Scene Size Bounds for PFA Imaging with Postfiltering

The polar format algorithm (PFA) for synthetic aperture radar (SAR) image formation utilizes a first-order Taylor approximation of the differential range to improve computational efficiency, leading to image distortion and defocus. Limiting scene size by bounding the second-order Taylor series terms can restrict the impact of these errors, or alternatively, one may correct for these errors through spatially-variant filtering in post processing. In this letter we analyze the increase in allowable scene size that is realized through such processing.