改进的接收机固定双站NLCS成像方法

该文针对机载双站SAR收、发系统分置的特点,首先建立了接收机静止模式下双站SAR的回波信号模型,然后分析该模式下几何特点、距离徙动及距离徙动差和方位向调频率的变化情况,接着讨论距离多谱勒域距离向调频率的变化情况,并提出了方位向调频率扰动函数的解析表达式,在此基础上结合单站的CS算法实现接收机静止的双站SAR数据聚焦,并对应用此成像算法所得扭曲聚焦图像进行几何校正处理。仿真实验验证了该文提出的方法的正确性和在接收机静止模式下应用此算法处理大测绘带成像的可行性。

An Improved NLCS Imaging Algorithm of Bistatic SAR with a Stationary Receiver

This paper starts from a signal model of a stationary receiver configuration in airborne bistatic SAR systems which are characterized by spatially separated transmitters and receivers. Through analyzing the system geometrical characteristic, the range cell migration, the influence of the difference on the range cell migration and the change of the linear FM rate both in range and azimuth direction in RD field are discussed. And then a nonlinear perturbation function is deduced to equalize the targets’ FM rates in azimuth direction. After that, an imaging algorithm based on the CSA for bistatic SAR with a stationary receiver is get, and the distorted image is corrected. Finally the validity and the feasibility of dealing with big mapping zone of the algorithm proposed with this paper is supported with point target simulation experiments.