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Publications of year 1992
Articles in journal or book chapters

Richard Bamler.
A Comparison of RangeDoppler and Wavenumber Domain SAR Focusing Algorithms.
IEEE Transactions on Geoscience and Remote Sensing,
30(4):706713,
July 1992.
Keyword(s): SAR Processing,
RangeDoppler Algorithm,
Range Migration Algorithm,
omegak,
Wavenumber Domain Algorithm,
Secondary Range Compression,
Comparison of Algorithms.
Abstract: 
Focusing of SAR data requires a spacevariant twodimensional correlation. Different algorithms are compared with each other in terms of their focusing quality and their ability to handle the spacevariance of the correlation kernel: the rangeDoppler approach with and without secondary range compression, modified rangeDoppler algorithms, and four versions of the wavenumber domain processor. The phase aberrations of the different algorithms are given in analytic form. Numerical examples are presented for Seasat and ERS1. A novel systems theoretical derivation of the wavenumber domain algorithm is presented. 
@Article{bamler92:Comparison,
Title = {{A Comparison of RangeDoppler and Wavenumber Domain SAR Focusing Algorithms}},
Author = {Richard Bamler},
Month = Jul,
Number = {4},
Pages = {706713},
Volume = {30},
Year = {1992},
Abstract = {Focusing of SAR data requires a spacevariant twodimensional correlation. Different algorithms are compared with each other in terms of their focusing quality and their ability to handle the spacevariance of the correlation kernel: the rangeDoppler approach with and without secondary range compression, modified rangeDoppler algorithms, and four versions of the wavenumber domain processor. The phase aberrations of the different algorithms are given in analytic form. Numerical examples are presented for Seasat and ERS1. A novel systems theoretical derivation of the wavenumber domain algorithm is presented.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, RangeDoppler Algorithm, Range Migration Algorithm, omegak, Wavenumber Domain Algorithm, Secondary Range Compression, Comparison of Algorithms},
Pdf = {../../../docs/bamlertgars92.pdf}
}

C. Y. Chang and John C. Curlander.
Application of the Multiple PRF Technique to Resolve Doppler Centroid Estimation Ambiguity for Spaceborne SAR.
IEEE Transactions on Geoscience and Remote Sensing,
30(5):941949,
September 1992.
Keyword(s): SAR Processing,
Doppler Centroid,
Doppler Centroid Estimation,
Multiple PRF Technique,
Range CrossCorrelation Technique,
Clutterlock,
SIRC.
Abstract: 
Estimation of the Doppler centroid ambiguity is a necessary element of the signal processing for synthetic aperture radar (SAR) systems with large antenna pointing errors. Without proper resolution of the Doppler centroid estimation (DCE) ambiguity, the image quality will be degraded in the system impulse response function and the geometric fidelity. Two techniques for resolution of DCE ambiguity for the spaceborne SAR are presented in this paper. They include a brief review of the range crosscorrelation technique and presentation of a new technique using multiple pulse repetition frequencies (PRFs). We formulate an algorithm employing simple integer arithmetic for radar systems, such as moving target indicator radar (MTIR) systems, where the PRFs contain a large common divisor. For SAR systems, where other performance factors control selection of the PRFs, an algorithm is devised to resolve the ambiguity that uses PRFs of arbitrary numerical values. The performance of this multiple PRF technique is analyzed based on a statistical error model. An example is presented that demonstrates for the Shuttle Imaging RadarC (SIRC) Cband SAR, the probability of correct ambiguity resolution is higher than 95 percent for antenna attitude errors as large as 3?. 
@Article{ChangCurl92:Doppler,
Title = {{Application of the Multiple PRF Technique to Resolve Doppler Centroid Estimation Ambiguity for Spaceborne SAR}},
Author = {C. Y. Chang and John C. Curlander},
Month = sep,
Number = {5},
Pages = {941949},
Volume = {30},
Year = {1992},
Abstract = {Estimation of the Doppler centroid ambiguity is a necessary element of the signal processing for synthetic aperture radar (SAR) systems with large antenna pointing errors. Without proper resolution of the Doppler centroid estimation (DCE) ambiguity, the image quality will be degraded in the system impulse response function and the geometric fidelity. Two techniques for resolution of DCE ambiguity for the spaceborne SAR are presented in this paper. They include a brief review of the range crosscorrelation technique and presentation of a new technique using multiple pulse repetition frequencies (PRFs). We formulate an algorithm employing simple integer arithmetic for radar systems, such as moving target indicator radar (MTIR) systems, where the PRFs contain a large common divisor. For SAR systems, where other performance factors control selection of the PRFs, an algorithm is devised to resolve the ambiguity that uses PRFs of arbitrary numerical values. The performance of this multiple PRF technique is analyzed based on a statistical error model. An example is presented that demonstrates for the Shuttle Imaging RadarC (SIRC) Cband SAR, the probability of correct ambiguity resolution is higher than 95 percent for antenna attitude errors as large as 3?.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Multiple PRF Technique, Range CrossCorrelation Technique, Clutterlock, SIRC},
Pdf = {../../../docs/changCurl92.pdf}
}

C. Y. Chang,
M. Jin,
and John C. Curlander.
SAR Processing Based on the Exact TwoDimensional Transfer Function.
IGARSS '92, International Geoscience and Remote Sensing Symposium,
pp 355359,
May 1992.
Keyword(s): SAR Processing,
Azimuth Processing,
RangeDoppler Algorithm,
Range Migration Algorithm,
Wavenumber Domain Algorithm,
omegak,
Point Target Transfer Funtion,
TwoDimensional Fourier Transform,
Doppler Centroid,
Doppler Rate Estimation,
Autofocus.
Abstract: 
The twodimensional transfer funtions of several synthetic aperture radar (SAR) focussing algorithms are derived considering the spaceborne SAR environments. The formulation includes the factors of the earth rotation and the antenna squint angles. The resultant functions are explicitly expressed in terms of Doppler centroid frequency and Doppler frequency rate, which can be conveniently and accurately estimated from the SAR data. Point target simulation results show that the algorithm based on the twodimensional Fourier transformation outperforms the onedimensional one for processing data acquired from high squint angles. The twodimensional Fourier transformation approach appears to be a viable and simple solution for the processor design of future spceborne SAR systems. 
@Article{Cur92:SARProc,
Title = {{SAR Processing Based on the Exact TwoDimensional Transfer Function}},
Author = {C. Y. Chang and M. Jin and John C. Curlander},
Month = may,
Pages = {355359},
Year = {1992},
Abstract = {The twodimensional transfer funtions of several synthetic aperture radar (SAR) focussing algorithms are derived considering the spaceborne SAR environments. The formulation includes the factors of the earth rotation and the antenna squint angles. The resultant functions are explicitly expressed in terms of Doppler centroid frequency and Doppler frequency rate, which can be conveniently and accurately estimated from the SAR data. Point target simulation results show that the algorithm based on the twodimensional Fourier transformation outperforms the onedimensional one for processing data acquired from high squint angles. The twodimensional Fourier transformation approach appears to be a viable and simple solution for the processor design of future spceborne SAR systems.},
Comment = {++ Overview of 4 azmuth processing algorithms: * Exact Transfer Function Algorithm (ETF) * RangeDoppler Algorithm (RD) * Secondary Range Compression Algorithm (SRC) * Squint Imaging Mode Algorithm (SIM) For each of them, the point target transfer function is given and results are discussed.},
Journal = {IGARSS '92, International Geoscience and Remote Sensing Symposium},
Keywords = {SAR Processing, Azimuth Processing, RangeDoppler Algorithm, Range Migration Algorithm, Wavenumber Domain Algorithm, omegak, Point Target Transfer Funtion, TwoDimensional Fourier Transform, Doppler Centroid, Doppler Rate Estimation, Autofocus},
Pdf = {../../../docs/Curlander92.pdf}
}

Jorgen Dall.
A Fast Autofocus Algorithm for Synthetic Aperture Radar Processing.
IEEE International Conference on Acoustics, Speech, and Signal Processing ICASSP,
3:58,
September 1992.
Keyword(s): SAR Processing,
Doppler Rate Estimation,
Autofocus,
Airborne SAR.
Abstract: 
Highresolution synthetic aperture radar (SAR) imaging requires the motion of the radar platform to be known very accurately. Otherwise, phase errors are induced in the processing of the raw SAR data, and bad focusing results. In particular, a constant error in the measured alongtrack velocity or the crosstrack acceleration leads to a phase error that varies quadratically over the synthetic aperture. The process of estimating this quadratic phase error directly from the radar data is termed autofocus. A novel autofocus algorithm with a computational complexity which is at least an order of magnitude lower than that of other algorithms providing comparable accuracies is presented. The algorithm has been tested on data from the Danish Airborne SAR, and the performance is compared with that of the traditional map drift algorithm. 
@Article{Dal92:Fast,
Title = {{A Fast Autofocus Algorithm for Synthetic Aperture Radar Processing}},
Author = {Jorgen Dall},
Month = sep,
Pages = {58},
Volume = {3},
Year = {1992},
Abstract = {Highresolution synthetic aperture radar (SAR) imaging requires the motion of the radar platform to be known very accurately. Otherwise, phase errors are induced in the processing of the raw SAR data, and bad focusing results. In particular, a constant error in the measured alongtrack velocity or the crosstrack acceleration leads to a phase error that varies quadratically over the synthetic aperture. The process of estimating this quadratic phase error directly from the radar data is termed autofocus. A novel autofocus algorithm with a computational complexity which is at least an order of magnitude lower than that of other algorithms providing comparable accuracies is presented. The algorithm has been tested on data from the Danish Airborne SAR, and the performance is compared with that of the traditional map drift algorithm.},
Journal = {IEEE International Conference on Acoustics, Speech, and Signal Processing ICASSP},
Keywords = {SAR Processing, Doppler Rate Estimation, Autofocus, Airborne SAR},
Pdf = {../../../docs/Dal92.pdf}
}

Mita D. Desai and W. Kenneth Jenkins.
Convolution Backprojection Image Reconstruction for Spotlight Mode Synthetic Aperture Radar.
IEEE Transactions on Image Processing,
1(4):505  517,
October 1992.
Keyword(s): SAR Processing,
Spotlight SAR,
BackProjection,
Convolution BackProjection.
Abstract: 
Synthetic aperture radar (SAR) image reconstruction falls into the class of inverse (deconvolution) problems. A spotlight mode SAR system obtains line integrals (projections) of the ground reflectivity at various look angles as the radar platform progresses along the flight trajectory. The image of the ground area is then reconstructed from this set of projections. Conventionally, the SAR image has been produced by a direct Fourier reconstruction algorithm referred to here as the 2D inverse FFT method. This method has two major problems: 1) due to the batch processing nature of the FFT, all returns must be recorded before the image processing can begin, and 2) a polartocartesian interpolation, which is computationally intensive and error prone due to interpolation inaccuracies, is necessary before a 2D inverse FFT can be performed. In this paper, a method based on a convolution backprojection (CBP) algorithm is presented. CBP is a widely used technique in computeraided tomography (CAT). The CBP algorithm has been modified and applied to image reconstruction from SAR data. A quantitative evaluation using computer simulation of the CBP algorithm for spotlight mode SAR is presented. Its performance is then compared with the 2D inverse FFT method with respect to the multiplicative noise ratio (MNR). Conclusions are supported by a reconstruction example on real SAR data collected by the Lincoln Laboratory's high resolution (0.3 m) radar. 
@Article{DesaiJenkins92:Backprojection,
Title = {{Convolution Backprojection Image Reconstruction for Spotlight Mode Synthetic Aperture Radar}},
Author = {Mita D. Desai and W. Kenneth Jenkins},
Month = Oct,
Number = {4},
Pages = {505  517},
Volume = {1},
Year = {1992},
Abstract = {Synthetic aperture radar (SAR) image reconstruction falls into the class of inverse (deconvolution) problems. A spotlight mode SAR system obtains line integrals (projections) of the ground reflectivity at various look angles as the radar platform progresses along the flight trajectory. The image of the ground area is then reconstructed from this set of projections. Conventionally, the SAR image has been produced by a direct Fourier reconstruction algorithm referred to here as the 2D inverse FFT method. This method has two major problems: 1) due to the batch processing nature of the FFT, all returns must be recorded before the image processing can begin, and 2) a polartocartesian interpolation, which is computationally intensive and error prone due to interpolation inaccuracies, is necessary before a 2D inverse FFT can be performed. In this paper, a method based on a convolution backprojection (CBP) algorithm is presented. CBP is a widely used technique in computeraided tomography (CAT). The CBP algorithm has been modified and applied to image reconstruction from SAR data. A quantitative evaluation using computer simulation of the CBP algorithm for spotlight mode SAR is presented. Its performance is then compared with the 2D inverse FFT method with respect to the multiplicative noise ratio (MNR). Conclusions are supported by a reconstruction example on real SAR data collected by the Lincoln Laboratory's high resolution (0.3 m) radar.},
Journal = {IEEE Transactions on Image Processing},
Keywords = {SAR Processing, Spotlight SAR, BackProjection, Convolution BackProjection},
Pdf = {../../../docs/desaiJenkins92.pdf}
}

M. C. Dobson,
F. T. Ulaby,
T. LeToan,
A. Beaudoin,
E. S. Kasischke,
and N. Christensen.
Dependence of radar backscatter on coniferous forest biomass.
IEEE Trans. Geosci. Remote Sens.,
30(2):412415,
March 1992.
Keyword(s): SAR Processing,
Forest,
Forest parameters,
biomass,
Cband,
Duke,
France,
Lband,
Landes,
North Carolina,
Pband,
SAR data,
United States,
age,
coniferous forest biomass,
maritime pines,
plantations,
radar backscatter,
remote sensing,
backscatter,
ecology,
forestry,
remote sensing by radar.
Abstract: 
Two independent experimental efforts have examined the dependence of radar backscatter on aboveground biomass of monospecie conifer forests using polarimetric airborne SAR data at P, L and Cbands. Plantations of maritime pines near Landes, France, range in age from 8 to 46 years with aboveground biomass between 5 and 105 tons/ha. Loblolly pine stands established on abandoned agricultural fields near Duke, NC, range in age from 4 to 90 years and extend the range of aboveground biomass to 560 tons/ha for the older stands. These two experimental forests are largely complementary with respect to biomass. Radar backscatter is found to increase approximately linearly with increasing biomass until it saturates at a biomass level that depends on the radar frequency. The biomass saturation level is about 200 tons/ha at Pband and 100 tons/ha at Lband, and the Cband backscattering coefficient shows much less sensitivity to total aboveground biomass 
@Article{DobsonUlabyLeToanBeaudoinKasischkeChristensen1992:BiomassBackscatter,
Title = {Dependence of radar backscatter on coniferous forest biomass},
Author = {Dobson, M. C. and Ulaby, F. T. and LeToan, T. and Beaudoin, A. and Kasischke, E. S. and Christensen, N.},
Doi = {10.1109/36.134090},
ISSN = {01962892},
Month = mar,
Number = {2},
Pages = {412415},
Volume = {30},
Year = {1992},
Abstract = {Two independent experimental efforts have examined the dependence of radar backscatter on aboveground biomass of monospecie conifer forests using polarimetric airborne SAR data at P, L and Cbands. Plantations of maritime pines near Landes, France, range in age from 8 to 46 years with aboveground biomass between 5 and 105 tons/ha. Loblolly pine stands established on abandoned agricultural fields near Duke, NC, range in age from 4 to 90 years and extend the range of aboveground biomass to 560 tons/ha for the older stands. These two experimental forests are largely complementary with respect to biomass. Radar backscatter is found to increase approximately linearly with increasing biomass until it saturates at a biomass level that depends on the radar frequency. The biomass saturation level is about 200 tons/ha at Pband and 100 tons/ha at Lband, and the Cband backscattering coefficient shows much less sensitivity to total aboveground biomass},
Journal = {IEEE Trans. Geosci. Remote Sens.},
Keywords = {SAR Processing, Forest, Forest parameters, biomass;Cband;Duke;France;Lband;Landes;North Carolina;Pband;SAR data;United States;age;coniferous forest biomass;maritime pines;plantations;radar backscatter;remote sensing;backscatter;ecology;forestry;remote sensing by radar}
}

Duane T Eppler,
L Dennis Farmer,
Alan W Lohanick,
Mark R Anderson,
Donald J Cavalieri,
Josefino Comiso,
Per Gloersen,
Caren Garrity,
Thomas C Grenfell,
Martti Hallikainen,
and others.
Passive microwave signatures of sea ice.
Microwave remote sensing of sea ice,
pp 4771,
1992.
@Article{Eppler1992,
author = {Eppler, Duane T and Farmer, L Dennis and Lohanick, Alan W and Anderson, Mark R and Cavalieri, Donald J and Comiso, Josefino and Gloersen, Per and Garrity, Caren and Grenfell, Thomas C and Hallikainen, Martti and others},
title = {Passive microwave signatures of sea ice},
journal = {Microwave remote sensing of sea ice},
year = {1992},
pages = {4771},
owner = {ofrey},
publisher = {Wiley Online Library},
}

Giorgio Franceschetti,
Maurizio Migliaccio,
Daniele Riccio,
and Gilda Schirinzi.
SARAS: A Synthetic Aperture Radar (SAR) Raw Signal Simulator.
IEEE Transactions on Geoscience and Remote Sensing,
30(1):110123,
January 1992.
Keyword(s): SAR Processing,
Simulation,
SAR Simulator,
Raw Data Simulator.
Abstract: 
A SAR simulator of an extended threedimensional scene is presented. It is based on a facet model for the scene, asymptotic evaluation of SAR unit response, and a twodimensional fast Fourier transform code for the data processing. Prescribed statistics of the model account for a realistic speckle of the image. The simulator is implemented in Synthetic Aperture Radar Advance Simulators (SARAS), whose performance is described and illustrated by a number of examples. 
@Article{FMRS92:SARAS,
Title = {{SARAS: A Synthetic Aperture Radar (SAR) Raw Signal Simulator}},
Author = {Giorgio Franceschetti and Maurizio Migliaccio and Daniele Riccio and Gilda Schirinzi},
Month = Jan,
Number = {1},
Pages = {110123},
Volume = {30},
Year = {1992},
Abstract = {A SAR simulator of an extended threedimensional scene is presented. It is based on a facet model for the scene, asymptotic evaluation of SAR unit response, and a twodimensional fast Fourier transform code for the data processing. Prescribed statistics of the model account for a realistic speckle of the image. The simulator is implemented in Synthetic Aperture Radar Advance Simulators (SARAS), whose performance is described and illustrated by a number of examples.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, Simulation, SAR Simulator, Raw Data Simulator},
Pdf = {../../../docs/FMRS92.pdf}
}

A. Freeman.
SAR calibration: an overview.
IEEE Trans. Geosci. Remote Sens.,
30(6):11071121,
November 1992.
Keyword(s): calibration,
polarimetry,
radiometry,
reviews,
synthetic aperture radar,
airborne data,
Earth surface,
syntheticaperture radar,
spaceborne SAR image data,
radar backscatter,
image quality,
radiometric calibration,
polarimetric radar calibration,
phase calibration,
interferometric SAR,
Calibration,
Spaceborne radar,
Synthetic aperture radar,
Radar imaging,
Radar polarimetry,
Radar measurements,
Backscatter,
Image quality,
Radiometry,
Equations.
Abstract: 
Progress in syntheticaperture radar, (SAR) calibration is reviewed. The difficulties of calibrating both airborne and spaceborne SAR image data are addressed. The quantities measured by a SAR, i.e. radar backscatter, are defined and mathematical formulations for the three basic types of SAR image are developed. The difficulties in establishing science requirements for calibration are discussed. The measurement of SAR image quality is briefly addressed. The problem of radiometric calibration is introduced via the SAR form of the radar equation, with both internal and external calibration approaches considered. The development of algorithms for polarimetric radar calibration is reviewed and the problems involved in phase calibration of interferometric SAR are discussed. Future challenges in the field of SAR calibration are considered.<> 
@Article{freemanTGRS1992SARCalibrationOverview,
author = {A. {Freeman}},
title = {{SAR} calibration: an overview},
journal = {IEEE Trans. Geosci. Remote Sens.},
year = {1992},
volume = {30},
number = {6},
pages = {11071121},
month = nov,
issn = {01962892},
abstract = {Progress in syntheticaperture radar, (SAR) calibration is reviewed. The difficulties of calibrating both airborne and spaceborne SAR image data are addressed. The quantities measured by a SAR, i.e. radar backscatter, are defined and mathematical formulations for the three basic types of SAR image are developed. The difficulties in establishing science requirements for calibration are discussed. The measurement of SAR image quality is briefly addressed. The problem of radiometric calibration is introduced via the SAR form of the radar equation, with both internal and external calibration approaches considered. The development of algorithms for polarimetric radar calibration is reviewed and the problems involved in phase calibration of interferometric SAR are discussed. Future challenges in the field of SAR calibration are considered.<>},
doi = {10.1109/36.193786},
file = {:freemanTGRS1992SARCalibrationOverview.pdf:PDF},
keywords = {calibration;polarimetry;radiometry;reviews;synthetic aperture radar;airborne data;Earth surface;syntheticaperture radar;spaceborne SAR image data;radar backscatter;image quality;radiometric calibration;polarimetric radar calibration;phase calibration;interferometric SAR;Calibration;Spaceborne radar;Synthetic aperture radar;Radar imaging;Radar polarimetry;Radar measurements;Backscatter;Image quality;Radiometry;Equations},
owner = {ofrey},
}

Claudio Prati and Fabio Rocca.
Focusing SAR Data With TimeVarying Doppler Centroid.
IEEE Transactions on Geoscience and Remote Sensing,
30(3):550559,
May 1992.
Keyword(s): SAR Processing,
Doppler Centroid,
Doppler Centroid Estimation,
Clutterlock.
Abstract: 
SAR data spatially sampled at the Nyquist limit can be correctly processed if the Doppler centroid is precisely known. Whenever the Doppler centroid shows rapid variations either with range or azimuth, more care is required in order to take advantage of the computational efficiency of frequency domain techniques. In this paper it is shown that such focusing techniques can still be exploited, provided that SAR raw data are previously modified and a spacevarying nondimensional filter is applied to the focused image. The computational cost increases, but it is still smaller than timespace domain processing. Results obtained with simulated SIRC/XSAR data and SPOTlight geometries are presented. 
@Article{pratiRocca92:Doppler,
Title = {{Focusing SAR Data With TimeVarying Doppler Centroid}},
Author = {Claudio Prati and Fabio Rocca},
Month = May,
Number = {3},
Pages = {550559},
Volume = {30},
Year = {1992},
Abstract = {SAR data spatially sampled at the Nyquist limit can be correctly processed if the Doppler centroid is precisely known. Whenever the Doppler centroid shows rapid variations either with range or azimuth, more care is required in order to take advantage of the computational efficiency of frequency domain techniques. In this paper it is shown that such focusing techniques can still be exploited, provided that SAR raw data are previously modified and a spacevarying nondimensional filter is applied to the focused image. The computational cost increases, but it is still smaller than timespace domain processing. Results obtained with simulated SIRC/XSAR data and SPOTlight geometries are presented.},
Journal = {IEEE Transactions on Geoscience and Remote Sensing},
Keywords = {SAR Processing, Doppler Centroid, Doppler Centroid Estimation, Clutterlock},
Pdf = {../../../docs/pratiRocca92.pdf}
}

R. Keith Raney.
An exact wide field digital imaging algorithm.
International Journal of Remote Sensing,
13:991998,
March 1992.
Keyword(s): SAR Processing,
Chirp Scaling,
Extended Chirp Scaling,
ECS.
Abstract: 
A new imaging algorithm is presented for Synthetic Aperture Radar (SAR) that is exact in the sense that it is capable of producing a complex image with excellent geometrical, radiometrical and phase fidelity. No interpolations or significant approximations are required, yet the method accomplishes range curvature correction over the complete range swath. The key to the approach is a quadratic phase perturbation of the range linearly frequency modulated signals while in the range signal, azimuth frequency transform (Doppler) domain. Range curvature correction is completed by a phase multiply in the twodimensional frequency domain. Other operations required are relatively conventional. The method is generalizable to imaging geometries encountered in squint and spotlight SAR, inverse SAR, seismics, sonar, and tomography. 
@Article{raney92:ChirpScaling,
Title = {An exact wide field digital imaging algorithm},
Author = {Raney, R. Keith},
Month = mar,
Pages = {991998},
Url = {http://www.informaworld.com/smpp/content~db=all~content=a777329067},
Volume = {13},
Year = {1992},
Abstract = {A new imaging algorithm is presented for Synthetic Aperture Radar (SAR) that is exact in the sense that it is capable of producing a complex image with excellent geometrical, radiometrical and phase fidelity. No interpolations or significant approximations are required, yet the method accomplishes range curvature correction over the complete range swath. The key to the approach is a quadratic phase perturbation of the range linearly frequency modulated signals while in the range signal, azimuth frequency transform (Doppler) domain. Range curvature correction is completed by a phase multiply in the twodimensional frequency domain. Other operations required are relatively conventional. The method is generalizable to imaging geometries encountered in squint and spotlight SAR, inverse SAR, seismics, sonar, and tomography.},
Journal = {International Journal of Remote Sensing},
Keywords = {SAR Processing, Chirp Scaling, Extended Chirp Scaling, ECS},
Pdf = {../../../docs/raney92.pdf}
}

Ernesto Rodriguez and J. M. Martin.
Theory and design of interferometric synthetic aperture radars.
IEE Proceedings  Radar and Signal Processing,
139(2):147159,
April 1992.
Keyword(s): SAR Processing,
InSAR,
interferometry,
radar interferometry,
SAR interferometry,
electromagnetic wave interferometry,
geophysical equipment,
Monte Carlo methods,
radar systems,
radar theory,
remote sensing by radar,
topography (Earth),
geophysical technique,
remote sensing,
design,
interferometric synthetic aperture radars,
high spatial resolution,
height accuracy,
signal statistics,
optimal estimator,
interferometric phase,
heighterror budget,
highresolution global topographic mapping,
Monte Carlo simulation,
InSAR system,
Interferometry,
Geophysical measurements,
Monte Carlo methods,
Radar,
Radar theory,
Radar imaging,
Remote sensing.
Abstract: 
SAR Processing, InSAR, SAR interferometry,Interferometric synthetic aperture radar (InSAR) is a method which may provide a means of estimating global topography with high spatial resolution and height accuracy. The authors present a derivation of the signal statistics, an optimal estimator of the interferometric phase, and the expressions necessary to calculate the heighterror budget. These expressions are used to derive methods of optimising the InSARsystem parameters, and are then used in a specific design example for a system to perform highresolution global topographic mapping with a oneyear mission lifetime, subject to current technological constraints. A Monte Carlo simulation of this InSAR system is performed to evaluate its performance for realistic topography. The results indicate that this system has the potential to satisfy the stringent accuracy and resolution requirements for geophysical use of global topographic data. 
@Article{rodriguezMartinIEEProc1992TheoryAndDesignOfInSAR,
author = {Ernesto Rodriguez and J. M. Martin},
title = {Theory and design of interferometric synthetic aperture radars},
journal = {IEE Proceedings  Radar and Signal Processing},
year = {1992},
volume = {139},
number = {2},
pages = {147159},
month = {April},
issn = {0956375X},
abstract = {SAR Processing, InSAR, SAR interferometry,Interferometric synthetic aperture radar (InSAR) is a method which may provide a means of estimating global topography with high spatial resolution and height accuracy. The authors present a derivation of the signal statistics, an optimal estimator of the interferometric phase, and the expressions necessary to calculate the heighterror budget. These expressions are used to derive methods of optimising the InSARsystem parameters, and are then used in a specific design example for a system to perform highresolution global topographic mapping with a oneyear mission lifetime, subject to current technological constraints. A Monte Carlo simulation of this InSAR system is performed to evaluate its performance for realistic topography. The results indicate that this system has the potential to satisfy the stringent accuracy and resolution requirements for geophysical use of global topographic data.},
doi = {10.1049/ipf2.1992.0018},
file = {:rodriguezMartinIEEProc1992TheoryAndDesignOfInSAR.pdf:PDF},
keywords = {SAR Processing, InSAR, interferometry, radar interferometry, SAR interferometry, electromagnetic wave interferometry;geophysical equipment;Monte Carlo methods;radar systems;radar theory;remote sensing by radar;topography (Earth);geophysical technique;remote sensing;design;interferometric synthetic aperture radars;high spatial resolution;height accuracy;signal statistics;optimal estimator;interferometric phase;heighterror budget;highresolution global topographic mapping;Monte Carlo simulation;InSAR system;Interferometry;Geophysical measurements;Monte Carlo methods;Radar;Radar theory;Radar imaging;Remote sensing},
owner = {ofrey},
}

Mehrdad Soumekh.
A System Model and Inversion for Synthetic Aperture Radar Imaging.
IEEE Transactions on Image Processing,
1(1):6476,
January 1992.
Keyword(s): SAR Processing,
Wavenumber Domain Algorithm,
omegak,
Range Migration Algorithm.
Abstract: 
A system model and its corresponding inversion for synthetic aperture radar (SAR) imaging are presented. The system model incorporates the spherical nature of a radar's radiation pattern at far field. The inverse method based on this model performs a spatial Fourier transform (Doppler processing) on the recorded signals with respect to the available coordinates of a translational radar (SAR) or target (inverse SAR). It is shown that the transformed data provide samples of the spatial Fourier transform of the target's reflectivity function. The inverse method can be modified to incorporate deviations of the radar's motion from its prescribed straight line path. The effects of finite aperture on resolution, reconstruction, and sampling constraints for the imaging problem are discussed. 
@Article{soumekh92:Process,
Title = {{A System Model and Inversion for Synthetic Aperture Radar Imaging}},
Author = {Mehrdad Soumekh},
Month = Jan,
Number = {1},
Pages = {6476},
Url = {http://ieeexplore.ieee.org/iel4/83/3590/00128031.pdf},
Volume = {1},
Year = {1992},
Abstract = {A system model and its corresponding inversion for synthetic aperture radar (SAR) imaging are presented. The system model incorporates the spherical nature of a radar's radiation pattern at far field. The inverse method based on this model performs a spatial Fourier transform (Doppler processing) on the recorded signals with respect to the available coordinates of a translational radar (SAR) or target (inverse SAR). It is shown that the transformed data provide samples of the spatial Fourier transform of the target's reflectivity function. The inverse method can be modified to incorporate deviations of the radar's motion from its prescribed straight line path. The effects of finite aperture on resolution, reconstruction, and sampling constraints for the imaging problem are discussed.},
Journal = {IEEE Transactions on Image Processing},
Keywords = {SAR Processing, Wavenumber Domain Algorithm, omegak, Range Migration Algorithm},
Pdf = {../../../docs/soumekh92.pdf}
}

A. G. Stove.
Linear FMCW radar techniques.
IEE Proceedings F  Radar and Signal Processing,
139(5):343350,
October 1992.
Keyword(s): SAR Processing,
FMCW,
FMCW radar,
frequency modulation,
military systems,
radar systems,
automotive radars,
frequency modulated continuous wave,
linear FMCW radar,
low probability of intercept waveform,
moving target indication,
naval tactical navigation radars,
reflected power canceller,
solidstate transmitters,
Frequency modulation,
Radar.
Abstract: 
Frequency modulated continuous wave (FMCW) radar uses a very low probability of intercept waveform, which is also well suited to make good use of simple solidstate transmitters. FMCW is finding applications in such diverse fields as naval tactical navigation radars, smart ammunition sensors and automotive radars. The paper discusses some features of FMCW radar which are not dealt with in much detail in the generally available literature. In particular, it discusses the effects of noise reflected back from the transmitter to the receiver and the application of moving target indication to FMCW radars. Some of the strengths and weaknesses of FMCW radar are considered. The paper describes how the strengths are utilised in some systems and how the weaknesses can be mitigated. It also discusses a modern implementation of a reflected power canceller, which can be used to suppress the leakage between the transmitter and the receiver, a well known problem with continuous wave radars. 
@Article{stove1992LFMCW,
author = {A. G. Stove},
title = {Linear {FMCW} radar techniques},
journal = {IEE Proceedings F  Radar and Signal Processing},
year = {1992},
volume = {139},
number = {5},
pages = {343350},
month = oct,
issn = {0956375X},
abstract = {Frequency modulated continuous wave (FMCW) radar uses a very low probability of intercept waveform, which is also well suited to make good use of simple solidstate transmitters. FMCW is finding applications in such diverse fields as naval tactical navigation radars, smart ammunition sensors and automotive radars. The paper discusses some features of FMCW radar which are not dealt with in much detail in the generally available literature. In particular, it discusses the effects of noise reflected back from the transmitter to the receiver and the application of moving target indication to FMCW radars. Some of the strengths and weaknesses of FMCW radar are considered. The paper describes how the strengths are utilised in some systems and how the weaknesses can be mitigated. It also discusses a modern implementation of a reflected power canceller, which can be used to suppress the leakage between the transmitter and the receiver, a well known problem with continuous wave radars.},
doi = {10.1049/ipf2.1992.0048},
file = {:stove1992LFMCW.pdf:PDF},
keywords = {SAR Processing, FMCW, FMCW radar, frequency modulation;military systems;radar systems;automotive radars;frequency modulated continuous wave;linear FMCW radar;low probability of intercept waveform;moving target indication;naval tactical navigation radars;reflected power canceller;solidstate transmitters;Frequency modulation;Radar},
owner = {ofrey},
pdf = {../../../docs/stove1992LFMCW.pdf},
}

H.A. Zebker and J. Villasenor.
Decorrelation in interferometric radar echoes.
IEEE Trans. Geosci. Remote Sens.,
30(5):950959,
September 1992.
Keyword(s): SAR Processing,
geophysical techniques,
radiowave interferometry,
remote sensing by radar,
synthetic aperture radar,
Decorrelation,
Temporal Decorrelation,
topography (Earth),
Oregon,
United States,
backscatter,
decorrelation,
digital terrain model generation,
echo correlation statistics,
forested area,
global digital terrain map,
interferometric radar echoes,
radar interferometric technique,
remote sensing,
single synthetic aperture radar,
surficial change,
topographic mapping,
unvegetated lava flows,
vegetated surfaces,
Decorrelation,
Digital elevation models,
Noise level,
Propulsion,
Radar antennas,
Space technology,
Spaceborne radar,
Surface topography,
Synthetic aperture radar,
Terrain mapping.
Abstract: 
A radar interferometric technique for topographic mapping of surfaces, implemented utilizing a single synthetic aperture radar (SAR) system in a nearly repeating orbit, is discussed. The authors characterize the various sources contributing to the echo correlation statistics, and isolate the term which most closely describes surficial change. They then examine the application of this approach to topographic mapping of vegetated surfaces which may be expected to possess varying backscatter over time. It is found that there is decorrelation increasing with time but that digital terrain model generation remains feasible. The authors present such a map of a forested area in Oregon which also includes some nearly unvegetated lava flows. Such a technique could provide a global digital terrain map 
@Article{zebkerVillasenor1992DecorrelationInSAR,
author = {Zebker, H.A. and Villasenor, J.},
title = {Decorrelation in interferometric radar echoes},
journal = {IEEE Trans. Geosci. Remote Sens.},
year = {1992},
volume = {30},
number = {5},
pages = {950959},
month = sep,
issn = {01962892},
abstract = {A radar interferometric technique for topographic mapping of surfaces, implemented utilizing a single synthetic aperture radar (SAR) system in a nearly repeating orbit, is discussed. The authors characterize the various sources contributing to the echo correlation statistics, and isolate the term which most closely describes surficial change. They then examine the application of this approach to topographic mapping of vegetated surfaces which may be expected to possess varying backscatter over time. It is found that there is decorrelation increasing with time but that digital terrain model generation remains feasible. The authors present such a map of a forested area in Oregon which also includes some nearly unvegetated lava flows. Such a technique could provide a global digital terrain map},
doi = {10.1109/36.175330},
file = {:zebkerVillasenor1992DecorrelationInSAR.pdf:PDF},
keywords = {SAR Processing, geophysical techniques;radiowave interferometry;remote sensing by radar;synthetic aperture radar;Decorrelation, Temporal Decorrelation,topography (Earth);Oregon;United States;backscatter;decorrelation;digital terrain model generation;echo correlation statistics;forested area;global digital terrain map;interferometric radar echoes;radar interferometric technique;remote sensing;single synthetic aperture radar;surficial change;topographic mapping;unvegetated lava flows;vegetated surfaces;Decorrelation;Digital elevation models;Noise level;Propulsion;Radar antennas;Space technology;Spaceborne radar;Surface topography;Synthetic aperture radar;Terrain mapping},
pdf = {../../../docs/zebkerVillasenor1992DecorrelationInSAR.pdf},
}

J. J. van Zyl and C. F. Burnette.
Bayesian classification of polarimetric SAR images using adaptive a priori probabilities.
International Journal of Remote Sensing,
13(5):835840,
1992.
Abstract: 
Most implementations of Bayesian classification assume fixed a priori probabilities. These implementations can be placed into two general categories: (1) those that assume equal a priori probabilities and (2) those that assume unequal but fixed a priori probabilities. We report here on results of classifying polarimetric SAR images using a scheme in which the classification is done iteratively. The first classification is done assuming fixed (but not necessarily equal) a priori probabilities. The results of this first classification are then used in successive iterations to change the a priori probabilities adaptively. The results show that only a few iterations are necessary to improve the classification accuracy dramatically. 
@Article{vanZylBurnetteIJRS1992BaysianClassificationPolSARImages,
author = {van Zyl, J. J. and Burnette, C. F.},
title = {Bayesian classification of polarimetric SAR images using adaptive a priori probabilities},
journal = {International Journal of Remote Sensing},
year = {1992},
volume = {13},
number = {5},
pages = {835840},
abstract = {Most implementations of Bayesian classification assume fixed a priori probabilities. These implementations can be placed into two general categories: (1) those that assume equal a priori probabilities and (2) those that assume unequal but fixed a priori probabilities. We report here on results of classifying polarimetric SAR images using a scheme in which the classification is done iteratively. The first classification is done assuming fixed (but not necessarily equal) a priori probabilities. The results of this first classification are then used in successive iterations to change the a priori probabilities adaptively. The results show that only a few iterations are necessary to improve the classification accuracy dramatically.},
doi = {10.1080/01431169208904157},
eprint = {https://doi.org/10.1080/01431169208904157},
owner = {ofrey},
publisher = {Taylor \& Francis},
url = {https://doi.org/10.1080/01431169208904157},
}
Conference articles

Ian G. Cumming,
Frank Wong,
and R. Keith Raney.
A SAR Processing Algorithm With No Interpolation.
In IGARSS '92, International Geoscience and Remote Sensing Symposium,
pages 376379,
May 1992.
Keyword(s): SAR Processing,
Differential Range Deramp  Frequency Domain Algorithm,
DRDFD Algorithm,
Range Migration Algorithm,
omegak,
Wavenumber Domain Algorithm,
Comparison of Algorithms.
Abstract: 
Current SAR processing algorithms incorporate interpolators to perform key functions. It turns out that the interpolators are difficult to implement, and are one of the largest sources of error in the processing. In this paper, we introduce a new algorithm which eliminates the use of the interpolation operation, yet achieves accurate range migration correction over the full range swath. The algorithm can handle large apertures and large squints, and has noticeably better phase and geometry accuracy than current algorithms, even when the apertures and squints are high. The new algorithm is called Differential Range Deramp  Frequency Domain (DRDFD) Algorithm, because its key operation is to use the linearFM property of the range chirp to differentially shift the range energy as a function of azimuth frequency, and then to do the remaining range cell migration correction in the twodimensional frequency domain. In this paper, the new algorithm is described, and simulation results are given to demonstrate its focusing, phase and geometric performance with squinted SAR data. In addition, an image is shown made from SEASAT data. 
@InProceedings{CummWongRaney92:Processing,
Title = {{A SAR Processing Algorithm With No Interpolation}},
Author = {Ian G. Cumming and Frank Wong and R. Keith Raney},
Booktitle = {IGARSS '92, International Geoscience and Remote Sensing Symposium},
Month = May,
Pages = {376379},
Url = {http://ieeexplore.ieee.org/iel2/1014/12510/00576716.pdf},
Year = {1992},
Abstract = {Current SAR processing algorithms incorporate interpolators to perform key functions. It turns out that the interpolators are difficult to implement, and are one of the largest sources of error in the processing. In this paper, we introduce a new algorithm which eliminates the use of the interpolation operation, yet achieves accurate range migration correction over the full range swath. The algorithm can handle large apertures and large squints, and has noticeably better phase and geometry accuracy than current algorithms, even when the apertures and squints are high. The new algorithm is called Differential Range Deramp  Frequency Domain (DRDFD) Algorithm, because its key operation is to use the linearFM property of the range chirp to differentially shift the range energy as a function of azimuth frequency, and then to do the remaining range cell migration correction in the twodimensional frequency domain. In this paper, the new algorithm is described, and simulation results are given to demonstrate its focusing, phase and geometric performance with squinted SAR data. In addition, an image is shown made from SEASAT data.},
Keywords = {SAR Processing, Differential Range Deramp  Frequency Domain Algorithm, DRDFD Algorithm, Range Migration Algorithm, omegak, Wavenumber Domain Algorithm, Comparison of Algorithms},
Pdf = {../../../docs/CummWongRaney92.pdf}
}

Didier Dendal and Jean L. Marchand.
Omegak Techniques Advantages and Weaker Aspects.
In IGARSS '92, International Geoscience and Remote Sensing Symposium,
pages 366368,
May 1992.
Keyword(s): SAR Processing,
Range Migration Algorithm,
omegak,
Wavenumber Domain Algorithm,
Comparison of Algorithms.
Abstract: 
Wave equation techniques and the omegak algorithm are very attractive for future SAR space missions with on board reconstruction. The aim of the present work is to point out the stronger advantages and the weaker aspects of this algorithm compared to current SAR processors. Theoretical assumptions and approximations, practical limitations and drawbacks of the method will be outlined in contradistinction to its more positive aspects. A sensitivity analysis, with some positive conclusions, has also been performed. It will appear that there is no great revolution with regard to the traditional algorithms and that the major problems and chief restrictions are always the same, as well as the unavoidable antagonism between processing speed and reconstruction precision, even if some secondary effects are more easily handled there. 
@InProceedings{DendalMarchand92:Processing,
Title = {{Omegak Techniques Advantages and Weaker Aspects}},
Author = {Didier Dendal and Jean L. Marchand},
Booktitle = {IGARSS '92, International Geoscience and Remote Sensing Symposium},
Month = May,
Pages = {366368},
Url = {http://ieeexplore.ieee.org/iel2/1014/12510/00576713.pdf},
Year = {1992},
Abstract = {Wave equation techniques and the omegak algorithm are very attractive for future SAR space missions with on board reconstruction. The aim of the present work is to point out the stronger advantages and the weaker aspects of this algorithm compared to current SAR processors. Theoretical assumptions and approximations, practical limitations and drawbacks of the method will be outlined in contradistinction to its more positive aspects. A sensitivity analysis, with some positive conclusions, has also been performed. It will appear that there is no great revolution with regard to the traditional algorithms and that the major problems and chief restrictions are always the same, as well as the unavoidable antagonism between processing speed and reconstruction precision, even if some secondary effects are more easily handled there.},
Keywords = {SAR Processing, Range Migration Algorithm, omegak, Wavenumber Domain Algorithm, Comparison of Algorithms},
Pdf = {../../../docs/DendalMarchand92.pdf}
}

P.H. Eichel,
D.C. Ghiglia,
C.V. Jakowatz,
and D.E. Wahl.
Phase Gradient Autofocus for SAR Phase Correction: Explanation and Demonstration of Algorithmic Steps.
In Digital Signal Processing workshop, 1992. The,
September 1992.
Keyword(s): SAR Processing,
Autofocus,
Phase Gradient Autofocus.
@InProceedings{Eichel1992,
Title = {Phase Gradient Autofocus for SAR Phase Correction: Explanation and Demonstration of Algorithmic Steps},
Author = {Eichel, P.H. and Ghiglia, D.C. and Jakowatz, C.V. and Wahl, D.E.},
Booktitle = {Digital Signal Processing workshop, 1992. The},
Month = sep,
Year = {1992},
Keywords = {SAR Processing, Autofocus, Phase Gradient Autofocus},
Owner = {ofrey}
}

Ralf Horn and Erich Meier.
A Refined Procedure To Generate Calibrated Imagery From Airborne Synthetic Aperture Radar Data.
In Geoscience and Remote Sensing Symposium, 1992. IGARSS '92. International,
pages 406408,
1992.
Keyword(s): SAR Processing,
AGC,
Automatic Gain Control,
STC,
Sensitivity Time Control,
Calibration,
Radiometry,
Radiometric Calibration,
Radiometric Correction,
APG,
Antenna Gain Pattern,
ESAR,
ESAR.
Abstract: 
The paper desciibes a procedure realized at DLR to generate calibrated imagery from synthetic aperture radar systems installed on board of small aircrafts. It has been especially developed for the DLR experimental radar system ESAR, which uses antennas fixed directly to the body of a DO 228 aircraft. A receiver gain control system (STC) is implemented. The correction of the STC variable receiver gain, the compensation of the translational and rotational motion errors of the aircraft and the calibration of the radar data in the SAR processor are described. First preliminary results obtained from a recent experiment in Switzerland are shown. 
@InProceedings{hornMeier92:STC,
Title = {A Refined Procedure To Generate Calibrated Imagery From Airborne Synthetic Aperture Radar Data},
Author = {Horn, Ralf and Meier, Erich},
Booktitle = {Geoscience and Remote Sensing Symposium, 1992. IGARSS '92. International},
Pages = {406408},
Url = {http://ieeexplore.ieee.org/iel2/1014/12510/00576724.pdf},
Year = {1992},
Abstract = {The paper desciibes a procedure realized at DLR to generate calibrated imagery from synthetic aperture radar systems installed on board of small aircrafts. It has been especially developed for the DLR experimental radar system ESAR, which uses antennas fixed directly to the body of a DO 228 aircraft. A receiver gain control system (STC) is implemented. The correction of the STC variable receiver gain, the compensation of the translational and rotational motion errors of the aircraft and the calibration of the radar data in the SAR processor are described. First preliminary results obtained from a recent experiment in Switzerland are shown.},
Keywords = {SAR Processing, AGC, Automatic Gain Control, STC, Sensitivity Time Control, Calibration, Radiometry, Radiometric Calibration,Radiometric Correction, APG, Antenna Gain Pattern, ESAR, ESAR},
Owner = {ofrey},
Pdf = {../../../docs/hornMeier92.pdf}
}

Alberto Moreira,
Artur Brodscholl,
Jacob Dom,
Frank Kochsiek,
and Winfried Poetzsch.
Airborne Realtime SAR Processing Activities at DLR.
In Geoscience and Remote Sensing Symposium, 1992. IGARSS '92. International,
pages 412414,
1992.
Keyword(s): SAR Processing,
RealTime SAR Processing,
Subaperture Processing,
RealTime Subaperture Processing,
Hardware Processor,
STC,
Sensitivity Time Control.
@InProceedings{moreiraBrodschollDomKochsiekPotzsch92:realTimeSARProc,
Title = {Airborne Realtime SAR Processing Activities at DLR},
Author = {Moreira, Alberto and Brodscholl, Artur and Dom, Jacob and Kochsiek, Frank and Poetzsch, Winfried},
Booktitle = {Geoscience and Remote Sensing Symposium, 1992. IGARSS '92. International},
Pages = {412414},
Url = {http://ieeexplore.ieee.org/iel2/1014/12510/00576726.pdf},
Year = {1992},
Keywords = {SAR Processing, RealTime SAR Processing, Subaperture Processing, RealTime Subaperture Processing, Hardware Processor, STC, Sensitivity Time Control},
Owner = {ofrey},
Pdf = {../../../docs/moreiraBrodschollDomKochsiekPotzsch92.pdf}
}

R. Keith Raney.
A New and Fundamental Fourier Transform Pair.
In IGARSS '92, International Geoscience and Remote Sensing Symposium,
volume 1,
pages 106107,
1992.
Keyword(s): SAR Processing,
Wavenumber Domain Algorithm,
omegak,
Wavenumber Domain Algorithm,
Stationary Phase Method,
Closed Form Fourier Transform.
Abstract: 
A closed form Fourier transform relationship between the range signal, azimuth signal domain and the range signal, azimuth frequency (or Doppler) domain is presented. The derivation assumes the presence of a large timebandwidth pulse modulation in range. The expression is valid over a wide angular field of view, and expressed using the hyperbolic range equation. The resulting Fourier transform pair is of general utility in SAR, tomography, active seismics and related imaging problems, and allows more insight into the imaging process in the presence of range curvature than is normally available. 
@InProceedings{raney:fourier,
Title = {{A New and Fundamental Fourier Transform Pair}},
Author = {R. Keith Raney},
Booktitle = {IGARSS '92, International Geoscience and Remote Sensing Symposium},
Pages = {106107},
Url = {http://ieeexplore.ieee.org/iel2/1014/12510/00576640.pdf},
Volume = {1},
Year = {1992},
Abstract = {A closed form Fourier transform relationship between the range signal, azimuth signal domain and the range signal, azimuth frequency (or Doppler) domain is presented. The derivation assumes the presence of a large timebandwidth pulse modulation in range. The expression is valid over a wide angular field of view, and expressed using the hyperbolic range equation. The resulting Fourier transform pair is of general utility in SAR, tomography, active seismics and related imaging problems, and allows more insight into the imaging process in the presence of range curvature than is normally available.},
Keywords = {SAR Processing, Wavenumber Domain Algorithm, omegak, Wavenumber Domain Algorithm, Stationary Phase Method, Closed Form Fourier Transform},
Pdf = {../../../docs/raney.pdf}
}

Hartmut Runge and Richard Bamler.
A Novel High Precision SAR Focussing Algorithm Based On Chirp Scaling.
In IGARSS '92, International Geoscience and Remote Sensing Symposium,
pages 372  375,
May 1992.
Keyword(s): SAR Processing,
Chirp Scaling Algorithm,
Range Migration Algorithm,
omegak,
Wavenumber Domain Algorithm,
RangeDoppler Algorithm,
Comparison of Algorithms,
Squinted SAR.
Abstract: 
Azimuth compression of synthetic aperture radar data is an inherently twodimensional problem because the SAR reference function migrates through several range resolution cells. This effect is referred to as range cell migration. For perfect focusing of the image the fact has to be accounted for that the amount of range cell migration varies with range. In classical rangeDoppler SAR processors as well as with twodimensional frequency domain processors a spacevariant interpolation is required in order to compensate for this effect. In general, interpolation will degrade the final image quality and is computation time consuming. The proposed new algorithm avoids any interpolation step. It is essential for the algorithm that the SAR data are transformed to the rangeDoppler domain prior to range compression. In this domain each range line is premultiplied with a particular phase function which is designed to perfectly straighten the range cell migration trajectories even for arbitrarily wide swath by the subsequent range compression step. This new method for range migration correction is the key element of a new SAR processing algorithm described in detail. The proposed method is inherently phase preserving. Its focusing quality is neither limited by high squint nor by wide swath. The implementation is simple because only multiplications and Fourier transforms are required. The paper presents a detailed derivation of the algorithm theory and illustrates possible implementations. 
@InProceedings{RungeBamler92:Processing,
Title = {{A Novel High Precision SAR Focussing Algorithm Based On Chirp Scaling}},
Author = {Hartmut Runge and Richard Bamler},
Booktitle = {IGARSS '92, International Geoscience and Remote Sensing Symposium},
Month = May,
Pages = {372  375},
Url = {http://ieeexplore.ieee.org/iel2/1014/12510/00576715.pdf},
Year = {1992},
Abstract = {Azimuth compression of synthetic aperture radar data is an inherently twodimensional problem because the SAR reference function migrates through several range resolution cells. This effect is referred to as range cell migration. For perfect focusing of the image the fact has to be accounted for that the amount of range cell migration varies with range. In classical rangeDoppler SAR processors as well as with twodimensional frequency domain processors a spacevariant interpolation is required in order to compensate for this effect. In general, interpolation will degrade the final image quality and is computation time consuming. The proposed new algorithm avoids any interpolation step. It is essential for the algorithm that the SAR data are transformed to the rangeDoppler domain prior to range compression. In this domain each range line is premultiplied with a particular phase function which is designed to perfectly straighten the range cell migration trajectories even for arbitrarily wide swath by the subsequent range compression step. This new method for range migration correction is the key element of a new SAR processing algorithm described in detail. The proposed method is inherently phase preserving. Its focusing quality is neither limited by high squint nor by wide swath. The implementation is simple because only multiplications and Fourier transforms are required. The paper presents a detailed derivation of the algorithm theory and illustrates possible implementations.},
Comment = {++},
Keywords = {SAR Processing, Chirp Scaling Algorithm, Range Migration Algorithm, omegak, Wavenumber Domain Algorithm, RangeDoppler Algorithm, Comparison of Algorithms, Squinted SAR},
Pdf = {../../../docs/RungeBamler92.pdf}
}
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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: Mon Feb 1 16:39:00 2021
Author: Othmar Frey, Earth Observation and Remote Sensing, Institute of Environmental Engineering, Swiss Federal Institute of Technology  ETH Zurich .
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