A Spatial Variation Compensation Imaging Algorithm for Harmonic SAR

As a new imaging radar system, harmonic synthetic aperture radar (H-SAR) has the advantage of no fundamental frequency clutter. We analyze H-SARs characteristics and find that the H-SAR encounters defocusing due to the severe spatial variation along the range dimension (SVRD). The traditional algorithm to solve the SVRD by scene segmentation causes image overlap during subregion mosaicking. In this article, we propose a novel spatial variation compensation imaging algorithm. The proposed algorithm divides the imaging region into subregions according to the derived focusing range depth and constructs an individual azimuth-matched vector group for each subregion. Each azimuth-matched vector group is combined into an azimuth-matched matrix to compensate for the SVRD. The imaging results using both simulated and real data demonstrate the effectiveness of the proposed algorithm.