高分辨率光学遥感卫星几何链路定位精度分析

Analysis of Geolocation Accuracy of High Resolution Optical Remote Sensing Satellite Geometric Chain

为了提高高分辨率光学遥感卫星无控制点定位精度,针对如何进行定位精度指标分配的问题,介绍了高分辨率光学遥感卫星几何链路的概念,分析了几何链路中各环节的系统误差和随机误差,采用双线阵相机立体定位方式推导了定位精度计算方法,得出了高程精度的主要影响因素,并以满足1∶10 000测图比例尺要求为例,进行了定位精度指标分析,提出了提高定位精度的措施。结果表明,主距误差对高程精度影响极小,可忽略不计;卫星姿态角误差是高程精度的主要影响因素,其中俯仰角误差的影响最大;姿态角测量与确定精度达到0.4″、星敏与相机间夹角稳定性精度达到0.1″,可使相对高程精度达到1.497m,满足相对高程精度要求。利用几何链路分析定位精度的方法可用于高分辨率光学遥感卫星定位精度指标分配。

To improve the geolocation accuracy of high resolution optical remote sensing satellite without ground control points in view of the index assignment, a conception of geometric chain is introduced and stochastic error and systematic error are analyzed. Based on the stereo geolocation method, the geolocation accuracy algorithm is derived and the main influencing factor on height accuracy is obtained. Taking the map scale of 1∶10 000 as an example, the value of index is analyzed and the method of increasing geolocation accuracy is put forward. The result is that the focal length error has minimal impact which can be ignored and the attitude error is the main influencing factor which is mainly shown in pitch angle. The relative height accuracy reach 1.497 m which can meet the accuracy requirement, if the satellite attitude measurement and determination accuracy reach 0.4″ and the stability accuracy of the angle between the star tracker and the camera reach 0.1″. The method using geometric chain to analyze the geolocation accuracy is applicable to the geolocation accuracy index assignment of high resolution optical remote sensing satellite.