基于高精度景象匹配的SAR平台定位方法研究

为了提高SAR平台定位精度，本文提出了一种基于景象匹配的SAR平台定位的方法。该方法利用成像中间时刻SAR平台与SAR图像中心线上物点共线的特性，先在图像中心线上均匀选取若干点作为匹配点，并与光学基准图进行高精度景象匹配获取它们的物点坐标；然后根据这些物点坐标估计出图像中心线在当地水平面投影的直线方程；最后利用直线信息和斜距高度信息计算SAR平台在水平面上的投影点位置，进而计算得到成像中间时刻SAR平台的空间位置。为了进一步提高匹配精度，分别提出了对正侧视和斜视SAR图像匹配区域进行几何粗校正的方法。本文还分析了不同误差因素对平台定位精度的影响，并给出了精度估计公式。仿真和实际图像实验结果表明，本文方法正确可行，具有较高的定位精度，具备工程实用价值。

SAR position method based on high precision scene matching

Aimed to improve the location precision of SAR platform, a location method based on scene matching is proposed in this paper. According to that the platform is on the centerline of SAR image at the imaging central time, some points on the centerline are equably engaged as control points in the proposal method , whose spatial position can be obtained by highly precision matching with optical reference image. Then equation of the projection line on the local horizon of centerline can be estimated with the points. Finally we can calculate the projection point position of the SAR platform on the projection line, as well as the spatial position of the platform. Considering the difference between boresight and squint imaging mode, rough rectifying methods are respectively proposed according to the two modes to improve the matching precision. The impact of different errors on location precision is also analyzed in this paper and the precision estimation formulas are derived. Both simulation and real data test results show accuracy, high precision and practical value for engineering of the proposal method.