星载聚束式SAR改进的Frequency Scaling成像算法

本文提出一种适用于星载聚束式合成孔径雷达(SAR)的改进Frequency Scaling算法.基于斜视距离等效模型,推导出改进的FS算法,给出改进的FS因子和相关因子以及算法的实现步骤.在斜视情况下改进的FS因子可避免距离向频谱混迭,并可进行更精确的二次距离压缩,改进的方位因子可以减小算法所需要的方位时间展宽,提高方位处理效率.为解决高分辨率星载聚束式 SAR脉冲重复频率(PRF)过高等问题,在算法中结合了子孔径处理,并分析了采用子孔径处理的必要性及其实现方法.最后,通过计算机仿真,验证了算法的有效性.

Refined Frequency Scaling Algorithm for Spaceborne Spotlight SAR Imaging

A refined frequency scaling algorithm for spaceborne spotlight synthetic aperture radar (SAR) imaging is presented.The algorithm can process dechirped raw data directly.Based on the squinted range equivalent model that is fitter for spaceborne geometrical relation than the broadside range model,the complete derivation of the algorithm is presented and the refined frequency scaling factors of each signal domain are given.The refined factors can process the secondary range compression more accurately and avoid that range bandwidth is aliased or shifted outside the processed bandwidth for squinted mode.The refined azimuth scaling factor can decease azimuth time expansion and improve efficiency of azimuth processing.Besides,in order to decrease very high pulse repetition frequency (PRF) and data rate of spaceborne spotlight SAR and alleviate the design difficulties of spaceborne system,a subaperture approach is introduced.The necessity and implementation of the subaperture approach are analyzed.Finally,the computer simulation shows the validity of the refined algorithm.