结合视线方向运动补偿的滑动聚束SAR子孔径成像算法

An imaging algorithm for sliding spotlight SAR using subaperture with line-of-sight motion compensation

滑动聚束合成孔径雷达(SAR)是一种新兴的成像模式,既可以提高方位向分辨率又能够扩展成像范围。其数据处理时需要考虑两个关键问题:一是系统脉冲重复频率(PRF)不足,方位向信号发生混叠;二是合成孔径长度的增加使运动误差的影响更为突出,运动补偿(MOCO)精度要求提高。基于子孔径技术,提出了一种改进的高分辨率成像算法。划分子孔径克服了PRF不足的问题;子孔径数据处理采用结合视线(LOS)方向运动补偿的Omega-K算法,实现更高精度的运动补偿,提高了聚焦质量。最终的方位向分辨率达到0.1m,具有实际工程应用价值。点目标仿真和实测数据处理验证了算法的有效性。

Sliding spotlight synthetic aperture radar（SAR）is a rising imaging mode,whose azimuth resolution is higher and imaged area is greater.When processing data,two key problems should be considered.Firstly,system＇s pulse repetition frequency（PRF）is always insufficient,which makes the azimuth signal folding.Secondly,the effect of motion error enhances because of longer synthetic aperture,consequently the accuracy of motion compensation（MOCO）should be increased.This paper presents a modified high-resolution imaging scheme based on subaperture.Subaperture method is used to overcome the problem that PRF is insufficient.Meanwhile,processing of subaperture data chooses Omega-K algorithm with line-of-sight（LOS）motion compensation to implement high-precision motion compensation,improving focused quality.The presented algorithm can attain 0.1mazimuth resolution and has the value of practice.Simulations with point targets and processing of real data are used to confirm the validity of the proposed algorithm.