基于频域扩展和SPECAN的全孔径TOPSAR成像算法

摘要

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.%摘 要:TOPSAR(Terrain Observation by Progressive scans SAR)是星载SAR的一种新工作模式,这种工作模式在保持ScanSAR宽测绘带优点的同时,解决了扇贝效应(scalloping)等问题,具有广泛的应用前景.针对TOPSAR信号在时域和频域都混叠的特点,该文提出了一种新的全孔径TOPSAR成像算法,算法利用频域扩展来解决TOPSAR的频域混叠问题,利用SPECAN(SPECtral ANalysis)技术来避免输出图像时域混叠,结构紧凑,处理效率较高.通过点阵目标和分布目标的仿真来验证了算法的有效性,并分析了算法的计算量,通过与几种现有的全孔径成像算法对比,说明了算法的高效性.