A Novel Imaging Algorithm for Spotlight SAR Based on Scaling Transform

Based on the principle of planar wavefront assumption, a novel point of view in processing the spotlight synthetic aperture radar (SAR) data is proposed in this letter. After match filtering and motion compensation to the scene center, from the perspective of range cell migration correction (RCMC), two scaling transforms (a range-frequency scaling with a subsequent azimuth-time scaling) are proposed to correct the range cell migration caused by the coupling between the range-frequency and azimuth-time. Moreover, to reduce the spectrum loss (the loss of image resolution), two constant scaling factors are introduced to optimize the range-frequency and azimuth-time scaling transforms, which enable the presented algorithm to realize the flexible and efficient imaging ability. Simulation results are conducted to validate the efficacy of this algorithm.