A new formulation of polar format algorithm for bistatic spotlight SAR

In this paper, a new interpretation of the polar format algorithm (PFA) for bistatic spotlight synthetic aperture radar (SAR) imaging is presented. From the viewpoint of two-dimensional decoupling, we examine the commonly adopted implementation of the PFA, i.e., the separable 1-D range and azimuth resampling procedures for their roles in range cell migration (RCM) correction, respectively. It is shown that the range resampling corrects for the RCM associated with the down-range coordinate of target, while the azimuth resampling compensates for the RCM associated with the cross-range coordinate of target. The presented work provides a new perspective on the mechanism of RCM correction in PFA.