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Publications of year 1995

Books and proceedings

  1. Walter G. Carrara, Ron S. Goodman, and Ronald M. Majewski. Spotlight Synthetic Aperture Radar: Signal Processing Algorithms. Artech House Inc., 1995. Keyword(s): SAR Processing, Spotlight SAR, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Chirp Scaling Algorithm, Polar Format Algorithm, Autofocus Techniques, Demodulation, Quadrature Demodulation, Hilbert Transform.
    Abstract: The book gives an excellent theoretical and practical background of SAR in general and specifically of spotlight SAR. The rich experience of the authors in spotlight SAR processing is reflected by a very detailed summary of the associated theory as well as a lot of SAR image examples. These images illustrate the techniques described in the book and provide a valuable connection to practice. This book can be highly recommended to all scientists and engineers involved in SAR system design and SAR data evaluation, -- International Journal of Electronics and Communications, January 1996. Contents: Synthetic Aperture Radar Fundamentals. Spotlight SAR and Polar Format Algorithm. Digital Polar Format Processing. Phase Errors. Autofocus Techniques. Processor Design Examples. SAR System Performance. Spotlight Processing Applications. Range Migration Algorithm. Chirp Scaling Algorithm. Comparison of Image Formation Algorithms. Appendices.

    @Book{carrara:SARProc,
    Title = {{Spotlight Synthetic Aperture Radar: Signal Processing Algorithms}},
    Author = {Walter G. Carrara and Ron S. Goodman and Ronald M. Majewski},
    Publisher = {Artech House Inc.},
    Url = {http://www.techbooks.co.uk/artech/book310.htm},
    Year = {1995},
    Abstract = {The book gives an excellent theoretical and practical background of SAR in general and specifically of spotlight SAR. The rich experience of the authors in spotlight SAR processing is reflected by a very detailed summary of the associated theory as well as a lot of SAR image examples. These images illustrate the techniques described in the book and provide a valuable connection to practice. This book can be highly recommended to all scientists and engineers involved in SAR system design and SAR data evaluation, -- International Journal of Electronics and Communications, January 1996. Contents: Synthetic Aperture Radar Fundamentals. Spotlight SAR and Polar Format Algorithm. Digital Polar Format Processing. Phase Errors. Autofocus Techniques. Processor Design Examples. SAR System Performance. Spotlight Processing Applications. Range Migration Algorithm. Chirp Scaling Algorithm. Comparison of Image Formation Algorithms. Appendices.},
    Comment = {Appendix A: A Fast Algorithm for Digital Quadrature Demodulation},
    Keywords = {SAR Processing, Spotlight SAR, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Chirp Scaling Algorithm, Polar Format Algorithm, Autofocus Techniques,Demodulation,Quadrature Demodulation, Hilbert Transform} 
    }
    


Articles in journal or book chapters

  1. G. Fornaro and G. Franceschetti. Image registration in interferometric SAR processing. IEE Proceedings - Radar, Sonar and Navigation, 142(6):313-320, December 1995. Keyword(s): SAR Processing, InSAR, SAR Interferometry, IFSAR applications, common reference output system, image registration, interferometric SAR processing, linear stretch, phase difference, raw data processing stage, received signal, scaling compensation, shifting compensation, spectral shift, geophysical signal processing, image registration, radar imaging, radiowave interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar.
    Abstract: In interferometric synthetic aperture radar (IFSAR) applications image registration is needed to extract the correct phase difference between the two received signals. The authors present a new image registration procedure implemented at the raw data processing stage; the two complex SAR images are generated with respect to a common reference output system. The registration task is achieved via scaling and shifting compensation that can be efficiently and easily included in a standard SAR processing code. Examples on real as well as on simulated data validate the procedure. An algorithm to estimate the correct processing parameters, whenever the orbital information is inaccurate, is also presented and is based on the relation between spectral shift and linear stretch of the two images

    @Article{487697,
    Title = {Image registration in interferometric SAR processing},
    Author = {Fornaro, G. and Franceschetti, G.},
    Doi = {10.1049/ip-rsn:19952174},
    ISSN = {1350-2395},
    Month = dec,
    Number = {6},
    Pages = {313-320},
    Volume = {142},
    Year = {1995},
    Abstract = {In interferometric synthetic aperture radar (IFSAR) applications image registration is needed to extract the correct phase difference between the two received signals. The authors present a new image registration procedure implemented at the raw data processing stage; the two complex SAR images are generated with respect to a common reference output system. The registration task is achieved via scaling and shifting compensation that can be efficiently and easily included in a standard SAR processing code. Examples on real as well as on simulated data validate the procedure. An algorithm to estimate the correct processing parameters, whenever the orbital information is inaccurate, is also presented and is based on the relation between spectral shift and linear stretch of the two images},
    Journal = {IEE Proceedings - Radar, Sonar and Navigation},
    Keywords = {SAR Processing, InSAR, SAR Interferometry, IFSAR applications;common reference output system;image registration;interferometric SAR processing;linear stretch;phase difference;raw data processing stage;received signal;scaling compensation;shifting compensation;spectral shift;geophysical signal processing;image registration;radar imaging;radiowave interferometry;remote sensing by radar;spaceborne radar;synthetic aperture radar} 
    }
    


  2. Giorgio Franceschetti, Riccardo Lanari, and E. S. Marzouk. Efficient and High Precision Space-Variant Processing of SAR Data. IEEE Transactions on Aerospace and Electronic Systems, 31(1):227-237, January 1995. Keyword(s): SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Range-Doppler Algorithm, Space-Variance Compensation, Space-Variant Processing, Earth Rotation Effect, Nonstandard Fourier Transform.
    Abstract: We investigate the space-variance of the synthetic aperture radar (SAR) transfer function due to focus depth variation and Earth rotation effect. We introduce a procedure for efficient space-variance compensation which is based on the use of a nonstandard Fourier transform (FT). A number of experiments confirming theoretical results are presented

    @Article{francescLanaMar95:Processing,
    Title = {{Efficient and High Precision Space-Variant Processing of SAR Data}},
    Author = {Giorgio Franceschetti and Riccardo Lanari and E. S. Marzouk},
    Month = Jan,
    Number = {1},
    Pages = {227-237},
    Url = {http://ieeexplore.ieee.org/iel4/7/8392/00366305.pdf},
    Volume = {31},
    Year = {1995},
    Abstract = {We investigate the space-variance of the synthetic aperture radar (SAR) transfer function due to focus depth variation and Earth rotation effect. We introduce a procedure for efficient space-variance compensation which is based on the use of a nonstandard Fourier transform (FT). A number of experiments confirming theoretical results are presented},
    Journal = {IEEE Transactions on Aerospace and Electronic Systems},
    Keywords = {SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Range-Doppler Algorithm, Space-Variance Compensation, Space-Variant Processing, Earth Rotation Effect, Nonstandard Fourier Transform},
    Pdf = {../../../docs/francescLanaMar95.pdf} 
    }
    


  3. Richard M. Goldstein. Atmospheric limitations to repeat-track radar interferometry. Geophysical Research Letters, 22(18):2517-2520, 1995. Keyword(s): SAR Processing, SAR Processing, Interferometry, SAR interferometry, Atmospheric Composition and Structure: Troposphere-composition and chemistry, Geodesy and Gravity: Space geodetic surveys, Geodesy and Gravity: Instruments and techniques, Radio Science: Remote sensing.
    Abstract: In its recent radar imaging mission, the Shuttle Imaging Radar satellite (SIR-C) devoted three days to repeat-track interferometry. We have analyzed the data from a test site in the Mojave desert of California. Although good topography (+/-10 m on 21 m postings) was obtained, most of the error was caused by turbulent water vapor in the lower atmosphere. Spatial structure of 6 km and all smaller sizes was observed. The RMS, one-way time delay was found to be 0.24 cm. Essentially identical results were obtained at two wavelengths, 24 and 5.7 cm.

    @Article{goldsteinGRL1995AtmosphereInSAR,
    author = {Goldstein, Richard M.},
    title = {Atmospheric limitations to repeat-track radar interferometry},
    journal = {Geophysical Research Letters},
    year = {1995},
    volume = {22},
    number = {18},
    pages = {2517-2520},
    issn = {1944-8007},
    abstract = {In its recent radar imaging mission, the Shuttle Imaging Radar satellite (SIR-C) devoted three days to repeat-track interferometry. We have analyzed the data from a test site in the Mojave desert of California. Although good topography (+/-10 m on 21 m postings) was obtained, most of the error was caused by turbulent water vapor in the lower atmosphere. Spatial structure of 6 km and all smaller sizes was observed. The RMS, one-way time delay was found to be 0.24 cm. Essentially identical results were obtained at two wavelengths, 24 and 5.7 cm.},
    doi = {10.1029/95GL02475},
    file = {:goldsteinGRL1995AtmosphereInSAR.pdf:PDF},
    keywords = {SAR Processing, SAR Processing, Interferometry, SAR interferometry, Atmospheric Composition and Structure: Troposphere-composition and chemistry, Geodesy and Gravity: Space geodetic surveys, Geodesy and Gravity: Instruments and techniques, Radio Science: Remote sensing},
    pdf = {../../../docs/goldsteinGRL1995AtmosphereInSAR.pdf},
    url = {http://dx.doi.org/10.1029/95GL02475},
    
    }
    


  4. J.O. Hagberg, L. M. H. Ulander, and J. Askne. Repeat-pass SAR interferometry over forested terrain. IEEE Trans. Geosci. Remote Sens., 33(2):331-340, March 1995. Keyword(s): SAR Processing, SAR interferometry, forest, forested terrain, forestry, general system model, geophysical method, interferometry, land surface topography, measurement technique, radar remote sensing, repeat pass method, scene scattering, synthetic aperture radar, topographic map, vegetation mapping, forestry, geophysical techniques, radar applications, radar imaging, remote sensing, remote sensing by radar, synthetic aperture radar, topography (Earth).
    Abstract: Repeat-pass synthetic aperture radar (SAR) interferometry provides the possibility of producing topographic maps and geocoded as well as radiometrically calibrated radar images. However, the usefulness of such maps and images depends on our understanding of how different types of terrain affect the radar measurements. It is essential that the scene coherence between passes is sufficient. In this paper, the authors derive a general system model including both radar system and scene scattering properties. The model is used to interpret measurements over a forested area where the scene coherence varies between 0.2 and 0.5. The coherence is found to be sensitive to temperature changes around 0 deg Celsius but surprisingly insensitive to wind speed. The interferometric height discontinuity at the forest to open-field boundary shows good agreement with in situ tree height measurements. For a dense boreal forest, but is observed to decrease for a less dense forest. This suggests the possibility of estimating bole volume from the interferometric tree height and a ground DEM. The decrease of scene coherence over a dense forest with increasing baseline is also used to estimate the effective scattering layer thickness

    @Article{HagbergUlanderAskne1995,
    Title = {Repeat-pass {SAR} interferometry over forested terrain},
    Author = {Hagberg, J.O. and Ulander, L. M. H. and Askne, J.},
    Doi = {10.1109/36.377933},
    ISSN = {0196-2892},
    Month = mar,
    Number = {2},
    Pages = {331-340},
    Volume = {33},
    Year = {1995},
    Abstract = {Repeat-pass synthetic aperture radar (SAR) interferometry provides the possibility of producing topographic maps and geocoded as well as radiometrically calibrated radar images. However, the usefulness of such maps and images depends on our understanding of how different types of terrain affect the radar measurements. It is essential that the scene coherence between passes is sufficient. In this paper, the authors derive a general system model including both radar system and scene scattering properties. The model is used to interpret measurements over a forested area where the scene coherence varies between 0.2 and 0.5. The coherence is found to be sensitive to temperature changes around 0 deg Celsius but surprisingly insensitive to wind speed. The interferometric height discontinuity at the forest to open-field boundary shows good agreement with in situ tree height measurements. For a dense boreal forest, but is observed to decrease for a less dense forest. This suggests the possibility of estimating bole volume from the interferometric tree height and a ground DEM. The decrease of scene coherence over a dense forest with increasing baseline is also used to estimate the effective scattering layer thickness},
    Journal = {IEEE Trans. Geosci. Remote Sens.},
    Keywords = {SAR Processing, SAR interferometry;forest;forested terrain;forestry;general system model;geophysical method;interferometry;land surface topography;measurement technique;radar remote sensing;repeat pass method;scene scattering;synthetic aperture radar;topographic map;vegetation mapping;forestry;geophysical techniques;radar applications;radar imaging;remote sensing;remote sensing by radar;synthetic aperture radar;topography (Earth)} 
    }
    


  5. Marc L. Imhoff. Radar backscatter and biomass saturation: ramifications for global biomass inventory. IEEE Transactions on Geoscience and Remote Sensing, 33(2):511-518, March 1995. Keyword(s): SAR Processing, backscatter, forestry, geophysical techniques, radar applications, radar cross-sections, radar imaging, remote sensing by radar, synthetic aperture radar, 0.44 to 5.3 GHz, C-band, Hawaii, L-band, P-band, SAR, UHF SHF microwave, biomass saturation, biome, broadleaf evergreen forest, canopy, coniferous forest, forestry, geophysical measurement technique, global biomass inventory, land surface, phytomass, radar backscatter, radar remote sensing, synthetic aperture radar, vegetated surface, vegetation mapping, Space-borne SAR, SAR Tomography, Tomography.
    Abstract: Two SAR and biomass data sets of forests with different canopy architectures were examined for commonalties regarding backscatter/biomass saturation. The SAR data were collected using the NASA/JPL AIRSAR at incidence angles between 40 deg and 50 deg for tropical broadleaf evergreen forests in Hawaii and coniferous forests in North America and Europe. Radar signal saturation limits with respect to biomass for both forest types were determined to be ~100 tons/ha for P-band (0.44 GHz), ~40 tons/ha for L-band (1.25 GHz), and ~20 tons/ha for C-band (5.3 GHz). The effect of the saturation limits on making global biomass inventories with SAR sensors was assessed by comparing the biomass saturation limits to a global vegetation type and biomass data base. C-band can be used to measure biomass in biomes covering 25% of the world's total ice-free vegetated surface area accounting for 4% of Earth's store of terrestrial phytomass. L- and P-band can be used to measure biomass in biomes covering 37% and 62% of the total vegetated surface area accounting for 8% and 19% of Earth's pool of terrestrial phytomass respectively. Biomes occupying approximately 38% of Earth's vegetated surface area containing 81% of the estimated total terrestrial phytomass have biomass densities above the saturation limit of current SAR systems (>100 tons/ha for P-band). Since P-band radar systems cannot currently operate effectively from orbit, the use of SAR sensors for biomass surveys may be limited even further to the L-band threshold. Emphasis should be shifted toward using SAR to characterize forest regeneration and development up to the saturation limits shown in this article rather than attempting to measure biomass directly in heavy forests. The development of new and innovative technologies for measuring biomass in high density vegetation is encouraged

    @Article{imhoff95:RadarBackscatterAndBiomass,
    Title = {Radar backscatter and biomass saturation: ramifications for global biomass inventory},
    Author = {Imhoff, Marc L.},
    Doi = {10.1109/36.377953},
    ISSN = {0196-2892},
    Month = mar,
    Number = {2},
    Pages = {511-518},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=377953&isnumber=8610},
    Volume = {33},
    Year = {1995},
    Abstract = {Two SAR and biomass data sets of forests with different canopy architectures were examined for commonalties regarding backscatter/biomass saturation. The SAR data were collected using the NASA/JPL AIRSAR at incidence angles between 40 deg and 50 deg for tropical broadleaf evergreen forests in Hawaii and coniferous forests in North America and Europe. Radar signal saturation limits with respect to biomass for both forest types were determined to be ~100 tons/ha for P-band (0.44 GHz), ~40 tons/ha for L-band (1.25 GHz), and ~20 tons/ha for C-band (5.3 GHz). The effect of the saturation limits on making global biomass inventories with SAR sensors was assessed by comparing the biomass saturation limits to a global vegetation type and biomass data base. C-band can be used to measure biomass in biomes covering 25% of the world's total ice-free vegetated surface area accounting for 4% of Earth's store of terrestrial phytomass. L- and P-band can be used to measure biomass in biomes covering 37% and 62% of the total vegetated surface area accounting for 8% and 19% of Earth's pool of terrestrial phytomass respectively. Biomes occupying approximately 38% of Earth's vegetated surface area containing 81% of the estimated total terrestrial phytomass have biomass densities above the saturation limit of current SAR systems (>100 tons/ha for P-band). Since P-band radar systems cannot currently operate effectively from orbit, the use of SAR sensors for biomass surveys may be limited even further to the L-band threshold. Emphasis should be shifted toward using SAR to characterize forest regeneration and development up to the saturation limits shown in this article rather than attempting to measure biomass directly in heavy forests. The development of new and innovative technologies for measuring biomass in high density vegetation is encouraged},
    Journal = {IEEE Transactions on Geoscience and Remote Sensing},
    Keywords = {SAR Processing, backscatter, forestry, geophysical techniques, radar applications, radar cross-sections, radar imaging, remote sensing by radar, synthetic aperture radar, 0.44 to 5.3 GHz, C-band, Hawaii, L-band, P-band, SAR, UHF SHF microwave, biomass saturation, biome, broadleaf evergreen forest, canopy, coniferous forest, forestry, geophysical measurement technique, global biomass inventory, land surface, phytomass, radar backscatter, radar remote sensing, synthetic aperture radar, vegetated surface, vegetation mapping, Space-borne SAR, SAR Tomography, Tomography},
    Owner = {ofrey},
    Pdf = {../../../docs/imhoff95.pdf} 
    }
    


  6. C.V. Jakowatz and P.A. Thompson. A new look at spotlight mode synthetic aperture radar as tomography: imaging 3-D targets. Image Processing, IEEE Transactions on, 4(5):699-703, 1995. Keyword(s): SAR Processing, SAR Tomography, Tomography, Fourier transforms, image reconstruction, radar imaging, synthetic aperture radar, tomography, 3D Fourier transform, 3D tomographic formulation, demodulated radar return data, layover, projection effect, radar target reflectivities, reconstructed 2D SAR image, spotlight mode synthetic aperture radar, tomography.
    Abstract: A new 3D tomographic formulation of spotlight mode synthetic aperture radar (SAR) is developed. This extends the pioneering work of Munson et al. (1983), who first formally described SAR in terms of tomography but who made the simplifying assumption that the target scene was 2D. The present authors treat the more general and practical case in which the radar target reflectivities comprise a 3D function. The main goal is to demonstrate that the demodulated radar return data from a spotlight mode collection represent a certain set of samples of the 3D Fourier transform of the target reflectivity function and to do so using a tomographic paradigm instead of traditional range-Doppler analysis. They also show that the tomographic approach is useful in interpreting the reconstructed 2D SAR image corresponding to a 3D scene. Specifically, the well-known SAR phenomenon of layover is easily explained in terms of tomographic projections and is shown to be analogous to the projection effect in conventional optical imaging

    @Article{jakowatzThompson95:Tomo,
    Title = {A new look at spotlight mode synthetic aperture radar as tomography: imaging 3-D targets},
    Author = {Jakowatz, C.V. and Thompson, P.A.},
    ISSN = {1057-7149},
    Number = {5},
    Pages = {699--703},
    Url = {http://ieeexplore.ieee.org/iel4/83/8672/00382506.pdf},
    Volume = {4},
    Year = {1995},
    Abstract = {A new 3D tomographic formulation of spotlight mode synthetic aperture radar (SAR) is developed. This extends the pioneering work of Munson et al. (1983), who first formally described SAR in terms of tomography but who made the simplifying assumption that the target scene was 2D. The present authors treat the more general and practical case in which the radar target reflectivities comprise a 3D function. The main goal is to demonstrate that the demodulated radar return data from a spotlight mode collection represent a certain set of samples of the 3D Fourier transform of the target reflectivity function and to do so using a tomographic paradigm instead of traditional range-Doppler analysis. They also show that the tomographic approach is useful in interpreting the reconstructed 2D SAR image corresponding to a 3D scene. Specifically, the well-known SAR phenomenon of layover is easily explained in terms of tomographic projections and is shown to be analogous to the projection effect in conventional optical imaging},
    Journal = {Image Processing, IEEE Transactions on},
    Keywords = {SAR Processing, SAR Tomography, Tomography, Fourier transforms, image reconstruction, radar imaging, synthetic aperture radar, tomography, 3D Fourier transform, 3D tomographic formulation, demodulated radar return data, layover, projection effect, radar target reflectivities, reconstructed 2D SAR image, spotlight mode synthetic aperture radar, tomography},
    Owner = {ofrey},
    Pdf = {../../../docs/jakowatzThompsonTomo95.pdf} 
    }
    


  7. K. K. Knaell and G. P. Cardillo. Radar tomography for the generation of three-dimensional images. IEE Proceedings - Radar, Sonar and Navigation, 142(2):54-60, April 1995. Keyword(s): SAR Processing, SAR Tomography, TomoSAR, computerised tomography, Fourier transforms, microwave imaging, radar computing, radar cross-sections, radar imaging, radar tomography, three-dimensional images generation, computer-aided tomography, 2D cross-sectional image, radar imaging, microwave energy reflection, radar cross-section density, 1D projection, Fourier slice theorem states, backprojection algorithm, sampled transform function, 1D range profiles, point spread functions, Tomography, Fourier transforms, Microwave imaging, Radar data processing, Radar cross sections, Radar imaging.
    Abstract: Computer-aided tomography is normally a process by which a 2D cross-sectional image of an object is obtained by illuminating it from many different directions in a plane. For the case of radar imaging, microwave energy reflected by the object is processed to produce an image which maps the object's radar cross-section (RCS) density into the image plane. Each observation provides a 1D projection of the RCS density. The Fourier slice theorem states that the Fourier transform (FT) of each projection is equal to the functional value of the 2D FT of the RCS density along a related projection. By accumulating the FT of many 1D projections, it is possible to accumulate a sample representation of the FT of the RCS density. The image can then be obtained using the backprojection algorithm by taking the inverse FT of the sampled transform function. The authors extend the tomographic technique to the generation of 3D images from 1D range profiles. It is seen that the Fourier slice theorem, the backprojection image generation algorithm, and the backprojected function are useful concepts in the interpretation of 3D imagery. Point spread functions (PSFs) for various radar and observation parameters are illustrated.

    @Article{knaellCardilloIEEProcRadSonNav1995SARTomography,
    author = {Knaell, K. K. and Cardillo, G. P.},
    title = {Radar tomography for the generation of three-dimensional images},
    journal = {IEE Proceedings - Radar, Sonar and Navigation},
    year = {1995},
    volume = {142},
    number = {2},
    pages = {54-60},
    month = {April},
    issn = {1350-2395},
    abstract = {Computer-aided tomography is normally a process by which a 2D cross-sectional image of an object is obtained by illuminating it from many different directions in a plane. For the case of radar imaging, microwave energy reflected by the object is processed to produce an image which maps the object's radar cross-section (RCS) density into the image plane. Each observation provides a 1D projection of the RCS density. The Fourier slice theorem states that the Fourier transform (FT) of each projection is equal to the functional value of the 2D FT of the RCS density along a related projection. By accumulating the FT of many 1D projections, it is possible to accumulate a sample representation of the FT of the RCS density. The image can then be obtained using the backprojection algorithm by taking the inverse FT of the sampled transform function. The authors extend the tomographic technique to the generation of 3D images from 1D range profiles. It is seen that the Fourier slice theorem, the backprojection image generation algorithm, and the backprojected function are useful concepts in the interpretation of 3D imagery. Point spread functions (PSFs) for various radar and observation parameters are illustrated.},
    doi = {10.1049/ip-rsn:19951791},
    file = {:knaellCardilloIEEProcRadSonNav1995SARTomography.pdf:PDF},
    keywords = {SAR Processing, SAR Tomography, TomoSAR,computerised tomography;Fourier transforms;microwave imaging;radar computing;radar cross-sections;radar imaging;radar tomography;three-dimensional images generation;computer-aided tomography;2D cross-sectional image;radar imaging;microwave energy reflection;radar cross-section density;1D projection;Fourier slice theorem states;backprojection algorithm;sampled transform function;1D range profiles;point spread functions;Tomography;Fourier transforms;Microwave imaging;Radar data processing;Radar cross sections;Radar imaging},
    
    }
    


  8. Nick Marechal. Tomographic formulation of interferometric SAR for terrain elevation mapping. IEEE Transactions on Geoscience and Remote Sensing, 33(3):726-739, May 1995. Keyword(s): SAR Processing, SAR Interferometry, Interferometry, InSAR, Spotlight SAR, SAR Tomography, geophysical signal processing, geophysical techniques, radar applications, radar imaging, remote sensing by radar, synthetic aperture radar, topography (Earth)SAR image, SAR image model, baseline separation, correlation, equations, geophysical measurement technique, image pair decorrelation, interferometric SAR, phase difference, radar remote sensing, spotlight synthetic aperture radar, terrain elevation mapping, terrain mapping, tomographic formulation, tomography, topographic height error variance model.
    Abstract: Topographic mapping with spotlight synthetic aperture radar (SAR) using an interferometric technique is studied. Included is a review of the equations for determination of terrain elevation from the phase difference between a pair of SAR images formed from data collected at two differing imaging geometries. This paper builds upon the systems analysis of Li and Goldstein in which image pair decorrelation as a function of the \u201cbaseline\u201d separation between the receiving antennas was first analyzed. In this paper correlation and topographic height error variance models are developed based on a SAR image model derived from a tomographic image formation perspective. The models are general in the sense that they are constructed to analyze the case of single antenna, two-pass interferometry with arbitrary antenna line of sight, and velocity vector directions. Correlation and height error variance sensitivity to SAR system parameters and terrain gradients are studied

    @Article{marechal1995:TomoFormulationForInSAR,
    author = {Marechal, Nick},
    title = {{Tomographic formulation of interferometric {SAR} for terrain elevation mapping}},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    year = {1995},
    volume = {33},
    number = {3},
    pages = {726--739},
    month = {May},
    issn = {0196-2892},
    abstract = {Topographic mapping with spotlight synthetic aperture radar (SAR) using an interferometric technique is studied. Included is a review of the equations for determination of terrain elevation from the phase difference between a pair of SAR images formed from data collected at two differing imaging geometries. This paper builds upon the systems analysis of Li and Goldstein in which image pair decorrelation as a function of the \u201cbaseline\u201d separation between the receiving antennas was first analyzed. In this paper correlation and topographic height error variance models are developed based on a SAR image model derived from a tomographic image formation perspective. The models are general in the sense that they are constructed to analyze the case of single antenna, two-pass interferometry with arbitrary antenna line of sight, and velocity vector directions. Correlation and height error variance sensitivity to SAR system parameters and terrain gradients are studied},
    doi = {10.1109/36.387588},
    file = {:marechal1995.pdf:PDF},
    keywords = {SAR Processing, SAR Interferometry, Interferometry, InSAR, Spotlight SAR, SAR Tomography, geophysical signal processing, geophysical techniques, radar applications, radar imaging, remote sensing by radar, synthetic aperture radar, topography (Earth)SAR image, SAR image model, baseline separation, correlation, equations, geophysical measurement technique, image pair decorrelation, interferometric SAR, phase difference, radar remote sensing, spotlight synthetic aperture radar, terrain elevation mapping, terrain mapping, tomographic formulation, tomography, topographic height error variance model},
    owner = {ofrey},
    pdf = {../../../docs/marechal1995.pdf},
    url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=387588&isnumber=8788},
    
    }
    


  9. Didier Massonnet, Pierre Briole, and Alain Arnaud. Deflation of Mount Etna monitored by spaceborne radar. Nature, 375(6532):567-570, June 1995. Keyword(s): SAR Processing, Interferometry, SAR interferometry, differential SAR interferometry, DInSAR, Deformation Mapping, Deformation Monitoring, ERS-1, Displacement, Surface Displacement, Surface Deformation, Volcano Monitoring, Etna, Mount Etna, Deflation, Spaceborne SAR, C-band.
    Abstract: Ground-based measurements of volcano deformation can be used to assess eruptive hazard, but require the costly (and often hazardous) installation and maintenance of an instrument network. Here we show that spaceborne radar interferometry, which has already shown its utility in mapping earthquake-related deformation1, can be used to monitor long-term volcano deformation. Two families of synthetic aperture radar images, acquired from ascending and descending orbits by the satellite ERS-1, and looking at Mount Etna from opposite sides, cover the time period from 17 May 1992 to 24 October 1993, and include the second half of Etna's most recent eruption. Despite artefacts of the interferometric technique, we can observe a volcano-wide deflation, which is an expected consequence of the eruption, but which had not previously been appreciated. We quantify it using a simple model based on the change of pressure in a sphere located in an elastic half-space; the modelled deformation increases linearly with time until the end of the eruption. Our results show that it will be possible to use this technique to detect the inflation of volcanic edifices that usually precedes eruptions.

    @Article{massonnetBrioleArnaudNature1995DInSAREtnaVolcanoDeflation,
    author = {Massonnet, Didier and Briole, Pierre and Arnaud, Alain},
    title = {Deflation of Mount Etna monitored by spaceborne radar},
    journal = {Nature},
    year = {1995},
    volume = {375},
    number = {6532},
    pages = {567-570},
    month = jun,
    abstract = {Ground-based measurements of volcano deformation can be used to assess eruptive hazard, but require the costly (and often hazardous) installation and maintenance of an instrument network. Here we show that spaceborne radar interferometry, which has already shown its utility in mapping earthquake-related deformation1, can be used to monitor long-term volcano deformation. Two families of synthetic aperture radar images, acquired from ascending and descending orbits by the satellite ERS-1, and looking at Mount Etna from opposite sides, cover the time period from 17 May 1992 to 24 October 1993, and include the second half of Etna's most recent eruption. Despite artefacts of the interferometric technique, we can observe a volcano-wide deflation, which is an expected consequence of the eruption, but which had not previously been appreciated. We quantify it using a simple model based on the change of pressure in a sphere located in an elastic half-space; the modelled deformation increases linearly with time until the end of the eruption. Our results show that it will be possible to use this technique to detect the inflation of volcanic edifices that usually precedes eruptions.},
    comment = {10.1038/375567a0},
    file = {:massonnetBrioleArnaudNature1995DInSAREtnaVolcanoDeflation.pdf:PDF},
    keywords = {SAR Processing, Interferometry, SAR interferometry, differential SAR interferometry, DInSAR, Deformation Mapping, Deformation Monitoring, ERS-1, Displacement, Surface Displacement, Surface Deformation, Volcano Monitoring, Etna, Mount Etna, Deflation, Spaceborne SAR, C-band},
    owner = {ofrey},
    pdf = {../../../docs/massonnetBrioleArnaudNature1995DInSAREtnaVolcanoDeflation.pdf},
    url = {http://dx.doi.org/10.1038/375567a0},
    
    }
    


  10. J. Moreira, M. Schwabisch, G. Fornaro, R. Lanari, R. Bamler, D. Just, U. Steinbrecher, H. Breit, M. Eineder, G. Franceschetti, D. Geudtner, and H. Rinkel. X-SAR interferometry: first results. IEEE Transactions on Geoscience and Remote Sensing, 33(4):950 -956, July 1995. Keyword(s): SAR Processing, InSAR, SAR interferometry, SIR-C, Space Shuttle, X-SAR, X-band SHF microwave, digital elevation model, geodesy, geophysical measurement technique, ground range geometry, land surface topography, radar remote sensing, repeat pass interferometry, spaceborne radar, synthetic aperture radar, terrain mapping, geophysical techniques, radar applications, radar imaging, remote sensing by radar, spaceborne radar, synthetic aperture radar, topography (Earth).
    Abstract: Repeat-pass interferometry data were acquired during the first and second SIR-C/X-SAR missions in April and October 1994. This paper presents the first results from X-SAR interferometry at four different sites. The temporal separations were one day and six months. At two sites the coherence requirements were met, resulting in high quality interferograms. A digital elevation model in ground range geometry has been derived. The limitations of the X-SAR interferometry are discussed

    @Article{406681,
    author = {Moreira, J. and Schwabisch, M. and Fornaro, G. and Lanari, R. and Bamler, R. and Just, D. and Steinbrecher, U. and Breit, H. and Eineder, M. and Franceschetti, G. and Geudtner, D. and Rinkel, H.},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {X-SAR interferometry: first results},
    year = {1995},
    issn = {0196-2892},
    month = jul,
    number = {4},
    pages = {950 -956},
    volume = {33},
    abstract = {Repeat-pass interferometry data were acquired during the first and second SIR-C/X-SAR missions in April and October 1994. This paper presents the first results from X-SAR interferometry at four different sites. The temporal separations were one day and six months. At two sites the coherence requirements were met, resulting in high quality interferograms. A digital elevation model in ground range geometry has been derived. The limitations of the X-SAR interferometry are discussed},
    doi = {10.1109/36.406681},
    keywords = {SAR Processing, InSAR;SAR interferometry;SIR-C;Space Shuttle;X-SAR;X-band SHF microwave;digital elevation model;geodesy;geophysical measurement technique;ground range geometry;land surface topography;radar remote sensing;repeat pass interferometry;spaceborne radar;synthetic aperture radar;terrain mapping;geophysical techniques;radar applications;radar imaging;remote sensing by radar;spaceborne radar;synthetic aperture radar;topography (Earth)},
    
    }
    


  11. H. C. Stankwitz, R. J. Dallaire, and J. R. Fienup. Nonlinear apodization for sidelobe control in SAR imagery. IEEE Transactions on Aerospace and Electronic Systems, 31(1):267-279, January 1995. Keyword(s): SAR Processing, Apodization, Nonlinear Apodization, Dual Apodization, Complex Dual Apodization, Multiapodization, Spatially Variant Apodization, DA, CDA, SVA, Fourier transform, SAR imagery, antenna design, complex-valued SAR imagery, digital filtering, mainlobe resolution, nonlinear apodization techniques, sequential nonlinear operations, ships. sidelobe control, sonar, spectral weighting, synthetic aperture radar imagery, Nyquist diagrams, fast Fourier transforms, frequency-domain analysis, synthetic aperture radars.
    Abstract: Synthetic aperture radar (SAR) imagery often requires sidelobe control, or apodization, via weighting of the frequency domain aperture. This is of particular importance when imaging scenes containing objects such as ships or buildings having very large radar cross sections. Sidelobe improvement using spectral weighting is invariably at the expense of mainlobe resolution presented here is a class of nonlinear operators which significantly reduce sidelobe levels without degrading mainlobe resolution implementation is via sequential nonlinear operations applied to complex-valued (undetected) SAR imagery. SAR imaging is used to motivate the concepts developed in this work. However, these nonlinear apodization techniques have potentially broad and far-ranging applications in antenna design, sonar, digital filtering etc., i.e., whenever data can be represented as the Fourier transform of a finite-aperture signal.<>

    @Article{stankwitzDallaireFienup1995:NonLinearApodization,
    Title = {Nonlinear apodization for sidelobe control in SAR imagery},
    Author = {Stankwitz, H. C. and Dallaire, R. J. and Fienup, J. R.},
    Doi = {10.1109/7.366309},
    ISSN = {0018-9251},
    Month = jan,
    Number = {1},
    Pages = {267-279},
    Volume = {31},
    Year = {1995},
    Abstract = {Synthetic aperture radar (SAR) imagery often requires sidelobe control, or apodization, via weighting of the frequency domain aperture. This is of particular importance when imaging scenes containing objects such as ships or buildings having very large radar cross sections. Sidelobe improvement using spectral weighting is invariably at the expense of mainlobe resolution presented here is a class of nonlinear operators which significantly reduce sidelobe levels without degrading mainlobe resolution implementation is via sequential nonlinear operations applied to complex-valued (undetected) SAR imagery. SAR imaging is used to motivate the concepts developed in this work. However, these nonlinear apodization techniques have potentially broad and far-ranging applications in antenna design, sonar, digital filtering etc., i.e., whenever data can be represented as the Fourier transform of a finite-aperture signal.<>},
    Journal = {{IEEE} Transactions on Aerospace and Electronic Systems},
    Keywords = {SAR Processing, Apodization, Nonlinear Apodization, Dual Apodization, Complex Dual Apodization, Multiapodization, Spatially Variant Apodization, DA, CDA, SVA, Fourier transform,SAR imagery,antenna design, complex-valued SAR imagery, digital filtering, mainlobe resolution, nonlinear apodization techniques, sequential nonlinear operations, ships. sidelobe control, sonar, spectral weighting, synthetic aperture radar imagery, Nyquist diagrams, fast Fourier transforms, frequency-domain analysis, synthetic aperture radars},
    Owner = {ofrey} 
    }
    


  12. Petre Stoica and M. Cedervall. On LP-MUSIC. IEEE Transactions on Signal Processing, 43(2):552-555, February 1995. Keyword(s): SAR Processing, MUSIC, SAR Tomography, frequency estimation, noise, prediction theory, signal processing, LP-MUSIC, consistency properties, frequency estimates, linear prediction algorithm, linear prediction-MUSIC, noisy data, signal subspace, spatial frequency estimation, temporal frequency estimation.
    Abstract: Studies the consistency properties of a method recently proposed for temporal or spatial frequency estimation from noisy data. The method in question is a MUSIC technique that makes use of a linear prediction algorithm to determine the signal subspace. It is shown that the signal subspace determined by the subject linear prediction-MUSIC (LP-MUSIC) algorithm can collapse in certain scenarios and. Hence, that the LP-MUSIC frequency estimates are not always consistent. The difficulties LP-MUSIC may encounter in some cases are illustrated by means of numerical examples

    @Article{stoicaCedervall1995:LPMUSIC,
    Title = {On LP-MUSIC},
    Author = {Stoica, Petre and Cedervall, M.},
    Doi = {10.1109/78.348140},
    ISSN = {1053-587X},
    Month = {Feb},
    Number = {2},
    Pages = {552-555},
    Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=348140&isnumber=8053},
    Volume = {43},
    Year = {1995},
    Abstract = {Studies the consistency properties of a method recently proposed for temporal or spatial frequency estimation from noisy data. The method in question is a MUSIC technique that makes use of a linear prediction algorithm to determine the signal subspace. It is shown that the signal subspace determined by the subject linear prediction-MUSIC (LP-MUSIC) algorithm can collapse in certain scenarios and. Hence, that the LP-MUSIC frequency estimates are not always consistent. The difficulties LP-MUSIC may encounter in some cases are illustrated by means of numerical examples},
    Journal = {IEEE Transactions on Signal Processing},
    Keywords = {SAR Processing, MUSIC, SAR Tomography, frequency estimation, noise, prediction theory, signal processing, LP-MUSIC, consistency properties, frequency estimates, linear prediction algorithm, linear prediction-MUSIC, noisy data, signal subspace, spatial frequency estimation, temporal frequency estimation},
    Owner = {ofrey},
    Pdf = {../../../docs/stoicaCedervall1995} 
    }
    


Conference articles

  1. Kenneth Abend and John W. McCorkle. Radio and TV interference extraction for ultrawideband radar. In Dominick A. Giglio, editor, Algorithms for Synthetic Aperture Radar Imagery II, Dominick A. Giglio; Ed., volume 2487, pages 119-129, 1995. SPIE. Keyword(s): SAR Processing, RFI Suppression, Ultra-Wideband SAR, Airborne SAR.
    Abstract: This paper describes a computationally efficient, high-performance, UWB radar interference suppression algorithm. An adaptive FIR (finite impulse response) prediction-error noise- whitening filter exhibits minimal computational complexity and achieves 30 dB interference reduction per pulse (1 microsecond(s) long) with 16-bit simulated interference. Using measured interference data digitized to 8-bits with a 6.5 effective bit digitizer, collected just north of Washington, DC at the Army Research Laboratory, the technique achieved 20 to 27 dB of reduction. To minimize the computational load, the filter weights are periodically determined from data collected during a fraction of a radar range sweep. These weights are found to be effective for hundreds of subsequent radar pulses. Previous work on an estimate-and-subtract, tone-extraction technique resulted in 20 dB average interference reduction on the same measured data with a computational load linearly related to the number of tones extracted. The adaptive filtering approach uses an over-determined system producing an FIR filter with N taps, independent of the number of interference signals. An iterative technique to reduce the range sidelobes caused by the filter's impulse response is also presented. The computational load of this iterative stage is, at worst, linearly related to the number of targets whose sidelobes are extracted. It is shown that, with a small reduction in performance, the sidelobe reduction can be accomplished with a relatively small increase in the overall computational load. The computational complexity of the proposed technique relative to the estimate-and- subtract technique depends on the signal and interference environment and on the acceptable sidelobe level. A comprehensive radio and TV interference simulator was developed to test the interference suppression algorithm. It avoids difficulties in memory requirements and code complexity typically encountered in high-sample rate, long duration, and UWB simulations. Data was generated for various population densities, sampling rates, and quantization levels. Results using the simulation data showed that the performance of the algorithm was related to the quantization level with more bits producing better results.

    @InProceedings{abendMccorkle95:RFI,
    Title = {{Radio and TV interference extraction for ultrawideband radar}},
    Author = {Abend, Kenneth and McCorkle, John W.},
    Booktitle = {Algorithms for Synthetic Aperture Radar Imagery II, Dominick A. Giglio; Ed.},
    Editor = {Dominick A. Giglio},
    Pages = {119--129},
    Publisher = {SPIE},
    Url = {http://bookstore.spie.org/index.cfm?fuseaction=CartAddItem&cachedsearch=1&productid=210832&CFID=2210291&CFTOKEN=57730651&producttype=pdf},
    Volume = {2487},
    Year = {1995},
    Abstract = {This paper describes a computationally efficient, high-performance, UWB radar interference suppression algorithm. An adaptive FIR (finite impulse response) prediction-error noise- whitening filter exhibits minimal computational complexity and achieves 30 dB interference reduction per pulse (1 microsecond(s) long) with 16-bit simulated interference. Using measured interference data digitized to 8-bits with a 6.5 effective bit digitizer, collected just north of Washington, DC at the Army Research Laboratory, the technique achieved 20 to 27 dB of reduction. To minimize the computational load, the filter weights are periodically determined from data collected during a fraction of a radar range sweep. These weights are found to be effective for hundreds of subsequent radar pulses. Previous work on an estimate-and-subtract, tone-extraction technique resulted in 20 dB average interference reduction on the same measured data with a computational load linearly related to the number of tones extracted. The adaptive filtering approach uses an over-determined system producing an FIR filter with N taps, independent of the number of interference signals. An iterative technique to reduce the range sidelobes caused by the filter's impulse response is also presented. The computational load of this iterative stage is, at worst, linearly related to the number of targets whose sidelobes are extracted. It is shown that, with a small reduction in performance, the sidelobe reduction can be accomplished with a relatively small increase in the overall computational load. The computational complexity of the proposed technique relative to the estimate-and- subtract technique depends on the signal and interference environment and on the acceptable sidelobe level. A comprehensive radio and TV interference simulator was developed to test the interference suppression algorithm. It avoids difficulties in memory requirements and code complexity typically encountered in high-sample rate, long duration, and UWB simulations. Data was generated for various population densities, sampling rates, and quantization levels. Results using the simulation data showed that the performance of the algorithm was related to the quantization level with more bits producing better results.},
    Keywords = {SAR Processing, RFI Suppression, Ultra-Wideband SAR, Airborne SAR},
    Pdf = {../../../docs/abendMccorkle95.pdf} 
    }
    


  2. A. Beaudoin, N. Stussi, D. Troufleau, N. Desbois, L. Piet, and M. Deshayes. On the use of ERS-1 SAR data over hilly terrain: Necessity of radiometric corrections for thematic applications. In Geoscience and Remote Sensing Symposium, 1995. IGARSS '95, volume 3, pages 2179-2182, 1995. Keyword(s): SAR Processing, SAR Geocoding, Geocoding, Radiometric Calibration, Radiometric Correction, Calibration, DEM, ERS-1, Mediterranean forest, acquisition geometry, empirical cosine model, geophysical measurement technique, geophysical techniques, hilly terrain mapping, land surface, quantitative use, radar imaging, radar remote sensing, radiometric correction, remote sensing by radar, spaceborne radar, synthetic aperture radar, thematic applications, vegetation mapping.
    Abstract: A radiometric correction method for the quantitative use of ERS SAR data acquired over hilly terrain is illustrated over a Mediterranean forest test-site. It is based on a DEM coupled to the SAR acquisition geometry. It is shown that uncorrected ?0 information is mainly related to the ground scattering area (8 dB variations), and the useful thematic information (2-3 dB) is therefore masked. Once calibrated, pixel intensity decreases with local incidence angle (variations up to 1.5 dB) and this variability can be reduced using an empirical cosine model. Then, the thematic benefits of such corrections are illustrated for surface discrimination and parameter estimation, along with a discussion on applicability and limitations

    @InProceedings{beaudoinStussiTroufleauDesboisPietDeshayes95:Radiometry,
    author = {Beaudoin, A. and Stussi, N. and Troufleau, D. and Desbois, N. and Piet, L. and Deshayes, M.},
    booktitle = {Geoscience and Remote Sensing Symposium, 1995. IGARSS '95},
    title = {On the use of ERS-1 SAR data over hilly terrain: Necessity of radiometric corrections for thematic applications},
    year = {1995},
    pages = {2179-2182},
    volume = {3},
    abstract = {A radiometric correction method for the quantitative use of ERS SAR data acquired over hilly terrain is illustrated over a Mediterranean forest test-site. It is based on a DEM coupled to the SAR acquisition geometry. It is shown that uncorrected ?0 information is mainly related to the ground scattering area (8 dB variations), and the useful thematic information (2-3 dB) is therefore masked. Once calibrated, pixel intensity decreases with local incidence angle (variations up to 1.5 dB) and this variability can be reduced using an empirical cosine model. Then, the thematic benefits of such corrections are illustrated for surface discrimination and parameter estimation, along with a discussion on applicability and limitations},
    keywords = {SAR Processing, SAR Geocoding, Geocoding, Radiometric Calibration,Radiometric Correction, Calibration,DEM, ERS-1, Mediterranean forest,acquisition geometry, empirical cosine model, geophysical measurement technique, geophysical techniques, hilly terrain mapping, land surface, quantitative use, radar imaging, radar remote sensing, radiometric correction, remote sensing by radar, spaceborne radar, synthetic aperture radar, thematic applications, vegetation mapping},
    owner = {ofrey},
    pdf = {../../../docs/beaudoinStussiTroufleauDesboisPietDeshayes95.pdf},
    url = {http://ieeexplore.ieee.org/iel3/3940/11411/00524141.pdf},
    
    }
    


  3. Fulvio Gini and Fabrizio Lombardini. A novel linear-quadratic technique for coherent radar detection in mixed clutter environment. In European Microwave Conference, 1995. 25th, volume 1, pages 360-364, Oct. 1995.
    @InProceedings{Gini1995a,
    author = {Gini, Fulvio and Lombardini, Fabrizio},
    booktitle = {European Microwave Conference, 1995. 25th},
    title = {A novel linear-quadratic technique for coherent radar detection in mixed clutter environment},
    year = {1995},
    month = {Oct.},
    pages = {360--364},
    volume = {1},
    doi = {10.1109/EUMA.1995.336980},
    owner = {ofrey},
    
    }
    


  4. Fulvio Gini, Fabrizio Lombardini, and Lucio Verrazzani. A robust approach to decentralized CFAR detection in spiky clutter. In European Microwave Conference, 1995. 25th, volume 1, pages 584-588, Oct. 1995.
    @InProceedings{Gini1995,
    author = {Gini, Fulvio and Lombardini, Fabrizio and Verrazzani, Lucio},
    booktitle = {European Microwave Conference, 1995. 25th},
    title = {A robust approach to decentralized CFAR detection in spiky clutter},
    year = {1995},
    month = {Oct.},
    pages = {584--588},
    volume = {1},
    doi = {10.1109/EUMA.1995.337027},
    owner = {ofrey},
    
    }
    


  5. Ron S. Goodman, Sreenidhi Tummala, and Walter G. Carrara. Issues in Ultra-Wideband, Widebeam SAR Image Formation. In The Record of the 1995 IEEE Radar Conference, pages 479-485, May 1995. Keyword(s): SAR Processing, Range Migration Algorithm, Wavefront Reconstruction, Wavenumber Domain Algorithm, omega-k, RFI Suppression, Motion Compensation, Autofocus Techniques, Ultra-Wideband SAR, Sidelobe Control, P-Band, FOPEN, Airborne SAR.
    Abstract: The formation of low-frequency, ultra-wideband/widebeam (UWB/WB) SAR imagery faces inherent challenges not present in conventional SAR systems operating at higher frequencies. Small angle approximations and other shortcuts taken in conventional SAR processors may be inappropriate for the UWB/WB SAR processor. The severe range migration associated with fine resolution UWB/WB SAR poses a significant problem for the image formation algorithm. The combination of a long synthetic aperture and a wide azimuth beamwidth has important implications for motion compensation implementation and performance. We survey the major challenges to UWB/WB SAR image formation. The emphasis is on the formation of fine resolution digital imagery from low frequency UWB/WB data collected in the stripmap mode by an airborne SAR system. We examine the differences in image formation and data processing between UWB/WB systems and conventional SAR systems. We illustrate aspects of UWB/WB image formation with imagery from the P3 ultra-wideband radar system - a 0.3 m resolution SAR which operates in the VHF/UHF frequency bands

    @InProceedings{GoodmanTummalaCarrara95:UWB,
    Title = {{Issues in Ultra-Wideband, Widebeam SAR Image Formation}},
    Author = {Ron S. Goodman and Sreenidhi Tummala and Walter G. Carrara},
    Booktitle = {The Record of the 1995 IEEE Radar Conference},
    Month = May,
    Pages = {479-485},
    Url = {http://ieeexplore.ieee.org/iel3/3929/11378/00522595.pdf},
    Year = {1995},
    Abstract = {The formation of low-frequency, ultra-wideband/widebeam (UWB/WB) SAR imagery faces inherent challenges not present in conventional SAR systems operating at higher frequencies. Small angle approximations and other shortcuts taken in conventional SAR processors may be inappropriate for the UWB/WB SAR processor. The severe range migration associated with fine resolution UWB/WB SAR poses a significant problem for the image formation algorithm. The combination of a long synthetic aperture and a wide azimuth beamwidth has important implications for motion compensation implementation and performance. We survey the major challenges to UWB/WB SAR image formation. The emphasis is on the formation of fine resolution digital imagery from low frequency UWB/WB data collected in the stripmap mode by an airborne SAR system. We examine the differences in image formation and data processing between UWB/WB systems and conventional SAR systems. We illustrate aspects of UWB/WB image formation with imagery from the P3 ultra-wideband radar system - a 0.3 m resolution SAR which operates in the VHF/UHF frequency bands},
    Keywords = {SAR Processing, Range Migration Algorithm, Wavefront Reconstruction, Wavenumber Domain Algorithm, omega-k, RFI Suppression, Motion Compensation, Autofocus Techniques, Ultra-Wideband SAR, Sidelobe Control, P-Band, FOPEN, Airborne SAR},
    Pdf = {../../../docs/GoodmanTummalaCarrara95.pdf} 
    }
    


  6. Francesco Holecz, Anthony Freeman, and Jakob van Zyl. Topographic effects on the antenna gain pattern correction. In IGARSS '95, Geoscience and Remote Sensing Symposium, volume 1, pages 587-589, 1995. Keyword(s): SAR Processing, SAR Geocoding, Geocoding, SIR-C, X-SAR, antenna gain pattern correction, antenna radiation patterns, radiometric calibration, calibration, Radiometric Correction, remote sensing by radar, satellite antennas, Spaceborne SAR, terrain effect, terrain mapping, topographic effect, ERS-1, ERS-2, JERS-1, RADARSAT, SIR-C, X-SAR.
    Abstract: The purpose of this paper is to analyse and quantify the topographic effects on the antenna gain pattern correction of existing spaceborne Synthetic Aperture Radar systems, namely ERS-1, JERS-1, SIR-C, and X-SAR. Simulations and real SAR data of a test site are used. The corrections are carried out taking into account the local surface topography and compared with the standard method based on a reference ellipsoid. Results show that elevation variations in the ERS-1 and JERS-1 cases do not. affect significantly the antenna gain pattern correction. For extreme topographic differences, greater than 3000 m, a reference altitude for the radiometric calibration is suggested. On the other hand, for the low-orbit SRL-1J2 terrain information is strongly recommended, particularly, if relief differences within the image are significant, namely greater than 1000 m. Furthermore, it will be shown that in the SIR-C case, even if the polarizations of the am tenna gain patterns are slightly different, polarimetric calibration errors due to relief variations can be neglected. Finally, implications for forthcoming spaceborne SAR systems, i.e. ERS-2 and RADARSAT, are discussed.

    @InProceedings{holeczFreemanVanZyl95:AGP,
    Title = {Topographic effects on the antenna gain pattern correction},
    Author = {Holecz, Francesco and Freeman, Anthony and van Zyl, Jakob},
    Booktitle = {IGARSS '95, Geoscience and Remote Sensing Symposium},
    Pages = {587--589},
    Url = {http://ieeexplore.ieee.org/iel3/3940/11409/00520462.pdf},
    Volume = {1},
    Year = {1995},
    Abstract = {The purpose of this paper is to analyse and quantify the topographic effects on the antenna gain pattern correction of existing spaceborne Synthetic Aperture Radar systems, namely ERS-1, JERS-1, SIR-C, and X-SAR. Simulations and real SAR data of a test site are used. The corrections are carried out taking into account the local surface topography and compared with the standard method based on a reference ellipsoid. Results show that elevation variations in the ERS-1 and JERS-1 cases do not. affect significantly the antenna gain pattern correction. For extreme topographic differences, greater than 3000 m, a reference altitude for the radiometric calibration is suggested. On the other hand, for the low-orbit SRL-1J2 terrain information is strongly recommended, particularly, if relief differences within the image are significant, namely greater than 1000 m. Furthermore, it will be shown that in the SIR-C case, even if the polarizations of the am tenna gain patterns are slightly different, polarimetric calibration errors due to relief variations can be neglected. Finally, implications for forthcoming spaceborne SAR systems, i.e. ERS-2 and RADARSAT, are discussed.},
    Keywords = {SAR Processing, SAR Geocoding, Geocoding, SIR-C, X-SAR, antenna gain pattern correction, antenna radiation patterns,radiometric calibration, calibration,Radiometric Correction, remote sensing by radar, satellite antennas, Spaceborne SAR, terrain effect, terrain mapping, topographic effect, ERS-1, ERS-2, JERS-1, RADARSAT, SIR-C, X-SAR},
    Owner = {ofrey},
    Pdf = {../../../docs/holeczFreemanVanZyl95.pdf} 
    }
    


  7. P. Pasquali, C. Prati, F. Rocca, M. Seymour, J. Fortuny, E. Ohlmer, and A.J. Sieber. A 3-D SAR experiment with EMSL data. In Geoscience and Remote Sensing Symposium, 1995. IGARSS '95. 'Quantitative Remote Sensing for Science and Applications', International, volume 1, pages 784-786, 1995. Keyword(s): SAR Processing, Tomography, SAR Tomography, radar applications, radar imaging, remote sensing by radar, synthetic aperture radar, topography (Earth), EMSL, European Microwave Signature Laboratory o, JRC, geodesy, geophysical measurement technique, horizontal slice, interferometric SAR image, land surface topography, multi-baseline SAR, radar remote sensing, synthetic aperture radar, target reconstruction, terrain mapping, three dimensional structure.
    Abstract: In usual SAR systems the image spectrum is regularly sampled along azimuth and slant range. A third dimension is found in the baseline of interferometric SAR images. An experiment on the use of multi-baseline SAR images far 3D target reconstruction is presented. The data have been collected in the European Microwave Signature Laboratory of JRC. The volume is presented as horizontal slices of the target at different depths.

    @InProceedings{pasqualiPratiRoccaSeymourFortunyOhlmerSieber95:3DSAR,
    Title = {A 3-D SAR experiment with EMSL data},
    Author = {Pasquali, P. and Prati, C. and Rocca, F. and Seymour, M. and Fortuny, J. and Ohlmer, E. and Sieber, A.J.},
    Booktitle = {Geoscience and Remote Sensing Symposium, 1995. IGARSS '95. 'Quantitative Remote Sensing for Science and Applications', International},
    Pages = {784--786},
    Url = {http://ieeexplore.ieee.org/iel3/3940/11409/00520585.pdf},
    Volume = {1},
    Year = {1995},
    Abstract = {In usual SAR systems the image spectrum is regularly sampled along azimuth and slant range. A third dimension is found in the baseline of interferometric SAR images. An experiment on the use of multi-baseline SAR images far 3D target reconstruction is presented. The data have been collected in the European Microwave Signature Laboratory of JRC. The volume is presented as horizontal slices of the target at different depths.},
    Keywords = {SAR Processing, Tomography, SAR Tomography, radar applications, radar imaging, remote sensing by radar, synthetic aperture radar, topography (Earth), EMSL, European Microwave Signature Laboratory o, JRC, geodesy, geophysical measurement technique, horizontal slice, interferometric SAR image, land surface topography, multi-baseline SAR, radar remote sensing, synthetic aperture radar, target reconstruction, terrain mapping, three dimensional structure},
    Owner = {ofrey},
    Pdf = {../../../docs/pasqualiPratiRoccaSeymourFortunyOhlmerSieber95.pdf} 
    }
    


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This collection of SAR literature is far from being complete.
It is rather a collection of papers which I store in my literature data base. Hence, the list of publications under PUBLICATIONS OF AUTHOR'S NAME should NOT be mistaken for a complete bibliography of that author.




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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