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Title: Synthetic aperture radar motion compensation using autofocus. Final report, August 13, 1996--March 6, 1997

Publication Date:
Research Org.:
Technology Service Corp., Santa Monica, CA (United States)
Sponsoring Org.:
USDOE Office of Energy Research, Washington, DC (United States)
OSTI Identifier:
Report Number(s):
ON: TI97020744; TRN: AHC29906%%1
DOE Contract Number:
Type / Phase:
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: May 1997
Country of Publication:
United States

Citation Formats

Kirk, J.C. Jr. Synthetic aperture radar motion compensation using autofocus. Final report, August 13, 1996--March 6, 1997. United States: N. p., 1997. Web.
Kirk, J.C. Jr. Synthetic aperture radar motion compensation using autofocus. Final report, August 13, 1996--March 6, 1997. United States.
Kirk, J.C. Jr. 1997. "Synthetic aperture radar motion compensation using autofocus. Final report, August 13, 1996--March 6, 1997". United States. doi:.
title = {Synthetic aperture radar motion compensation using autofocus. Final report, August 13, 1996--March 6, 1997},
author = {Kirk, J.C. Jr.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1997,
month = 5

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  • The purpose of the Signal Based Motion Compensation (SBMC) for Synthetic Aperture Radar (SAR) effort is to develop a method to measure and compensate for both down range and cross range motion of the radar in order to provide high quality focused SAR imagery in the absence of precision measurements of the platform motion. Currently SAR systems require very precise navigation sensors for motion compensation. These sensors are very expensive and are often supplied in pairs for reliability. In the case of GPS they can be jammed, further degrading performance. This makes for a potentially very expensive and possibly vulnerablemore » SAR system. SBMC can eliminate or reduce the need for these expensive navigation sensors thus reducing the cost of budget minded SAR systems. The results on this program demonstrated the capability of the SBMC approach.« less
  • Synthetic Aperture Radar (SAR) imaging is a class of coherent range and Doppler signal processing techniques applied to remote sensing. The aperture is synthesized by recording and processing coherent signals at known positions along the flight path. Demands for greater image resolution put an extreme burden on requirements for inertial measurement units that are used to maintain accurate pulse-to-pulse position information. The recently developed Phase Gradient Autofocus algorithm relieves this burden by taking a data-driven digital signal processing approach to estimating the range-invariant phase aberrations due to either uncompensated motions of the SAR platform or to atmospheric turbulence. Although themore » performance of this four-step algorithm has been demonstrated, its convergence has not been modeled mathematically. A new sensitivity study of algorithm performance is a necessary step towards this model. Insights that are significant to the application of this algorithm to both SAR and to other coherent imaging applications are developed. New details on algorithm implementation identify an easily avoided biased phase estimate. A new algorithm for defining support of the point spread function is proposed, which promises to reduce the number of iterations required even for rural scenes with low signal-to-clutter ratios.« less
  • When residual range migration due to either real or apparent motion errors exceeds the range resolution, conventional autofocus algorithms fail. A new migration-correction autofocus algorithm has been developed that estimates the migration and applies phase and frequency corrections to properly focus the image.
  • This report represents the culmination of over nine years of research activity in the study of superconducting and magnetically ordered materials using the muon spin rotation ({mu}SR) and neutron scattering techniques. Because all the activities that took place up until March 1996 have been covered in previous annual reports, this final report includes only a brief overview of activities prior to that date, and concentrates on the period from March 1996 through August 1997. The primary activity undertaken in this project has been studies of high-temperature superconductors and their close chemical relatives with the {mu}SR technique. These experiments extend frommore » early work done with a relatively primitive muon beam at the AGS of Brookhaven National Laboratory and large polycrystalline samples of the earliest known high-{Tc} materials to studies of very small high-purity single crystals of the best high-{Tc} materials currently available using the highest quality surface muon beams and specially-designed low-background spectrometers at the Tri-University Meson Facility (TRIUMF) in the past three years. During the period since the last annual report five {mu}SR experiments were done at TRIUMF with DOE support. A study of single-crystal high-temperature superconductors was done in July 1996. A study of the quasicrystal materials Gd{sub 8}Mg{sub 42}Zn{sub 50} and Tb{sub 8}Mg{sub 42}Zn{sub 50} was done by D.R. Noakes in collaboration with G.M. Kalvius of the Technical University of Munich and R. Waeppling of Uppsala University during the first week of December 1996. During the second week of December 1996 a study of the cryocrystals CH{sub 4} and CF{sub 4} was done by D.R. Noakes in collaboration with S. Storchak of Moscow State University and J.H. Brewer of the University of British Columbia. A study of high-{Tc} superconductors was done at TRIUMF during the third week of December 1996 by C.E. Stronach and D.R. Noakes.« less