Full Aperture Imagining Algorithm of TOPSAR Based on Frequency Domain Extension and SPECAN

Terrain Observation by Progressive scans SAR (TOPSAR) is a new and prospective mode of space-borne SAR. It keeps the wide swath advantage of ScanSAR, and solves the problems as scalloping. The signal of TOPSAR is alias in both frequency domain and time domain, to solve the problems, this article proposes a new full aperture imaging algorithm. The algorithm uses the frequency domain extension to solve the frequency domain alias and uses SPECtral ANalysis (SPECAN) technique to avoid the time domain alias of the output image. It is compact and efficient. Lattice-point targets and distribute targets are simulated to validate the algorithm. The amount of the computation is analyzed and the algorithm is compared with two existing full aperture algorithms to validate the effectiveness.