利用偏置矩阵提高天绘一号卫星影像定位精度

Improving Positioning Accuracy of TH-1 High Resolution Image Based on Bias Matrix

受卫星姿态、位置精度以及传感器安装误差的影响,卫星对地定位会不可避免地产生系统误差。将定位系统误差归结为偏置矩阵,并推导了基于共线方程的表达形式。针对天绘一号高分辨影像进行实验,结果表明,该系列影像利用辅助姿态轨道数据直接定位时,存在不容忽视的系统误差;采用少量地面控制点可以解算偏置矩阵,从而将定位精度提升一个数量级,同时偏置矩阵对一定时间内的其他影像也有纠正作用。

Due to the limited accuracy of exterior orientation parameters and installation error of imaging payloads,systematic error is inevitable in satellite's ground positioning.In this paper,the bias matrix was introduced to compensate systematic error.The specific expression based on collinearity equation was deduced.Experiment on high resolution image of TH-1indicates that the system error of direct positioning using auxiliary attitude and orbit data is should not be ignored.The bias matrix,which could be detected by a few ground control points,is capable of improving the accuracy to one order of magnitude.Due to the stability of angular error,the detected matrix is not only effective to the source image,but also useful to other images within a certain time range.