Fast Correction for Residual Distortion in PFA Wavefront Curvature Correction for General BiSAR

Abstract

Geometric distortion is a common issue in polar format imaging for bistatic SAR (BiSAR). The existing results on PFA geometric distortion all adopt 2-D interpolation to correct the distortion, suffering high computational burden. This paper utilizes image-division in a previously presented wavefront curvature correction method and proposed a fast correction for PFA geometric distortion. Regarding the distortion of each sub-image as a center shift and a residual distortion, the new correction only handles the residual distortion. Within a relatively small sub-image, the residual distortion can be modeled as a couple of simplified expressions, then the correction can be easily realized through a two-step phase compensation. The flowchart of the proposed correction is designed and numerical simulations are carried out to verify the effectiveness.