Real-time ultra-fine-resolution 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.

References:

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, 1994, pp1210-1215.

Doerry, Armin, "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.