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Publications of year 1991

Books and proceedings

  1. John C. Curlander and Robert N. McDonough. Synthetic Aperture Radar - Systems and Signal Processing. John Wiley & Sons, New York, 1991. Keyword(s): SAR Processing, Radar Equation, Matched Filter, Pulse Compression, Range Compression Processing, Azimuth Processing, range-Doppler, Clutterlock, Doppler Centroid Estimation, Doppler Centroid, Autofocus, Doppler Ambiguity Resolver, DAR, Doppler Rate Estimation, Azimuth FM Rate, Autofocus Techniques, Radiometric Calibration, Geometric Calibration, Rectangular Algorithm, Deramp Compression, Step Transform Processing, Polar Processing, Fourier Transform, Convolution, Interpolation, Satellite Orbits.
    Abstract: Synthetic Aperture Radar: Systems and Signal Processing specifiecally addresses these items, as applied to the design and implementation of the spaceborne SAR system with a strong emphasis on signal processing techniques. The reader will find that the book has been written with tree key goals. The first is to present a complete picture of SAR from a theoretical perspective by deriving from basic principles the SAR signal processing algorithms. The second goal is to provide some insight into the practical aspects of the sensor and ground system design and implementation. the third is to analyze the system performance given the common error sources and demonstrate their effect on the output image products. This text provieds in a single source the information required both for SAR system design as well as image data analysis. The book serves as an aid for both the radar engineer and the application scientist. The text is generously annotated with figures, plots and images in an effort to make the ideas as accessible as possible. The material is presented such that this text can be used both as an introduction to SAR for new workers in the field and as a reference to the experienced engineer involved in system design and development.
    Comments: ++ Notes 

    @Book{Curlander91:Synthetic,
Title = {{Synthetic Aperture Radar - Systems and Signal Processing}},
Author = {John C. Curlander and Robert N. McDonough},
Publisher = {John Wiley \& Sons},
Year = {1991},
Abstract = {Synthetic Aperture Radar: Systems and Signal Processing specifiecally addresses these items, as applied to the design and implementation of the spaceborne SAR system with a strong emphasis on signal processing techniques. The reader will find that the book has been written with tree key goals. The first is to present a complete picture of SAR from a theoretical perspective by deriving from basic principles the SAR signal processing algorithms. The second goal is to provide some insight into the practical aspects of the sensor and ground system design and implementation. the third is to analyze the system performance given the common error sources and demonstrate their effect on the output image products. This text provieds in a single source the information required both for SAR system design as well as image data analysis. The book serves as an aid for both the radar engineer and the application scientist. The text is generously annotated with figures, plots and images in an effort to make the ideas as accessible as possible. The material is presented such that this text can be used both as an introduction to SAR for new workers in the field and as a reference to the experienced engineer involved in system design and development.},
Address = {New York},
Comments = {++ Notes},
Keyword = {SAR Processing,Radar Equation, Matched Filter, Pulse Compression, Range Compression Processing, Azimuth Processing, range-Doppler, Clutterlock, Doppler Centroid Estimation, Doppler Centroid, Autofocus, Doppler Ambiguity Resolver, DAR, Doppler Rate Estimation, Azimuth FM Rate, Autofocus Techniques, Radiometric Calibration, Geometric Calibration, Rectangular Algorithm, Deramp Compression, Step Transform Processing, Polar Processing, Fourier Transform, Convolution, Interpolation, Satellite Orbits},
Owner = {ofrey} 
}


Articles in journal or book chapters

  1. Richard Bamler. Doppler Frequency Estimation and the Cramer-Rao Bound. IEEE Transactions on Geoscience and Remote Sensing, 29(3):385-390, May 1991. Keyword(s): SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Cramer-Rao Bound, Correlation-Based Estimator, Maximum-Likelihood Estimator, Accuracy Comparison, Clutterlock.
    Abstract: This paper addresses the problem of Doppler frequency estimation in the presence of speckle and receiver noise. An ultimate accuracy bound for Doppler frequency estimation is derived from the Cramer-Rao inequality. It is shown that estimates based on the correlation of the signal power spectra with an arbitrary weighting function are approximately Gaussian-distributed. Their variance is derived in terms of the weighting function. It is shown that a special case of a correlation-based estimator is a maximum-likelihood estimator that reaches the Cramer-Rao bound. These general results are applied to the problem of Doppler centroid estimation from SAR data. Different estimators known from the literature are investigated with respect to their accuracy. Numerical examples are presented and compared with experimental results. 

    @Article{bamler91:Doppler,
Title = {{Doppler Frequency Estimation and the Cramer-Rao Bound}},
Author = {Richard Bamler},
Month = May,
Number = {3},
Pages = {385-390},
Volume = {29},
Year = {1991},
Abstract = {This paper addresses the problem of Doppler frequency estimation in the presence of speckle and receiver noise. An ultimate accuracy bound for Doppler frequency estimation is derived from the Cramer-Rao inequality. It is shown that estimates based on the correlation of the signal power spectra with an arbitrary weighting function are approximately Gaussian-distributed. Their variance is derived in terms of the weighting function. It is shown that a special case of a correlation-based estimator is a maximum-likelihood estimator that reaches the Cramer-Rao bound. These general results are applied to the problem of Doppler centroid estimation from SAR data. Different estimators known from the literature are investigated with respect to their accuracy. Numerical examples are presented and compared with experimental results.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Cramer-Rao Bound, Correlation-Based Estimator, Maximum-Likelihood Estimator, Accuracy Comparison, Clutterlock},
Pdf = {../../../docs/bamler91.pdf} 
}


  2. Richard Bamler and Hartmut Runge. PRF-Ambiguity Resolving by Wavelength Diversity. IEEE Transactions on Geoscience and Remote Sensing, 29(6):997-1003, November 1991. Keyword(s): SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Doppler Ambiguity Resolver, DAR, Wavelength Diversity, Clutterlock.
    Abstract: For high-precision synthetic aperture radar (SAR) processing, the determination of the Doppler centroid is indispensable. The Doppler frequency estimated from azimuth spectra, however, suffers from the fact that the data are sampled with the pulse repetition frequency (PRF) and an ambiguity about the correct PRF band remains. A new algorithm to resolve this ambiguity is proposed. It uses the fact that the Doppler centroid depends linearly on the transmitted radar frequency for a given antenna squint angle. This dependence is not subject to PRF ambiguities. It can be measured by Fourier transforming the SAR data in the range direction and estimating the Doppler centroid at each range frequency. The achievable accuracy is derived theoretically and verified with Seasat data of different scene content. The algorithm works best with low contrast scenes, where the conventional look correlation technique fails. It needs no iterative processing of the SAR data and causes only low computational load. 

    @Article{BamlRunge91:Doppler,
Title = {{PRF-Ambiguity Resolving by Wavelength Diversity}},
Author = {Richard Bamler and Hartmut Runge},
Month = Nov,
Number = {6},
Pages = {997-1003},
Volume = {29},
Year = {1991},
Abstract = {For high-precision synthetic aperture radar (SAR) processing, the determination of the Doppler centroid is indispensable. The Doppler frequency estimated from azimuth spectra, however, suffers from the fact that the data are sampled with the pulse repetition frequency (PRF) and an ambiguity about the correct PRF band remains. A new algorithm to resolve this ambiguity is proposed. It uses the fact that the Doppler centroid depends linearly on the transmitted radar frequency for a given antenna squint angle. This dependence is not subject to PRF ambiguities. It can be measured by Fourier transforming the SAR data in the range direction and estimating the Doppler centroid at each range frequency. The achievable accuracy is derived theoretically and verified with Seasat data of different scene content. The algorithm works best with low contrast scenes, where the conventional look correlation technique fails. It needs no iterative processing of the SAR data and causes only low computational load.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Doppler Ambiguity Resolver, DAR, Wavelength Diversity, Clutterlock},
Pdf = {../../../docs/bamlerRunge91.pdf} 
}


  3. Stefan Buckreuss. Motion errors in an airborne synthetic aperture radar system. European Transactions on Telecommunications, 2(6):655-664, 1991. Keyword(s): SAR Processing, Airborne SAR, Motion Compensation, MoComp, motion errors.
    Abstract: Abstract The Institute for Radio Frequency Technology of the German Aerospace Research Establishment (DLR) in Oberpfaffenhofen operates an experimental synthetic aperture radar, E-SAR. The Radar configuration was developed by DLR [1, 2] and consists of a L/C/X-band SAR System and antennas with a wide beamwidth in azimuth and elevation. The system is installed in a small Dornier DO 228 aircraft, which operates at low altitudes between 1000 m - 3000 m above ground. Due to atmospheric turbulences, the aircraft is displaced from its nominal flight path, causing a variation of the phase history of the returned radar signal. This eventually results in a degraded image quality and therefore a highly accurate motion compensation becomes necessary. It is intended to integrate an inertial measurement unit (IMU) within the E-SAR system to support the used motion compensation algorithm during data processing [3]. The required relative accuracy of the IMU can be determined by means of statistics i.e. an approach is demonstrated to estimate the power spectral density (PSD) of the tolerable uncompensated aircraft motion. The performance of an IMU motion compensation system has been evaluated by analysis, as well as by computer simulation. 

    @Article{buckreussEToT1991MotionErrorsInAirborneSAR,
author = {Buckreuss, Stefan},
journal = {European Transactions on Telecommunications},
title = {Motion errors in an airborne synthetic aperture radar system},
year = {1991},
number = {6},
pages = {655-664},
volume = {2},
abstract = {Abstract The Institute for Radio Frequency Technology of the German Aerospace Research Establishment (DLR) in Oberpfaffenhofen operates an experimental synthetic aperture radar, E-SAR. The Radar configuration was developed by DLR [1, 2] and consists of a L/C/X-band SAR System and antennas with a wide beamwidth in azimuth and elevation. The system is installed in a small Dornier DO 228 aircraft, which operates at low altitudes between 1000 m - 3000 m above ground. Due to atmospheric turbulences, the aircraft is displaced from its nominal flight path, causing a variation of the phase history of the returned radar signal. This eventually results in a degraded image quality and therefore a highly accurate motion compensation becomes necessary. It is intended to integrate an inertial measurement unit (IMU) within the E-SAR system to support the used motion compensation algorithm during data processing [3]. The required relative accuracy of the IMU can be determined by means of statistics i.e. an approach is demonstrated to estimate the power spectral density (PSD) of the tolerable uncompensated aircraft motion. The performance of an IMU motion compensation system has been evaluated by analysis, as well as by computer simulation.},
doi = {https://doi.org/10.1002/ett.4460020609},
keywords = {SAR Processing, Airborne SAR, Motion Compensation, MoComp, motion errors},
owner = {ofrey},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ett.4460020609},

}


  4. Ciro Cafforio, Claudio Prati, and Fabio Rocca. SAR Data Focusing Using Seismic Migration Techniques. IEEE Transactions on Aerospace and Electronic Systems, 27(2):194-207, March 1991. Keyword(s): SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Stationary Phase Method.
    Abstract: The focusing of synthetic-aperture-radar (SAR) data using migration techniques quite similar to those used in geophysics is treated. The algorithm presented works in the omega-kx domain. Because time delays can be easily accommodated with phase shifts that increase linearly with omega, range migration poses no problem. The algorithm is described in plane geometry first, where range migration and phase history can be exactly matched. The effects of the sphericity of the Earth, of the Earth's rotation, and of the satellite trajectory curvature are taken into account, showing that the theoretically achievable spatial resolution is well within the requirements of present day and near future SAR missions. Terrestrial swaths as wide as 100 km can be focused simultaneously with no serious degradation. The algorithm has been tested with synthetic data, with Seasat-A data, and with airplane data (NASA-AIR). The experimental results fully support the theoretical analysis. 

    @Article{cafforio:rangemigr,
Title = {{SAR Data Focusing Using Seismic Migration Techniques}},
Author = {Ciro Cafforio and Claudio Prati and Fabio Rocca},
Month = mar,
Number = {2},
Pages = {194-207},
Url = {http://ieeexplore.ieee.org/iel4/7/2582/00078293.pdf},
Volume = {27},
Year = {1991},
Abstract = {The focusing of synthetic-aperture-radar (SAR) data using migration techniques quite similar to those used in geophysics is treated. The algorithm presented works in the omega-kx domain. Because time delays can be easily accommodated with phase shifts that increase linearly with omega, range migration poses no problem. The algorithm is described in plane geometry first, where range migration and phase history can be exactly matched. The effects of the sphericity of the Earth, of the Earth's rotation, and of the satellite trajectory curvature are taken into account, showing that the theoretically achievable spatial resolution is well within the requirements of present day and near future SAR missions. Terrestrial swaths as wide as 100 km can be focused simultaneously with no serious degradation. The algorithm has been tested with synthetic data, with Seasat-A data, and with airplane data (NASA-AIR). The experimental results fully support the theoretical analysis.},
Journal = {IEEE Transactions on Aerospace and Electronic Systems},
Keywords = {SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Stationary Phase Method},
Pdf = {../../../docs/cafforio91.pdf} 
}


  5. Charles Elachi, Eastwood Im, Ladislav E. Roth, and Charles L. Werner. Cassini Titan Radar Mapper. Proceedings of the IEEE, 79(6):867-880, June 1991. Keyword(s): SAR Processing, Cassini Radar, Saturn, astronomical instruments, planetary satellites, radar applications, radioastronomy, space vehicles, Cassini Saturn Mission, Cassini Titan Radar Mapper, Titan, antenna configuration, design constraints, multimode radar, radar modes, surface imaging, topographic mapping, Instruments, Laser radar, Moon, Optical design, Payloads, Probes, Radar antennas, Radar imaging, Saturn, Surface topography.
    Abstract: The Cassini Titan Radar Mapper is a multimode radar instrument designed to probe the optically inaccessible surface of Titan, Saturn's largest moon. The instrument is to be included in the payload of the Cassini Saturn Mission, scheduled for launch in 1995. The individual modes of Cassini Radar Mapper will allow topographic mapping and surface imaging at few hundred meters resolution. The requirements that lay behind the design are briefly discussed, and the configuration and capability of the instrument are described. The present limited knowledge of Titan's surface and the measurement requirements imposed on the radar instrument are addressed. Also discussed are the Cassini mission and the projected orbits, which imposed another set of design constraints that led to the multitude of modes and to an unconventional antenna configuration. The antenna configuration and the different radar modes are described 

    @Article{elachiImRothWernerProcIEEE1991CassiniRadarTitanMapper,
author = {Elachi, Charles and Im, Eastwood and Roth, Ladislav E. and Werner, Charles L.},
title = {Cassini Titan Radar Mapper},
journal = {Proceedings of the IEEE},
year = {1991},
volume = {79},
number = {6},
pages = {867-880},
month = jun,
issn = {0018-9219},
abstract = {The Cassini Titan Radar Mapper is a multimode radar instrument designed to probe the optically inaccessible surface of Titan, Saturn's largest moon. The instrument is to be included in the payload of the Cassini Saturn Mission, scheduled for launch in 1995. The individual modes of Cassini Radar Mapper will allow topographic mapping and surface imaging at few hundred meters resolution. The requirements that lay behind the design are briefly discussed, and the configuration and capability of the instrument are described. The present limited knowledge of Titan's surface and the measurement requirements imposed on the radar instrument are addressed. Also discussed are the Cassini mission and the projected orbits, which imposed another set of design constraints that led to the multitude of modes and to an unconventional antenna configuration. The antenna configuration and the different radar modes are described},
doi = {10.1109/5.90164},
file = {:elachiImRothWernerProcIEEE1991CassiniRadarTitanMapper.pdf:PDF},
keywords = {SAR Processing, Cassini Radar, Saturn;astronomical instruments;planetary satellites;radar applications;radioastronomy;space vehicles;Cassini Saturn Mission;Cassini Titan Radar Mapper;Titan;antenna configuration;design constraints;multimode radar;radar modes;surface imaging;topographic mapping;Instruments;Laser radar;Moon;Optical design;Payloads;Probes;Radar antennas;Radar imaging;Saturn;Surface topography},
owner = {ofrey},
pdf = {../../../docs/elachiImRothWernerProcIEEE1991CassiniRadarTitanMapper.pdf},

}


  6. J.W. McCoy, N. Magotra, and B.K. Chang. Coherent Doppler tomography---a technique for narrow band SAR. IEEE Aerospace and Electronic Systems Magazine, 6(2):19-22, February 1991. Keyword(s): SAR Processing, SAR Tomography, Tomography, coherent Doppler tomography, coherent processing, computational overhead, high-resolution global mapping, imaging, multiple discrete frequencies, narrow band SAR, narrowband synthetic aperture radar, noncoherent subaperture processing, point spread function, radar platform, satellite geometry configuration, sidelobe level, simulation, single-frequency signal, spaceborne applications, Doppler effect, aerospace computing, aerospace instrumentation, computerised picture processing, digital simulation, radar theory;.
    Abstract: Some concerns regarding a technique of narrowband synthetic aperture radar (N-SAR) imaging called coherent Doppler tomography (CDT), which may be a good candidate for spaceborne applications, are addressed. Using a single-frequency signal, are addressed. Using a single-frequency signal, resolution of two tenths of a wavelength can be achieved in the point spread function if the radar platform circles the ground path to be imaged. However, the high sidelobe level of -8-dB in the point spread function results in an unacceptable dynamic range. To reduce the sidelobe level, two approaches are presented: coherent processing using multiple discrete frequencies and noncoherent subaperture processing. Simulation results demonstrate that the sidelobe level is substantially reduced by both methods. However, the resolution is degraded and the computational overhead is greatly increased for noncoherent subaperture processing. Also presented is a possible satellite geometry configuration that could utilize N-SAR processing to provide high-resolution global mapping capability.<> 

    @Article{67844,
author = {McCoy, J.W. and Magotra, N. and Chang, B.K.},
journal = {IEEE Aerospace and Electronic Systems Magazine},
title = {Coherent {D}oppler tomography---a technique for narrow band {SAR}},
year = {1991},
issn = {0885-8985},
month = feb,
number = {2},
pages = {19-22},
volume = {6},
abstract = {Some concerns regarding a technique of narrowband synthetic aperture radar (N-SAR) imaging called coherent Doppler tomography (CDT), which may be a good candidate for spaceborne applications, are addressed. Using a single-frequency signal, are addressed. Using a single-frequency signal, resolution of two tenths of a wavelength can be achieved in the point spread function if the radar platform circles the ground path to be imaged. However, the high sidelobe level of -8-dB in the point spread function results in an unacceptable dynamic range. To reduce the sidelobe level, two approaches are presented: coherent processing using multiple discrete frequencies and noncoherent subaperture processing. Simulation results demonstrate that the sidelobe level is substantially reduced by both methods. However, the resolution is degraded and the computational overhead is greatly increased for noncoherent subaperture processing. Also presented is a possible satellite geometry configuration that could utilize N-SAR processing to provide high-resolution global mapping capability.<>},
doi = {10.1109/62.67844},
keywords = {SAR Processing, SAR Tomography, Tomography, coherent Doppler tomography;coherent processing;computational overhead;high-resolution global mapping;imaging;multiple discrete frequencies;narrow band SAR;narrowband synthetic aperture radar;noncoherent subaperture processing;point spread function;radar platform;satellite geometry configuration;sidelobe level;simulation;single-frequency signal;spaceborne applications;Doppler effect;aerospace computing;aerospace instrumentation;computerised picture processing;digital simulation;radar theory;},

}


  7. Claudio Prati, Fabio Rocca, Yuval Kost, and Elvio Damonti. Blind Deconvolution for Doppler Centroid Estimation in High Frequency SAR. IEEE Transactions on Geoscience and Remote Sensing, 29(6):934-941, November 1991. Keyword(s): SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Doppler Ambiguity Resolver, DAR, Clutterlock.
    Abstract: For high quality SAR processing, the Doppler centroid frequency is needed. However, SAR data are sampled along the azimuth direction at the Pulse Repetition Frequency (PRF); the estimation of the Doppler centroid frequency by means of spectral analysis techniques may produce ambiguous results due to aliases. The mathematical expression of the residual error that occurs when SAR data are focused with an incorrect alias of the PRF is thus derived. Then, a blind deconvolution technique is used to estimate the actual PRF replica from the focused image. Squinted X-band data, corresponding to those that will be generated by the SIR-C mission, have benn generated from the JPL-AirSAR L and C band data by means of an inversion of the focusing process. Even if the real data may show differences with respect to the simulated data, the blind deconvolution method appears to be more precise and robust than the other conventional techniques tested. 

    @Article{pratRocKosDam:DopCentrEstim,
Title = {{Blind Deconvolution for Doppler Centroid Estimation in High Frequency SAR}},
Author = {Claudio Prati and Fabio Rocca and Yuval Kost and Elvio Damonti},
Month = Nov,
Number = {6},
Pages = {934-941},
Volume = {29},
Year = {1991},
Abstract = {For high quality SAR processing, the Doppler centroid frequency is needed. However, SAR data are sampled along the azimuth direction at the Pulse Repetition Frequency (PRF); the estimation of the Doppler centroid frequency by means of spectral analysis techniques may produce ambiguous results due to aliases. The mathematical expression of the residual error that occurs when SAR data are focused with an incorrect alias of the PRF is thus derived. Then, a blind deconvolution technique is used to estimate the actual PRF replica from the focused image. Squinted X-band data, corresponding to those that will be generated by the SIR-C mission, have benn generated from the JPL-AirSAR L and C band data by means of an inversion of the focusing process. Even if the real data may show differences with respect to the simulated data, the blind deconvolution method appears to be more precise and robust than the other conventional techniques tested.},
Comment = {+ Description of Doppler centroid/ambiguity estimation from raw data.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Doppler Ambiguity Resolver, DAR, Clutterlock},
Pdf = {../../../docs/PratiRoccaKostDam91.pdf} 
}


  8. A. M. Smith. A new approach to range-Doppler SAR processing. International Journal of Remote Sensing, 12(2):235-251, 1991. Keyword(s): SAR Processing, Range-Doppler Algorithm, RDA, Azimuth Focusing, Spaceborne SAR, Ambiguity Analysis, Stripmap Mode.
    Abstract: In this paper we present a general analysis of frequency domain SAR processing based on the relationship between the phase of the two-dimensional Fourier transform of a point response to its range-time history. The paper demonstrates how this provides an appropriate basis for the design of a coherent strip-mode processor, free of geometric or phase distortion and artefacts and without excessive computational cost. In consequence the paper is highly relevant to the real-time, precision, processing of SAR data. The paper comments on the relevance of the analysis to ambiguity estimation and the processing of very long integration time SAR data. 

    @Article{smith1991,
author = {Smith, A. M.},
title = {A new approach to range-{Doppler} {SAR} processing},
journal = {International Journal of Remote Sensing},
year = {1991},
volume = {12},
number = {2},
pages = {235-251},
abstract = {In this paper we present a general analysis of frequency domain SAR processing based on the relationship between the phase of the two-dimensional Fourier transform of a point response to its range-time history. The paper demonstrates how this provides an appropriate basis for the design of a coherent strip-mode processor, free of geometric or phase distortion and artefacts and without excessive computational cost. In consequence the paper is highly relevant to the real-time, precision, processing of SAR data. The paper comments on the relevance of the analysis to ambiguity estimation and the processing of very long integration time SAR data.},
doi = {10.1080/01431169108929650},
file = {:smith1991.pdf:PDF},
keywords = {SAR Processing, Range-Doppler Algorithm, RDA, Azimuth Focusing, Spaceborne SAR, Ambiguity Analysis, Stripmap Mode},
pdf = {../../../docs/smith1991.pdf},
url = {http://www.tandfonline.com/doi/abs/10.1080/01431169108929650},

}


  9. Lars M. H. Ulander. Accuracy of Using Point Targets for SAR Calibration. IEEE Transactions on Aerospace and Electronic Systems, 27(1):139-148, January 1991. Keyword(s): SAR Processing, Radiometric Calibration, calibration, measurement errors, radar, radiometry, remote sensing by radar, RMS errors, SAR calibration, equivalent rectangle system resolution, impulse response, integral method, nonlinear phase errors, reference point targets, synthetic aperture radar, system focus.
    Abstract: The peak and integral methods for radiometric calibration of a synthetic aperture radar (SAR) using reference point targets are analyzed. Both calibration methods are shown to be unbiased, but the peak method requires knowledge of the equivalent rectangle system resolution which is sensitive to system focus. Exact expressions for the RMS errors of both methods are derived. It is shown that the RMS error resulting from the peak method is always smaller than or equal to that from the integral method for a well-focused system. However, for robust radiometric calibration of SAR, or when nonlinear phase errors are present, the integral method is recommended, because it does not require detailed knowledge of the impulse response and the resulting RMS error is not dependent on system focus. 

    @Article{ulander1991:MoCoCalibration,
author = {Ulander, Lars M. H.},
title = {{Accuracy of Using Point Targets for SAR Calibration}},
journal = {IEEE Transactions on Aerospace and Electronic Systems},
year = {1991},
volume = {27},
number = {1},
pages = {139-148},
month = {Jan},
issn = {0018-9251},
abstract = {The peak and integral methods for radiometric calibration of a synthetic aperture radar (SAR) using reference point targets are analyzed. Both calibration methods are shown to be unbiased, but the peak method requires knowledge of the equivalent rectangle system resolution which is sensitive to system focus. Exact expressions for the RMS errors of both methods are derived. It is shown that the RMS error resulting from the peak method is always smaller than or equal to that from the integral method for a well-focused system. However, for robust radiometric calibration of SAR, or when nonlinear phase errors are present, the integral method is recommended, because it does not require detailed knowledge of the impulse response and the resulting RMS error is not dependent on system focus.},
doi = {10.1109/7.68156},
file = {:ulander1991.pdf:PDF},
keywords = {SAR Processing, Radiometric Calibration, calibration, measurement errors, radar, radiometry, remote sensing by radar, RMS errors, SAR calibration, equivalent rectangle system resolution, impulse response, integral method, nonlinear phase errors, reference point targets, synthetic aperture radar, system focus},
pdf = {../../../docs/ulander1991.pdf},
url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=68156&isnumber=2418},

}


  10. Michael W. Whitt, Fawwaz T. Ulaby, Paul Polatin, and Valdis V. Liepa. A general polarimetric radar calibration technique. IEEE Transactions on Antennas and Propagation, 39(1):62-67, January 1991. Keyword(s): Polarimetric Calibration, calibration, polarimetry, radar systems, distortion matrices, general polarimetric radar calibration technique, received waves, scattering matrices, single-antenna radar, transmitted waves, Calibration, Distortion measurement, Layout, Phase measurement, Polarization, Radar antennas, Radar imaging, Radar measurements, Radar polarimetry, Radar scattering.
    Abstract: A polarimetric radar calibration procedure is introduced and verified with experimental results. The procedure requires measurements of three known targets in order to determine the distortion matrices that characterize the effect of the measurement system on the transmitted and received waves. The scattering matrices for the known targets can be of any form, provided that a limited set of constraints is satisfied. A special case, wherein the transmit and receive distortion matrices are the transpose of each other, is considered. This case is useful for some single antenna systems and has the advantage that only two known targets are required 

    @Article{whittUlabyPolatinLiepaTAP1991PolarimetricCalibration,
author = {Michael W. Whitt and Fawwaz T. Ulaby and Paul Polatin and Valdis V. Liepa},
title = {A general polarimetric radar calibration technique},
journal = {IEEE Transactions on Antennas and Propagation},
year = {1991},
volume = {39},
number = {1},
pages = {62-67},
month = jan,
issn = {0018-926X},
abstract = {A polarimetric radar calibration procedure is introduced and verified with experimental results. The procedure requires measurements of three known targets in order to determine the distortion matrices that characterize the effect of the measurement system on the transmitted and received waves. The scattering matrices for the known targets can be of any form, provided that a limited set of constraints is satisfied. A special case, wherein the transmit and receive distortion matrices are the transpose of each other, is considered. This case is useful for some single antenna systems and has the advantage that only two known targets are required},
doi = {10.1109/8.64436},
file = {:whittUlabyPolatinLiepaTAP1991PolarimetricCalibration.pdf:PDF},
keywords = {Polarimetric Calibration, calibration;polarimetry;radar systems;distortion matrices;general polarimetric radar calibration technique;received waves;scattering matrices;single-antenna radar;transmitted waves;Calibration;Distortion measurement;Layout;Phase measurement;Polarization;Radar antennas;Radar imaging;Radar measurements;Radar polarimetry;Radar scattering},
owner = {ofrey},
pdf = {../../../docs/whittUlabyPolatinLiepaTAP1991PolarimetricCalibration.pdf},

}


Conference articles

  1. Richard Bamler. A Systematic Comparison of SAR Focussing Algorithms. In IGARSS '91, International Geoscience and Remote Sensing Symposium, volume 2, pages 1005-1009, 1991. Keyword(s): SAR Processing, Range-Doppler Algorithm, Wavenumber Domain Algorithm, omega-k, Secondary Range Compression, Comparison of Algorithms.
    Abstract: Focussing of SAR data is an inherently space-variant two-dimensional correlation. Six different algorithms are compared with each other in terms of their focussing quality and their ability to handle the space-variance of the correlation kernel: range-Doppler with and without secondary range compression, a modified range-Doppler algorithm, and three versions of the wavenumber domain processor. Quantitative examples are given for SEASAT and ERS-1. 

    @InProceedings{bamler:compare,
Title = {{A Systematic Comparison of SAR Focussing Algorithms}},
Author = {Richard Bamler},
Booktitle = {IGARSS '91, International Geoscience and Remote Sensing Symposium},
Pages = {1005-1009},
Url = {http://ieeexplore.ieee.org/iel2/528/12537/00580289.pdf},
Volume = {2},
Year = {1991},
Abstract = {Focussing of SAR data is an inherently space-variant two-dimensional correlation. Six different algorithms are compared with each other in terms of their focussing quality and their ability to handle the space-variance of the correlation kernel: range-Doppler with and without secondary range compression, a modified range-Doppler algorithm, and three versions of the wavenumber domain processor. Quantitative examples are given for SEASAT and ERS-1.},
Keywords = {SAR Processing, Range-Doppler Algorithm, Wavenumber Domain Algorithm, omega-k, Secondary Range Compression, Comparison of Algorithms},
Pdf = {../../../docs/bamler_igarss91.pdf} 
}


  2. Terry M. Calloway, Charles V. Jakowatz, Paul A. Thompson, and Paul H. Eichel. Comparison of synthetic-aperture radar autofocus techniques: phase gradient versus subaperture. In Franklin T. Luk, editor, , volume 1566, pages 353-364, 1991. SPIE. Keyword(s): SAR Processing, Autofocus, Comparison of Algorithms, Comparison of Autofocus Algorithms, Phase Gradient Algorithm, PGA, Subaperture-based Autofocus, subaperture correlation, look-misregistration autofocus, Map Drift. 
    @Conference{callowayJakowatzThompsonEichelAutofocusComparisonPGASubaperture1991,
author = {Terry M. Calloway and Charles V. Jakowatz, Jr. and Paul A. Thompson and Paul H. Eichel},
title = {Comparison of synthetic-aperture radar autofocus techniques: phase gradient versus subaperture},
year = {1991},
editor = {Franklin T. Luk},
volume = {1566},
number = {1},
pages = {353-364},
publisher = {SPIE},
doi = {10.1117/12.49837},
file = {:callowayJakowatzThompsonEichelAutofocusComparisonPGASubaperture1991.pdf:PDF},
journal = {Advanced Signal Processing Algorithms, Architectures, and Implementations II},
keywords = {SAR Processing, Autofocus, Comparison of Algorithms, Comparison of Autofocus Algorithms, Phase Gradient Algorithm, PGA, Subaperture-based Autofocus, subaperture correlation, look-misregistration autofocus, Map Drift},
location = {San Diego, CA, USA},
owner = {ofrey},
pdf = {../../../docs/callowayJakowatzThompsonEichelAutofocusComparisonPGASubaperture1991.pdf},
url = {http://link.aip.org/link/?PSI/1566/353/1},

}


  3. M. Cocard, A. Geiger, E. Meier, and D. Nuesch. X-SAR Geometric Error Budget Analysis. In Proc. IEEE Int. Geosci. Remote Sens. Symp., volume I, pages 247-251, 1991. 
    @InProceedings{cocardGeigerMeierNuesch91:XSARGEBA,
author = {Cocard, M. and Geiger, A. and Meier, E. and Nuesch, D.},
title = {X-{SAR} Geometric Error Budget Analysis},
booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
year = {1991},
volume = {I},
pages = {247--251},
owner = {ofrey},
timestamp = {2007.10.18},

}


  4. Jorgen Dall. A new frequency domain autofocus algorithm for SAR. In IGARSS '91, Geoscience and Remote Sensing Symposium, volume 2, pages 1069 - 1072, 1991. Keyword(s): SAR Processing, Autofocus, SAC, Shift and Correlate Algorithm, Doppler Rate Estimation, Map Drift, Airborne SAR.
    Abstract: A new autofocus algorithm with a very high computational efficiency is presented. Although based on a completely different principle, this 'shift-and-correlate' algorithm has some similarity with the traditional map drift algorithm. Theory and preliminary tests indicate that the two algorithms have comparable accuracies. However, with the new algorithm the number of arithmetic operations is reduced by a factor of about 50. This, in combination with its non-iterative nature, makes it very suitable for real-time processing. 

    @InProceedings{dall91:Autofocus,
author = {Jorgen Dall},
booktitle = {IGARSS '91, Geoscience and Remote Sensing Symposium},
title = {A new frequency domain autofocus algorithm for SAR},
year = {1991},
pages = {1069 -- 1072},
volume = {2},
abstract = {A new autofocus algorithm with a very high computational efficiency is presented. Although based on a completely different principle, this 'shift-and-correlate' algorithm has some similarity with the traditional map drift algorithm. Theory and preliminary tests indicate that the two algorithms have comparable accuracies. However, with the new algorithm the number of arithmetic operations is reduced by a factor of about 50. This, in combination with its non-iterative nature, makes it very suitable for real-time processing.},
keywords = {SAR Processing, Autofocus, SAC, Shift and Correlate Algorithm, Doppler Rate Estimation, Map Drift, Airborne SAR},
owner = {ofrey},
pdf = {../../../docs/dall91.pdf},
url = {http://ieeexplore.ieee.org/iel2/528/12537/00580305.pdf},

}


  5. Tapan Misra and Alberto Moreira. A New Method For Generation Of Optimum Matched Filter From Replica Data For Pulse Compression. In Geoscience and Remote Sensing Symposium, 1991. IGARSS '91. 'Remote Sensing: Global Monitoring for Earth Management'., International, volume 2, pages 1011-1014, 1991. Keyword(s): SAR Processing, Range Compression, Pulse Compression, Matched Filter, Replica, Chirp Replica, Optimum Matched Filter. 
    @InProceedings{misraMoreira91:OptimMatchedFilt,
Title = {A New Method For Generation Of Optimum Matched Filter From Replica Data For Pulse Compression},
Author = {Misra, Tapan and Moreira, Alberto},
Booktitle = {Geoscience and Remote Sensing Symposium, 1991. IGARSS '91. 'Remote Sensing: Global Monitoring for Earth Management'., International},
Pages = {1011--1014},
Url = {http://ieeexplore.ieee.org/iel2/528/12537/00580291.pdf},
Volume = {2},
Year = {1991},
Keywords = {SAR Processing, Range Compression, Pulse Compression, Matched Filter, Replica, Chirp Replica, Optimum Matched Filter},
Owner = {ofrey},
Pdf = {../../../docs/misraMoreira91.pdf} 
}


  6. T.E. Scheuer and Frank Wong. Comparison of SAR Processors Based on a Wave Equation Formulation. In IGARSS '91, International Geoscience and Remote Sensing Symposium, volume 2, pages 635-639, June 1991. Keyword(s): SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Range-Doppler Algorithm, Comparison of Algorithms.
    Abstract: In this paper, we utilize a wave equation framework to describe SAR processing. Within this framework, various conventional and new processing techniques can be reliably compared. In particular, we compare wave equation implementations of the conventional range-Doppler algorithm and the seismic/SAR algorithm recently proposed. The range-Doppler algorithm is a matched filter solution of the Kirchhoff integral in range-time and Doppler-wavenumber space, while the seismic/SAR algorithm is a frequency-wavenumber or plane wave solution to the wave equation using the measured data as a boundary condition. Thus, both processors can be viewed as boundary value solutions to the electromagnetic wave equation. Point spread function analysis, of simulated ERS-1 data and of actual SEASAT data, shows that both processors provide very accurate relative amplitude and phase results. Nevertheless, we expect that future SAR processors may incorporate features of both techniques. 

    @InProceedings{ScheuerWong91:Comparison,
Title = {{Comparison of SAR Processors Based on a Wave Equation Formulation}},
Author = {T.E. Scheuer and Frank Wong},
Booktitle = {IGARSS '91, International Geoscience and Remote Sensing Symposium},
Month = Jun,
Pages = {635-639},
Url = {http://ieeexplore.ieee.org/iel2/528/12537/00579968.pdf},
Volume = {2},
Year = {1991},
Abstract = {In this paper, we utilize a wave equation framework to describe SAR processing. Within this framework, various conventional and new processing techniques can be reliably compared. In particular, we compare wave equation implementations of the conventional range-Doppler algorithm and the seismic/SAR algorithm recently proposed. The range-Doppler algorithm is a matched filter solution of the Kirchhoff integral in range-time and Doppler-wavenumber space, while the seismic/SAR algorithm is a frequency-wavenumber or plane wave solution to the wave equation using the measured data as a boundary condition. Thus, both processors can be viewed as boundary value solutions to the electromagnetic wave equation. Point spread function analysis, of simulated ERS-1 data and of actual SEASAT data, shows that both processors provide very accurate relative amplitude and phase results. Nevertheless, we expect that future SAR processors may incorporate features of both techniques.},
Keywords = {SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm, Range-Doppler Algorithm, Comparison of Algorithms},
Pdf = {../../../docs/ScheuerWong91.pdf} 
}


  7. Carmine Tarantino. Comparison Between Different Doppler Centroid Estimation Methods For Spaceborne SAR Processing. In Geoscience and Remote Sensing Symposium, 1991. IGARSS '91. 'Remote Sensing: Global Monitoring for Earth Management'., International, volume 2, pages 1047-1049, 1991. Keyword(s): SAR Processing, Doppler Centroid Estimation, Spectra Correlation Estimator, SIR-B.
    Abstract: High accuracy estimation of Doppler centroid values is an important input for precision SAR processing. This paper describes the resutls of the numberical comparison between two different algorithms for Doppler centroid estimation. The Spectra Correlation Estimator and the Clutterlock Algorithm Estimator are tested by processing real SIR-B SAR data. The comparison of these two algorithms according to the required accuracy, the scene type and the processing time is proposed and results are analyzed. Test resutls indicate that an estimation accuracy of a few Hz is obtained. 

    @InProceedings{tarantino91:dopCen,
Title = {Comparison Between Different Doppler Centroid Estimation Methods For Spaceborne SAR Processing},
Author = {Tarantino, Carmine},
Booktitle = {Geoscience and Remote Sensing Symposium, 1991. IGARSS '91. 'Remote Sensing: Global Monitoring for Earth Management'., International},
Pages = {1047--1049},
Url = {http://ieeexplore.ieee.org/iel2/528/12537/00580300.pdf},
Volume = {2},
Year = {1991},
Abstract = {High accuracy estimation of Doppler centroid values is an important input for precision SAR processing. This paper describes the resutls of the numberical comparison between two different algorithms for Doppler centroid estimation. The Spectra Correlation Estimator and the Clutterlock Algorithm Estimator are tested by processing real SIR-B SAR data. The comparison of these two algorithms according to the required accuracy, the scene type and the processing time is proposed and results are analyzed. Test resutls indicate that an estimation accuracy of a few Hz is obtained.},
Keywords = {SAR Processing, Doppler Centroid Estimation, Spectra Correlation Estimator, SIR-B},
Owner = {ofrey},
Pdf = {../../../docs/tarantino91.pdf} 
}


  8. Daniel E. Wahl, Charles V. Jakowatz, Dennis C. Ghiglia, and Paul H. Eichel. Relationships between autofocus methods for SAR and self-survey techniques for SONAR. In Andrew G. Tescher, editor, , volume 1567, pages 32-40, 1991. SPIE. Keyword(s): SAR Processing, Autofocus, Phase Gradient Algorithm, PGA, Subaperture-based Autofocus, subaperture correlation, look-misregistration autofocus, Map Drift, SONAR. 
    @Conference{wahlJakowatzGhiliaEichelAutofocusSARandSONAR1991,
author = {Daniel E. Wahl and Charles V. Jakowatz, Jr. and Dennis C. Ghiglia and Paul H. Eichel},
title = {Relationships between autofocus methods for SAR and self-survey techniques for SONAR},
year = {1991},
editor = {Andrew G. Tescher},
volume = {1567},
number = {1},
pages = {32-40},
publisher = {SPIE},
doi = {10.1117/12.50862},
file = {:wahlJakowatzGhiliaEichelAutofocusSARandSONAR1991.pdf:PDF},
journal = {Applications of Digital Image Processing XIV},
keywords = {SAR Processing, Autofocus, Phase Gradient Algorithm, PGA, Subaperture-based Autofocus, subaperture correlation, look-misregistration autofocus, Map Drift, SONAR},
location = {San Diego, CA, USA},
owner = {ofrey},
pdf = {../../../docs/wahlJakowatzGhiliaEichelAutofocusSARandSONAR1991.pdf},
url = {http://link.aip.org/link/?PSI/1567/32/1},

}


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Please note that access to full text PDF versions of papers is restricted to the Chair of Earth Observation and Remote Sensing, Institute of Environmental Engineering, ETH Zurich.
Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright.

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: Fri Feb 24 14:22:26 2023
Author: Othmar Frey, Earth Observation and Remote Sensing, Institute of Environmental Engineering, Swiss Federal Institute of Technology - ETH Zurich .

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