PRECISION FOCUSING ALGORITHMS FOR SPACEBORNE SYNTHETIC-APERTURE RADAR(SAR)

The two-dimensional transfer function is derived from the Synthetic Ap erture Radar (SAR) imaging model. Using this expression, the approxima tions made in the classical range-Doppler and recent chirp-scaling alg orithms are examined. An alternative algorithm to the chirp-scaling al gorithm is presented. Unlike the chirp-scaling algorithm, this algorit hm does not require the transmitted signal to be a linear FM signal an d can be easily incorporated into processors using the range-Doppler a lgorithm. The processing starts with range compressed data rather than from the raw SAR data. Results from processing simulated point target s and the Seasat Goldstone area data show comparable image quality.