BACK TO INDEX BACK TO OTHMAR FREY'S HOMEPAGE Publications of year 1988 Articles in journal or book chapters
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| Abstract: | Simulations were used to investigate the effect of covariance matrix sample size on the system performance of adaptive arrays using the sample matrix inversion (SMI) algorithm. Inadequate estimation of the covariance matrix results in adapted antenna patterns with high sidelobes and distorted mainbeams. A technique to reduce these effects by modifying the covariance matrix estimate is described from the point of view of eigenvector decomposition. This diagonal loading technique reduces the system nulling capability against low-level interference, but parametric studies show that it is an effective approach in many situations |
@Article{carlson1988:DiagonalLoading,
Title = {{Covariance matrix estimation errors and diagonal loading in adaptive arrays}},
Author = {Carlson, B.D.},
Doi = {10.1109/7.7181},
ISSN = {0018-9251},
Month = {Jul},
Number = {4},
Pages = {397-401},
Url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7181&isnumber=377},
Volume = {24},
Year = {1988},
Abstract = {Simulations were used to investigate the effect of covariance matrix sample size on the system performance of adaptive arrays using the sample matrix inversion (SMI) algorithm. Inadequate estimation of the covariance matrix results in adapted antenna patterns with high sidelobes and distorted mainbeams. A technique to reduce these effects by modifying the covariance matrix estimate is described from the point of view of eigenvector decomposition. This diagonal loading technique reduces the system nulling capability against low-level interference, but parametric studies show that it is an effective approach in many situations},
Journal = {IEEE Transactions on Aerospace and Electronic Systems},
Keywords = {SAR Processing, Beamforming, array processing, antenna phased arrays, antenna theory, digital simulation, eigenvalues and eigenfunctions, estimation theory, matrix algebraadapted antenna patterns, adaptive arrays, covariance matrix sample size, diagonal loading, distorted mainbeams, eigenvector decomposition, estimation errors, low-level interference, nulling, sample matrix inversion, sidelobes},
Owner = {ofrey},
Pdf = {../../../docs/carlson1988.pdf}
}
Keyword(s): SAR Processing,
Phase Unwrapping,
Branch-Cut,
Branch-Cut Phase Unwrapping,
SAR Interferometry,
Spaceborne SAR,
InSAR,
DInSAR,
geophysical image processing,
geophysical techniques,
radar interferometry,
synthetic aperture radar.
| Abstract: | Interferometric synthetic aperture radar observations provide a means for obtaining high-resolution digital topographic maps from measurements of amplitude and phase of two complex radar images. The phase of the radar echoes may only be measured modulo 2pi; however, the whole phase at each point in the image is needed to obtain elevations. We present here our approach to unwrapping the 2pi ambiguities in the two-dimensional data set. We find that noise and geometrical radar layover corrupt our measurements locally, and these local errors can propagate to form global phase errors that affect the entire image. We show that the local errors, or residues, can be readily identified and avoided in the global phase estimation. We present a rectified digital topographic map derived from our unwrapped phase values. |
@Article{goldsteinZebkerWernerBranchCutPhaseUnwrapping1988,
author = {Goldstein, Richard M. and Zebker, Howard A. and Werner, Charles L.},
title = {Satellite radar interferometry: Two-dimensional phase unwrapping},
journal = {Radio Science},
year = {1988},
volume = {23},
number = {4},
pages = {713-720},
issn = {1944-799X},
abstract = {Interferometric synthetic aperture radar observations provide a means for obtaining high-resolution digital topographic maps from measurements of amplitude and phase of two complex radar images. The phase of the radar echoes may only be measured modulo 2pi; however, the whole phase at each point in the image is needed to obtain elevations. We present here our approach to unwrapping the 2pi ambiguities in the two-dimensional data set. We find that noise and geometrical radar layover corrupt our measurements locally, and these local errors can propagate to form global phase errors that affect the entire image. We show that the local errors, or residues, can be readily identified and avoided in the global phase estimation. We present a rectified digital topographic map derived from our unwrapped phase values.},
doi = {10.1029/RS023i004p00713},
file = {:goldsteinZebkerWernerBranchCutPhaseUnwrapping1988.pdf:PDF},
keywords = {SAR Processing, Phase Unwrapping, Branch-Cut, Branch-Cut Phase Unwrapping, SAR Interferometry, Spaceborne SAR, InSAR, DInSAR, geophysical image processing;geophysical techniques; radar interferometry; synthetic aperture radar},
pdf = {../../../docs/goldsteinZebkerWernerBranchCutPhaseUnwrapping1988.pdf},
url = {http://dx.doi.org/10.1029/RS023i004p00713},
}
Keyword(s): Interpolation,
Band-Limited,
Reconstruction,
Unevenly Spaced Data.
| Abstract: | This paper adresses the problem of reconstructing a band-limited signal from a finite number of unevenly spaced sampled data. A Fourier analysis of the available unevenly spaced sampled data is presented. The result is utilized to develop an interpolation scheme from the available data. Conditions for accurate reconstruction are examined. Algorithms to implement the reconstruction scheme are discussed. The method's application in one-dimensional and two-dimensional reconstruction problems are shown. |
@Article{soumekh88:interpol,
Title = {{Band-Limited Interpolation from Unevenly Spaced Sampled Data}},
Author = {Mehrdad Soumekh},
Month = Jan,
Number = {1},
Pages = {110-122},
Url = {http://ieeexplore.ieee.org/iel1/29/97/00001497.pdf},
Volume = {36},
Year = {1988},
Abstract = {This paper adresses the problem of reconstructing a band-limited signal from a finite number of unevenly spaced sampled data. A Fourier analysis of the available unevenly spaced sampled data is presented. The result is utilized to develop an interpolation scheme from the available data. Conditions for accurate reconstruction are examined. Algorithms to implement the reconstruction scheme are discussed. The method's application in one-dimensional and two-dimensional reconstruction problems are shown.},
Journal = {IEEE Transactions on Acoustics, Speech, and Signal Processing},
Keywords = {Interpolation, Band-Limited, Reconstruction, Unevenly Spaced Data},
Pdf = {../../../docs/soumekh88.pdf}
}
Keyword(s): SAR Processing,
Template Correlation,
2D Filter,
Nonseparable SAR Processing,
Range Migration Algorithm,
omega-k,
Wavenumber Domain Algorithm.
| Abstract: | The author examines the nonseparable, template correlation approach to digital-strip-mode synthetic-aperture radar (SAR) phase history processing and concludes that it can now outperform the traditional separable approaches in the areas of speed, image quality, control simplicity, and flexibility. A working nonseparable frequency-domain SAR processor is described and evaluated. The image quality is seen to be superior to that resulting from the separable approaches. Based on the working intermediate hardware implementation, the author strongly suggests that future VHSIC and other advanced implementation will provide extremely fast (real time), high-quality, small, flexible SAR processors. |
@Article{DiCenzo88:NonseparableProc,
Title = {{A New Look at Nonseparable Synthetic Aperture Radar Processing}},
Author = {Alan di Cenzo},
Month = May,
Number = {3},
Pages = {218-223},
Url = {http://ieeexplore.ieee.org/iel4/7/4950/00192089.pdf},
Volume = {24},
Year = {1988},
Abstract = {The author examines the nonseparable, template correlation approach to digital-strip-mode synthetic-aperture radar (SAR) phase history processing and concludes that it can now outperform the traditional separable approaches in the areas of speed, image quality, control simplicity, and flexibility. A working nonseparable frequency-domain SAR processor is described and evaluated. The image quality is seen to be superior to that resulting from the separable approaches. Based on the working intermediate hardware implementation, the author strongly suggests that future VHSIC and other advanced implementation will provide extremely fast (real time), high-quality, small, flexible SAR processors.},
Journal = {IEEE Transactions on Aerospace and Electronic Systems},
Keywords = {SAR Processing, Template Correlation, 2D Filter, Nonseparable SAR Processing, Range Migration Algorithm, omega-k, Wavenumber Domain Algorithm},
Pdf = {../../../docs/DiCenzo88.pdf}
}
Conference articles
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J. L. Bauck and W. K. Jenkins.
Tomographic Processing of Spotlight-Mode Synthetic Aperture Radar Signals with Compensation for Wavefront Curvature.
In ICASSP '88, International Conference on Acoustics, Speech, and Signal Processing,
volume 2,
pages 1192-1195,
April 1988.
Keyword(s): SAR Processing,
Bistatic SAR,
Back-Projection,
bistatic synthetic aperture radar,
Azimuth Focusing,
convolution back-projection,
elliptical-arc projections,
final reconstructed image,
ground patch,
image resource,
pixel,
weighting,
radar cross-sections,
radar theory,
Spotlight mode,
Airborne SAR,
Tomographic Processing,
Tomography,
Wavefront Curvature.
Abstract: An algorithm is introduced which corrects for problems which arise in spotlight-mode synthetic aperture radar (SAR) when a significant amount of wavefront curvature is present. Wavefront curvature can be problematic when it is desired to reconstruct high-resolution images of ground patches which subtend a large angle at the radar. The proposed, non-Fourier, algorithm uses mappings to modify the convolution-backprojection method of computed tomography, providing reconstructions from circular-arc projections that are of the same high quality as those made from standard straight-line projections using the unmodified algorithm. In addition, other problems in high-resolution SAR imaging are identified which have solutions involving tomographic concepts, including situations which give rise to fan-beam-like projections. The new algorithm can be modified to deal with these problems as well. @InProceedings{BauckJenkins88:Backproj, author = {J. L. Bauck and W. K. Jenkins}, booktitle = {ICASSP '88, International Conference on Acoustics, Speech, and Signal Processing}, title = {{Tomographic Processing of Spotlight-Mode Synthetic Aperture Radar Signals with Compensation for Wavefront Curvature}}, year = {1988}, month = apr, pages = {1192-1195}, volume = {2}, abstract = {An algorithm is introduced which corrects for problems which arise in spotlight-mode synthetic aperture radar (SAR) when a significant amount of wavefront curvature is present. Wavefront curvature can be problematic when it is desired to reconstruct high-resolution images of ground patches which subtend a large angle at the radar. The proposed, non-Fourier, algorithm uses mappings to modify the convolution-backprojection method of computed tomography, providing reconstructions from circular-arc projections that are of the same high quality as those made from standard straight-line projections using the unmodified algorithm. In addition, other problems in high-resolution SAR imaging are identified which have solutions involving tomographic concepts, including situations which give rise to fan-beam-like projections. The new algorithm can be modified to deal with these problems as well.}, keywords = {SAR Processing, Bistatic SAR, Back-Projection, bistatic synthetic aperture radar; Azimuth Focusing, convolution back-projection; elliptical-arc projections;final reconstructed image;ground patch;image resource;pixel;weighting;radar cross-sections;radar theory, Spotlight mode, Airborne SAR, Tomographic Processing, Tomography, Wavefront Curvature}, pdf = {../../../docs/bauckJenkins88.pdf}, } -
D.J. DiFilippo,
G.E. Haslam,
and W.S. Widnall.
Evaluation of a Kalman filter for SAR motion compensation.
In IEEE Position Location and Navigation Symposium, PLANS '88,
pages 259-268,
December 1988.
Keyword(s): SAR Processing,
Motion Compensation,
Residual Errors,
Kalman filters,
filtering and prediction theory,
military systems,
radar antennas,
Kalman filter,
SAR motion compensation,
SARMCS,
air turbulence,
airborne SAR,
aircraft maneuvers,
inertial measurement unit,
low-cost strapdown IMU,
radar antenna,
synthetic aperture radar.
Abstract: A synthetic aperture radar motion compensation system (SARMCS) is being developed at the Defence Research Establishment Ottawa to compensate an airborne SAR for spurious motions of the radar antenna that may be caused by air turbulence of aircraft maneuvers. A Kalman filter has been developed as part of this SAR motion compensation system which uses a low-cost strapdown IMU (inertial measurement unit), to measure antenna motion. The function of the Kalman filter is to control misalignments of the strapdown analytical platform, since analysis has indicated that these errors are dominant contributors to motion compensation error. Representative results from processing raw recorded flight data have verified the proper operation of all aspects of the Kalman filter and have indicated that the filter performance is consistent with the motion compensation requirements. Some examples of actual SAR strip-map imagery are shown in order to demonstrate the enhancement provided by the SARMCS. @InProceedings{DiFilippoHaslamWidnall88:MoCoResidualErrors, Title = {{Evaluation of a Kalman filter for SAR motion compensation}}, Author = {DiFilippo, D.J. and Haslam, G.E. and Widnall, W.S.}, Booktitle = {IEEE Position Location and Navigation Symposium, PLANS '88}, Month = dec, Pages = {259-268}, Url = {http://ieeexplore.ieee.org/iel2/776/5023/00195492.pdf}, Year = {1988}, Abstract = {A synthetic aperture radar motion compensation system (SARMCS) is being developed at the Defence Research Establishment Ottawa to compensate an airborne SAR for spurious motions of the radar antenna that may be caused by air turbulence of aircraft maneuvers. A Kalman filter has been developed as part of this SAR motion compensation system which uses a low-cost strapdown IMU (inertial measurement unit), to measure antenna motion. The function of the Kalman filter is to control misalignments of the strapdown analytical platform, since analysis has indicated that these errors are dominant contributors to motion compensation error. Representative results from processing raw recorded flight data have verified the proper operation of all aspects of the Kalman filter and have indicated that the filter performance is consistent with the motion compensation requirements. Some examples of actual SAR strip-map imagery are shown in order to demonstrate the enhancement provided by the SARMCS.}, Keywords = {SAR Processing, Motion Compensation, Residual Errors, Kalman filters, filtering and prediction theory, military systems, radar antennas, Kalman filter, SAR motion compensation, SARMCS, air turbulence, airborne SAR, aircraft maneuvers, inertial measurement unit, low-cost strapdown IMU, radar antenna, synthetic aperture radar}, Pdf = {../../../docs/DiFilippoHaslamWidnall88.pdf} } -
James E. Harris,
Randall S. Ostler,
Douglas M. Chabries,
and Richard W. Christiansen.
Quality Measures for SAR Images.
In IEEE International Conference on Acoustics, Speech, and Signal Processing ICASSP,
volume 2,
pages 1064-1067,
April 1988.
Keyword(s): SAR Processing,
Quality Assessment,
Quality Measures.
Abstract: Synthetic aperture radar (SAR) contains information features different from those of infrared images and conventional photography. Image quality measures specifically created for SAR are necessary to measure SAR processor performance especially in the context of lossy image data compression. The quality measures discussed include several existing measures and newly developed measures created to better gauge specific features of SAR imagery. Each quality performance measure is evaluated subjectively to determine the applicability to SAR image fidelity. @InProceedings{HarrOstlChabChris88:Quali, Title = {{Quality Measures for SAR Images}}, Author = {James E. Harris and Randall S. Ostler and Douglas M. Chabries and Richard W. Christiansen}, Booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing ICASSP}, Month = apr, Pages = {1064-1067}, Url = {http://ieeexplore.ieee.org/iel2/723/5035/00196777.pdf}, Volume = {2}, Year = {1988}, Abstract = {Synthetic aperture radar (SAR) contains information features different from those of infrared images and conventional photography. Image quality measures specifically created for SAR are necessary to measure SAR processor performance especially in the context of lossy image data compression. The quality measures discussed include several existing measures and newly developed measures created to better gauge specific features of SAR imagery. Each quality performance measure is evaluated subjectively to determine the applicability to SAR image fidelity.}, Keywords = {SAR Processing, Quality Assessment, Quality Measures}, Pdf = {../../../docs/HarrOstlChabChris88.pdf} }
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This collection of SAR literature is far from being complete.
It is rather a collection of papers which I store in my literature data base. Hence, the list of publications under PUBLICATIONS OF AUTHOR'S NAME
should NOT be mistaken for a complete bibliography of that author.
Last modified: 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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