一种基于运动补偿的后向投影成像算法

A new BP imaging algorithm based on motion compensation

BP算法采用逐像素方式成像,理论上成像保相性较RD、CS算法好,逐渐用于InSAR成像。但是经典BP成像算法存在改变了常规SAR定位模型、基线三轴分量有时变性、不利于后续InSAR区域网平差处理等缺点。本文通过构建虚拟直线APC轨迹、建立斜平面像成像坐标系、逐像素计算地面点坐标等方式,实现了基于运动补偿的BP成像。利用毫米波InSAR回波数据进行了对比实验,实验结果表明:文中提出的算法能够在斜平面内成像,单SAR天线轨迹为直线,InSAR基线三轴分量在一景内为定值,能够用于后续干涉处理。

The Back-project(BP)algorithm using the pixel-by-pixel imaging mode theoretically performs better in phase preservation compared with Range-Doppler(RD)and Chirp scaling(CS)algorithms,and it has been gradually applied in InSAR imaging.However,the classical BP algorithm has some disadvantages,such as changing the traditional positioning model,producing time-variant baseline components and making it diffcult for subsequent boundle adjustment.In this paper,a new BP imaging algorithm based on motion compensation is realized by constructing a virtual straightline antenna phase center(APC)trajectory,establishing the slant plane imaging coordinate and computing ground point coordinates pixel by pixel.The millimeter InSAR imaging experiment result shows that the new algorithm can image in slant plane,and keep the APC tracjectory linear and the baseline components constant in one scene,which can be used for subsequent interferometric processing.