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BACK TO INDEX Publications of year 2007 Articles in journal or book chapters
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| Abstract: | Standard synthetic aperture radar (SAR) processing algorithms use analytically derived transfer functions in the 2D frequency and range/Doppler domains. These rely on the assumption of hyperbolic range histories of monostatic SARs with straight flight paths. For bistatic SARs, the range histories are no longer hyperbolic, and simple analytic transforms do not exist. This paper offers two solutions for bistatic SAR data processing under the restriction of quasi-stationarity, i.e., sufficiently equal velocity vectors of transmitter and receiver. 1) Moderately bistatic configurations can be handled satisfactorily by using hyperbolic range functions with a modified velocity parameter, which is a solution already well known for the accommodation of curved orbits in the monostatic case. This "equivalent velocity" approach is shown to be of surprising range of validity even for pronounced bistatic situations. It is not to be confused with the "equivalent monostatic flight path" approximation, which is shown to be inapplicable for any practical case. 2) With increasing separation of transmitter and receiver, the equivalent velocity approximation deteriorates. To cope with extreme bistatic configurations, a general approach named "NuSAR" is proposed, where the involved transfer functions are replaced by numerically computed ones. This paper describes how the transfer functions are computed from the given orbits and the shape of the Earth surface. In any of these two cases, the bistatic SAR data can be processed by standard SAR processors; only the conventional transfer functions need to be replaced. Neither are there time-domain prefocusing or post focusing steps required nor complicated mathematical expansions involved. The presented algorithms are also applicable to very high resolution wide-swath (or squinted) SARs on curved orbits. |
@ARTICLE{BamlerMeyerLiebhart2007:BiStaticNumericSAR,
author={Bamler, R. and Meyer, F. and Liebhart, W.},
journal=IEEE_J_GRS,
title={Processing of Bistatic {SAR} Data From Quasi-Stationary Configurations},
year={2007},
month=nov,
volume={45},
number={11},
pages={3350-3358},
abstract={Standard synthetic aperture radar (SAR) processing algorithms use analytically derived transfer functions in the 2D frequency and range/Doppler domains. These rely on the assumption of hyperbolic range histories of monostatic SARs with straight flight paths. For bistatic SARs, the range histories are no longer hyperbolic, and simple analytic transforms do not exist. This paper offers two solutions for bistatic SAR data processing under the restriction of quasi-stationarity, i.e., sufficiently equal velocity vectors of transmitter and receiver. 1) Moderately bistatic configurations can be handled satisfactorily by using hyperbolic range functions with a modified velocity parameter, which is a solution already well known for the accommodation of curved orbits in the monostatic case. This "equivalent velocity" approach is shown to be of surprising range of validity even for pronounced bistatic situations. It is not to be confused with the "equivalent monostatic flight path" approximation, which is shown to be inapplicable for any practical case. 2) With increasing separation of transmitter and receiver, the equivalent velocity approximation deteriorates. To cope with extreme bistatic configurations, a general approach named "NuSAR" is proposed, where the involved transfer functions are replaced by numerically computed ones. This paper describes how the transfer functions are computed from the given orbits and the shape of the Earth surface. In any of these two cases, the bistatic SAR data can be processed by standard SAR processors; only the conventional transfer functions need to be replaced. Neither are there time-domain prefocusing or post focusing steps required nor complicated mathematical expansions involved. The presented algorithms are also applicable to very high resolution wide-swath (or squinted) SARs on curved orbits.},
keywords={SAR Processing,Bistatic SAR,Earth surface;NuSAR approach;bistatic SAR data processing;curved orbit;equivalent velocity approximation;hyperbolic range function;quasistationarity restriction;quasistationary configuration;radar receiver;radar transmitter;range Doppler domain;synthetic aperture radar;time-domain post focusing;time-domain prefocusing;transfer functions;velocity vector;data acquisition;geophysical signal processing;geophysical techniques;radar signal processing;remote sensing by radar;synthetic aperture radar;transfer functions;},
doi={10.1109/TGRS.2007.895436},
ISSN={0196-2892},
}
Keywords: SAR Processing, Apodization, Spatially Variant Apodization, SVA, SAR system, finite signal sampling rate condition, nonlinear filtering, robust SVA method, sidelobe levels signal resolution, synthetic aperture radar, target detection capability, two-dimensional generalization, variant filter, image resolution.
| Abstract: | Linear apodization, or data weighting, is the traditional procedure to improve sidelobe levels in a finite sampled signal at the expense of resolution. New apodization methods, such as spatially variant apodization (SVA), apply nonlinear filtering to the signal in order to completely remove sidelobes without any loss of resolution. However, the results are strongly influenced by signal sampling rate. Some variations which improve results have been previously published, but sidelobe cancellation gets worse since sampling frequency is not settled at Nyquist (or a multiple). This paper presents a new and efficient technique based on SVA that drastically reduces sidelobe levels for every sampling rate condition. The algorithm is, essentially, a parameter optimization of a variant filter for each pixel of the image. A one-dimensional case and a two-dimensional generalization are presented, as well as some applications to target detection capability in a synthetic aperture radar (SAR) system. |
@ARTICLE{castilloRubioLlorenteRomanoBurgosGarcia2007:SpatiallyVariantApodization,
author = {Castillo-Rubio, C. and Llorente-Romano, S. and Burgos-Garcia, M.},
title = {Robust {SVA} method for every sampling rate condition},
journal = {IEEE Transactions on Aerospace and Electronic Systems},
year = {2007},
volume = {43},
pages = {571 -580},
number = {2},
month = apr,
abstract = {Linear apodization, or data weighting, is the traditional procedure to improve sidelobe levels in a finite sampled signal at the expense of resolution. New apodization methods, such as spatially variant apodization (SVA), apply nonlinear filtering to the signal in order to completely remove sidelobes without any loss of resolution. However, the results are strongly influenced by signal sampling rate. Some variations which improve results have been previously published, but sidelobe cancellation gets worse since sampling frequency is not settled at Nyquist (or a multiple). This paper presents a new and efficient technique based on SVA that drastically reduces sidelobe levels for every sampling rate condition. The algorithm is, essentially, a parameter optimization of a variant filter for each pixel of the image. A one-dimensional case and a two-dimensional generalization are presented, as well as some applications to target detection capability in a synthetic aperture radar (SAR) system.},
doi = {10.1109/TAES.2007.4285354},
issn = {0018-9251},
keywords = {SAR Processing, Apodization, Spatially Variant Apodization, SVA, SAR system, finite signal sampling rate condition, nonlinear filtering, robust SVA method, sidelobe levels signal resolution, synthetic aperture radar, target detection capability, two-dimensional generalization, variant filter, image resolution}
}
Keywords: SAR Processing, Apodization, Spatially Variant Apodization, Nyquist rate, bidimensional finite impulse response filter, nonlinear sidelobe reduction technique, spatially variant apodization, squinted synthetic aperture radar image, synthetic aperture radar, FIR filters, radar imaging, synthetic aperture radar, Algorithms, Image Enhancement, Image Interpretation, Computer-Assisted, Information Storage and Retrieval, Radar, Reproducibility of Results, Sensitivity and Specificity;.
| Abstract: | Spatially variant apodization (SVA) is a nonlinear sidelobe reduction technique that improves sidelobe level and preserves resolution at the same time. This method implements a bidimensional finite impulse response filter with adaptive taps depending on image information. Some papers that have been previously published analyze SVA at the Nyquist rate or at higher rates focused on strip synthetic aperture radar (SAR). This paper shows that traditional SVA techniques are useless when the sensor operates with a squint angle. The reasons for this behaviour are analyzed, and a new implementation that largely improves the results is presented. The algorithm is applied to simulated SAR images in order to demonstrate the good quality achieved along with efficient computation. |
@ARTICLE{castilloRubioLlorenteRomanoBurgosGarcia2007TIP:SpatiallyVariantApodization,
author = {Castillo-Rubio, C.F. and Llorente-Romano, S. and Burgos-Garcia, C.M.},
title = {Spatially Variant Apodization for Squinted Synthetic Aperture Radar Images},
journal = {IEEE Transactions on Image Processing},
year = {2007},
volume = {16},
pages = {2023-2027},
number = {8},
month = aug,
abstract = {Spatially variant apodization (SVA) is a nonlinear sidelobe reduction technique that improves sidelobe level and preserves resolution at the same time. This method implements a bidimensional finite impulse response filter with adaptive taps depending on image information. Some papers that have been previously published analyze SVA at the Nyquist rate or at higher rates focused on strip synthetic aperture radar (SAR). This paper shows that traditional SVA techniques are useless when the sensor operates with a squint angle. The reasons for this behaviour are analyzed, and a new implementation that largely improves the results is presented. The algorithm is applied to simulated SAR images in order to demonstrate the good quality achieved along with efficient computation.},
doi = {10.1109/TIP.2007.899603},
issn = {1057-7149},
keywords = {SAR Processing, Apodization, Spatially Variant Apodization, Nyquist rate;bidimensional finite impulse response filter;nonlinear sidelobe reduction technique;spatially variant apodization;squinted synthetic aperture radar image;synthetic aperture radar;FIR filters;radar imaging;synthetic aperture radar;Algorithms;Image Enhancement;Image Interpretation, Computer-Assisted;Information Storage and Retrieval;Radar;Reproducibility of Results;Sensitivity and Specificity;}
}
Keywords: SAR Processing, SAR Tomography, Tomography, geophysical techniques, radar applications, singular value decomposition, vegetation, EMSL, European Microwave Signature Laboratory, dual-baseline coherence tomography, maize plants, matrix singular value decomposition, numerical stability, regularization technique, scattering mechanisms, tomograms, vegetation.
| Abstract: | In this letter, we consider a dual-baseline formulation of coherence tomography and show how practical application of the method is limited by numerical stability. To help reduce this, we propose a regularization technique based on a matrix singular value decomposition to stabilize the inversion. We then apply the new dual-baseline algorithm to ground-based radar data from the European Microwave Signature Laboratory. We consider a sample of maize plants and employ dual-baseline interferometric data to reconstruct vertical tomograms through the vegetation as a function of frequency. We use these reconstructions to interpret the primary scattering mechanisms and their polarization dependence. |
@ARTICLE{cloude2007:DualBaselineCoherentTomo,
author = {Cloude, Shane R.},
title = {Dual-Baseline Coherence Tomography},
journal = {IEEE Geoscience and Remote Sensing Letters},
year = {2007},
volume = {4},
pages = {127-131},
number = {1},
month = jan,
abstract = {In this letter, we consider a dual-baseline formulation of coherence tomography and show how practical application of the method is limited by numerical stability. To help reduce this, we propose a regularization technique based on a matrix singular value decomposition to stabilize the inversion. We then apply the new dual-baseline algorithm to ground-based radar data from the European Microwave Signature Laboratory. We consider a sample of maize plants and employ dual-baseline interferometric data to reconstruct vertical tomograms through the vegetation as a function of frequency. We use these reconstructions to interpret the primary scattering mechanisms and their polarization dependence.},
doi = {10.1109/LGRS.2006.885893},
issn = {1545-598X},
keywords = {SAR Processing, SAR Tomography, Tomography, geophysical techniques, radar applications, singular value decomposition, vegetation, EMSL, European Microwave Signature Laboratory, dual-baseline coherence tomography, maize plants, matrix singular value decomposition, numerical stability, regularization technique, scattering mechanisms, tomograms, vegetation},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/cloude2007.pdf},
url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4063282&isnumber=4063275}
}
Keywords: SAR Processing, Multilook Beat Frequency, MLPF, Doppler Centroid Estimation, Doppler Ambiguity Resolver, DAR, Doppler radar, fast Fourier transforms, frequency estimation, radar signal processing, remote sensing by radar, sensitivity, synthetic aperture radarDoppler ambiguity, Doppler centroid estimator, FFT, Fourier transform, MLBF algorithm, RADARSAT-1, ScanSAR, cross beating, estimation sensitivity, multilook beat frequency algorithm, range migration, target trajectory.
| Abstract: | The multilook beat frequency (MLBF) algorithm is the Doppler centroid estimator most commonly used in practice to solve the Doppler ambiguity. However, it still makes errors, notably in medium- or low-contrast scenes. In this paper, we present two ways in which the estimation sensitivity of the MLBF algorithm can be improved. First, we give a more thorough frequency-domain explanation of how the MLBF algorithm works and explain how cross beating and range migration cause estimation difficulties. The first improvement to the algorithm replaces the fast Fourier transform (FFT)-based beat frequency estimator with a more accurate one that uses phase increments. It avoids the FFT limitations of resolution and quantization, especially when the signal is discontinuous in one range cell due to range cell migration or burst mode operation (ScanSAR). A second improvement uses range cell migration correction to straighten the target trajectories before the beat frequency estimator is applied. This has the effect of narrowing the bandwidth of the beat signal and reducing the effect of cross beating. Finally, experiments with RADARSAT-1 data are used to illustrate the improved estimation accuracy of the modified algorithm |
@ARTICLE{cummingLi2007:MLBFExtended,
author = {Cumming, Ian G. and Li, S.},
title = {{Adding Sensitivity to the MLBF Doppler Centroid Estimator}},
journal = {IEEE Transactions on Geoscience and Remote Sensing},
year = {2007},
volume = {45},
pages = {279--292},
number = {2},
month = {Feb. },
abstract = {The multilook beat frequency (MLBF) algorithm is the Doppler centroid estimator most commonly used in practice to solve the Doppler ambiguity. However, it still makes errors, notably in medium- or low-contrast scenes. In this paper, we present two ways in which the estimation sensitivity of the MLBF algorithm can be improved. First, we give a more thorough frequency-domain explanation of how the MLBF algorithm works and explain how cross beating and range migration cause estimation difficulties. The first improvement to the algorithm replaces the fast Fourier transform (FFT)-based beat frequency estimator with a more accurate one that uses phase increments. It avoids the FFT limitations of resolution and quantization, especially when the signal is discontinuous in one range cell due to range cell migration or burst mode operation (ScanSAR). A second improvement uses range cell migration correction to straighten the target trajectories before the beat frequency estimator is applied. This has the effect of narrowing the bandwidth of the beat signal and reducing the effect of cross beating. Finally, experiments with RADARSAT-1 data are used to illustrate the improved estimation accuracy of the modified algorithm},
doi = {10.1109/TGRS.2006.887010},
issn = {0196-2892},
keywords = {SAR Processing, Multilook Beat Frequency, MLPF, Doppler Centroid Estimation, Doppler Ambiguity Resolver, DAR, Doppler radar, fast Fourier transforms, frequency estimation, radar signal processing, remote sensing by radar, sensitivity, synthetic aperture radarDoppler ambiguity, Doppler centroid estimator, FFT, Fourier transform, MLBF algorithm, RADARSAT-1, ScanSAR, cross beating, estimation sensitivity, multilook beat frequency algorithm, range migration, target trajectory},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/cummingLi2007.pdf},
url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4069101&isnumber=4069093}
}
Keywords: HRTI-3 specification, TanDEM-X mission concept, TerraSAR-X add-on for Digital Elevation Measurement, TerraSAR-X radar satellites, bistatic data acquisition, global digital elevation model, high-resolution SAR interferometry, radar applications, radar imaging techniques, remote sensing applications, satellite formation flying concept, spaceborne radar interferometer, synchonization, synthetic aperture radar, data acquisition, digital elevation models, geophysical techniques, radar imaging, radar interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar;.
| Abstract: | TanDEM-X (TerraSAR-X add-on for digital elevation measurements) is an innovative spaceborne radar interferometer that is based on two TerraSAR-X radar satellites flying in close formation. The primary objective of the TanDEM-X mission is the generation of a consistent global digital elevation model (DEM) with an unprecedented accuracy, which is equaling or surpassing the HRTI-3 specification. Beyond that, TanDEM-X provides a highly reconfigurable platform for the demonstration of new radar imaging techniques and applications. This paper gives a detailed overview of the TanDEM-X mission concept which is based on the systematic combination of several innovative technologies. The key elements are the bistatic data acquisition employing an innovative phase synchronization link, a novel satellite formation flying concept allowing for the collection of bistatic data with short along-track baselines, as well as the use of new interferometric modes for system verification and DEM calibration. The interferometric performance is analyzed in detail, taking into account the peculiarities of the bistatic operation. Based on this analysis, an optimized DEM data acquisition plan is derived which employs the combination of multiple data takes with different baselines. Finally, a collection of instructive examples illustrates the capabilities of TanDEM-X for the development and demonstration of new remote sensing applications. |
@ARTICLE{kriegerMoreiraFiedlerHajnsekWernerYounisZink2007:TandemXInSAR,
author={Krieger, G. and Moreira, A. and Fiedler, H. and Hajnsek, I. and Werner, M. and Younis, M. and Zink, M.},
journal=IEEE_J_GRS,
title={{TanDEM-X}: A Satellite Formation for High-Resolution {SAR} Interferometry},
year={2007},
month=nov,
volume={45},
number={11},
pages={3317--3341},
abstract={TanDEM-X (TerraSAR-X add-on for digital elevation measurements) is an innovative spaceborne radar interferometer that is based on two TerraSAR-X radar satellites flying in close formation. The primary objective of the TanDEM-X mission is the generation of a consistent global digital elevation model (DEM) with an unprecedented accuracy, which is equaling or surpassing the HRTI-3 specification. Beyond that, TanDEM-X provides a highly reconfigurable platform for the demonstration of new radar imaging techniques and applications. This paper gives a detailed overview of the TanDEM-X mission concept which is based on the systematic combination of several innovative technologies. The key elements are the bistatic data acquisition employing an innovative phase synchronization link, a novel satellite formation flying concept allowing for the collection of bistatic data with short along-track baselines, as well as the use of new interferometric modes for system verification and DEM calibration. The interferometric performance is analyzed in detail, taking into account the peculiarities of the bistatic operation. Based on this analysis, an optimized DEM data acquisition plan is derived which employs the combination of multiple data takes with different baselines. Finally, a collection of instructive examples illustrates the capabilities of TanDEM-X for the development and demonstration of new remote sensing applications.},
keywords={HRTI-3 specification;TanDEM-X mission concept;TerraSAR-X add-on for Digital Elevation Measurement;TerraSAR-X radar satellites;bistatic data acquisition;global digital elevation model;high-resolution SAR interferometry;radar applications;radar imaging techniques;remote sensing applications;satellite formation flying concept;spaceborne radar interferometer;synchonization;synthetic aperture radar;data acquisition;digital elevation models;geophysical techniques;radar imaging;radar interferometry;remote sensing by radar;spaceborne radar;synthetic aperture radar;},
doi={10.1109/TGRS.2007.900693},
ISSN={0196-2892},
}
Keywords: SAR Processing, Radiometric Calibration, Calibration, Image enhancement, Image processing, Synthetic aperture radar, Terrain mapping, SAR geocoding, Radiometric normalization.
| Abstract: | Terrain undulations affect the geometric and radiometric quality of synthetic aperture radar images. The correction of these effects becomes indispensable when quantitative image analysis is performed with respect to the derivation of geo- and biophysical parameters. The paper presents a rigorous approach for geometric and radiometric correction of SAR images. Using a digital elevation model, the imaging geometry is reconstructed and is used to perform geometric and radiometric correction of terrain induced distortions. The importance of a stringent radiometric correction based on the integration of the image brightness is emphasized. The approach guarantees that the energy contained in the image data is preserved throughout the geocoding process. The resulting backscattering images are fully terrain corrected and can be used for further quantitative investigations and may also improve qualitative studies as e.g. land cover classifications. The technique is applicable for different sensor types and image products, including already geocoded SAR images. The effect of different resolutions of digital elevation models used for the correction of the backscattering coefficient is investigated. |
@ARTICLE{LoewMauser2007:GeoRadiometricCorr,
author = {L{\"o}w, Alexander and Mauser, Wolfram},
title = {{Generation of geometrically and radiometrically terrain corrected SAR image products}},
journal = {Remote Sensing of Environment},
year = {2007},
volume = {106},
pages = {337--349},
number = {3},
month = {feb},
abstract = {Terrain undulations affect the geometric and radiometric quality of synthetic aperture radar images. The correction of these effects becomes indispensable when quantitative image analysis is performed with respect to the derivation of geo- and biophysical parameters. The paper presents a rigorous approach for geometric and radiometric correction of SAR images. Using a digital elevation model, the imaging geometry is reconstructed and is used to perform geometric and radiometric correction of terrain induced distortions. The importance of a stringent radiometric correction based on the integration of the image brightness is emphasized. The approach guarantees that the energy contained in the image data is preserved throughout the geocoding process. The resulting backscattering images are fully terrain corrected and can be used for further quantitative investigations and may also improve qualitative studies as e.g. land cover classifications. The technique is applicable for different sensor types and image products, including already geocoded SAR images. The effect of different resolutions of digital elevation models used for the correction of the backscattering coefficient is investigated.},
keywords = {SAR Processing, Radiometric Calibration, Calibration, Image enhancement, Image processing, Synthetic aperture radar, Terrain mapping, SAR geocoding, Radiometric normalization},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/loewMauser2007.pdf},
url = {http://www.sciencedirect.com/science/article/B6V6V-4M57H9F-1/2/f58e22796d6ead0c64253c63e0c5f48f}
}
Keywords: SAR Processing, Biomass, Forest, VHFRaDAR, profiling LiDAR, biomass, RaDAR-LiDAR synergy, VHFSAR DATA, SMALL-FOOTPRINT LIDAR, AIRBORNE LASER DATA, STEM VOLUME, STAND CHARACTERISTICS, AERIAL-PHOTOGRAPHY, VEGETATION BIOMASS, CONIFEROUS FOREST, BOREAL FORESTS, SCANNER DATA.
| Abstract: | A low frequency (80-120 MHz) VHF RaDAR, BioSAR, specifically designed for forest biomass estimation and a profiling LiDAR, PALS, were flown over loblolly pine plantations in the southeastern United States. LiDAR-only, RaDAR-only, and joint LiDAR-RaDAR linear models were developed to determine if returns from two sensors could be used to estimate pine biomass more accurately and precisely than returns from either sensor alone. The best five-variable RaDAR model explained 81.8\% (R (2)) of the stem green biomass variability, with a regression RMSE of 57.5 t/ha. The best one-variable LiDAR model explained 93.3\37763250470f the biomass variation (RMSE=33.9 t/ha). Combining the RaDAR normalized volumetric returns with the profiling LiDAR ranging measurements did little to improve the best LiDAR-only model. The best LiDAR-RaDAR model explained 93.8\1001275514f the biomass variation (RSME=32.7 t/ha). Cross-validation and training/test validation procedures demonstrated (1) that all models are unbiased and (2) the increased precision of the LiDAR-only and LiDAR-RaDAR models. The results of this investigation and a companion study indicate that there is little to be gained combining VHF-RaDAR volumetric returns and profiling LiDAR ranging measurements in pine forests; a LiDAR ranging system is sufficient for accurate, precise biomass estimation. |
@ARTICLE{nelsonHydeJohnsonEmessieneImhoffCampbellEdwards2007:RaDARLiDARSynergy,
author = {Nelson, Ross F. and Hyde, Peter and Johnson, Patrick and Emessiene, Bomono and Imhoff, Marc L. and Campbell, Robert and Edwards, Wilson},
title = {Investigating {RaDAR-LiDAR} synergy in a {North Carolina} pine forest},
journal = {Remote Sensing of Environment},
year = {2007},
volume = {110},
pages = {98-108},
number = {1},
month = {sep},
abstract = {A low frequency (80-120 MHz) VHF RaDAR, BioSAR, specifically designed for forest biomass estimation and a profiling LiDAR, PALS, were flown over loblolly pine plantations in the southeastern United States. LiDAR-only, RaDAR-only, and joint LiDAR-RaDAR linear models were developed to determine if returns from two sensors could be used to estimate pine biomass more accurately and precisely than returns from either sensor alone. The best five-variable RaDAR model explained 81.8\% (R (2)) of the stem green biomass variability, with a regression RMSE of 57.5 t/ha. The best one-variable LiDAR model explained 93.3\37763250470f the biomass variation (RMSE=33.9 t/ha). Combining the RaDAR normalized volumetric returns with the profiling LiDAR ranging measurements did little to improve the best LiDAR-only model. The best LiDAR-RaDAR model explained 93.8\1001275514f the biomass variation (RSME=32.7 t/ha). Cross-validation and training/test validation procedures demonstrated (1) that all models are unbiased and (2) the increased precision of the LiDAR-only and LiDAR-RaDAR models. The results of this investigation and a companion study indicate that there is little to be gained combining VHF-RaDAR volumetric returns and profiling LiDAR ranging measurements in pine forests; a LiDAR ranging system is sufficient for accurate, precise biomass estimation.},
doi = {{10.1016/j.rse.2007.02.006}},
issn = {{0034-4257}},
keywords = {SAR Processing, Biomass, Forest, VHFRaDAR, profiling LiDAR, biomass, RaDAR-LiDAR synergy, VHFSAR DATA, SMALL-FOOTPRINT LIDAR, AIRBORNE LASER DATA, STEM VOLUME, STAND CHARACTERISTICS, AERIAL-PHOTOGRAPHY, VEGETATION BIOMASS, CONIFEROUS FOREST, BOREAL FORESTS, SCANNER DATA},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/nelsonHydeJohnsonEmessieneImhoffCampbellEdwards2007.pdf},
url = {http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V6V-4NF2HJT-1-1&_cdi=5824&_user=5294990&_orig=search&_coverDate=090.000000140.0000002007&_sk=998899998&view=c&wchp=dGLzVtb-zSkWA&md5=c6e6d79abfd854eb19f8ebc9f402a25a&ie=/sdarticle.pdf}
}
Keywords: SAR Processing, Time-Domain Back-Projection, InSAR, Interferometry, SAR Interferometry, Glacier Displacement Measurement, ERS, Spaceborne SAR.
| Abstract: | Synthetic aperture radar (SAR) interferometry has the potential to measure temperate glacier displacement with a large coverage of the surface compared with pointwise terrestrial ground measurements. The significant topographic relief in mountainous areas, however, where most alpine glaciers are located, makes the use of SAR imagery rather difficult. Among the difficulties, when the resolution increases, the focusing of satellite SAR images, usually performed in the frequency domain with a constant-height hypothesis, becomes a critical issue. SAR processing in the temporal domain is a different approach that enables the use of information such as the local topography. In this paper, we present an original method to perform this temporal domain focusing by modeling the relative motion of the satellite and Earth points. The method allows production of SAR single look complex (SLC) images directly in ground geometry and reduces the need for resampling and phase correction to obtain interferograms. A tandem pair of European remote sensing (ERS) SAR images acquired over the Mont-Blanc area is used to illustrate the proposed approach. The results are presented with amplitude images and interferograms measuring glacier 1 day displacements and are compared with the results from the differential interferometric automated process applied to survey of nature (DIAPASON) and repeated orbit interferometry package (ROI-PAC) conventional SAR processors. |
@ARTICLE{NicolasVasileGayTupinTrouve2007:TDBPInSAR,
author = {Jean-Marie Nicolas and Gabriel Vasile and Michel Gay and Florence Tupin and Emmanuel Trouv{\'e}},
title = {{SAR processing in the temporal domain: application to direct interferogram generation and mountain glacier monitoring}},
journal = {Canadian Journal of Remote Sensing},
year = {2007},
volume = {33},
pages = {52--59},
number = {1},
abstract = {Synthetic aperture radar (SAR) interferometry has the potential to measure temperate glacier displacement with a large coverage of the surface compared with pointwise terrestrial ground measurements. The significant topographic relief in mountainous areas, however, where most alpine glaciers are located, makes the use of SAR imagery rather difficult. Among the difficulties, when the resolution increases, the focusing of satellite SAR images, usually performed in the frequency domain with a constant-height hypothesis, becomes a critical issue. SAR processing in the temporal domain is a different approach that enables the use of information such as the local topography. In this paper, we present an original method to perform this temporal domain focusing by modeling the relative motion of the satellite and Earth points. The method allows production of SAR single look complex (SLC) images directly in ground geometry and reduces the need for resampling and phase correction to obtain interferograms. A tandem pair of European remote sensing (ERS) SAR images acquired over the Mont-Blanc area is used to illustrate the proposed approach. The results are presented with amplitude images and interferograms measuring glacier 1 day displacements and are compared with the results from the differential interferometric automated process applied to survey of nature (DIAPASON) and repeated orbit interferometry package (ROI-PAC) conventional SAR processors.},
keywords = {SAR Processing, Time-Domain Back-Projection, InSAR, Interferometry, SAR Interferometry, Glacier Displacement Measurement, ERS, Spaceborne SAR},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/NicolasVasileGayTupinTrouve2007.pdf},
url = {http://pubs.nrc-cnrc.gc.ca/cjrs/m07-005.html}
}
Keywords: SAR Processing, Apodization, Spatially Variant Apodization, SVA, SAR images, apodization effect, homogeneous regions, main lobe resolution preservation, pixel complex amplitude, probability density function, radar cross sections, sidelobe level reduction, statistical moments, statistical properties, supervised classification, synthetic aperture radar images, geophysical techniques, image classification, radar cross-sections, synthetic aperture radar.
| Abstract: | This paper investigates the effect of apodization on the statistical properties of synthetic aperture radar (SAR) images and its impact on the capability of extracting information from homogeneous regions of apodized SAR images. The statistical model for the pixel complex amplitude of the apodized image is derived in terms of both probability density function and statistical moments. Knowledge of the statistical properties is then used to develop appropriate schemes for parameter estimation and supervised classification of homogeneous regions with different radar cross sections in apodized SAR images. The performance analysis shows that the new techniques (properly derived for the apodized case) provide information extraction capabilities only slightly worse than those provided by the conventional techniques applied to the nonapodized case. This allows us to conclude that the use of nonlinear apodization yields sidelobe level reduction and main lobe resolution preservation that can be traded with the small losses above. A full characterization of the estimation and classification performance of these new techniques shows that nonlinear apodization globally introduces a performance degradation comparable to a reduction of the number of looks of a factor of 1.455 for a homogeneous region. |
@ARTICLE{pastinaColoneLombardo2007:Apodization,
author = {Pastina, D. and Colone, F. and Lombardo, P.},
title = {Effect of Apodization on {SAR} Image Understanding},
journal = {IEEE Transactions on Geoscience and Remote Sensing},
year = {2007},
volume = {45},
pages = {3533-3551},
number = {11},
month = nov,
abstract = {This paper investigates the effect of apodization on the statistical properties of synthetic aperture radar (SAR) images and its impact on the capability of extracting information from homogeneous regions of apodized SAR images. The statistical model for the pixel complex amplitude of the apodized image is derived in terms of both probability density function and statistical moments. Knowledge of the statistical properties is then used to develop appropriate schemes for parameter estimation and supervised classification of homogeneous regions with different radar cross sections in apodized SAR images. The performance analysis shows that the new techniques (properly derived for the apodized case) provide information extraction capabilities only slightly worse than those provided by the conventional techniques applied to the nonapodized case. This allows us to conclude that the use of nonlinear apodization yields sidelobe level reduction and main lobe resolution preservation that can be traded with the small losses above. A full characterization of the estimation and classification performance of these new techniques shows that nonlinear apodization globally introduces a performance degradation comparable to a reduction of the number of looks of a factor of 1.455 for a homogeneous region.},
doi = {10.1109/TGRS.2007.905309},
issn = {0196-2892},
keywords = {SAR Processing, Apodization, Spatially Variant Apodization, SVA, SAR images,apodization effect,homogeneous regions,main lobe resolution preservation,pixel complex amplitude, probability density function,radar cross sections,sidelobe level reduction,statistical moments, statistical properties,supervised classification,synthetic aperture radar images, geophysical techniques,image classification,radar cross-sections,synthetic aperture radar}
}
Keywords: SAR Processing, Motion Compensation, PTA-Algorithm, Precise Topography- and Aperture-Dependent (PTA) Algorithm, SATA, Subaperture Topography- and Aperture-dependent (SATA) Algorithm, Frequency Division (FD) Algorithm, Topography-Based Motion Compensation, ESAR, L-Band Calibration, image registration, interferometry, motion compensation (MoCo), synthetic aperture radar (SAR), Comparison, Comparsion of Motion Compensation Algorithms, InSAR, Airborne SAR.
| Abstract: | This letter presents a comparison between three Fourier-based motion compensation (MoCo) algorithms for airborne synthetic aperture radar (SAR) systems. These algorithms circumvent the limitations of conventional MoCo, namely the assumption of a reference height and the beam-center approximation. All these approaches rely on the inherent time-frequency relation in SAR systems but exploit it differently, with the consequent differences in accuracy and computational burden. After a brief overview of the three approaches, the performance of each algorithm is analyzed with respect to azimuthal topography accommodation, angle accommodation, and maximum frequency of track deviations with which the algorithm can cope. Also, an analysis on the computational complexity is presented. Quantitative results are shown using real data acquired by the Experimental SAR system of the German Aerospace Center (DLR). |
@ARTICLE{PratsMacedoReigberScheiberMallorqui2007:MoComp,
author = {Prats, P. and C{\^a}mara de Macedo, Karlus A. and Reigber, A. and Scheiber, R. and Mallorqui, J. J.},
title = {Comparison of Topography- and Aperture-Dependent Motion Compensation Algorithms for Airborne SAR},
journal = {Geoscience and Remote Sensing Letters, IEEE},
year = {2007},
volume = {4},
pages = {349--353},
number = {3},
abstract = {This letter presents a comparison between three Fourier-based motion compensation (MoCo) algorithms for airborne synthetic aperture radar (SAR) systems. These algorithms circumvent the limitations of conventional MoCo, namely the assumption of a reference height and the beam-center approximation. All these approaches rely on the inherent time-frequency relation in SAR systems but exploit it differently, with the consequent differences in accuracy and computational burden. After a brief overview of the three approaches, the performance of each algorithm is analyzed with respect to azimuthal topography accommodation, angle accommodation, and maximum frequency of track deviations with which the algorithm can cope. Also, an analysis on the computational complexity is presented. Quantitative results are shown using real data acquired by the Experimental SAR system of the German Aerospace Center (DLR).},
booktitle = {Geoscience and Remote Sensing Letters, IEEE},
issn = {1545-598X},
keywords = {SAR Processing, Motion Compensation,PTA-Algorithm, Precise Topography- and Aperture-Dependent (PTA) Algorithm, SATA, Subaperture Topography- and Aperture-dependent (SATA) Algorithm, Frequency Division (FD) Algorithm, Topography-Based Motion Compensation, ESAR, L-Band Calibration, image registration, interferometry, motion compensation (MoCo), synthetic aperture radar (SAR),Comparison, Comparsion of Motion Compensation Algorithms, InSAR,
Airborne SAR},
owner = {ofrey},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/PratsMacedoReigberScheiberMallorqui2007.pdf},
url = {http://ieeexplore.ieee.org/iel5/8859/4271437/04271465.pdf}
}
Keywords: SAR Processing, Non-Linear Flight Path, SAR Tomography, 3D Feature Extraction, Feature Extraction, Curvilinear SAR.
| Abstract: | Curvilinear synthetic aperture radar (SAR), as a more practicable 3-D SAR imaging system, utilizes parametric target feature estimates extracted from the received data to reconstruct the target image. The reconstructed image quality is then impacted by the estimation accuracy of the features. In this letter, through discussing the correlation between the system parameters and the estimation performance of the curvilinear SAR, a conclusion can be drawn on how the overall location accuracy of a target is determined by the correlation between the azimuth and elevation coordinates of the flight path, compactly characterizing the curvilinear aperture. Consequently, a new index, determined only with the aperture parameters, is proposed as an aperture evaluator, which is referred to as the feature-independent aperture evaluator (FAE). FAE can be used for guiding the operational aperture design. |
@ARTICLE{suPengWang2007:NonLinearSARTOMO,
author = {Su, Z. and Peng, Y. and Wang, X.},
title = {{Feature-Independent Aperture Evaluator for the Curvilinear SAR}},
journal = {Geoscience and Remote Sensing Letters, IEEE},
year = {2007},
volume = {4},
pages = {191--195},
number = {2},
abstract = {Curvilinear synthetic aperture radar (SAR), as a more practicable 3-D SAR imaging system, utilizes parametric target feature estimates extracted from the received data to reconstruct the target image. The reconstructed image quality is then impacted by the estimation accuracy of the features. In this letter, through discussing the correlation between the system parameters and the estimation performance of the curvilinear SAR, a conclusion can be drawn on how the overall location accuracy of a target is determined by the correlation between the azimuth and elevation coordinates of the flight path, compactly characterizing the curvilinear aperture. Consequently, a new index, determined only with the aperture parameters, is proposed as an aperture evaluator, which is referred to as the feature-independent aperture evaluator (FAE). FAE can be used for guiding the operational aperture design.},
keywords = {SAR Processing, Non-Linear Flight Path, SAR Tomography, 3D Feature Extraction, Feature Extraction, Curvilinear SAR},
pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/suPengWang2007.pdf},
url = {http://ieeexplore.ieee.org/iel5/8859/4156144/04156172.pdf}
}
Conference articles
-
A. Ahlander,
H. Hellsten,
K. Lind,
J. Lindgren,
and B. Svensson.
Architectural Challenges in Memory-Intensive, Real-Time Image Forming.
In Int. Conf. on Parallel Processing,
pages 35-35,
Sept. 2007.
Keywords: SAR Processing, Backprojection, Time-Domain Back-Projection, Fast-Factorized Back-Projection, FFBP, GBP, interpolation, parallel algorithms, parallel architectures, radar imaging, real-time systems, storage management, synthetic aperture radarcomplex memory access pattern, computer architecture, flight path error compensation, memory-intensive real-time image forming, parallel algorithm, performance-intensive data interpolation, synthetic aperture radar system.Abstract: The real-time image forming in future, high-end synthetic aperture radar systems is an example of an application that puts new demands on computer architectures. The initial question is whether it is at all possible to meet the demands with state-of-the-art technology or foreseeable new technology. It is therefore crucial to understand the computational flow, with its associated memory, bandwidth and processing demands. In this paper we analyse the application in order to, primarily, understand the algorithms and identify the challenges they present on a basic architectural level. The processing in the radar system is characterized by working on huge data sets, having complex memory access patterns, and doing real-time compensations for flight path errors. We propose algorithm solutions and execution schemes in interplay with a two-level (coarse-grain/fine-grain) system parallelization approach, and we provide approximate models on which the demands are quantified. In particular, we consider the choice of method for the performance- intensive data interpolations. This choice presents a trade-off problem between computational performance and size of working memory. The results of this "upstream " study will serve as a basis for further, more detailed architecture studies. @INPROCEEDINGS{ahlanderHellstenLindLindgrenSvensson2007:TDBPRealTime, author = {Ahlander, A. and Hellsten, H. and Lind, K. and Lindgren, J. and Svensson, B.}, title = {Architectural Challenges in Memory-Intensive, Real-Time Image Forming}, booktitle = {Int. Conf. on Parallel Processing}, year = {2007}, pages = {35-35}, month = {Sept.}, abstract = {The real-time image forming in future, high-end synthetic aperture radar systems is an example of an application that puts new demands on computer architectures. The initial question is whether it is at all possible to meet the demands with state-of-the-art technology or foreseeable new technology. It is therefore crucial to understand the computational flow, with its associated memory, bandwidth and processing demands. In this paper we analyse the application in order to, primarily, understand the algorithms and identify the challenges they present on a basic architectural level. The processing in the radar system is characterized by working on huge data sets, having complex memory access patterns, and doing real-time compensations for flight path errors. We propose algorithm solutions and execution schemes in interplay with a two-level (coarse-grain/fine-grain) system parallelization approach, and we provide approximate models on which the demands are quantified. In particular, we consider the choice of method for the performance- intensive data interpolations. This choice presents a trade-off problem between computational performance and size of working memory. The results of this "upstream " study will serve as a basis for further, more detailed architecture studies.}, doi = {10.1109/ICPP.2007.18}, issn = {0190-3918}, keywords = {SAR Processing, Backprojection, Time-Domain Back-Projection, Fast-Factorized Back-Projection, FFBP, GBP, interpolation, parallel algorithms, parallel architectures, radar imaging, real-time systems, storage management, synthetic aperture radarcomplex memory access pattern, computer architecture, flight path error compensation, memory-intensive real-time image forming, parallel algorithm, performance-intensive data interpolation, synthetic aperture radar system}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/ahlanderHellstenLindLindgrenSvensson2007.pdf}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4343842&isnumber=4343799} } -
Christian Andres,
Torben Keil,
Raik Herrmann,
and Rolf Scheiber.
A multiprocessing framework for SAR image processing.
In ,
pages 524--527,
July 2007.
Keywords: SAR Processing, Airborne SAR, application program interfaces, geophysics computing, grid computing, image processing, multiprocessing systems, synthetic aperture radar, workstation clusters, F-SAR, SAR image processing, airborne SAR sensor, application programming interface, cluster grids, different architectures, multiprocessing framework, source code, synthetic aperture radar, workstation cluster.Abstract: This paper introduces a framework developed for image processing of synthetic aperture radar (SAR) images. It encapsulates features of modern hardware architectures, including symmetric and asymmetric multiprocessing, within an easy and intuitive to use application programming interface (API). The multiprocessing part is designed for unified usage of different architectures reaching from multicore processors to cluster of workstations to grids of clusters. So an application using the framework can be ported from one architecture to another without any changes in the source code. The framework builds the bottom layer of the processing system developed for the German Aerospace Center's (DLR) new airborne SAR sensor, the F-SAR. @INPROCEEDINGS{andresKeilHerrmannScheiber2007:SARMultiProcessingFrame, author = {Andres, Christian and Keil, Torben and Herrmann, Raik and Scheiber, Rolf}, title = {{A multiprocessing framework for SAR image processing}}, year = {2007}, pages = {524--527}, month = {jul}, abstract = {This paper introduces a framework developed for image processing of synthetic aperture radar (SAR) images. It encapsulates features of modern hardware architectures, including symmetric and asymmetric multiprocessing, within an easy and intuitive to use application programming interface (API). The multiprocessing part is designed for unified usage of different architectures reaching from multicore processors to cluster of workstations to grids of clusters. So an application using the framework can be ported from one architecture to another without any changes in the source code. The framework builds the bottom layer of the processing system developed for the German Aerospace Center's (DLR) new airborne SAR sensor, the F-SAR.}, doi = {10.1109/IGARSS.2007.4422846}, journal = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007}, keywords = {SAR Processing, Airborne SAR, application program interfaces, geophysics computing, grid computing, image processing, multiprocessing systems, synthetic aperture radar, workstation clusters, F-SAR, SAR image processing, airborne SAR sensor, application programming interface, cluster grids, different architectures, multiprocessing framework, source code, synthetic aperture radar, workstation cluster}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/andresKeilHerrmannScheiber2007.pdf}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4422846&isnumber=4422708} } -
Wang Bin,
Wang Yanping,
Hong Wen,
and Wu Yirong.
Simulation research of parametric methods for multi-baseline SAR tomography.
In Synthetic Aperture Radar, 2007. APSAR 2007. 1st Asian and Pacific Conference on,
pages 203--206,
5-9 Nov. 2007.
@INPROCEEDINGS{Bin2007, author = {Wang Bin and Wang Yanping and Hong Wen and Wu Yirong}, title = {Simulation research of parametric methods for multi-baseline SAR tomography}, booktitle = {Synthetic Aperture Radar, 2007. APSAR 2007. 1st Asian and Pacific Conference on}, year = {2007}, pages = {203--206}, month = {5-9 Nov.}, doi = {10.1109/APSAR.2007.4418589}, owner = {ofrey}, timestamp = {2009.07.01} } -
Hubert M. J. Cantalloube,
Élise Colin-Koeniguer,
and Hélène Oriot.
High resolution SAR imaging along circular trajectories.
In IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007,
pages 850-853,
July 2007.
Keywords: SAR Processing, Autofocus, Phase Gradient Autofocus, PGA, Autofocus by Deterministic Trajectory Triangulation Technique, data acquisition, Motion Compensation, MoComp, Residual Motion Errors, radar antennas, radar polarimetry, remote sensing by radar, synthetic aperture radar, L-band radar, P-band radar, Sweden, X-band sensor, Airborne SAR, aircraft attitude fluctuation, circular trajectories, Non-Linear Flight Track, high resolution SAR imaging, joint FOI-ONERA campaign, narrower antenna pattern, polarimetric full circle radar acquisition, steerable antenna.Abstract: After a first series of full circle SAR acquisitions in L- and P-bands during a 2004 joint FOI-ONERA campaign in Sweden, ONERA experimented in 2006 high resolution (15 cm) polarimetric, full circle acquisitions in France and Germany using its X-band sensor. In order to cope with narrower antenna pattern and aircraft attitude fluctuations, a steerable antenna was used. Furthermore, an experimental setup for retrieving high accuracy trajectory was installed. This paper describes the processing of this signals. @INPROCEEDINGS{cantalloubeColinKoeniguerOriot2007:NonLinearFlightTracks, author = {Cantalloube, Hubert M. J. and Colin-Koeniguer, \'Elise and Oriot, H\'el\`ene}, title = {{High resolution SAR imaging along circular trajectories}}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007}, year = {2007}, pages = {850-853}, month = {July}, abstract = {After a first series of full circle SAR acquisitions in L- and P-bands during a 2004 joint FOI-ONERA campaign in Sweden, ONERA experimented in 2006 high resolution (15 cm) polarimetric, full circle acquisitions in France and Germany using its X-band sensor. In order to cope with narrower antenna pattern and aircraft attitude fluctuations, a steerable antenna was used. Furthermore, an experimental setup for retrieving high accuracy trajectory was installed. This paper describes the processing of this signals.}, doi = {10.1109/IGARSS.2007.4422930}, keywords = {SAR Processing, Autofocus, Phase Gradient Autofocus, PGA, Autofocus by Deterministic Trajectory Triangulation Technique, data acquisition, Motion Compensation, MoComp, Residual Motion Errors, radar antennas, radar polarimetry, remote sensing by radar, synthetic aperture radar, L-band radar, P-band radar, Sweden, X-band sensor, Airborne SAR, aircraft attitude fluctuation, circular trajectories, Non-Linear Flight Track, high resolution SAR imaging, joint FOI-ONERA campaign, narrower antenna pattern, polarimetric full circle radar acquisition, steerable antenna}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/cantalloubeColinKoeniguerOriot2007.pdf}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4422930&isnumber=4422708} } -
Karlus A. Câmara de Macedo,
Rolf Scheiber,
and Alberto Moreira.
An autofocus approach for residual motion errors with application to airborne repeat-pass SAR interferometry.
In IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007,
Barcelona, Spain,
pages 4886 - 4889,
July 2007.
Keywords: SAR Processing, Autofocus, Residual Motion Errors, WPCA, Weighted PCA, Weighted Phase Curvature Autofocus, Phase Curvature Autofocus, PCA, Phase Gradient Autofocus, PGA, Repeat-Pass Interferometry, Interferometry, E-SAR, airborne SAR, Baseline Calibration, Tomography, SAR Tomography.Abstract: Airborne repeat-pass SAR data are very sensible to sub-wavelength deviations from the reference track. To enable repeat-pass interferometry a high-precision navigation system is needed. Due to the limit of accuracy of such systems, deviations in the order of centimeters remain between the nominal and the processed reference track causing mainly undesirable phase undulations and misregistration in the interferograms, referred as residual motion errors. Up to now only interferometric approaches, as multi-squint, are used to estimate those deviations to compensate for such residuals. In this paper we present for the first time the use of the Autofocus technique for residual motion errors. A very robust autofocus technique has to be used since the accuracy of the estimated motion has to be at millimeter scale. Because we deal with low-altitude-stripmap mode data we propose a new robust autofocus technique based on the WLS (Weighted Least-Squares) phase estimation and Phase Curvature Autofocus (PCA) extended to the rangedependent case. We call this new technique WPCA (Weighted PCA). While the multi-squint approach is only able to estimate the baseline variation from coregistered images, the autofocus approach has the advantage of being able to estimate motion deviations independendtly for each image. Repeat-pass data of the E-SAR system of the German Aerospace Center (DLR) are used to demostrate the performance of the proposed approach. @INPROCEEDINGS{deMacedoScheiberMoreira2007:Autofocus, author = {C{\^a}mara de Macedo, Karlus A. and Scheiber, Rolf and Moreira, Alberto}, title = {{An autofocus approach for residual motion errors with application to airborne repeat-pass SAR interferometry}}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007}, year = {2007}, pages = {4886 - 4889}, address = {Barcelona, Spain}, month = {July}, abstract = {Airborne repeat-pass SAR data are very sensible to sub-wavelength deviations from the reference track. To enable repeat-pass interferometry a high-precision navigation system is needed. Due to the limit of accuracy of such systems, deviations in the order of centimeters remain between the nominal and the processed reference track causing mainly undesirable phase undulations and misregistration in the interferograms, referred as residual motion errors. Up to now only interferometric approaches, as multi-squint, are used to estimate those deviations to compensate for such residuals. In this paper we present for the first time the use of the Autofocus technique for residual motion errors. A very robust autofocus technique has to be used since the accuracy of the estimated motion has to be at millimeter scale. Because we deal with low-altitude-stripmap mode data we propose a new robust autofocus technique based on the WLS (Weighted Least-Squares) phase estimation and Phase Curvature Autofocus (PCA) extended to the rangedependent case. We call this new technique WPCA (Weighted PCA). While the multi-squint approach is only able to estimate the baseline variation from coregistered images, the autofocus approach has the advantage of being able to estimate motion deviations independendtly for each image. Repeat-pass data of the E-SAR system of the German Aerospace Center (DLR) are used to demostrate the performance of the proposed approach.}, keywords = {SAR Processing, Autofocus, Residual Motion Errors, WPCA, Weighted PCA, Weighted Phase Curvature Autofocus, Phase Curvature Autofocus, PCA, Phase Gradient Autofocus, PGA, Repeat-Pass Interferometry, Interferometry, E-SAR, airborne SAR, Baseline Calibration, Tomography, SAR Tomography}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/deMacedoScheiberMoreira2007.pdf}, url = {http://www.ieeexplore.ieee.org//iel5/4422707/4422708/04423956.pdf} } -
G. Fornaro,
F. Lombardini,
M. Pardini,
F. Serafino,
F. Soldovieri,
and M. Costantini.
Spaceborne multi-dimensional SAR imaging: Current status and perspectives.
In Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International,
pages 5277--5280,
23-28 July 2007.
@INPROCEEDINGS{Fornaro2007, author = {Fornaro, G. and Lombardini, F. and Pardini, M. and Serafino, F. and Soldovieri, F. and Costantini, M.}, title = {Spaceborne multi-dimensional SAR imaging: Current status and perspectives}, booktitle = {Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International}, year = {2007}, pages = {5277--5280}, month = {23-28 July}, doi = {10.1109/IGARSS.2007.4424053}, owner = {ofrey}, timestamp = {2009.07.01} } -
Othmar Frey,
Felix Morsdorf,
and Erich Meier.
Tomographic Processing of Multi-Baseline P-Band SAR Data for Imaging of a Forested Area.
In IEEE International Geoscience and Remote Sensing Symposium, IGARSS '07,
2007.
Keywords: SAR Processing, SAR Tomography, Tomographic Processing, Multi-Baseline SAR, Time-Domain Back-Projection, Back-Projection, E-SAR, P-Band, Forestry.Abstract: Recently, various attempts have been undertaken to obtain information about the structure of forested areas from multi-baseline synthetic aperture radar data. Tomographic processing of such data has been demonstrated but the quality of the focused tomographic image is limited by several factors. In particular Fourier-based focusing methods are susceptible to irregular and sparse sampling, two problems, that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. We propose a tomographic focusing method based on the time-domain back-projection algorithm, which maintains the geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular sampling without introducing any approximations with respect to the geometry. We assess the tomographic focusing quality with the help of the impulse response of simulated point targets and an in-scene corner reflector. And, in particular, preliminary results obtained with the newly acquired P-band tomographic data set consisting of eleven flight tracks are presented. @INPROCEEDINGS{freyMorsdorfMeier07IGARSS:Tomo, author = {Othmar Frey and Felix Morsdorf and Erich Meier}, title = {{Tomographic Processing of Multi-Baseline P-Band SAR Data for Imaging of a Forested Area}}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS '07}, year = {2007}, abstract = {Recently, various attempts have been undertaken to obtain information about the structure of forested areas from multi-baseline synthetic aperture radar data. Tomographic processing of such data has been demonstrated but the quality of the focused tomographic image is limited by several factors. In particular Fourier-based focusing methods are susceptible to irregular and sparse sampling, two problems, that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. We propose a tomographic focusing method based on the time-domain back-projection algorithm, which maintains the geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular sampling without introducing any approximations with respect to the geometry. We assess the tomographic focusing quality with the help of the impulse response of simulated point targets and an in-scene corner reflector. And, in particular, preliminary results obtained with the newly acquired P-band tomographic data set consisting of eleven flight tracks are presented.}, keywords = {SAR Processing, SAR Tomography, Tomographic Processing, Multi-Baseline SAR, Time-Domain Back-Projection, Back-Projection, E-SAR, P-Band, Forestry}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/myPublications/PAPERS/freyMorsdorfMeier07IGARSS.pdf}, url = {http://ieeexplore.ieee.org/iel5/4422707/4422708/04422753.pdf} } -
Othmar Frey,
Felix Morsdorf,
and Erich Meier.
Tomographic SAR Imaging of a Forested Area by Time-Domain Back-Projection.
In M.E. Schaepman,
S. Liang,
N.E. Groot,
and M. Kneubühler, editors,
10th Intl. Symposium on Physical Measurements and Spectral Signatures in Remote Sensing,
volume XXXVI,
2007.
Intl. Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences.
Keywords: SAR Processing, SAR Tomography, Tomographic Processing, Multi-Baseline SAR, Time-Domain Back-Projection, Back-Projection, E-SAR, P-Band, Forestry.Abstract: Recently, various attempts have been undertaken to retrieve information about the three-dimensional structure of vegetation from multibaseline synthetic aperture radar data. Although tomographic processing of such data has been demonstrated, yet, there are still several problems that limit the focusing quality. In particular, the frequency-domain based focusing methods are susceptible to irregular and sparse sampling, two problems, which are unavoidable in case of multi-pass, multi-baseline radar data acquired by an airborne system. We propose a time-domain back-projection algorithm, which maintains the original geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular and sparse sampling without introducing any geometric approximations. Preliminary results obtained with a newly acquired P-band tomographic data set consisting of eleven flight tracks are shown and discussed. @INPROCEEDINGS{freyMorsdorfMeierISPMSRS2007:Tomo, author = {Othmar Frey and Felix Morsdorf and Erich Meier}, title = {{Tomographic SAR Imaging of a Forested Area by Time-Domain Back-Projection}}, booktitle = {10th Intl. Symposium on Physical Measurements and Spectral Signatures in Remote Sensing}, year = {2007}, editor = {M.E. Schaepman and S. Liang and N.E. Groot and M. Kneub{\"u}hler}, volume = {XXXVI}, number = {7/C50}, organization = {Intl. Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences}, abstract = {Recently, various attempts have been undertaken to retrieve information about the three-dimensional structure of vegetation from multibaseline synthetic aperture radar data. Although tomographic processing of such data has been demonstrated, yet, there are still several problems that limit the focusing quality. In particular, the frequency-domain based focusing methods are susceptible to irregular and sparse sampling, two problems, which are unavoidable in case of multi-pass, multi-baseline radar data acquired by an airborne system. We propose a time-domain back-projection algorithm, which maintains the original geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular and sparse sampling without introducing any geometric approximations. Preliminary results obtained with a newly acquired P-band tomographic data set consisting of eleven flight tracks are shown and discussed.}, keywords = {SAR Processing, SAR Tomography, Tomographic Processing, Multi-Baseline SAR, Time-Domain Back-Projection, Back-Projection, E-SAR, P-Band, Forestry}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/myPublications/PAPERS/freyMorsdorfMeierISPMSRS2007.pdf}, url = {http://skgr0103.wur.nl/~schae001/ispmsrs/P23_Frey_SAR.pdf} } -
Wang Jinfeng,
Zhou Peng,
and Pi Yiming.
SAR tomography imaging based on high-order spectrum analysis.
In Synthetic Aperture Radar, 2007. APSAR 2007. 1st Asian and Pacific Conference on,
pages 364--367,
5-9 Nov. 2007.
@INPROCEEDINGS{Jinfeng2007, author = {Wang Jinfeng and Zhou Peng and Pi Yiming}, title = {SAR tomography imaging based on high-order spectrum analysis}, booktitle = {Synthetic Aperture Radar, 2007. APSAR 2007. 1st Asian and Pacific Conference on}, year = {2007}, pages = {364--367}, month = {5-9 Nov.}, doi = {10.1109/APSAR.2007.4418627}, owner = {ofrey}, timestamp = {2009.07.01} } -
F. Lombardini.
New potentials of differential SAR tomography: Volumetric differential interferometry and robust DEM generation.
In Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International,
pages 5281--5284,
23-28 July 2007.
@INPROCEEDINGS{Lombardini2007b, author = {Lombardini, F.}, title = {New potentials of differential SAR tomography: Volumetric differential interferometry and robust DEM generation}, booktitle = {Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International}, year = {2007}, pages = {5281--5284}, month = {23-28 July}, doi = {10.1109/IGARSS.2007.4424054}, owner = {ofrey}, timestamp = {2009.07.01} } -
Fabrizio Lombardini,
Matteo Pardini,
and Fulvio Gini.
Sector interpolation for 3D SAR imaging with baseline diversity data.
In Waveform Diversity and Design Conference, 2007. International,
pages 297--301,
4-8 June 2007.
@INPROCEEDINGS{Lombardini2007a, author = {Lombardini, Fabrizio and Pardini, Matteo and Gini, Fulvio}, title = {Sector interpolation for 3D SAR imaging with baseline diversity data}, booktitle = {Waveform Diversity and Design Conference, 2007. International}, year = {2007}, pages = {297--301}, month = {4-8 June}, doi = {10.1109/WDDC.2007.4339430}, owner = {ofrey} } -
Fabrizio Lombardini,
Ludwig Rössing,
Joachim H. G. Ender,
and F. Viviani.
Towards a Complete Processing Chain of Multibaseline Airborne InSAR Data for Layover Scatterers Separation.
In Urban Remote Sensing Joint Event, 2007,
pages 1--6,
11-13 April 2007.
Abstract: Interest is continuing to grow in exploiting the advanced multibaseline operation of synthetic aperture radar interferometry (InSAR) to solve layover effects, that can degrade conventional InSAR topographic mapping. In this work we report about experiments of the functionality of “layover-free†or “higher-order†interferometry with the dual-baseline single-pass SAR interferometer AER-II. Estimation of the number of multiple layover scatterers, i.e. of the interferometric order, and model-based spatial spectral estimation are integrated to process the three-antenna non uniform array data. Results are discussed for a bridge over the valley test site. @INPROCEEDINGS{LombardiniRoessingEnderViviani2007a:Tomo, author = {Lombardini, Fabrizio and R{\"o}ssing, Ludwig and Joachim H. G. Ender and Viviani, F.}, title = {Towards a Complete Processing Chain of Multibaseline Airborne InSAR Data for Layover Scatterers Separation}, booktitle = {Urban Remote Sensing Joint Event, 2007}, year = {2007}, pages = {1--6}, month = {11-13 April}, abstract = {Interest is continuing to grow in exploiting the advanced multibaseline operation of synthetic aperture radar interferometry (InSAR) to solve layover effects, that can degrade conventional InSAR topographic mapping. In this work we report about experiments of the functionality of “layover-free†or “higher-order†interferometry with the dual-baseline single-pass SAR interferometer AER-II. Estimation of the number of multiple layover scatterers, i.e. of the interferometric order, and model-based spatial spectral estimation are integrated to process the three-antenna non uniform array data. Results are discussed for a bridge over the valley test site.}, doi = {10.1109/URS.2007.371875}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/LombardiniRoessingEnderViviani2007a.pdf}, url = {http://ieeexplore.ieee.org/iel5/4234358/4234359/04234474.pdf} } -
Andrea Monti-Guarnieri and Stefano Tebaldini.
A new framework for multi-pass SAR interferometry with distributed targets.
In IEEE International Geoscience and Remote Sensing Symposium,
pages 5289-5293,
July 2007.
Keywords: Monte Carlo methods, digital elevation models, radar interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar, topography (Earth)DEM, InSAR, LOS displacement, Monte Carlo simulation, distributed scattering, multipass spaceborne SAR interferometry, repeated pass ENVISAT images, residual topography, synthetic aperture radar interferometry.Abstract: This paper focuses on multi-pass spaceborne synthetic aperture radar interferometry (InSAR) in presence of distributed scattering, paying particular attention to the role of target decorrelation in the estimation process. This phenomenon is accounted for by splitting the analysis into two steps. In the first step we estimate the interferometric phases from the data, while in the second step we use these phases to retrieve the physical parameters of interest, such as LOS displacement and residual topography. This approach is suited both to derive the performances of InSAR with different decorrelation models and for providing an actual estimate of LOS motion and DEM. Results achieved from Monte-Carlo simulations and a set of repeated pass ENVISAT images are shown. @INPROCEEDINGS{montiGuarnieriTebaldiniIGARSS2007:Tomo, author = {Monti-Guarnieri, Andrea and Tebaldini, Stefano}, title = {A new framework for multi-pass {SAR} interferometry with distributed targets}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium}, year = {2007}, pages = {5289-5293}, month = {jul}, abstract = {This paper focuses on multi-pass spaceborne synthetic aperture radar interferometry (InSAR) in presence of distributed scattering, paying particular attention to the role of target decorrelation in the estimation process. This phenomenon is accounted for by splitting the analysis into two steps. In the first step we estimate the interferometric phases from the data, while in the second step we use these phases to retrieve the physical parameters of interest, such as LOS displacement and residual topography. This approach is suited both to derive the performances of InSAR with different decorrelation models and for providing an actual estimate of LOS motion and DEM. Results achieved from Monte-Carlo simulations and a set of repeated pass ENVISAT images are shown.}, doi = {10.1109/IGARSS.2007.4424056}, keywords = {Monte Carlo methods, digital elevation models, radar interferometry, remote sensing by radar, spaceborne radar, synthetic aperture radar, topography (Earth)DEM, InSAR, LOS displacement, Monte Carlo simulation, distributed scattering, multipass spaceborne SAR interferometry, repeated pass ENVISAT images, residual topography, synthetic aperture radar interferometry}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/montiGuarnieriTebaldiniIGARSS2007.pdf}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4424056&isnumber=4422708} } -
Matteo Nannini and Rolf Scheiber.
Height dependent motion compensation and coregistration for airborne SAR tomography.
In International Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007,
pages 5041-5044,
July 2007.
Keywords: SAR Processing, SAR Tomography, Tomography, geophysical signal processing, image registration, Motion Compensation, radar imaging, remote sensing by radar, synthetic aperture radar2D SAR repeat-pass processing, E-SAR system, L-Band, German Aerospace Centre, SAR imaging, airborne SAR tomography, data acquisition, height dependent motion compensation, image coregistration, multiple phase center separation, processing correction, tomogram quality, volumetric target.Abstract: SAR tomography (SARTom) is an imaging technique that allows multiple phase centers separation in the vertical (height) direction. It is performed after standard 2D SAR repeat-pass processing and operates on a stack of coregistered SAR images. Theoretically, the coregistration between two images is height dependent and the use of a reference height (or a DEM) is needed, although not ideal in the case of volumetric target (multiple phase centers in one resolution cell). In this paper, the drawbacks related to the choice of this reference in a tomographic context are analysed and a height dependent coregistration approach is proposed. In order to do this, it is also necessary to remove processing corrections related to the reference height, such as motion compensation, and make them height dependent. The inclusion of the height dependency during the tomographic SAR processing results in a better quality of the final tomograms in terms of pseudo-power and phase centers separation. The results of the proposed approach are validated on real data acquired by the E-SAR system of the German Aerospace Centre - DLR. @INPROCEEDINGS{nanniniScheiber2007:Tomo, author = {Nannini, Matteo and Scheiber, Rolf}, title = {{Height dependent motion compensation and coregistration for airborne SAR tomography}}, booktitle = {International Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007}, year = {2007}, pages = {5041-5044}, month = {July}, abstract = {SAR tomography (SARTom) is an imaging technique that allows multiple phase centers separation in the vertical (height) direction. It is performed after standard 2D SAR repeat-pass processing and operates on a stack of coregistered SAR images. Theoretically, the coregistration between two images is height dependent and the use of a reference height (or a DEM) is needed, although not ideal in the case of volumetric target (multiple phase centers in one resolution cell). In this paper, the drawbacks related to the choice of this reference in a tomographic context are analysed and a height dependent coregistration approach is proposed. In order to do this, it is also necessary to remove processing corrections related to the reference height, such as motion compensation, and make them height dependent. The inclusion of the height dependency during the tomographic SAR processing results in a better quality of the final tomograms in terms of pseudo-power and phase centers separation. The results of the proposed approach are validated on real data acquired by the E-SAR system of the German Aerospace Centre - DLR.}, doi = {10.1109/IGARSS.2007.4423994}, keywords = {SAR Processing, SAR Tomography, Tomography, geophysical signal processing, image registration, Motion Compensation, radar imaging, remote sensing by radar, synthetic aperture radar2D SAR repeat-pass processing, E-SAR system, L-Band, German Aerospace Centre, SAR imaging, airborne SAR tomography, data acquisition, height dependent motion compensation, image coregistration, multiple phase center separation, processing correction, tomogram quality, volumetric target}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/nanniniScheiberTomo2007.pdf}, url = {http://ieeexplore.ieee.org/iel5/4422707/4422708/04423994.pdf} } -
Pau Prats,
Christian Andres,
Rolf Scheiber,
Karlus A. Câmara de Macedo,
Jens Fischer,
and Andreas Reigber.
Glacier displacement field estimation using airborne SAR interferometry.
In IEEE International Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007.,
pages 2098--2101,
July 2007.
Keywords: SAR Processing, SAR interferometry, InSAR, DInSAR, Spectral Diversity, Residual Motion Errors, Motion Compensation, MoComp, Airborne SAR, ESAR, airborne radar, glaciology, hydrological techniques, radar interferometry, synthetic aperture radar2D displacement map, Aletsch glacier, E-SAR, Experimental SAR, German Aerospace Center, Swiss Alps, across-track displacement, airborne SAR data, airborne, along-track displacement, extended multisquint approach, glacier displacement field estimation, slant-range geometry.Abstract: This paper deals with the methodology in the processing of airborne SAR data to measure glacier displacement fields. The possibility to retrieve a 2D displacement map of the deformation in slant-range geometry with an airborne platform is discussed. A new extended multisquint approach is proposed to simultaneously estimate residual motion errors and the along-track displacement of the glacier, while the across-track displacement is obtained by means of differential interferomatry. Experimental results are shown with data acquired by the Experimental SAR (E-SAR) of the German Aerospace Center over the Aletsch glacier in the Swiss Alps. @INPROCEEDINGS{pratsAndresScheiberdeMacedoFischerReigber2007:DInSARAletsch, author = {Prats, Pau and Andres, Christian and Scheiber, Rolf and C\^amara de Macedo, Karlus A. and Fischer, Jens and Reigber, Andreas}, title = {{Glacier displacement field estimation using airborne SAR interferometry}}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007.}, year = {2007}, pages = {2098--2101}, month = {jul}, abstract = {This paper deals with the methodology in the processing of airborne SAR data to measure glacier displacement fields. The possibility to retrieve a 2D displacement map of the deformation in slant-range geometry with an airborne platform is discussed. A new extended multisquint approach is proposed to simultaneously estimate residual motion errors and the along-track displacement of the glacier, while the across-track displacement is obtained by means of differential interferomatry. Experimental results are shown with data acquired by the Experimental SAR (E-SAR) of the German Aerospace Center over the Aletsch glacier in the Swiss Alps.}, doi = {10.1109/IGARSS.2007.4423247}, keywords = {SAR Processing, SAR interferometry, InSAR,DInSAR, Spectral Diversity, Residual Motion Errors, Motion Compensation, MoComp, Airborne SAR, ESAR, airborne radar, glaciology, hydrological techniques, radar interferometry, synthetic aperture radar2D displacement map, Aletsch glacier, E-SAR, Experimental SAR, German Aerospace Center, Swiss Alps, across-track displacement, airborne SAR data, airborne , along-track displacement, extended multisquint approach, glacier displacement field estimation, slant-range geometry}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/pratsAndresScheiberdeMacedoFischerReigber2007.pdf}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4423247&isnumber=4422708} } -
Rolf Scheiber,
Pau Prats,
Matteo Nannini,
Karlus A. Câmara de Macedo,
Christian Andres,
Jens Fischer,
and Ralf Horn.
Advances in airborne SAR interferometry using the experimental SAR system of DLR.
In European Radar Conference, EuRAD 2007.,
2007.
Keywords: SAR Processing, SAR Tomography, Tomography, InSAR, Interferometry, PTA, SATA, Residual Motion Errors, Motion Compensation, DInSAR, Differential InSAR, Differential Interferometry, E-SAR.Abstract: During recent years the experimental SAR (E-SAR) system of the German Aerospace Center (DLR) has continuously been operated to acquire data for different scientific applications in forestry, agriculture and glaciology. In this context, the data where mainly used to develop new scattering models in preparation of future space-borne missions posing increasing accuracy requirements especially for the processing of repeat-pass interferometric data. Also direct model-free methods like differential SAR interferometry for measuring displacements in the order of the wavelength or SAR tomography for real 3D microwave imaging of scattering volumes determined the development of advanced and very accurate motion compensation techniques. This paper first gives an overview of the updates of the E-SAR system performed during the last couple of years and then focusses on the recently developed airborne interferometric processing methods and their applications. @INPROCEEDINGS{scheiberPratsNanninideMacedoAndresFischerHorn2007:ESAR, author = {Scheiber, Rolf and Prats, Pau and Nannini, Matteo and C{\^a}mara de Macedo, Karlus A. and Andres, Christian and Fischer, Jens and Horn, Ralf}, title = {{Advances in airborne SAR interferometry using the experimental SAR system of DLR}}, booktitle = {European Radar Conference, EuRAD 2007.}, year = {2007}, abstract = {During recent years the experimental SAR (E-SAR) system of the German Aerospace Center (DLR) has continuously been operated to acquire data for different scientific applications in forestry, agriculture and glaciology. In this context, the data where mainly used to develop new scattering models in preparation of future space-borne missions posing increasing accuracy requirements especially for the processing of repeat-pass interferometric data. Also direct model-free methods like differential SAR interferometry for measuring displacements in the order of the wavelength or SAR tomography for real 3D microwave imaging of scattering volumes determined the development of advanced and very accurate motion compensation techniques. This paper first gives an overview of the updates of the E-SAR system performed during the last couple of years and then focusses on the recently developed airborne interferometric processing methods and their applications.}, keywords = {SAR Processing, SAR Tomography, Tomography, InSAR, Interferometry, PTA, SATA, Residual Motion Errors, Motion Compensation, DInSAR, Differential InSAR, Differential Interferometry, E-SAR}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/scheiberPratsNanninideMacedoAndresFischerHorn2007.pdf}, url = {http://ieeexplore.ieee.org/iel5/4404892/4404893/04404944.pdf} } -
Philipp Thompson,
Matteo Nannini,
and Rolf Scheiber.
Target separation in SAR image with the MUSIC algorithm.
In IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007.,
pages 468-471,
July 2007.
Keywords: SAR Processing, SAR Tomography, Tomography, radar imaging, synthetic aperture radar, DLR, E-SAR system, Fourier SAR image, MUSIC, MUSIC algorithm, Spectral Estimation, X-band, corner reflectors, post-processing implementation, super-resolution experiment, target separation, targets geometry.Abstract: The aim of this work is to exploit the MUSIC algorithm performance in order to enhance target separability in range and azimuth, i.e. achieve point targets separation inside a resolution cell. Simulations have been done in order to plan and check the feasibility of a super-resolution experiment that took place in September 2006 on the test site of Oberpfaffenhofen (Germany). The data set has been acquired with the E-SAR system of the DLR in X-band. The targets to be separated were seven small corner reflectors that have been placed in a way that their response falls in one or, at maximum, two resolution cells of the standard Fourier SAR image. A post-processing implementation of the MUSIC algorithm has been proposed allowing, in the already focused SAR image, to retrieve the targets geometry. Conditions and analysis of the results have been carried out. @INPROCEEDINGS{thompsonNanniniScheiberTomo2007:Music, author = {Thompson, Philipp and Nannini, Matteo and Scheiber, Rolf}, title = {{Target separation in SAR image with the MUSIC algorithm}}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007.}, year = {2007}, pages = {468-471}, month = {July}, abstract = {The aim of this work is to exploit the MUSIC algorithm performance in order to enhance target separability in range and azimuth, i.e. achieve point targets separation inside a resolution cell. Simulations have been done in order to plan and check the feasibility of a super-resolution experiment that took place in September 2006 on the test site of Oberpfaffenhofen (Germany). The data set has been acquired with the E-SAR system of the DLR in X-band. The targets to be separated were seven small corner reflectors that have been placed in a way that their response falls in one or, at maximum, two resolution cells of the standard Fourier SAR image. A post-processing implementation of the MUSIC algorithm has been proposed allowing, in the already focused SAR image, to retrieve the targets geometry. Conditions and analysis of the results have been carried out.}, doi = {10.1109/IGARSS.2007.4422832}, keywords = {SAR Processing, SAR Tomography, Tomography, radar imaging, synthetic aperture radar,DLR, E-SAR system, Fourier SAR image, MUSIC, MUSIC algorithm, Spectral Estimation, X-band, corner reflectors, post-processing implementation, super-resolution experiment, target separation, targets geometry}, owner = {ofrey}, pdf = {http://www.geo.uzh.ch/~ofrey/protected/PAPERS/thompsonNanniniScheiberTomo2007.pdf}, url = {http://ieeexplore.ieee.org/iel5/4422707/4422708/04422832.pdf} } -
Tan Wei-xian,
Hong Wen,
Wang Yan-ping,
and Wu Yi-rong.
A novel imaging approach for multi-baseline SAR tomography.
In Synthetic Aperture Radar, 2007. APSAR 2007. 1st Asian and Pacific Conference on,
pages 423--426,
5-9 Nov. 2007.
@INPROCEEDINGS{Wei-xian2007, author = {Tan Wei-xian and Hong Wen and Wang Yan-ping and Wu Yi-rong}, title = {A novel imaging approach for multi-baseline SAR tomography}, booktitle = {Synthetic Aperture Radar, 2007. APSAR 2007. 1st Asian and Pacific Conference on}, year = {2007}, pages = {423--426}, month = {5-9 Nov.}, doi = {10.1109/APSAR.2007.4418641}, owner = {ofrey}, timestamp = {2009.07.01} } -
Tan Weixian,
Wang Yanping,
Hong Wen,
Wu Yirong,
Li Nanjing,
Hu Chufeng,
and Zhang Linxi.
SAR Three-Dimensional Imaging Experiments with Microwave Anechoic Chamber SAR Data.
In Microwave Conference, 2007. APMC 2007. Asia-Pacific,
pages 1--4,
11-14 Dec. 2007.
@INPROCEEDINGS{Weixian2007, author = {Tan Weixian and Wang Yanping and Hong Wen and Wu Yirong and Li Nanjing and Hu Chufeng and Zhang Linxi}, title = {SAR Three-Dimensional Imaging Experiments with Microwave Anechoic Chamber SAR Data}, booktitle = {Microwave Conference, 2007. APMC 2007. Asia-Pacific}, year = {2007}, pages = {1--4}, month = {11-14 Dec.}, doi = {10.1109/APMC.2007.4555105}, owner = {ofrey}, timestamp = {2009.07.01} } -
Evan C. Zaugg and David G. Long.
Full motion compensation for LFM-CW synthetic aperture radar.
In IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007.,
pages 5198--5201,
23-28 July 2007.
Keywords: SAR Processing, LFM-CW, LFM-CW SAR, MoComp, motion compensation, CSA, ECS, Chirp Scaling, Extended Chirp Scaling, FSA, Frequency Scaling Algorithm, Range-Doppler Algorithm, synthetic aperture radar, Brigham Young University, muSAR system, LFM-CW signal model, SAR image quality, aircraft, atmospheric turbulence, high-resolution synthetic aperture radar systems, linear frequency-modulated continuous-wave signal, motion compensation, motion correction algorithms, unmanned aerial vehicle, Airborne SAR, geophysical techniques,.@INPROCEEDINGS{Zaugg2007, author = {Zaugg, Evan C. and Long, David G.}, title = {{Full motion compensation for LFM-CW synthetic aperture radar}}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2007.}, year = {2007}, pages = {5198--5201}, month = {23-28 July}, doi = {10.1109/IGARSS.2007.4424033}, keywords = {SAR Processing, LFM-CW, LFM-CW SAR, MoComp, motion compensation, CSA, ECS, Chirp Scaling, Extended Chirp Scaling, FSA, Frequency Scaling Algorithm, Range-Doppler Algorithm, synthetic aperture radar, Brigham Young University, muSAR system, LFM-CW signal model, SAR image quality, aircraft, atmospheric turbulence, high-resolution synthetic aperture radar systems, linear frequency-modulated continuous-wave signal, motion compensation, motion correction algorithms, unmanned aerial vehicle, Airborne SAR, geophysical techniques,}, owner = {ofrey} }
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Last modified: Wed Sep 8 19:32:46 2010
Author: Othmar Frey , Remote Sensing Laboratories (RSL), University of Zurich, Switzerland .
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