image formation places severe demands on the image formation hardware.
The process needs to be completely automated, but nevertheless efficient
to minimize hardware size and weight. To this end, Sandia has developed
the Overlapped Subaperture (OSA) image formation algorithm to efficiently
match image formation tasks to easily implemented DSP operations. This
is facilitated by Sandia's unique real-time motion compensation strategy.
Furthermore, residual phase errors are mitigated by the Sandia developed
Phase-Gradient Autofocus (PGA) algorithm.
Most Sandia designed
synthetic aperture radar systems have the ability to store the unprocessed
phase history data (raw radar returns). This data can be (and has been)
processed on ground-based computers (post-flight) with any of a variety
of image formation algorithms and their variations including Linear
Range-Doppler processing, Polar Format processing, Sandia developed
Polar-formatted Overlapped Subaperture (PFOSA) processing, Sandia developed
Tiered Subaperture (TSA) processing, and Migration processing.
Burns, B. L., J.
T. Cordaro, Imaging Synthetic Aperture Radar, US Patent 5,608,404
Burns, B. L., J.
T. Cordaro, "SAR image formation algorithm that compensates for the
spatially variant effects of antenna motion", SPIE 1994 Symposium on
OE/Aerospace Sensing and Dual Use Photonics, Algorithms for SAR Imagery
I, Vol. 2230, Orlando, FL, 4-8 April 1994.
Doerry, A. W.,
"Synthetic Aperture Radar Processing with Polar Formatted Subapertures",
Conference Record of The Twenty-Eighth Asilomar Conference on Signals,
Systems & Computers, Pacific Grove, California, Oct. 31 - Nov. 2,
"Patch diameter limits for tiered subaperture SAR image formation algorithms",
SPIE 1995 Symposium on OE/Aerospace Sensing and Dual Use Photonics,
Algorithms for SAR Imagery II, Vol. 2487, Orlando, FL, 17-21 April 1995.