干涉SAR提高地距方向分辨率的简明推导

A concise formula derivation for ground-range-resolution improvement by InSAR

用两种方法对干涉SAR提高地距方向分辨率进行证明。第一种方法首先证明空间分离的调频步进脉冲信号与通常的调频步进脉冲信号在匹配滤波满足一定条件时是等同的。接着证明干涉SAR在地距方向的信号模型与空间分离的调频步进脉冲信号模型是等同的,进而推导出干涉SAR地距方向的观测频谱展宽的公式。第二种方法从电磁波空间波数k在地距方向的投影出发,同样推导出干涉SAR地距方向观测频谱展宽的公式。计算表明干涉SAR两个通道的斜距相对测量误差对分辨率的改善有显著影响。

Two approaches were presented to show the improvement of ground resolution by cross-track interferometric SAR. In the first approach, an equivalent relation was firstly derived between the usual stepped-frequency chirp signal （SFCS） and the SFCS with all subchirps transmitted at different positions （SFCS DP） when some condition was contented during matched filtering, and then the signal model of InSAR in ground direction was shown to be equivalent to that of SFCS_ DP, and finally an broadened spatial spectrum observed in ground direction was derived. In the second approach, the projection of wave number k in ground direction was used to derive the widening of observed spatial spectrum. Simulations showed that the relative error of range measurements between two channels had remarkable influence on the final result.