基于ATI技术和象素匹配的星载SAR/GMTI实现方法

与机载合成孔径雷达相比,星载合成孔径雷达由于其复杂的空间几何关系、地球自转及地球曲率等因素的影响,使得星载SAR／GMTI的实现更为复杂。提出了当不满足相位偏置中心天线(DPCA)中脉冲重复频率和天线水平基线间的严格约束条件时,通过象素匹配法和星载SAR沿航迹向干涉(ATI)技术实现星载合成孔径雷达(SAR)动目标检测、测速及定位的一种方法。该方法采用沿航迹向线性排列的双孔径天线星载SAR结构,首先建立了星载SAR双孔径天线空间几何模型并详细分析了星载SAR双孔径天线机理及信号特性,然后利用常规方法成像的双天线SAR图像,分析并推导了基于ATI技术和象素匹配实现对地面背景杂波淹没的运动目标检测、径向速度分量估计以及目标定位的方法。最后,通过计算机仿真验证了其有效性。

An algorithm of spaceborne SAR/GMTI based on ATI and pixel match

Compared with airborne SAR,such factors as complicated spaceborne SAR spatial geometric relationship,earth rotation and earth surface curvature etc.make the realization of spaceborne SAR/GMTI complicated.An algorithm of spaceborne SAR moving target detection,radial velocity estimation and relocation based on dual-antenna along-track interferometry (ATI) with linear arrangement and image pixel match method is proposed.This algorithm needn't strictly satisfy the stringent constraint between pulse repeat frequency and antenna horizontal baseline in displaced phase center antenna (DPCA).Firstly,spatial geometric model of dual-antenna spaceborne SAR is established,with that its principle and signal properties are analyzed,then a spaceborne SAR/GMTI algorithm is analyzed and derived based on ATI technique and image pixel match using SAR images,which are formed by conventional imaging method.This algorithm can perform the detection,radial velocity estimation and relocation of moving targets masked by ground clutters.Finally,the computer simulation results validate its effectiveness.