tradeoff between azimuth scene size and azimuth resolution. In this extreme bistatic configuration, our original bistatic formula shows a limitation of accurately describing the bistatic point-target reference spectrum, owing to the assumption of equal contributions of transmitter and receiver to the total Doppler spectrum. We extend our previous formula using the weighting operation where the weighting factor is the ratio of the azimuth time-bandwidth product (TBP) of the platform to the total azimuth TBP. In this paper, the bistatic-deformation and azimuth-dependent range-cell-migration terms were removed with phase multiplications performed blockwise in range-azimuth subsections. The remaining quasi-monostatic term shows the characteristic of the conventional monostatic SAR besides an additional azimuth-scaling term. For the monostatic characteristic, any precision monostatic SAR processing algorithms can handle. In this paper, we prefer the wavenumber-domain algorithm (also known as Omega-K), since it can accurately correct the range dependence of the range-azimuth coupling, as well as the azimuth-frequency dependence. For the azimuth-scaling term, an inverse scaled Fourier transformation is performed to correct it. Finally, a hybrid spaceborne/airborne simulation experiment is conducted to validate the proposed processing procedure.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing,Bistatic SAR,SAR data processing;azimuth time-bandwidth product;azimuth-dependent range-cell-migration terms;azimuth-frequency dependence;bistatic formula;bistatic point-target reference spectrum;bistatic synthetic aperture radar;bistatic-deformation;hybrid spaceborne/airborne simulation experiment;inverse scaled Fourier transformation;inverse sliding-spotlight mode;sliding-spotlight mode;spaceborne/airborne hybrid bistatic configuration;total Doppler spectrum;wavenumber-domain algorithm;weighting factor;Fourier transforms;airborne radar;spaceborne radar;synthetic aperture radar} 
    }
    


  28. R. Wang, O. Loffeld, H. Nies, S. Knedlik, and J. Ender. Chirp-Scaling Algorithm for Bistatic SAR Data in the Constant-Offset Configuration. IEEE Trans. Geosci. Remote Sens., 47(3):952-964, March 2009. Keyword(s): SAR Processing, Bistatic SAR, Chirp Scaling Algorithm, ECS, CSA processor, Doppler phase parameters, Loffeld bistatic formula, SAR receiver velocity vector, SAR transmitter velocity vector, azimuth invariant configuration, azimuth stationary configuration, bistatic SAR data processing method, bistatic deformation term linearisation, bistatic motion error model, bistatic slant range displacement, chirp scaling algorithm, constant offset configuration, monostatic motion compensation technique, quasimonostatic term linearisation, trajectory deviation compensattion, zero Doppler plane, Doppler radar, chirp modulation, geophysical signal processing, motion compensation, radar receivers, radar signal processing, radar transmitters, remote sensing by radar, synthetic aperture radar.
    Abstract: This paper discusses the processing method for bistatic SAR data in the constant-offset configuration. The constant-offset configuration is also known as the azimuth stationary or invariant configuration where transmitter and receiver follow each other, moving on identical velocity vector. In this paper, the proposed processing method for bistatic SAR data is based on Loffeld's bistatic formula that consists of two terms, i.e., the quasi-monostatic (QM) term and bistatic-deformation (BD) term. Our basic idea is to linearize the aforementioned two terms and then incorporate the BD term into the QM term to obtain an analogous monostatic spectrum. Based on the new spectrum, any efficient 2-D frequency or range-Doppler domain processor can easily be employed to process the bistatic data, where the Doppler phase parameters of the processor need to be adjusted. In this paper, we concentrate on the application of chirp-scaling-algorithm (CSA) processor. In addition, a bistatic-motion error model is developed where the position deviations of the two platforms are simplified as the bistatic slant-range displacement in the zero Doppler plane. Using this model, the monostatic motion-compensation technique is applied and integrated into CSA to compensate the trajectory deviations of transmitter and receiver. Finally, real and simulated data are used to validate the proposed processing method.

    @Article{WangLoffeldNiesKnedlikEnder2009:BistaticConstOffset,
    Title = {Chirp-Scaling Algorithm for Bistatic {SAR} Data in the Constant-Offset Configuration},
    Author = {Wang, R. and Loffeld, O. and Nies, H. and Knedlik, S. and Ender, J.},
    Doi = {10.1109/TGRS.2008.2006275},
    ISSN = {0196-2892},
    Month = mar,
    Number = {3},
    Pages = {952-964},
    Volume = {47},
    Year = {2009},
    Abstract = {This paper discusses the processing method for bistatic SAR data in the constant-offset configuration. The constant-offset configuration is also known as the azimuth stationary or invariant configuration where transmitter and receiver follow each other, moving on identical velocity vector. In this paper, the proposed processing method for bistatic SAR data is based on Loffeld's bistatic formula that consists of two terms, i.e., the quasi-monostatic (QM) term and bistatic-deformation (BD) term. Our basic idea is to linearize the aforementioned two terms and then incorporate the BD term into the QM term to obtain an analogous monostatic spectrum. Based on the new spectrum, any efficient 2-D frequency or range-Doppler domain processor can easily be employed to process the bistatic data, where the Doppler phase parameters of the processor need to be adjusted. In this paper, we concentrate on the application of chirp-scaling-algorithm (CSA) processor. In addition, a bistatic-motion error model is developed where the position deviations of the two platforms are simplified as the bistatic slant-range displacement in the zero Doppler plane. Using this model, the monostatic motion-compensation technique is applied and integrated into CSA to compensate the trajectory deviations of transmitter and receiver. Finally, real and simulated data are used to validate the proposed processing method.},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing,Bistatic SAR, Chirp Scaling Algorithm, ECS, CSA processor;Doppler phase parameters;Loffeld bistatic formula;SAR receiver velocity vector;SAR transmitter velocity vector;azimuth invariant configuration;azimuth stationary configuration;bistatic SAR data processing method;bistatic deformation term linearisation;bistatic motion error model;bistatic slant range displacement;chirp scaling algorithm;constant offset configuration;monostatic motion compensation technique;quasimonostatic term linearisation;trajectory deviation compensattion;zero Doppler plane;Doppler radar;chirp modulation;geophysical signal processing;motion compensation;radar receivers;radar signal processing;radar transmitters;remote sensing by radar;synthetic aperture radar} 
    }
    


  29. Robert Wang, Otmar Loffeld, Holger Nies, Stefan Knedlik, and Joachim H. G. Ender. Chirp-Scaling Algorithm for Bistatic SAR Data in the Constant-Offset Configuration. IEEE Transactions on Geoscience and Remote Sensing, 47(3):952 -964, March 2009. Keyword(s): SAR Processing, Chirp Scaling Algorithm, CSA, Bistatic SAR, Doppler phase parameters, Loffeld bistatic formula, SAR receiver velocity vector, SAR transmitter velocity vector, azimuth invariant configuration, azimuth stationary configuration, bistatic SAR data processing method, bistatic deformation term linearisation, bistatic motion error model, bistatic slant range displacement, constant offset configuration, monostatic motion compensation technique, quasimonostatic term linearisation, trajectory deviation compensation, zero Doppler plane, Doppler radar, chirp modulation, geophysical signal processing, Motion Compensation, MoComp, radar receivers, radar signal processing, radar transmitters, remote sensing by radar, synthetic aperture radar, Extended Chirp Scaling, ECS.
    Abstract: This paper discusses the processing method for bistatic SAR data in the constant-offset configuration. The constant-offset configuration is also known as the azimuth stationary or invariant configuration where transmitter and receiver follow each other, moving on identical velocity vector. In this paper, the proposed processing method for bistatic SAR data is based on Loffeld's bistatic formula that consists of two terms, i.e., the quasi-monostatic (QM) term and bistatic-deformation (BD) term. Our basic idea is to linearize the aforementioned two terms and then incorporate the BD term into the QM term to obtain an analogous monostatic spectrum. Based on the new spectrum, any efficient 2-D frequency or range-Doppler domain processor can easily be employed to process the bistatic data, where the Doppler phase parameters of the processor need to be adjusted. In this paper, we concentrate on the application of chirp-scaling-algorithm (CSA) processor. In addition, a bistatic-motion error model is developed where the position deviations of the two platforms are simplified as the bistatic slant-range displacement in the zero Doppler plane. Using this model, the monostatic motion-compensation technique is applied and integrated into CSA to compensate the trajectory deviations of transmitter and receiver. Finally, real and simulated data are used to validate the proposed processing method.

    @Article{wangLoffeldNiesKnedlikEnder2010:ChirpScalingBiStatic,
    Title = {Chirp-Scaling Algorithm for Bistatic {SAR} Data in the Constant-Offset Configuration},
    Author = {Robert Wang and Otmar Loffeld and Holger Nies and Stefan Knedlik and Joachim H. G. Ender},
    Doi = {10.1109/TGRS.2008.2006275},
    ISSN = {0196-2892},
    Month = mar,
    Number = {3},
    Pages = {952 -964},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4711112},
    Volume = {47},
    Year = {2009},
    Abstract = {This paper discusses the processing method for bistatic SAR data in the constant-offset configuration. The constant-offset configuration is also known as the azimuth stationary or invariant configuration where transmitter and receiver follow each other, moving on identical velocity vector. In this paper, the proposed processing method for bistatic SAR data is based on Loffeld's bistatic formula that consists of two terms, i.e., the quasi-monostatic (QM) term and bistatic-deformation (BD) term. Our basic idea is to linearize the aforementioned two terms and then incorporate the BD term into the QM term to obtain an analogous monostatic spectrum. Based on the new spectrum, any efficient 2-D frequency or range-Doppler domain processor can easily be employed to process the bistatic data, where the Doppler phase parameters of the processor need to be adjusted. In this paper, we concentrate on the application of chirp-scaling-algorithm (CSA) processor. In addition, a bistatic-motion error model is developed where the position deviations of the two platforms are simplified as the bistatic slant-range displacement in the zero Doppler plane. Using this model, the monostatic motion-compensation technique is applied and integrated into CSA to compensate the trajectory deviations of transmitter and receiver. Finally, real and simulated data are used to validate the proposed processing method.},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {SAR Processing, Chirp Scaling Algorithm, CSA, Bistatic SAR, Doppler phase parameters, Loffeld bistatic formula, SAR receiver velocity vector, SAR transmitter velocity vector, azimuth invariant configuration, azimuth stationary configuration, bistatic SAR data processing method, bistatic deformation term linearisation, bistatic motion error model, bistatic slant range displacement, constant offset configuration, monostatic motion compensation technique, quasimonostatic term linearisation, trajectory deviation compensation, zero Doppler plane, Doppler radar, chirp modulation, geophysical signal processing, Motion Compensation, MoComp, radar receivers, radar signal processing, radar transmitters, remote sensing by radar, synthetic aperture radar, Extended Chirp Scaling, ECS},
    Owner = {ofrey},
    Pdf = {../../../docs/wangLoffeldNiesKnedlikEnder2010.pdf} 
    }
    


  30. Mengdao Xing, Xiuwei Jiang, Renbiao Wu, Feng Zhou, and Zheng Bao. Motion Compensation for UAV SAR Based on Raw Radar Data. IEEE Transactions on Geoscience and Remote Sensing, 47(8):2870-2883, August 2009. Keyword(s): SAR Processing, Motion Compensation. MoComp, 3D MOCO method, 3D motion error analysis, Doppler rate estimate, UAV SAR, Airborne SAR, aircraft properties, atmospheric turbulence, forward velocity, inertial navigation system, line-of-sight direction displacement, motion parameters extraction, raw radar data, synthetic aperture radar systems, unmanned aerial vehicle, UAV, error analysis, geophysical techniques, inertial navigation, radar imaging, remotely operated vehicles, synthetic aperture radar.
    Abstract: Unmanned aerial vehicle (UAV) synthetic aperture radar (SAR) is very important for battlefield awareness. For SAR systems mounted on a UAV, the motion errors can be considerably high due to atmospheric turbulence and aircraft properties, such as its small size, which makes motion compensation (MOCO) in UAV SAR more urgent than other SAR systems. In this paper, based on 3-D motion error analysis, a novel 3-D MOCO method is proposed. The main idea is to extract necessary motion parameters, i.e., forward velocity and displacement in line-of-sight direction, from radar raw data, based on an instantaneous Doppler rate estimate. Experimental results show that the proposed method is suitable for low- or medium-altitude UAV SAR systems equipped with a low-accuracy inertial navigation system.

    @Article{xingJiangWuZhouBaoTGRS2009MoCompUAVSAR,
    author = {Mengdao Xing and Xiuwei Jiang and Renbiao Wu and Feng Zhou and Zheng Bao},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Motion Compensation for {UAV} {SAR} Based on Raw Radar Data},
    year = {2009},
    issn = {0196-2892},
    month = aug,
    number = {8},
    pages = {2870-2883},
    volume = {47},
    abstract = {Unmanned aerial vehicle (UAV) synthetic aperture radar (SAR) is very important for battlefield awareness. For SAR systems mounted on a UAV, the motion errors can be considerably high due to atmospheric turbulence and aircraft properties, such as its small size, which makes motion compensation (MOCO) in UAV SAR more urgent than other SAR systems. In this paper, based on 3-D motion error analysis, a novel 3-D MOCO method is proposed. The main idea is to extract necessary motion parameters, i.e., forward velocity and displacement in line-of-sight direction, from radar raw data, based on an instantaneous Doppler rate estimate. Experimental results show that the proposed method is suitable for low- or medium-altitude UAV SAR systems equipped with a low-accuracy inertial navigation system.},
    doi = {10.1109/TGRS.2009.2015657},
    file = {:xingJiangWuZhouBaoTGRS2009MoCompUAVSAR.pdf:PDF},
    keywords = {SAR Processing, Motion Compensation. MoComp, 3D MOCO method, 3D motion error analysis, Doppler rate estimate, UAV SAR, Airborne SAR, aircraft properties, atmospheric turbulence, forward velocity, inertial navigation system, line-of-sight direction displacement, motion parameters extraction, raw radar data, synthetic aperture radar systems, unmanned aerial vehicle, UAV, error analysis, geophysical techniques, inertial navigation,radar imaging, remotely operated vehicles, synthetic aperture radar},
    owner = {ofrey},
    pdf = {../../../docs/xingJiangWuZhouBaoTGRS2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4895307},
    
    }
    


  31. Simon H. Yueh, Steve J. Dinardo, Ahmed Akgiray, Richard West, Donald W. Cline, and Kelly Elder. Airborne Ku-Band Polarimetric Radar Remote Sensing of Terrestrial Snow Cover. IEEE Transactions on Geoscience and Remote Sensing, 47(10):3347-3364, October 2009. Keyword(s): snow, ku-band, airborne radar, backscatter, hydrological techniques, ice, radar cross-sections, radar polarimetry, remote sensing by radar, snow, vegetation, AD 2006 to 2008, CLPX-II, Cold Land Processes Experiment, Colorado, HH/VV backscatter ratio, Ku-band polarimetric scatterometer, POLSCAT data acquisition, USA, airborne Ku-band polarimetric radar, biomass, freeze-thaw cycles, ice crust layers, ice lenses, radar echoes, radar signals, radiative transfer scattering model, remote sensing, snow-grain size, snow-water-equivalent accumulation, snowpack change, surface hoar growth, terrestrial snow cover, vegetation types, Microwave remote sensing, radar, snow.
    Abstract: Characteristics of the Ku-band polarimetric scatterometer (POLSCAT) data acquired from five sets of aircraft flights in the winter months of 2006-2008 for the second Cold Land Processes Experiment (CLPX-II) in Colorado are described in this paper. The data showed the response of the Ku-band radar echoes to snowpack changes for various types of background vegetation in the study site in north central Colorado. We observed about 0.15-0.5-dB increases in backscatter for every 1 cm of snow-water-equivalent (SWE) accumulation for areas with short vegetation (sagebrush and pasture). The region with the smaller amount of biomass, signified by the backscatter in November, seemed to have the stronger backscatter response to SWE in decibels. The data also showed the impact of surface hoar growth and freeze/thaw cycles, which created large snow-grain sizes, ice crust layers, and ice lenses and consequently increased the radar signals by a few decibels. The copolarized HH/VV backscatter ratio seems to indicate double-bounce scattering between the ground surface and snow or vegetation. The cross-polarized backscatter [vertical-horizontal (VH)] showed not only the influence of vegetation but also the strong response to snow accumulation. The observed HV/VV ratio suggests the importance of multiple scattering or nonspherical scattering geometry of snow grain in the dense-media radiative transfer scattering model. Comparison of the POLSCAT and QuikSCAT data was made and confirmed the effects of mixed terrain covers in the coarse-resolution QuikSCAT data.

    @Article{yuehDinardoAkgirayWestClineElderTGRS2009KuBandSnowCover,
    author = {Yueh, Simon H. and Dinardo, Steve J. and Akgiray, Ahmed and West, Richard and Cline, Donald W. and Elder, Kelly},
    title = {Airborne {Ku}-Band Polarimetric Radar Remote Sensing of Terrestrial Snow Cover},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    year = {2009},
    volume = {47},
    number = {10},
    pages = {3347-3364},
    month = oct,
    issn = {0196-2892},
    abstract = {Characteristics of the Ku-band polarimetric scatterometer (POLSCAT) data acquired from five sets of aircraft flights in the winter months of 2006-2008 for the second Cold Land Processes Experiment (CLPX-II) in Colorado are described in this paper. The data showed the response of the Ku-band radar echoes to snowpack changes for various types of background vegetation in the study site in north central Colorado. We observed about 0.15-0.5-dB increases in backscatter for every 1 cm of snow-water-equivalent (SWE) accumulation for areas with short vegetation (sagebrush and pasture). The region with the smaller amount of biomass, signified by the backscatter in November, seemed to have the stronger backscatter response to SWE in decibels. The data also showed the impact of surface hoar growth and freeze/thaw cycles, which created large snow-grain sizes, ice crust layers, and ice lenses and consequently increased the radar signals by a few decibels. The copolarized HH/VV backscatter ratio seems to indicate double-bounce scattering between the ground surface and snow or vegetation. The cross-polarized backscatter [vertical-horizontal (VH)] showed not only the influence of vegetation but also the strong response to snow accumulation. The observed HV/VV ratio suggests the importance of multiple scattering or nonspherical scattering geometry of snow grain in the dense-media radiative transfer scattering model. Comparison of the POLSCAT and QuikSCAT data was made and confirmed the effects of mixed terrain covers in the coarse-resolution QuikSCAT data.},
    doi = {10.1109/TGRS.2009.2022945},
    file = {:yuehDinardoAkgirayWestClineElderTGRS2009KuBandSnowCover.pdf:PDF},
    keywords = {snow, ku-band, airborne radar;backscatter;hydrological techniques;ice;radar cross-sections;radar polarimetry;remote sensing by radar;snow;vegetation;AD 2006 to 2008;CLPX-II;Cold Land Processes Experiment;Colorado;HH/VV backscatter ratio;Ku-band polarimetric scatterometer;POLSCAT data acquisition;USA;airborne Ku-band polarimetric radar;biomass;freeze-thaw cycles;ice crust layers;ice lenses;radar echoes;radar signals;radiative transfer scattering model;remote sensing;snow-grain size;snow-water-equivalent accumulation;snowpack change;surface hoar growth;terrestrial snow cover;vegetation types;Microwave remote sensing;radar;snow},
    owner = {ofrey},
    pdf = {../../../docs/yuehDinardoAkgirayWestClineElderTGRS2009KuBandSnowCover.pdf},
    
    }
    


  32. Evan C. Zaugg and David G. Long. Generalized Frequency-Domain SAR Processing. IEEE Transactions on Geoscience and Remote Sensing, 47(11):3761-3773, November 2009. Keyword(s): SAR Processing, Azimuth Focusing, Chirp Scaling Algorithm, CSA, Extended Chirp Scaling, ECS, range-Doppler algorithm, omega-k, wavenumber domain algorithm, range migration algorithm, frequency-domain analysis, geophysical techniques, synthetic aperture radar, 2D frequency domain analysis.
    Abstract: The range-Doppler algorithm and the chirp-scaling algorithm (CSA) process synthetic aperture radar (SAR) data with approximations to ideal SAR processing. These approximations are invalid for data from systems with wide beamwidths, large bandwidths, and/or low center frequencies. While simple and efficient, these frequency-domain methods are thus limited by the SAR parameters. This paper explores these limits and proposes a generalized chirp-scaling approach for extending the utility of frequency-domain processing. We demonstrate how different order approximations of the SAR signal in the 2-D frequency domain affect image focusing for varying SAR parameters. From these results, a guideline is set forth, which suggests the required order of approximation terms for proper focusing. A proposed generalized frequency-domain processing approach is derived. This method is an efficient arbitrary-order CSA that processes the data using the appropriate number of approximation terms. The new method is demonstrated using simulated data.

    @Article{zauggLongTGRS2009:GeneralizedFreqDomainProcessing,
    Title = {Generalized Frequency-Domain {SAR} Processing},
    Author = {Zaugg, Evan C. and Long, David G.},
    Doi = {10.1109/TGRS.2009.2025372},
    ISSN = {0196-2892},
    Month = nov,
    Number = {11},
    Pages = {3761-3773},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5208234},
    Volume = {47},
    Year = {2009},
    Abstract = {The range-Doppler algorithm and the chirp-scaling algorithm (CSA) process synthetic aperture radar (SAR) data with approximations to ideal SAR processing. These approximations are invalid for data from systems with wide beamwidths, large bandwidths, and/or low center frequencies. While simple and efficient, these frequency-domain methods are thus limited by the SAR parameters. This paper explores these limits and proposes a generalized chirp-scaling approach for extending the utility of frequency-domain processing. We demonstrate how different order approximations of the SAR signal in the 2-D frequency domain affect image focusing for varying SAR parameters. From these results, a guideline is set forth, which suggests the required order of approximation terms for proper focusing. A proposed generalized frequency-domain processing approach is derived. This method is an efficient arbitrary-order CSA that processes the data using the appropriate number of approximation terms. The new method is demonstrated using simulated data.},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {SAR Processing, Azimuth Focusing, Chirp Scaling Algorithm, CSA, Extended Chirp Scaling, ECS, range-Doppler algorithm, omega-k, wavenumber domain algorithm, range migration algorithm, frequency-domain analysis,geophysical techniques,synthetic aperture radar, 2D frequency domain analysis},
    Owner = {ofrey},
    Pdf = {../../../docs/zauggLongTGRS2009.pdf} 
    }
    


  33. Lei Zhang, Cheng-Wei Qiu, Mengdao Xing, and Zheng Bao. Azimuth preprocessing for monostatic and bistatic spotlight synthetic aperture radar maging based on spectral analysis convolution. Journal of Applied Remote Sensing, 3(1):1-20, January 2009. Keyword(s): SAR Processing, Bistatic SAR, SPECAN, Azimuth Focusing, Spotlight SAR, Spotlight-mode data.
    Abstract: Dechirping is a technique widely used to reduce sampling rate. It is well suited for the illumination of small scenes. In this paper, we extend this idea to mono/bistatic spotlight synthetic aperture radar (SAR) imaging. An azimuth preprocessor based on the spectral analysis (SPECAN) convolution is presented. The convolution overcomes the Doppler aliasing of echoed signals, while the wavenumber analytic formula keeps unchanged. Since the spatial characteristic of the signal is preserved, the preprocessing is well compatible with conventional focusing approaches, such as chirp scaling algorithm and frequency scaling algorithm. The proposed method is validated by simulations in both monostatic and bistatic cases.

    @Article{zhangQiuXingBao2009BistaticSpotlight,
    author = {Lei Zhang and Cheng-Wei Qiu and Mengdao Xing and Zheng Bao},
    title = {Azimuth preprocessing for monostatic and bistatic spotlight synthetic aperture radar maging based on spectral analysis convolution},
    journal = {Journal of Applied Remote Sensing},
    year = {2009},
    volume = {3},
    number = {1},
    pages = {1-20},
    month = jan,
    issn = {0196-2892},
    abstract = {Dechirping is a technique widely used to reduce sampling rate. It is well suited for the illumination of small scenes. In this paper, we extend this idea to mono/bistatic spotlight synthetic aperture radar (SAR) imaging. An azimuth preprocessor based on the spectral analysis (SPECAN) convolution is presented. The convolution overcomes the Doppler aliasing of echoed signals, while the wavenumber analytic formula keeps unchanged. Since the spatial characteristic of the signal is preserved, the preprocessing is well compatible with conventional focusing approaches, such as chirp scaling algorithm and frequency scaling algorithm. The proposed method is validated by simulations in both monostatic and bistatic cases.},
    doi = {10.1117/12.855630},
    file = {:zhangQiuXingBao2009BistaticSpotlight.pdf:PDF},
    keywords = {SAR Processing, Bistatic SAR, SPECAN, Azimuth Focusing, Spotlight SAR, Spotlight-mode data},
    pdf = {../../../docs/zhangQiuXingBao2009BistaticSpotlight.pdf},
    url = {http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JARSC4000003000001033565000001&idtype=cvips&gifs=yes},
    
    }
    


  34. Lei Zhang, Meng-dao Xing, Cheng-Wei Qiu, and Zheng Bao. Two-Dimensional Spectrum Matched Filter Banks for High-Speed Spinning-Target Three-Dimensional ISAR Imaging. IEEE Geoscience and Remote Sensing Letters, 6(3):368-372, July 2009. Keyword(s): SAR Processing, 3D SAR, ISAR, Spinning Targets, Rotating Targets.
    Abstract: In this letter, a 3-D inversed synthetic aperture radar imaging algorithm for targets in high-speed spinning is proposed based on 2-D spectrum matched filter (MF) banks. Each spectrum MF bank yields a focused slice for its corresponding scatterers. By extracting the spatial parameters from all slices, the 3-D image of the target can be constructed. Numeric simulation confirms the validity of the algorithm.

    @Article{ZhangXingQiuBao2009:,
    author = {Zhang, Lei and Xing, Meng-dao and Qiu, Cheng-Wei and Bao, Zheng},
    journal = {IEEE Geoscience and Remote Sensing Letters},
    title = {Two-Dimensional Spectrum Matched Filter Banks for High-Speed Spinning-Target Three-Dimensional ISAR Imaging},
    year = {2009},
    issn = {1545-598X},
    month = jul,
    number = {3},
    pages = {368-372},
    volume = {6},
    abstract = {In this letter, a 3-D inversed synthetic aperture radar imaging algorithm for targets in high-speed spinning is proposed based on 2-D spectrum matched filter (MF) banks. Each spectrum MF bank yields a focused slice for its corresponding scatterers. By extracting the spatial parameters from all slices, the 3-D image of the target can be constructed. Numeric simulation confirms the validity of the algorithm.},
    doi = {10.1109/LGRS.2009.2013487},
    keywords = {SAR Processing, 3D SAR, ISAR, Spinning Targets, Rotating Targets},
    owner = {ofrey},
    pdf = {../../../docs/ZhangXingQiuBao2009.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4785240&isnumber=5153590},
    
    }
    


  35. Zhu Zhengwei and Zhou Jianjiang. Optimum selection of common master image for ground deformation monitoring based on PS-DInSAR technique. Systems Engineering and Electronics, Journal of, 20(6):1213 -1220, December 2009. Keyword(s): SAR Processing, Persistent Scatterer Interferometry, PSI, SAR Interferometry, InSAR, DInSAR.
    Abstract: Considering the joint effects of various factors such as temporal baseline, spatial baseline, thermal noise, the difference of Doppler centroid frequency and the error of data processing on the interference correlation, an optimum selection method of common master images for ground deformation monitoring based on the permanent scatterer and differential SAR interferometry (PS-DInSAR) technique is proposed, in which the joint correlation coefficient is used as the evaluation function. The principle and realization method of PS-DInSAR technology is introduced, the factors affecting the DInSAR correlation are analysed, and the joint correlation function model and its solution are presented. Finally an experiment for the optimum selection of common master images is performed by using 25 SAR images over Shanghai taken by the ERS-1/2 as test data. The results indicate that the optimum selection method for PS-DInSAR common master images is effective and reliable.

    @Article{zhengweiJianjiang2009,
    Title = {Optimum selection of common master image for ground deformation monitoring based on PS-DInSAR technique},
    Author = {Zhengwei, Zhu and Jianjiang, Zhou},
    Month = dec,
    Number = {6},
    Pages = {1213 -1220},
    Volume = {20},
    Year = {2009},
    Abstract = {Considering the joint effects of various factors such as temporal baseline, spatial baseline, thermal noise, the difference of Doppler centroid frequency and the error of data processing on the interference correlation, an optimum selection method of common master images for ground deformation monitoring based on the permanent scatterer and differential SAR interferometry (PS-DInSAR) technique is proposed, in which the joint correlation coefficient is used as the evaluation function. The principle and realization method of PS-DInSAR technology is introduced, the factors affecting the DInSAR correlation are analysed, and the joint correlation function model and its solution are presented. Finally an experiment for the optimum selection of common master images is performed by using 25 SAR images over Shanghai taken by the ERS-1/2 as test data. The results indicate that the optimum selection method for PS-DInSAR common master images is effective and reliable.},
    Journal = {Systems Engineering and Electronics, Journal of},
    Keywords = {SAR Processing, Persistent Scatterer Interferometry, PSI, SAR Interferometry, InSAR, DInSAR} 
    }
    


Conference articles

  1. Nico Adam, Xiao Xiang Zhu, and Richard Bamler. Coherent stacking with TerraSAR-X imagery in urban areas. In Proc. Joint Urban Remote Sensing Event, pages 1-6, 2009.
    @InProceedings{AdamZhuBamler2009CohStacking,
    Title = {Coherent stacking with TerraSAR-X imagery in urban areas},
    Author = {Nico Adam and Xiao Xiang Zhu and Richard Bamler},
    Booktitle = {Proc. Joint Urban Remote Sensing Event},
    Doi = {10.1109/URS.2009.5137488},
    Pages = {1-6},
    Year = {2009},
    Owner = {ofrey} 
    }
    


  2. Nico Adam, Xiao Xiang Zhu, C. Minet, W. Liebhart, M. Eineder, and R. Bamler. Techniques and examples for the 3D reconstruction of complex scattering situations using TerraSAR-X. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume 3, 2009.
    @InProceedings{Adam2009a,
    Title = {Techniques and examples for the {3D} reconstruction of complex scattering situations using {TerraSAR-X}},
    Author = {Adam, Nico and Zhu, Xiao Xiang and Minet, C. and Liebhart, W. and Eineder, M. and Bamler, R.},
    Booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    Doi = {10.1109/IGARSS.2009.5417917},
    Volume = {3},
    Year = {2009},
    Owner = {ofrey} 
    }
    


  3. S. Auer, Xiao Xiang Zhu, S. Hinz, and R. Bamler. 3D analysis of scattering effects based on Ray Tracing techniques. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume 3, 2009.
    @InProceedings{auerZhuHinzBamler2009,
    Title = {{3D} analysis of scattering effects based on Ray Tracing techniques},
    Author = {Auer, S. and Zhu, Xiao Xiang and Hinz, S. and Bamler, R.},
    Booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    Doi = {10.1109/IGARSS.2009.5418256},
    Volume = {3},
    Year = {2009},
    Owner = {ofrey} 
    }
    


  4. Federica Bordoni, Marwan Younis, and Gerhard Krieger. Calibration Issue in SMART Synthetic Aperture Radar Based on Scan-On-Receive. In Advanced RF Sensors for Earth Observation (ARSI), Noordwijk, The Netherlands, 2009. ESA ESTEC. Keyword(s): SAR Processing, Scan-on-Receive, SCORE, Synthetic Aperture Radar, Digital Beam-Forming, DBF, Multichannel Receiver.
    Abstract: A new spaceborne Synthetic Aperture Radar (SAR) system based on SCan-On-REceive (SCORE) algorithm has been recently proposed in order to overcome the trade-off between spatial resolution and swath wide of current SAR systems. The compound architecture of the receiver, which employs multiple channels and Digital Beam-Forming technique, places new challenges to spaceborne SAR internal calibration (Cal) and requires the definition of a new Cal approach. In this paper a novel method for onboard internal Cal of the multichannel receiver of a SAR system based on SCORE is proposed and numerically analyzed.

    @InProceedings{BordoniYounisKriegerARSI2009,
    author = {Bordoni, Federica and Younis, Marwan and Krieger, Gerhard},
    title = {Calibration Issue in {SMART} Synthetic Aperture Radar Based on Scan-On-Receive},
    booktitle = {Advanced RF Sensors for Earth Observation (ARSI)},
    year = {2009},
    address = {Noordwijk, The Netherlands},
    organization = {ESA ESTEC},
    abstract = {A new spaceborne Synthetic Aperture Radar (SAR) system based on SCan-On-REceive (SCORE) algorithm has been recently proposed in order to overcome the trade-off between spatial resolution and swath wide of current SAR systems. The compound architecture of the receiver, which employs multiple channels and Digital Beam-Forming technique, places new challenges to spaceborne SAR internal calibration (Cal) and requires the definition of a new Cal approach. In this paper a novel method for onboard internal Cal of the multichannel receiver of a SAR system based on SCORE is proposed and numerically analyzed.},
    file = {:BordoniYounisKriegerARSI2009.pdf:PDF},
    keywords = {SAR Processing, Scan-on-Receive, SCORE, Synthetic Aperture Radar, Digital Beam-Forming, DBF, Multichannel Receiver},
    owner = {ofrey},
    pdf = {../../../docs/BordoniYounisKriegerARSI2009.pdf},
    url = {http://elib.dlr.de/61538/1/BorYouKri_ARSI09.pdf},
    
    }
    


  5. Federica Bordoni, Marwan Younis, E.M. Varona, and Gerhard Krieger. Adaptive scan-on-receive based on spatial spectral estimation for high-resolution, wide-swath Synthetic Aperture Radar. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume 1, pages 64-67, July 2009. Keyword(s): SAR Processing, Cramer Rao Lower Bound, Monte Carlo simulations, SCORE, scan-on-receive, Smart Multi-Aperture Radar Techniques, adaptive scan-on-receive, beam steering, high-resolution wide-swath synthetic aperture radar, signal power, spaceborne SMART SAR systems, spatial spectral estimation, beam steering, geophysical techniques, synthetic aperture radar.
    Abstract: Intensive research is currently ongoing in the field of Smart Multi-Aperture Radar Techniques (SMART) for high-resolution wide-swath Synthetic Aperture Radar (SAR) imaging. This work investigates the possibility of applying direction of arrival estimation methods to spaceborne SMART SAR systems, that employ receive beam steering. In particular, a new algorithm based on the actual spatial distribution of the received signal power is proposed. The performance of the algorithm is evaluated by Monte Carlo simulations and compared with that of the conventional scan-on-receive approach, in different operational scenarios. The Cramer Rao Lower Bound is also reported as a benchmark on the performance.

    @InProceedings{bordoniYounisVaronaKrieger2009,
    author = {Bordoni, Federica and Younis, Marwan and Varona, E.M. and Krieger, Gerhard},
    title = {Adaptive scan-on-receive based on spatial spectral estimation for high-resolution, wide-swath Synthetic Aperture Radar},
    booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    year = {2009},
    volume = {1},
    pages = {64-67},
    month = jul,
    abstract = {Intensive research is currently ongoing in the field of Smart Multi-Aperture Radar Techniques (SMART) for high-resolution wide-swath Synthetic Aperture Radar (SAR) imaging. This work investigates the possibility of applying direction of arrival estimation methods to spaceborne SMART SAR systems, that employ receive beam steering. In particular, a new algorithm based on the actual spatial distribution of the received signal power is proposed. The performance of the algorithm is evaluated by Monte Carlo simulations and compared with that of the conventional scan-on-receive approach, in different operational scenarios. The Cramer Rao Lower Bound is also reported as a benchmark on the performance.},
    doi = {10.1109/IGARSS.2009.5416941},
    file = {:bordoniYounisVaronaKrieger2009.pdf:PDF},
    keywords = {SAR Processing, Cramer Rao Lower Bound;Monte Carlo simulations;SCORE;scan-on-receive;Smart Multi-Aperture Radar Techniques;adaptive scan-on-receive;beam steering;high-resolution wide-swath synthetic aperture radar;signal power;spaceborne SMART SAR systems;spatial spectral estimation;beam steering;geophysical techniques;synthetic aperture radar},
    owner = {ofrey},
    pdf = {../../../docs/bordoniYounisVaronaKrieger2009.pdf},
    
    }
    


  6. Antonio De Maio, Gianfranco Fornaro, Antonio Pauciullo, and Diego Reale. Detection of double scatterers in SAR Tomography. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume 3, pages 172-175, July 2009. Keyword(s): SAR Processing, double scatterers, Bayesian Information Criterion, Generalized Likelihood Ratio Test, SAR Tomography, differential tomography, double scatterers, ground scatterers, high resolution radar systems, multi-dimensional SAR imaging, scatterers detection, SAR Interferometry, Multidimensional system, Spaceborne SAR, X-Band, Urban, Persistent Scatterer Interferometry, PSI, time series, geophysical image processing, image reconstruction, image resolution, radar imaging, radar interferometry, radar resolution, synthetic aperture radar, 3D reconstruction.
    Abstract: Multi-Dimensional (3D/4D) SAR imaging (SAR Tomography and Differential SAR Tomography) allows the localization and monitoring of ground scatterers, even interfering in the same azimuth-range pixel. Indeed, the presence of multiple scatterers has shown to affect even the performances of high resolution radar systems. In this paper we discuss two strategies for the detection of interfering scatterer pairs. The first one is based on the extension of the GLRT test already proposed for the detection of single scatterers, the second one is based on the BIC criteria commonly used in the contest of model order selection. Performances of the two decision schemes are evaluated on simulated data.

    @InProceedings{deMaioFornaroPauciulloRealeIGARSS2009TomoDoubleScatterer,
    author = {De Maio, Antonio and Fornaro, Gianfranco and Pauciullo, Antonio and Reale, Diego},
    title = {Detection of double scatterers in {SAR} Tomography},
    booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    year = {2009},
    volume = {3},
    pages = {172-175},
    month = jul,
    abstract = {Multi-Dimensional (3D/4D) SAR imaging (SAR Tomography and Differential SAR Tomography) allows the localization and monitoring of ground scatterers, even interfering in the same azimuth-range pixel. Indeed, the presence of multiple scatterers has shown to affect even the performances of high resolution radar systems. In this paper we discuss two strategies for the detection of interfering scatterer pairs. The first one is based on the extension of the GLRT test already proposed for the detection of single scatterers, the second one is based on the BIC criteria commonly used in the contest of model order selection. Performances of the two decision schemes are evaluated on simulated data.},
    doi = {10.1109/IGARSS.2009.5417945},
    file = {:deMaioFornaroPauciulloRealeIGARSS2009TomoDoubleScatterer.pdf:PDF},
    keywords = {SAR Processing, double scatterers,Bayesian Information Criterion;Generalized Likelihood Ratio Test, SAR Tomography, differential tomography;double scatterers;ground scatterers;high resolution radar systems;multi-dimensional SAR imaging;scatterers detection; SAR Interferometry;Multidimensional system; Spaceborne SAR, X-Band, Urban, Persistent Scatterer Interferometry, PSI, time series, geophysical image processing;image reconstruction;image resolution;radar imaging;radar interferometry; radar resolution;synthetic aperture radar;3D reconstruction},
    pdf = {../../../docs/deMaioFornaroPauciulloRealeIGARSS2009TomoDoubleScatterer.pdf},
    
    }
    


  7. A. Elsherbini and K. Sarabandi. Topography of sand covered bedrock using two-frequency airborne interferometric SAR measurements. In Proc. IEEE Int. Geoscience and Remote Sensing Symp, volume 2, pages II-250-II-253, July 2009. Keyword(s): airborne radar, geophysical prospecting, radar interferometry, remote sensing by radar, rocks, sand, synthetic aperture radar, terrain mapping, topography (Earth), InSAR processing, iterative algorithm, oil field search, sand covered bedrock, sand dunes, subsurface imaging, synthetic aperture radar, topography, two-frequency airborne interferometric SAR, Backscatter, Bandwidth, Frequency, Iterative algorithms, Petroleum, Receiving antennas, Signal design, Signal to noise ratio, Surface topography, Synthetic aperture radar interferometry, Interferometric synthetic aperture radar (InSAR), Subsurface Imaging, radar imaging, terrain mapping.
    @InProceedings{Elsherbini2009,
    author = {A. Elsherbini and K. Sarabandi},
    title = {Topography of sand covered bedrock using two-frequency airborne interferometric {SAR} measurements},
    booktitle = {Proc. IEEE Int. Geoscience and Remote Sensing Symp},
    year = {2009},
    volume = {2},
    month = jul,
    pages = {II-250-II-253},
    doi = {10.1109/IGARSS.2009.5418055},
    issn = {2153-6996},
    keywords = {airborne radar, geophysical prospecting, radar interferometry, remote sensing by radar, rocks, sand, synthetic aperture radar, terrain mapping, topography (Earth), InSAR processing, iterative algorithm, oil field search, sand covered bedrock, sand dunes, subsurface imaging, synthetic aperture radar, topography, two-frequency airborne interferometric SAR, Backscatter, Bandwidth, Frequency, Iterative algorithms, Petroleum, Receiving antennas, Signal design, Signal to noise ratio, Surface topography, Synthetic aperture radar interferometry, Interferometric synthetic aperture radar (InSAR), Subsurface Imaging, radar imaging, terrain mapping},
    owner = {ofrey},
    
    }
    


  8. H. Essen, M. Bräutigam, R. Sommer, A. Wahlen, W. Johannes, J. Wilcke, M. Schlechtweg, and A. Tessmann. SUMATRA, a W-band SAR for UAV application. In 2009 International Radar Conference Surveillance for a Safer World (RADAR 2009), pages 1-4, October 2009. Keyword(s): SAR Processing, W-Band, SUMATRA, Airborne SAR, UAV, Fraunhofer, airborne radar, aircraft, millimetre wave radar, remotely operated vehicles, synthetic aperture radar, HEMT amplifiers, IF amplifiers, LNA, SUMATRA-94, UAV application, data transmission equipment, frequency 94 GHz, miniaturized GPS, mixer, remotely piloted aircraft, synthetic aperture unmanned millimeterwave airborne test radar, w-band SAR, Airborne radar, Aircraft, Data communication, Global Positioning System, HEMTs, Hardware, Low-noise amplifiers, Power system modeling, Remote sensing, Unmanned aerial vehicles, HEMTAmplifiers, Millimeterwaves, SAR, UAV.
    Abstract: Based upon most recent advances in millimeterwave technology, especially monolithic integrated low noise or medium power HEMT amplifiers and an integrated receiver containing an LNA, Mixer and IF Amplifier, a miniaturized experimental radar at 94 GHz was designed with the aim to be used on board of a remotely piloted model aircraft. This highly advanced front-end technique was combined with of-the-shelf model aircraft hardware and miniaturized GPS and data transmission equipment which is readily available. Goal of the project is to demonstrate, that using modern 94-GHz front-end technique combined with achievable back-end components it is possible to set up a versatile SAR system usable for a wide range of remote sensing applications at medium range. The paper describes the current state of the research project SUMATRA-94 and gives some perspectives for future applications.

    @INPROCEEDINGS{EssenEtAlIEEERADARCONwbandSUMATRAARforUAV2009,
    author={H. Essen and M. Br\"autigam and R. Sommer and A. Wahlen and W. Johannes and J. Wilcke and M. Schlechtweg and A. Tessmann},
    booktitle={2009 International Radar Conference "Surveillance for a Safer World" (RADAR 2009)},
    title={SUMATRA, a W-band SAR for UAV application},
    year={2009},
    pages={1-4},
    abstract={Based upon most recent advances in millimeterwave technology, especially monolithic integrated low noise or medium power HEMT amplifiers and an integrated receiver containing an LNA, Mixer and IF Amplifier, a miniaturized experimental radar at 94 GHz was designed with the aim to be used on board of a remotely piloted model aircraft. This highly advanced front-end technique was combined with of-the-shelf model aircraft hardware and miniaturized GPS and data transmission equipment which is readily available. Goal of the project is to demonstrate, that using modern 94-GHz front-end technique combined with achievable back-end components it is possible to set up a versatile SAR system usable for a wide range of remote sensing applications at medium range. The paper describes the current state of the research project SUMATRA-94 and gives some perspectives for future applications.},
    keywords={SAR Processing, W-Band,SUMATRA, Airborne SAR, UAV, Fraunhofer, airborne radar;aircraft;millimetre wave radar;remotely operated vehicles;synthetic aperture radar;HEMT amplifiers;IF amplifiers;LNA;SUMATRA-94;UAV application;data transmission equipment;frequency 94 GHz;miniaturized GPS;mixer;remotely piloted aircraft;synthetic aperture unmanned millimeterwave airborne test radar;w-band SAR;Airborne radar;Aircraft;Data communication;Global Positioning System;HEMTs;Hardware;Low-noise amplifiers;Power system modeling;Remote sensing;Unmanned aerial vehicles;HEMTAmplifiers;Millimeterwaves;SAR;UAV},
    ISSN={1097-5764},
    month=oct,
    owner = {ofrey},
    
    }
    


  9. Othmar Frey and Erich Meier. A Comparative Tomographic Evaluation of Airborne Multi-Baseline SAR Data at P- and L-Band. In IEEE Int. Geosci. and Remote Sens. Symp., 2009. Note: Invited Talk, Abstract.
    @InProceedings{freyMeier09:IGARSSInvited,
    Title = {A Comparative Tomographic Evaluation of Airborne Multi-Baseline {SAR} Data at {P-} and {L-}Band},
    Author = {Othmar Frey and Erich Meier},
    Booktitle = {IEEE Int. Geosci. and Remote Sens. Symp.},
    Note = {Invited Talk, Abstract},
    Year = {2009} 
    }
    


  10. Leif J. Harcke. Time-domain backprojection for precise geodetic coding of spaceborne SAR imagery. In Radar Conference, 2009 IEEE, pages 1-3, May 2009. Keyword(s): SAR Processing, TDBP, Time-Domain Back-Projection, ALOS/PALSAR instrument, D-InSAR, WGS-84 Cartesian system, backprojection image formation, differential radar interferometry, geocoded image production, geodetic coding, position measurement, precise-orbit determination, reflector, space-borne SAR, spaceborne SAR imagery, time-domain back-projection, geodesy, position measurement, radar imaging, radar interferometry, spaceborne radar, synthetic aperture radar.
    Abstract: A new era of precise-orbit determination for space-borne SAR permits time-domain backprojection of the data for accurate geocoded image production. In this work, time-domain backprojection is applied to Level 1.0 data from the ALOS/PALSAR instrument to form imagery at two sites in southern California. The accuracy of the backprojection is verified by comparing the measured position of a corner reflector at a calibration site to its position in the formed SAR imagery. The observed offset of the corner reflector is lt;2 m in the range direction and 12 m in the cross-range or along track direction. Images backprojected in an absolute WGS-84 Cartesian system onto 1/3 arc second or 10 m posting digital elevation data exhibit no gross registration errors. This indicates that the backprojection image formation method may be useful for processing differential radar interferometry (D-InSAR) products, where topography terms must first be removed.

    @InProceedings{harcke2009TDBP,
    author = {Harcke, Leif J.},
    title = {Time-domain backprojection for precise geodetic coding of spaceborne {SAR} imagery},
    booktitle = {Radar Conference, 2009 IEEE},
    year = {2009},
    pages = {1-3},
    month = may,
    abstract = {A new era of precise-orbit determination for space-borne SAR permits time-domain backprojection of the data for accurate geocoded image production. In this work, time-domain backprojection is applied to Level 1.0 data from the ALOS/PALSAR instrument to form imagery at two sites in southern California. The accuracy of the backprojection is verified by comparing the measured position of a corner reflector at a calibration site to its position in the formed SAR imagery. The observed offset of the corner reflector is lt;2 m in the range direction and 12 m in the cross-range or along track direction. Images backprojected in an absolute WGS-84 Cartesian system onto 1/3 arc second or 10 m posting digital elevation data exhibit no gross registration errors. This indicates that the backprojection image formation method may be useful for processing differential radar interferometry (D-InSAR) products, where topography terms must first be removed.},
    doi = {10.1109/RADAR.2009.4977031},
    file = {:harcke2009TDBP.pdf:PDF},
    issn = {1097-5659},
    keywords = {SAR Processing, TDBP, Time-Domain Back-Projection, ALOS/PALSAR instrument;D-InSAR;WGS-84 Cartesian system;backprojection image formation;differential radar interferometry;geocoded image production;geodetic coding;position measurement;precise-orbit determination;reflector;space-borne SAR;spaceborne SAR imagery;time-domain back-projection;geodesy;position measurement;radar imaging;radar interferometry;spaceborne radar;synthetic aperture radar},
    pdf = {../../../docs/harcke2009TDBP.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4977031},
    
    }
    


  11. Scott Hensley, T. Michel, M. Simard, C. Jones, R. Muellerschoen, C. Le, H. Zebker, and B. Chapman. Residual motion estimation for UAVSAR: Implications of an electronically scanned array. In 2009 IEEE Radar Conference, pages 1-5, May 2009. Keyword(s): SAR Processing, Global Positioning System, antenna arrays, motion estimation, radar interferometry, synthetic aperture radar, UAVSAR, along-track offsets, electronically scanned antenna array, repeat pass radar interferometry, residual motion estimation, surface deformation, Antenna measurements, Azimuth, Data engineering, Earth, Geophysical measurements, Instruments, L-band, Motion estimation, Radar interferometry, Solids.
    Abstract: The UAVSAR instrument, employing an L-band actively electronically scanned antenna, had its genesis in the ESTO Instrument Incubator Program and after 3 years of development has begun collecting engineering and science data. System design was motivated by solid Earth applications where repeat pass radar interferometry can be used to measure subtle deformation of the surface, however flexibility and extensibility to support other applications were also major design drivers. In order to make geophysically useful repeat pass interferometric measurements it is necessary to reconstruct the repeat pass baseline with millimeter accuracy, however onboard motion metrology systems only achieve 5-15 cm accuracy. Thus it is necessary to recover the residual motion from the data itself. Algorithms for recovering the motion based on along-track offsets between the repeat pass interferometric pair of images were described in [3], [1] and [4]. Later these techniques were extended to use azimuth subbanded differential interferograms in [5]. This paper provides a derivation for the formula for the along-track offsets (or corresponding the subbanded differential phase), i.e. the relative displacement between two SAR images in a interferometric pair in the along track direction, as a function of baseline for systems employing an electronically scanned antenna. The standard formula for systems not employing electronically scanned antenna for the along-track offsets, Deltas, has the form in given equation where bc is the cross-track baseline, bh is the vertical baseline, thetaslscr is the look angle, thetasaz is the azimuth or squint angle, rho is the range and d = 1 for left looking systems and d = -1 for right looking systems. A key feature of this formula is the along-track offsets only range dependency is from the derivatives of the baseline with respect to along-track position. In the electronically scanned case this in no longer true and - an additional range dependency arises that is a function of the electronic steering angle.

    @InProceedings{hensleyMichelSimardJonesMuellerschoenLeZebkerChapmanRadarCon2009UAVSARResidualMotionfromDPCA,
    author = {Scott Hensley and T. Michel and M. Simard and C. Jones and R. Muellerschoen and C. Le and H. Zebker and B. Chapman},
    title = {Residual motion estimation for UAVSAR: Implications of an electronically scanned array},
    booktitle = {2009 IEEE Radar Conference},
    year = {2009},
    pages = {1-5},
    month = may,
    abstract = {The UAVSAR instrument, employing an L-band actively electronically scanned antenna, had its genesis in the ESTO Instrument Incubator Program and after 3 years of development has begun collecting engineering and science data. System design was motivated by solid Earth applications where repeat pass radar interferometry can be used to measure subtle deformation of the surface, however flexibility and extensibility to support other applications were also major design drivers. In order to make geophysically useful repeat pass interferometric measurements it is necessary to reconstruct the repeat pass baseline with millimeter accuracy, however onboard motion metrology systems only achieve 5-15 cm accuracy. Thus it is necessary to recover the residual motion from the data itself. Algorithms for recovering the motion based on along-track offsets between the repeat pass interferometric pair of images were described in [3], [1] and [4]. Later these techniques were extended to use azimuth subbanded differential interferograms in [5]. This paper provides a derivation for the formula for the along-track offsets (or corresponding the subbanded differential phase), i.e. the relative displacement between two SAR images in a interferometric pair in the along track direction, as a function of baseline for systems employing an electronically scanned antenna. The standard formula for systems not employing electronically scanned antenna for the along-track offsets, Deltas, has the form in given equation where bc is the cross-track baseline, bh is the vertical baseline, thetaslscr is the look angle, thetasaz is the azimuth or squint angle, rho is the range and d = 1 for left looking systems and d = -1 for right looking systems. A key feature of this formula is the along-track offsets only range dependency is from the derivatives of the baseline with respect to along-track position. In the electronically scanned case this in no longer true and - an additional range dependency arises that is a function of the electronic steering angle.},
    doi = {10.1109/RADAR.2009.4977065},
    file = {:hensleyMichelSimardJonesMuellerschoenLeZebkerChapmanRadarCon2009UAVSARResidualMotionfromDPCA.pdf:PDF},
    issn = {1097-5659},
    keywords = {SAR Processing, Global Positioning System;antenna arrays;motion estimation;radar interferometry;synthetic aperture radar;UAVSAR;along-track offsets;electronically scanned antenna array;repeat pass radar interferometry;residual motion estimation;surface deformation;Antenna measurements;Azimuth;Data engineering;Earth;Geophysical measurements;Instruments;L-band;Motion estimation;Radar interferometry;Solids},
    owner = {ofrey},
    
    }
    


  12. S. Hensley, H. Zebker, C. Jones, T. Michel, R. Muellerschoen, and B. Chapman. First deformation results using the NASA/JPL UAVSAR instrument. In Proc. Asian-Pacific Conference on Synthetic Aperture Radar, pages 1051-1055, October 2009. Keyword(s): active antennas, radar interferometry, synthetic aperture radar, deformation results, NASA/JPL UAVSAR instrument, L-band actively electronically scanned antenna, ESTO instrument incubator program, solid earth applications, radar interferometry, Ka-band single-pass radar interferometer, NASA Gulfstream III aircraft, NASA Dryden Flight Research Center, repeat-pass radar interferometric applications, 1NU measurement data, NASA, Instruments, L-band, Antenna measurements, Testing, Aircraft, Airborne radar, Solids, Earth, Radar interferometry.
    Abstract: The UAVSAR instrument, employing an L-band actively electronically scanned antenna, had its genesis in NASA's ESTO Instrument Incubator Program and after 4 years of development has begun collecting science data for investigators. System design was motivated by solid Earth applications where repeat pass radar interferometry can be used to measure subtle deformation of the surface, however flexibility and extensibility to support other applications were also major design drivers. In fact a Ka-band single-pass radar interferometer for making high precision topographic maps of ice sheets was developed and tested based to a large extent on components of the UAVSAR L-band radar. By designing the radar to be housed in an external unpressurized pod, it has the potential to be readily ported to many platforms. Initial testing is being carried out with the NASA Gulfstream III aircraft, which has been modified to accommodate the radar pod and has been equipped with precision autopilot capability developed by NASA Dryden Flight Research Center. With this the aircraft can fly within a 10 m diameter tube on any specified trajectory necessary for repeat-pass radar interferometric applications. To maintain the required pointing for repeat-pass interferometric applications we have employed an actively scanned antenna steered using INU measurement data. This paper presents a brief overview of some of the initial deformations made by the UAVSAR instrument.

    @InProceedings{hensleyZebkerJonesMichelMuellerschoenChapman2009FirstDeformationResultsUAVSAR,
    author = {S. {Hensley} and H. {Zebker} and C. {Jones} and T. {Michel} and R. {Muellerschoen} and B. {Chapman}},
    booktitle = {Proc. Asian-Pacific Conference on Synthetic Aperture Radar},
    title = {First deformation results using the {NASA/JPL} {UAVSAR} instrument},
    year = {2009},
    month = {Oct},
    pages = {1051-1055},
    abstract = {The UAVSAR instrument, employing an L-band actively electronically scanned antenna, had its genesis in NASA's ESTO Instrument Incubator Program and after 4 years of development has begun collecting science data for investigators. System design was motivated by solid Earth applications where repeat pass radar interferometry can be used to measure subtle deformation of the surface, however flexibility and extensibility to support other applications were also major design drivers. In fact a Ka-band single-pass radar interferometer for making high precision topographic maps of ice sheets was developed and tested based to a large extent on components of the UAVSAR L-band radar. By designing the radar to be housed in an external unpressurized pod, it has the potential to be readily ported to many platforms. Initial testing is being carried out with the NASA Gulfstream III aircraft, which has been modified to accommodate the radar pod and has been equipped with precision autopilot capability developed by NASA Dryden Flight Research Center. With this the aircraft can fly within a 10 m diameter tube on any specified trajectory necessary for repeat-pass radar interferometric applications. To maintain the required pointing for repeat-pass interferometric applications we have employed an actively scanned antenna steered using INU measurement data. This paper presents a brief overview of some of the initial deformations made by the UAVSAR instrument.},
    doi = {10.1109/APSAR.2009.5374246},
    keywords = {active antennas;radar interferometry;synthetic aperture radar;deformation results;NASA/JPL UAVSAR instrument;L-band actively electronically scanned antenna;ESTO instrument incubator program;solid earth applications;radar interferometry;Ka-band single-pass radar interferometer;NASA Gulfstream III aircraft;NASA Dryden Flight Research Center;repeat-pass radar interferometric applications;1NU measurement data;NASA;Instruments;L-band;Antenna measurements;Testing;Aircraft;Airborne radar;Solids;Earth;Radar interferometry},
    owner = {ofrey},
    
    }
    


  13. F. Hélière, C.C. Lin, F. Fois, M. Davidson, A. Thompson, and P. Bensi. BIOMASS: A P-band SAR Earth explorer core mission candidate. In Proc. IEEE Radar Conf., pages 1-6, May 2009. Keyword(s): BIOMASS mission, Earth explorer core mission candidate, P-band, forest area, forest biomass, forest disturbances, frequency 425 MHz, global maps, synthetic aperture radar, terrestrial carbon cycle, remote sensing by radar, spaceborne radar, synthetic aperture radar.
    Abstract: The greatest uncertainties in the global carbon cycle involve estimating how carbon dioxide is taken up by land. The BIOMASS mission aims to improve the present assessment and future projection of the terrestrial carbon cycle by providing consistent global maps of forest biomass and forest area, forest disturbances and recovery with time, and the extent and evolution of the forest flooding. The BIOMASS primary objectives can be achieved through P-band (435 MHz) synthetic aperture radar (SAR) observations of global forest cover. Two parallel industrial studies at phase 0 level were awarded respectively to Astrium GmbH and Thales Alenia Space Italy. This paper presents the resulting system concepts as elaborated by the industrial teams. The result of the phase 0 was presented to the user community in January 2009 in Lisbon together with other Earth Explorer candidates for further down-selection. If successfully selected after phase 0 and phase A, BIOMASS will be launched during 2016.

    @InProceedings{HeliereLinFoisDavidsonThompsonBensi2009:BIOMASSmission,
    Title = {{BIOMASS}: A {P-band} {SAR} {E}arth explorer core mission candidate},
    Author = {H\'eli\`ere, F. and Lin, C.C. and Fois, F. and Davidson, M. and Thompson, A. and Bensi, P.},
    Booktitle = {Proc. IEEE Radar Conf.},
    Doi = {10.1109/RADAR.2009.4977088},
    Month = may,
    Pages = {1-6},
    Year = {2009},
    Abstract = {The greatest uncertainties in the global carbon cycle involve estimating how carbon dioxide is taken up by land. The BIOMASS mission aims to improve the present assessment and future projection of the terrestrial carbon cycle by providing consistent global maps of forest biomass and forest area, forest disturbances and recovery with time, and the extent and evolution of the forest flooding. The BIOMASS primary objectives can be achieved through P-band (435 MHz) synthetic aperture radar (SAR) observations of global forest cover. Two parallel industrial studies at phase 0 level were awarded respectively to Astrium GmbH and Thales Alenia Space Italy. This paper presents the resulting system concepts as elaborated by the industrial teams. The result of the phase 0 was presented to the user community in January 2009 in Lisbon together with other Earth Explorer candidates for further down-selection. If successfully selected after phase 0 and phase A, BIOMASS will be launched during 2016.},
    ISSN = {1097-5659},
    Keywords = {BIOMASS mission;Earth explorer core mission candidate;P-band;forest area;forest biomass;forest disturbances;frequency 425 MHz;global maps;synthetic aperture radar;terrestrial carbon cycle;remote sensing by radar;spaceborne radar;synthetic aperture radar} 
    }
    


  14. Charles V. Jakowatz and Daniel E. Wahl. Considerations for autofocus of spotlight-mode SAR imagery created using a beamforming algorithm. In Edmund G. Zelnio and Frederick D. Garber, editors, , volume 7337, pages 73370A, 2009. SPIE. Keyword(s): SAR Processing, 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{jakowatzWahlAutofocusBeamformingSpotlight2009,
    author = {Charles V. Jakowatz and Daniel E. Wahl},
    title = {Considerations for autofocus of spotlight-mode {SAR} imagery created using a beamforming algorithm},
    year = {2009},
    editor = {Edmund G. Zelnio and Frederick D. Garber},
    volume = {7337},
    number = {1},
    pages = {73370A},
    publisher = {SPIE},
    doi = {10.1117/12.820049},
    eid = {73370A},
    file = {:jakowatzWahlAutofocusBeamformingSpotlight2009.pdf:PDF},
    journal = {Algorithms for Synthetic Aperture Radar Imagery XVI},
    keywords = {SAR Processing, 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, FL, USA},
    numpages = {9},
    owner = {ofrey},
    pdf = {../../../docs/jakowatzWahlAutofocusBeamformingSpotlight2009.pdf},
    url = {http://link.aip.org/link/?PSI/7337/73370A/1},
    
    }
    


  15. W.T.K. Johnson, P.A. Rosen, S. Hensley, and A. Freeman. Radar designs for the DESDynI mission. In IEEE Radar Conference, pages 1-3, May 2009. Keyword(s): DESDynI mission, InSAR, Lidar, SweepSAR, dual polarization, ecosystem structure, ice dynamics, interferometric radar design, near-polar orbit, quadpolarization, solid Earth, spacecraft, vegetation, electromagnetic wave polarisation, geophysical techniques, ice, optical radar, radar interferometry, synthetic aperture radar.
    Abstract: The interferometric radar (InSAR) design has undergone several iterations in the years that this mission has been under consideration. In the most recent proposal the InSAR is combined with a Lidar and the mission is called deformation, ecosystem structure, and dynamics of ice (DESDynI). This spacecraft would be in a near-polar orbit around the Earth and repeatedly collect data to monitor changes in the solid Earth, vegetation, and ice. The radar is a repeat pass interferometric SAR with dual and quad polarization capability. This paper examines the state of the configuration of the radar including a ldquoSweepSARrdquo method that has been incorporated as the present baseline.

    @InProceedings{JohnsonRosenHensleyFreeman2009:DESDynIRadarDesign,
    Title = {Radar designs for the {DESDynI} mission},
    Author = {Johnson, W.T.K. and Rosen, P.A. and Hensley, S. and Freeman, A.},
    Booktitle = {IEEE Radar Conference},
    Doi = {10.1109/RADAR.2009.4977119},
    Month = may,
    Pages = {1-3},
    Year = {2009},
    Abstract = {The interferometric radar (InSAR) design has undergone several iterations in the years that this mission has been under consideration. In the most recent proposal the InSAR is combined with a Lidar and the mission is called deformation, ecosystem structure, and dynamics of ice (DESDynI). This spacecraft would be in a near-polar orbit around the Earth and repeatedly collect data to monitor changes in the solid Earth, vegetation, and ice. The radar is a repeat pass interferometric SAR with dual and quad polarization capability. This paper examines the state of the configuration of the radar including a ldquoSweepSARrdquo method that has been incorporated as the present baseline.},
    ISSN = {1097-5659},
    Keywords = {DESDynI mission;InSAR;Lidar;SweepSAR;dual polarization;ecosystem structure;ice dynamics;interferometric radar design;near-polar orbit;quadpolarization;solid Earth;spacecraft;vegetation;electromagnetic wave polarisation;geophysical techniques;ice;optical radar;radar interferometry;synthetic aperture radar} 
    }
    


  16. G. Krieger, I. Hajnsek, Konstantinos P. Papathanassiou, M. Eineder, M. Younis, F. De Zan, P. Prats, S. Huber, M. Werner, H. Fiedler, A. Freeman, P. Rosen, S. Hensley, W. Johnson, L. Veilleux, B. Grafmueller, R. Werninghaus, R. Bamler, and A. Moreira. The Tandem-L mission proposal: Monitoring Earth's dynamics with high resolution SAR interferometry. In Proc. IEEE Radar Conf., pages 1-6, May 2009. Keyword(s): Earth's Dynamics Monitoring, Tandem-L mission, advanced digital beamforming techniques, biomass inventories, glacier movement observations, global forest height, high data acquisition, high resolution SAR interferometry, innovative interferometric radar mission, millimetric displacements measurements, polarimetric radar mission, synthetic aperture radar, tectonic shifts, data acquisition, glaciology, radar interferometry, radar polarimetry, remote sensing by radar, synthetic aperture radar, tectonics, vegetation.
    Abstract: Tandem-L is a proposal for an innovative interferometric and polarimetric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important mission objectives are global forest height and biomass inventories, large scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The innovative mission concept and the high data acquisition capacity of Tandem-L provide a unique data source to observe, analyze and quantify the dynamics of a wide range of mutually interacting 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. This paper provides an overview of the Tandem-L mission concept and its main application areas. Performance predictions show the great potential of Tandem-L to acquire a wide range of bio- and geophysical parameters with high accuracy on a global scale. Innovative aspects like the employment of advanced digital beamforming techniques to improve performance and coverage are discussed in detail.

    @InProceedings{KriegerEtAl_DLR_and_JPL:tandemL,
    author = {Krieger, G. and Hajnsek, I. and Papathanassiou, Konstantinos P. and Eineder, M. and Younis, M. and De Zan, F. and Prats, P. and Huber, S. and Werner, M. and Fiedler, H. and Freeman, A. and Rosen, P. and Hensley, S. and Johnson, W. and Veilleux, L. and Grafmueller, B. and Werninghaus, R. and Bamler, R. and Moreira, A.},
    title = {The {Tandem-L} mission proposal: Monitoring {E}arth's dynamics with high resolution {SAR} interferometry},
    booktitle = {Proc. IEEE Radar Conf.},
    year = {2009},
    pages = {1-6},
    month = may,
    abstract = {Tandem-L is a proposal for an innovative interferometric and polarimetric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important mission objectives are global forest height and biomass inventories, large scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The innovative mission concept and the high data acquisition capacity of Tandem-L provide a unique data source to observe, analyze and quantify the dynamics of a wide range of mutually interacting 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. This paper provides an overview of the Tandem-L mission concept and its main application areas. Performance predictions show the great potential of Tandem-L to acquire a wide range of bio- and geophysical parameters with high accuracy on a global scale. Innovative aspects like the employment of advanced digital beamforming techniques to improve performance and coverage are discussed in detail.},
    doi = {10.1109/RADAR.2009.4977077},
    issn = {1097-5659},
    keywords = {Earth's Dynamics Monitoring;Tandem-L mission;advanced digital beamforming techniques; biomass inventories;glacier movement observations;global forest height;high data acquisition;high resolution SAR interferometry;innovative interferometric radar mission;millimetric displacements measurements;polarimetric radar mission;synthetic aperture radar;tectonic shifts;data acquisition;glaciology;radar interferometry;radar polarimetry;remote sensing by radar;synthetic aperture radar;tectonics;vegetation},
    
    }
    


  17. F. Lombardini and M. Pardini. Detection of scatterer multiplicity in spaceborne SAR tomography with array errors. In Radar Conference, 2009 IEEE, pages 1-6, May 2009.
    @InProceedings{Lombardini2009,
    Title = {Detection of scatterer multiplicity in spaceborne SAR tomography with array errors},
    Author = {Lombardini, F. and Pardini, M.},
    Booktitle = {Radar Conference, 2009 IEEE},
    Doi = {10.1109/RADAR.2009.4977012},
    Month = may,
    Pages = {1--6},
    Year = {2009},
    Owner = {ofrey},
    Timestamp = {2009.07.01} 
    }
    


  18. Antonio Moccia and Alfredo Renga. Hybrid space-airborne bistatic SAR geometric resolutions. In Lorenzo Bruzzone, Claudia Notarnicola, and Francesco Posa, editors, , volume 7477, pages 74771Y, 2009. SPIE. Keyword(s): SAR Processing, Bistatic SAR, Geometric Resolution, Geometric Bistatic Resolution, Bistatic Resolution, Resolution, Airborne SAR, Spaceborne SAR.
    @Conference{mocciaRengaBistaticResolutions2010,
    author = {Antonio Moccia and Alfredo Renga},
    title = {Hybrid space-airborne bistatic SAR geometric resolutions},
    year = {2009},
    editor = {Lorenzo Bruzzone and Claudia Notarnicola and Francesco Posa},
    volume = {7477},
    number = {1},
    pages = {74771Y},
    publisher = {SPIE},
    doi = {10.1117/12.830930},
    eid = {74771Y},
    file = {:mocciaRengaBistaticResolutions2010.pdf:PDF},
    journal = {Image and Signal Processing for Remote Sensing XV},
    keywords = {SAR Processing, Bistatic SAR, Geometric Resolution, Geometric Bistatic Resolution, Bistatic Resolution, Resolution, Airborne SAR, Spaceborne SAR},
    location = {Berlin, Germany},
    numpages = {15},
    owner = {ofrey},
    pdf = {../../../docs/mocciaRengaBistaticResolutions2010.pdf},
    url = {http://link.aip.org/link/?PSI/7477/74771Y/1},
    
    }
    


  19. Alberto Moreira, Gerhard Krieger, Irena Hajnsek, Kostas Papathanassiou, Michael Eineder, Francesco De Zan, Marwan Younis, and Marian Werner. Tandem-L: Monitoring the Earth's Dynamics with InSAR and Pol-InSAR. In Proc. PolInSAR, Frascati, Italy (ESA SP-668), January 2009. Keyword(s): Earth's Dynamics Monitoring, Tandem-L mission, advanced digital beamforming techniques, biomass inventories, glacier movement observations, global forest height, high data acquisition, high resolution SAR interferometry, innovative interferometric radar mission, millimetric displacements measurements, polarimetric radar mission, synthetic aperture radar, tectonic shifts, data acquisition, glaciology, radar interferometry, radar polarimetry, remote sensing by radar, synthetic aperture radar, tectonics, vegetation.
    Abstract: Tandem-L is a proposal for an innovative interferometric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important application examples are global forest height and biomass inventories, measurements of Earth deformations due to tectonic processes, observations of 3-D structure changes in ice, and the monitoring of ocean surface currents. The innovative mission concept and the high data acquisition capacity of Tandem-L provide a unique data source to observe, analyze and quantify a wide range of mutually interacting 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 climate dynamics. The Tandem-L mission concept relies on a systematic data acquisition strategy using a pair of cooperating L-band SAR satellites flying in close formation. The satellite system is operated in two basic data acquisition modes: 1) The 3-D structure mode employs fully-polarimetric single-pass SAR interferometry (Pol-InSAR) to acquire structural parameters and quasi-tomographic images of volume scatterers like vegetation, sand, and ice. 2) The deformation mode employs repeat-pass interferometry (InSAR) in an ultra-wide swath mode to measure small shifts on the Earth surface with millimetric accuracy and short repetition intervals. This paper provides an overview of the Tandem-L mission concept and its main application areas. Performance predictions show the great potential of Tandem-L to acquire a wide range of bio- and geophysical products with high accuracy on a global scale. Furthermore, innovative technical aspects like for example the use of digital beamforming to improve performance and coverage will be presented.

    @InProceedings{moreiraKriegerHajnsekPapathanassiouEinederDeZanYounisWerner:tandemLatPOLINSAR2009,
    Title = {{Tandem-L}: Monitoring the {E}arth's Dynamics with {InSAR} and {Pol-InSAR}},
    Author = {Alberto Moreira and Gerhard Krieger and Irena Hajnsek and Kostas Papathanassiou and Michael Eineder and Francesco De Zan and Marwan Younis and Marian Werner},
    Booktitle = {Proc. {PolInSAR}},
    Month = jan,
    Year = {2009},
    Abstract = {Tandem-L is a proposal for an innovative interferometric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important application examples are global forest height and biomass inventories, measurements of Earth deformations due to tectonic processes, observations of 3-D structure changes in ice, and the monitoring of ocean surface currents. The innovative mission concept and the high data acquisition capacity of Tandem-L provide a unique data source to observe, analyze and quantify a wide range of mutually interacting 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 climate dynamics. The Tandem-L mission concept relies on a systematic data acquisition strategy using a pair of cooperating L-band SAR satellites flying in close formation. The satellite system is operated in two basic data acquisition modes: 1) The 3-D structure mode employs fully-polarimetric single-pass SAR interferometry (Pol-InSAR) to acquire structural parameters and quasi-tomographic images of volume scatterers like vegetation, sand, and ice. 2) The deformation mode employs repeat-pass interferometry (InSAR) in an ultra-wide swath mode to measure small shifts on the Earth surface with millimetric accuracy and short repetition intervals. This paper provides an overview of the Tandem-L mission concept and its main application areas. Performance predictions show the great potential of Tandem-L to acquire a wide range of bio- and geophysical products with high accuracy on a global scale. Furthermore, innovative technical aspects like for example the use of digital beamforming to improve performance and coverage will be presented.},
    Address = {Frascati, Italy (ESA SP-668)},
    Keywords = {Earth's Dynamics Monitoring;Tandem-L mission;advanced digital beamforming techniques;biomass inventories;glacier movement observations;global forest height;high data acquisition;high resolution SAR interferometry;innovative interferometric radar mission;millimetric displacements measurements;polarimetric radar mission;synthetic aperture radar;tectonic shifts;data acquisition;glaciology;radar interferometry;radar polarimetry;remote sensing by radar;synthetic aperture radar;tectonics;vegetation} 
    }
    


  20. Alessandro Parizzi, Xiaoying Cong, and Michael Eineder. First Results from Multifrequency Interferometry. A comparison of different decorrelation time constants at L-, C-, and X-Band. In Proc. FRINGE 2009, Frascati, Italy, pages 1-5, September 2009. Keyword(s): SAR Processing, Decorrelation, Temporal Decorrelation, Differential Interferometry, DInSAR, SAR Interferometry, Coherence.
    Abstract: The measurement of displacement from SAR images, using either interferometric or correlation techniques, is always carried out from a comparison between two or more acquisitions separated in time. It is therefore necessary to evaluate the level of phase decorrelation between the two acquisitions in order to understand the quality of the measures that can be obtained. The change of radar resolution cells in time is known to be the main responsible of the gradual decorrelation of the interferometric phase. However, a model that physically describes this process, is at the moment not available. Exploiting the test sites from GITEWS and Exupery, German projects focussed on determination of geo-risks, an analysis of the decorrelation time constants was performed on SAR data from PALSAR, ASAR and TerraSAR-X. Time series of the coherence have been computed and compared with simple statistical models. The time constants were analyzed as a measure of temporal decorrelation, in order to forecast the precision of displacement measures also for future missions. The extracted parameters were finally compared with the type of land covering using optical data and land use maps in order to determine a qualitative relationship between them and extend their validity in a more global context.

    @InProceedings{parizziCongEinederFRINGE2009TempDecorrelation,
    author = {Parizzi, Alessandro and Cong, Xiaoying and Eineder, Michael},
    title = {First Results from Multifrequency Interferometry. A comparison of different decorrelation time constants at {L-}, {C-}, and {X}-Band},
    booktitle = {Proc. FRINGE 2009},
    year = {2009},
    pages = {1-5},
    address = {Frascati, Italy},
    month = sep,
    abstract = {The measurement of displacement from SAR images, using either interferometric or correlation techniques, is always carried out from a comparison between two or more acquisitions separated in time. It is therefore necessary to evaluate the level of phase decorrelation between the two acquisitions in order to understand the quality of the measures that can be obtained. The change of radar resolution cells in time is known to be the main responsible of the gradual decorrelation of the interferometric phase. However, a model that physically describes this process, is at the moment not available. Exploiting the test sites from GITEWS and Exupery, German projects focussed on determination of geo-risks, an analysis of the decorrelation time constants was performed on SAR data from PALSAR, ASAR and TerraSAR-X. Time series of the coherence have been computed and compared with simple statistical models. The time constants were analyzed as a measure of temporal decorrelation, in order to forecast the precision of displacement measures also for future missions. The extracted parameters were finally compared with the type of land covering using optical data and land use maps in order to determine a qualitative relationship between them and extend their validity in a more global context.},
    file = {:parizziCongEinederFRINGE2009TempDecorrelation.pdf:PDF},
    keywords = {SAR Processing, Decorrelation, Temporal Decorrelation, Differential Interferometry, DInSAR, SAR Interferometry, Coherence},
    owner = {ofrey},
    pdf = {../../../docs/parizziCongEinederFRINGE2009TempDecorrelation.pdf},
    
    }
    


  21. L. Pipia, X. Fabregas, A. Aguasca, C. López-Martìnez, and J. J. Mallorquì. Polarimetric coherence optimization for interferometric differential applications. In Proc. IEEE Int. Geoscience and Remote Sensing Symp, volume 5, pages 146-149, July 2009. Keyword(s): GB-SAR, ground-based SAR, terrestrial SAR, data acquisition, optimisation, radar interferometry, radar polarimetry, DInSAR, X-band ground-based PolSAR acquisitions, deformation phase information, differential interferometric SAR, interferometric differential applications, optimized differential phase, polarimetric coherence optimization, polarimetric coherence-optimization techniques, synthetic PolSAR data, urban environment, zero-baseline fully-polarimetric data sets, Amplitude estimation, Analytical models, Convergence, Deformable models, Information retrieval, Interferometry, Optimization methods, Remote sensing, Scattering, Synthetic aperture radar, DInSAR, PolInSAR, ground-based SAR.
    @InProceedings{Pipia2009a,
    author = {L. Pipia and X. Fabregas and A. Aguasca and C. L{\'o}pez-Mart{\'i}nez and J. J. Mallorqu{\'i}},
    title = {Polarimetric coherence optimization for interferometric differential applications},
    booktitle = {Proc. IEEE Int. Geoscience and Remote Sensing Symp},
    year = {2009},
    volume = {5},
    month = jul,
    pages = {146-149},
    doi = {10.1109/IGARSS.2009.5417712},
    issn = {2153-6996},
    keywords = {GB-SAR,ground-based SAR, terrestrial SAR,data acquisition, optimisation, radar interferometry, radar polarimetry, DInSAR, X-band ground-based PolSAR acquisitions, deformation phase information, differential interferometric SAR, interferometric differential applications, optimized differential phase, polarimetric coherence optimization, polarimetric coherence-optimization techniques, synthetic PolSAR data, urban environment, zero-baseline fully-polarimetric data sets, Amplitude estimation, Analytical models, Convergence, Deformable models, Information retrieval, Interferometry, Optimization methods, Remote sensing, Scattering, Synthetic aperture radar, DInSAR, PolInSAR, ground-based SAR},
    owner = {ofrey},
    
    }
    


  22. R.K. Raney. DESDynI adopts hybrid polarity SAR architecture. In Radar Conference, 2009 IEEE, pages 1-4, May 2009. Keyword(s): DESDynI mission, L-band synthetic aperture radar, The National Research Council's Earth Science 2007 Decadal Survey, circular polarization, forest biomass, hybrid-polarity dual-polarised SAR, quadrature-polarimetric SAR mode, terrain surface deformation, polarisation, synthetic aperture radar.
    Abstract: DESDynl-Deformation, Ecosystem Structure, and Dynamics of Ice-is one of the first-tier missions recommended in The National Research Council's Earth Science 2007 Decadal Survey. DESDynI's L-band synthetic aperture radar (SAR) is designed to measure terrain surface deformation and forest biomass, hence its quadrature-polarimetric SAR mode. The objective to provide quantitative information on a global scale imposes severe requirements on the radar to maximize coverage and to sustain reliable operational calibration. These requirements are best served by the hybrid-polarity architecture, in which the radar transmits in circular polarization, and receives on two orthogonal linear polarizations, coherently, retaining their relative phase. This architecture offers many significant advantages over conventional all-linearly-polarized SARs. This paper reviews those advantages, summarizes key attributes of hybrid-polarity dual- and quadrature-polarized SARs including conditions under which the signal-to-noise ratio is conserved, and describes the evolution of this architecture from first principles.

    @InProceedings{Raney2009:DESDynIHybridPolaritySAR,
    Title = {{DESDynI} adopts hybrid polarity {SAR} architecture},
    Author = {Raney, R.K.},
    Booktitle = {Radar Conference, 2009 IEEE},
    Doi = {10.1109/RADAR.2009.4977046},
    Month = may,
    Pages = {1-4},
    Year = {2009},
    Abstract = {DESDynl-Deformation, Ecosystem Structure, and Dynamics of Ice-is one of the first-tier missions recommended in The National Research Council's Earth Science 2007 Decadal Survey. DESDynI's L-band synthetic aperture radar (SAR) is designed to measure terrain surface deformation and forest biomass, hence its quadrature-polarimetric SAR mode. The objective to provide quantitative information on a global scale imposes severe requirements on the radar to maximize coverage and to sustain reliable operational calibration. These requirements are best served by the hybrid-polarity architecture, in which the radar transmits in circular polarization, and receives on two orthogonal linear polarizations, coherently, retaining their relative phase. This architecture offers many significant advantages over conventional all-linearly-polarized SARs. This paper reviews those advantages, summarizes key attributes of hybrid-polarity dual- and quadrature-polarized SARs including conditions under which the signal-to-noise ratio is conserved, and describes the evolution of this architecture from first principles.},
    ISSN = {1097-5659},
    Keywords = {DESDynI mission;L-band synthetic aperture radar;The National Research Council's Earth Science 2007 Decadal Survey;circular polarization;forest biomass;hybrid-polarity dual-polarised SAR;quadrature-polarimetric SAR mode;terrain surface deformation;polarisation;synthetic aperture radar} 
    }
    


  23. David Small, Nuno Miranda, and Erich Meier. A revised radiometric normalisation standard for SAR. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume 4, pages 566-569, July 2009. Keyword(s): SAR Processing, ASAR, ERS-1, Earth ellipsoid model, Earth terrain-model, PALSAR, RADARSAT-1, SAR sensors, TerraSAR-X, beta nought SAR radiometry, elevation models, gamma nought SAR radiometry, image geolocation accuracy, radar cross section, radar imaging, radar measurements, radar scattering, radar terrain factors, radiometric calibration, radiometric normalisation standard, sigma nought SAR radiometry, terrain variations, radar cross-sections, radar imaging, radiometry, synthetic aperture radar, terrain mapping.
    Abstract: Improved geometric accuracy in SAR sensors implies that more complex models of the Earth may be used not only to geometrically rectify imagery, but also to more robustly calibrate their radiometry. Current beta, sigma, and gamma nought SAR radiometry conventions all assume a simple \E5\C0flat as Kansas\E5\C0 Earth ellipsoid model. We complement these simple models with improved radiometric calibration that accounts for local terrain variations. In the era of ERS-1 and RADARSAT-1, image geolocation accuracy was in the order of multiple samples, and tiepoint-free establishment of the relationship between radar and map geometries was not possible. Newer sensors such as ASAR, PALSAR, and TerraSAR-X all support accurate geolocation based on product annotations alone. We show that high geolocation accuracy, combined with availability of high-resolution accurate elevation models, enables a more robust radiometric calibration standard for modern SAR sensors that is based on gamma nought normalised using an Earth terrain-model.

    @InProceedings{smallMirandaMeier2009:RadiometricNormalization,
    Title = {A revised radiometric normalisation standard for {SAR}},
    Author = {Small, David and Miranda, Nuno and Meier, Erich},
    Booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    Doi = {10.1109/IGARSS.2009.5417439},
    Month = jul,
    Pages = {566-569},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5417439},
    Volume = {4},
    Year = {2009},
    Abstract = {Improved geometric accuracy in SAR sensors implies that more complex models of the Earth may be used not only to geometrically rectify imagery, but also to more robustly calibrate their radiometry. Current beta, sigma, and gamma nought SAR radiometry conventions all assume a simple \E5\C0flat as Kansas\E5\C0 Earth ellipsoid model. We complement these simple models with improved radiometric calibration that accounts for local terrain variations. In the era of ERS-1 and RADARSAT-1, image geolocation accuracy was in the order of multiple samples, and tiepoint-free establishment of the relationship between radar and map geometries was not possible. Newer sensors such as ASAR, PALSAR, and TerraSAR-X all support accurate geolocation based on product annotations alone. We show that high geolocation accuracy, combined with availability of high-resolution accurate elevation models, enables a more robust radiometric calibration standard for modern SAR sensors that is based on gamma nought normalised using an Earth terrain-model.},
    Keywords = {SAR Processing, ASAR;ERS-1;Earth ellipsoid model;Earth terrain-model;PALSAR;RADARSAT-1;SAR sensors;TerraSAR-X;beta nought SAR radiometry;elevation models;gamma nought SAR radiometry;image geolocation accuracy;radar cross section;radar imaging;radar measurements;radar scattering;radar terrain factors;radiometric calibration;radiometric normalisation standard;sigma nought SAR radiometry;terrain variations;radar cross-sections;radar imaging;radiometry;synthetic aperture radar;terrain mapping},
    Owner = {ofrey},
    Pdf = {../../../docs/smallMirandaMeier2009.pdf} 
    }
    


  24. David Small, Nuno Miranda, and Erich Meier. Local incidence angle considered harmful. In Proc. CEOS SAR Cal/Val Workshop, Pasadena, CA, Nov. 17\D019 2009.
    @InProceedings{smallMirandaMeierCEOS2009:RadiometricNormalization,
    Title = {Local incidence angle considered harmful},
    Author = {David Small and Nuno Miranda and Erich Meier},
    Booktitle = {Proc. CEOS SAR Cal/Val Workshop},
    Month = {Nov. 17\D019},
    Year = {2009},
    Address = {Pasadena, CA},
    Owner = {ofrey} 
    }
    


  25. Stefano Tebaldini and Fabio Rocca. On the impact of propagation disturbances on SAR Tomography: Analysis and compensation. In IEEE Radar Conference, pages 1-6, May 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, PSI, Persistent Scatterer Interferometry, Differential SAR Interferometry.
    Abstract: This paper is meant to discuss the role of propagation disturbances, such as those due to atmospheric disturbances or to residual platform motion, in SAR Tomography applications. It will be shown that phase stability requirements vary as a function of the number of targets within the system resolution cell, from which it follows that SAR Tomography applications require a higher phase stability, or a more accurate phase calibration, with respect to SAR Interferometry. Phase calibration will be discussed by comparing two approaches. The first is the traditional approach from Permanent Scatterers Interferometry, based on the assumption that it is possible to find stable targets in the imaged scene. The second is a new technique based on the Sum of Kronecker Products Decomposition, recently introduced in literature, which allows to isolate ground and volume contributions within the data provided the availability of multi-polarimetric acquisitions. As such, the latter approach is suited to carry out phase calibration in presence of volume scattering, as it is the case of forested areas. Experimental results will be provided basing on the analysis of the P-Band data-set relative to the forest site of Remningstorp, Sweden.

    @InProceedings{tebaldiniRoccaRADARConf2009:TomoPropgationDisturbance,
    Title = {On the impact of propagation disturbances on {SAR} Tomography: Analysis and compensation},
    Author = {Tebaldini, Stefano and Rocca, Fabio},
    Booktitle = {IEEE Radar Conference},
    Doi = {10.1109/RADAR.2009.4976991},
    Month = may,
    Pages = {1--6},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=04976991},
    Year = {2009},
    Abstract = {This paper is meant to discuss the role of propagation disturbances, such as those due to atmospheric disturbances or to residual platform motion, in SAR Tomography applications. It will be shown that phase stability requirements vary as a function of the number of targets within the system resolution cell, from which it follows that SAR Tomography applications require a higher phase stability, or a more accurate phase calibration, with respect to SAR Interferometry. Phase calibration will be discussed by comparing two approaches. The first is the traditional approach from Permanent Scatterers Interferometry, based on the assumption that it is possible to find stable targets in the imaged scene. The second is a new technique based on the Sum of Kronecker Products Decomposition, recently introduced in literature, which allows to isolate ground and volume contributions within the data provided the availability of multi-polarimetric acquisitions. As such, the latter approach is suited to carry out phase calibration in presence of volume scattering, as it is the case of forested areas. Experimental results will be provided basing on the analysis of the P-Band data-set relative to the forest site of Remningstorp, Sweden.},
    Keywords = {SAR Processing, SAR Tomography, Tomography, PSI, Persistent Scatterer Interferometry, Differential SAR Interferometry},
    Owner = {ofrey},
    Pdf = {../../../docs/tebaldiniRoccaRADARConf2009.pdf} 
    }
    


  26. Stefano Tebaldini and Fabio Rocca. Polarimetric Options for SAR Tomography of Forested Areas. In Proc. of PolInSAR - 4th Int. Workshop on Science and Applications of SAR Polarimetry and Polarimetric Interferometry, Frascati, Italy, January 2009. ESA SP-668. Keyword(s): SAR Processing, SAR Tomography, Tomography, E-SAR, P-Band.
    Abstract: The aim of this paper is to discuss the potentialities of SAR Tomography to infer information about the vertical structure of forested areas, basing on the availability of either multi-polarimetric or single-polarimetric data. The core of the analysis is represented by a model of the second order statistics of the multi-baseline, multi-polarimetric data that describes the imaged scene as the superposition of two distributed scattering mechanisms. In this framework, the well posing of the Tomographic problem can be discussed in a simple fashion, by considering the number of equations that arise from the data-set with respect to the number of the unknowns required to solve the model. As a result, it follows that through the exploitation of strongly structured models the vertical structure can be retrieved basing on single-polarimetric data as well, provided that a sufficient number of baselines is available. Still, the availability of multi-polarimetric and multi-baseline data offers the possibility to face the problem of the retrieval of the vertical structure of each scattering mechanism from a very general point of view, allowing to relax many of the assumptions that are otherwise mandatory. In other words, the availability of multipolarimetric data makes it possible to exploit not only model based approaches, but also model free, and hybrid approaches. As a result of this analysis, a new general methodology will be presented for the processing of multi-polarimetric and multibaseline data, that is consistent the inversion procedures usually exploited in single-baseline PolInSAR in the case where only single baseline data are available. Experimental results will be shown basing on a data-set of 9 P-Band SAR images of the forest site of Remningstorp, Sweden, acquired under the framework of the ESA campaign BioSAR 2007.

    @InProceedings{tebaldiniRocca2009PolInSAR:Tomo,
    Title = {Polarimetric Options for SAR Tomography of Forested Areas},
    Author = {Stefano Tebaldini and Fabio Rocca},
    Booktitle = {Proc. of PolInSAR - 4th Int. Workshop on Science and Applications of SAR Polarimetry and Polarimetric Interferometry},
    Month = {jan},
    Organization = {ESA SP-668},
    Url = {http://earth.esa.int/workshops/polinsar2009/participants/255/paper_255_s14_2te.pdf},
    Year = {2009},
    Abstract = {The aim of this paper is to discuss the potentialities of SAR Tomography to infer information about the vertical structure of forested areas, basing on the availability of either multi-polarimetric or single-polarimetric data. The core of the analysis is represented by a model of the second order statistics of the multi-baseline, multi-polarimetric data that describes the imaged scene as the superposition of two distributed scattering mechanisms. In this framework, the well posing of the Tomographic problem can be discussed in a simple fashion, by considering the number of equations that arise from the data-set with respect to the number of the unknowns required to solve the model. As a result, it follows that through the exploitation of strongly structured models the vertical structure can be retrieved basing on single-polarimetric data as well, provided that a sufficient number of baselines is available. Still, the availability of multi-polarimetric and multi-baseline data offers the possibility to face the problem of the retrieval of the vertical structure of each scattering mechanism from a very general point of view, allowing to relax many of the assumptions that are otherwise mandatory. In other words, the availability of multipolarimetric data makes it possible to exploit not only model based approaches, but also model free, and hybrid approaches. As a result of this analysis, a new general methodology will be presented for the processing of multi-polarimetric and multibaseline data, that is consistent the inversion procedures usually exploited in single-baseline PolInSAR in the case where only single baseline data are available. Experimental results will be shown basing on a data-set of 9 P-Band SAR images of the forest site of Remningstorp, Sweden, acquired under the framework of the ESA campaign BioSAR 2007.},
    Address = {Frascati, Italy},
    Keywords = {SAR Processing, SAR Tomography, Tomography, E-SAR, P-Band},
    Owner = {ofrey},
    Pdf = {../../../docs/tebaldiniRoccaGuarnieri2008.pdf} 
    }
    


  27. A. Wyholt and Lars M. H. Ulander. Evaluating VHF-band SAR autofocus algorithms using a forest backscatter model. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume 4, pages 9-12, July 2009. Keyword(s): SAR Processing, Autofocus, Time-Domain Back-Projection, TDBP, FFBP, SAR subimages, VHF-band SAR autofocus algorithms, fast factorized back-projection algorithm, forest backscatter model, forest clutter model, matching error, residual displacement errors, subimage matching, backscatter, focusing, geophysical image processing, image matching, remote sensing by radar, synthetic aperture radar.
    Abstract: The objective of this paper is to assess the accuracy of an autofocus method developed for the Fast Factorized Back-Projection (FFBP) algorithm in simulated scenarios. We specifically address the question whether correlation measurements between subimages will suffice in the focusing process in one arbitrary merging step. A forest clutter model is used together with a model of the impulse responses to simulate two SAR sub-images of a forest. Correlation is used for sub-image matching and residual displacement errors are compiled using simulation. We conclude that the matching error increases with increased number of trees per resolution cell but can be restored with a larger image size in the correlation measurements. We also conclude that the autofocus method will be successful.

    @InProceedings{wyholtUlander2009AutofocusFFBP,
    author = {Wyholt, A. and Ulander, Lars M. H.},
    title = {Evaluating {VHF}-band {SAR} autofocus algorithms using a forest backscatter model},
    booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
    year = {2009},
    volume = {4},
    pages = {9-12},
    month = jul,
    abstract = {The objective of this paper is to assess the accuracy of an autofocus method developed for the Fast Factorized Back-Projection (FFBP) algorithm in simulated scenarios. We specifically address the question whether correlation measurements between subimages will suffice in the focusing process in one arbitrary merging step. A forest clutter model is used together with a model of the impulse responses to simulate two SAR sub-images of a forest. Correlation is used for sub-image matching and residual displacement errors are compiled using simulation. We conclude that the matching error increases with increased number of trees per resolution cell but can be restored with a larger image size in the correlation measurements. We also conclude that the autofocus method will be successful.},
    doi = {10.1109/IGARSS.2009.5417608},
    file = {:wyholtUlander2009AutofocusFFBP.pdf:PDF},
    keywords = {SAR Processing, Autofocus, Time-Domain Back-Projection, TDBP, FFBP, SAR subimages;VHF-band SAR autofocus algorithms;fast factorized back-projection algorithm;forest backscatter model;forest clutter model;matching error;residual displacement errors;subimage matching;backscatter;focusing;geophysical image processing;image matching;remote sensing by radar;synthetic aperture radar},
    pdf = {../../../docs/wyholtUlander2009AutofocusFFBP.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5417608},
    
    }
    


  28. Ping Zhang, Jian Shang, and Ruliang Yang. A New algorithm improving SAR resolution based on SVA. In Radar Conference, 2009 IET International, pages 1-4, 2009. Keyword(s): SAR Processing, Apodization, Spatially Variant Apodization, SVA.
    Abstract: Resolution enhancement techniques in radar imaging have attracted considerable interest in recent years. The paper develops a new technique enhancing SAR resolution as well as suppressing sidelobes based on SVA technique. Spatially variant apodization (SVA) is a nonlinear sidelobe reduction method without lose the resolution of mainlobe. The signal bandwidth is extrapolated after SVA, which is the basis of resolution enhancement. An inverse weight function is used to equalize the SVA spectrum. A modified noninteger Nyquist spatially variant apodization (SVA) formulation is used to suppress sidelobes after extrapolation. Examples of 1D case and 2D case demonstrate enhanced image resolution with sidelobe reduction.

    @InProceedings{zhangShangYang2009:SpatiallyVariantApodization,
    Title = {A New algorithm improving {SAR} resolution based on {SVA}},
    Author = {Ping Zhang and Jian Shang and Ruliang Yang},
    Booktitle = {Radar Conference, 2009 IET International},
    Pages = {1-4},
    Year = {2009},
    Abstract = {Resolution enhancement techniques in radar imaging have attracted considerable interest in recent years. The paper develops a new technique enhancing SAR resolution as well as suppressing sidelobes based on SVA technique. Spatially variant apodization (SVA) is a nonlinear sidelobe reduction method without lose the resolution of mainlobe. The signal bandwidth is extrapolated after SVA, which is the basis of resolution enhancement. An inverse weight function is used to equalize the SVA spectrum. A modified noninteger Nyquist spatially variant apodization (SVA) formulation is used to suppress sidelobes after extrapolation. Examples of 1D case and 2D case demonstrate enhanced image resolution with sidelobe reduction.},
    ISSN = {0537-9989},
    Keywords = {SAR Processing, Apodization, Spatially Variant Apodization, SVA} 
    }
    


  29. Xiao Xiang Zhu, N. Adam, and R. Bamler. Space-borne high resolution tomographic interferometry. In Proc. Geoscience and Remote Sensing Symp.,2009 IEEE Int.,IGARSS 2009, volume 4, 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry.
    @InProceedings{Zhu2009,
    Title = {Space-borne high resolution tomographic interferometry},
    Author = {Xiao Xiang Zhu and Adam, N. and Bamler, R.},
    Booktitle = {Proc. Geoscience and Remote Sensing Symp.,2009 IEEE Int.,IGARSS 2009},
    Doi = {10.1109/IGARSS.2009.5417515},
    Volume = {4},
    Year = {2009},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry},
    Owner = {ofrey} 
    }
    


  30. Xiao Xiang Zhu, Nico Adam, R. Brcic, and Richard Bamler. Space-borne high resolution SAR tomography: experiments in urban environment using TS-X Data. In Proc. Joint Urban Remote Sensing Event, pages 1-8, 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry, TerraSAR-X, X-band.
    @InProceedings{Zhu2009a,
    Title = {Space-borne high resolution {SAR} tomography: experiments in urban environment using {TS-X} Data},
    Author = {Xiao Xiang Zhu and Adam, Nico and Brcic, R. and Bamler, Richard},
    Booktitle = {Proc. Joint Urban Remote Sensing Event},
    Doi = {10.1109/URS.2009.5137534},
    Pages = {1-8},
    Year = {2009},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry, TerraSAR-X, X-band},
    Owner = {ofrey} 
    }
    


  31. Xiao Xiang Zhu, Nico Adam, Ramon Brcic, and Richard Bamler. Space-borne high resolution SAR tomography: experiments in urban environment using TS-X Data. In Urban Remote Sensing Event, 2009 Joint, pages 1-8, May 2009. Keyword(s): SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry.
    @InProceedings{Xiao2009,
    Title = {Space-borne high resolution SAR tomography: experiments in urban environment using TS-X Data},
    Author = {Xiao Xiang Zhu and Adam, Nico and Brcic, Ramon and Bamler, Richard},
    Booktitle = {Urban Remote Sensing Event, 2009 Joint},
    Doi = {10.1109/URS.2009.5137534},
    Month = may,
    Pages = {1--8},
    Year = {2009},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Compressive Sensing, CS, InSAR, SAR Interferometry, Interferometry},
    Owner = {ofrey} 
    }
    


Internal reports

  1. Report of the DESDynI Applications Workshop. Technical report, Version 1, April 2009. Keyword(s): DESDynI mission, BIOMASS mission, Earth explorer core mission candidate, P-band, forest area, forest biomass, forest disturbances, global maps, synthetic aperture radar, terrestrial carbon cycle, remote sensing by radar, spaceborne radar, DESDynl mission, Deformation, Ecosystem Structure, and Dynamics of Ice, Earth Science Decadal Survey, National Research Council, biomass estimation, carbon cycle, cryosphere objectives, ecosystem function, integrated L-band InSAR, multibeam Lidar mission, solid Earth surface deformation, surface elevation changes, topography measure, vegetation structure, deformation, optical radar, radar interferometry, remote sensing by radar, topography (Earth), vegetation.
    @TechReport{DESDynIApplicationsWorkshopReport,
    Title = {Report of the {DESDynI} Applications Workshop},
    Month = apr,
    Year = {2009},
    Address = {Version 1},
    Keywords = {DESDynI mission, BIOMASS mission;Earth explorer core mission candidate;P-band;forest area;forest biomass;forest disturbances;global maps;synthetic aperture radar;terrestrial carbon cycle;remote sensing by radar;spaceborne radar; DESDynl mission; Deformation, Ecosystem Structure, and Dynamics of Ice;Earth Science Decadal Survey; National Research Council;biomass estimation;carbon cycle;cryosphere objectives; ecosystem function;integrated L-band InSAR;multibeam Lidar mission;solid Earth surface deformation; surface elevation changes;topography measure;vegetation structure;deformation; optical radar;radar interferometry;remote sensing by radar;topography (Earth);vegetation} 
    }
    


Miscellaneous

  1. PolInSAR 2009 Sorted Recommendations, January 2009.
    @Misc{PolInSAR2009SortedRecommendations,
    Title = {{PolInSAR} 2009 Sorted Recommendations},
    Month = jan,
    Organization = {ESA},
    Url = {http://earth.esa.int/workshops/polinsar2009/POLInSAR2009_sorted_rec.pdf},
    Year = {2009},
    Address = {Frascati, Italy} 
    }
    


  2. A. Colettaa, D. De Lisle, A. Moreira, A. Freeman, M. Shimada, T. Ainsworth, Konstatinos Papathanassiou, S. R. Cloude, P. Dubois-Fernandez, P. Lombardo, G. Trianni, K. Raney, A. Minchella, F. Charbonneau, L. Ferro-Famil, D. Floricioiu, S. Lehner, Irena Hajnsek, Ridha Touzi, Wolfgang Martin Boerner, Eric Pottier, and Fabio Rocca. Summaries and Recommendations of the POLInSAR 2009 Workshop, January 2009.
    @Misc{PolInSAR2009Recommendations,
    Title = {Summaries and Recommendations of the POLInSAR 2009 Workshop},
    Author = {A. Colettaa and De Lisle, D. and A. Moreira and A. Freeman and M. Shimada and T. Ainsworth and Konstatinos Papathanassiou and S. R. Cloude and P. Dubois-Fernandez and P. Lombardo and G. Trianni and K. Raney and A. Minchella and F. Charbonneau and L. Ferro-Famil and D. Floricioiu and S. Lehner and Irena Hajnsek and Ridha Touzi and Wolfgang Martin Boerner and Eric Pottier and Fabio Rocca},
    Month = jan,
    Organization = {ESA},
    Year = {2009},
    Address = {Frascati, Italy} 
    }
    


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This collection of SAR literature is far from being complete.
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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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