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Title: Correction of motion measurement errors beyond the range resolution of a synthetic aperture radar

Abstract

Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.

Inventors:
 [1];  [1];  [1]
  1. Albuquerque, NM
Publication Date:
Research Org.:
Sandia National Laboratories (SNL-NM), Albuquerque, NM
Sponsoring Org.:
USDOE
OSTI Identifier:
941140
Patent Number(s):
7,391,357
Application Number:
11/243,826
Assignee:
Sandia Corporation (Albuquerque, NM) ALO
DOE Contract Number:
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Doerry, Armin W, Heard, Freddie E, and Cordaro, J Thomas. Correction of motion measurement errors beyond the range resolution of a synthetic aperture radar. United States: N. p., 2008. Web.
Doerry, Armin W, Heard, Freddie E, & Cordaro, J Thomas. Correction of motion measurement errors beyond the range resolution of a synthetic aperture radar. United States.
Doerry, Armin W, Heard, Freddie E, and Cordaro, J Thomas. 2008. "Correction of motion measurement errors beyond the range resolution of a synthetic aperture radar". United States. doi:. https://www.osti.gov/servlets/purl/941140.
@article{osti_941140,
title = {Correction of motion measurement errors beyond the range resolution of a synthetic aperture radar},
author = {Doerry, Armin W and Heard, Freddie E and Cordaro, J Thomas},
abstractNote = {Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2008,
month = 6
}

Patent:

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  • Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.
  • Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.
  • This patent describes a phase gradient autofocus system for use in synthetic aperture imaging that accurately compensates for arbitrary phase errors in each imaged frame by locating highlighted areas and determining the phase disturbance or image spread associated with each of these highlight areas. An estimate of the image spread for each highlighted area in a line in the case of one dimensional processing or in a sector, in the case of two-dimensional processing, is determined. The phase error is determined using phase gradient processing. The phase error is then removed from the uncorrected image and the process is iterativelymore » performed to substantially eliminate phase errors which can degrade the image.« less
  • A phase gradient autofocus system for use in synthetic aperture imaging accurately compensates for arbitrary phase errors in each imaged frame by locating highlighted areas and determining the phase disturbance or image spread associated with each of these highlight areas. An estimate of the image spread for each highlighted area in a line in the case of one dimensional processing or in a sector, in the case of two-dimensional processing, is determined. The phase error is determined using phase gradient processing. The phase error is then removed from the uncorrected image and the process is iteratively performed to substantially eliminatemore » phase errors which can degrade the image.« less
  • A synthetic aperture radar (SAR) image is produced by using all phase histories of a set of phase histories to produce a first pixel array having a first azimuth resolution, and using less than all phase histories of the set to produce a second pixel array having a second azimuth resolution that is coarser than the first azimuth resolution. The first and second pixel arrays are combined to produce a third pixel array defining a desired SAR image that shows distinct shadows of moving objects while preserving detail in stationary background clutter.