应用激光测高仪提高测绘卫星定位精度的研究

双线阵立体测绘卫星定位对外方位元素的测量精度要求高,然而布设控制点成本高,缺少全世界范围内的控制点。针对这一问题,提出应用星载激光测高仪提高定位精度的方法。首先,分析了双线阵立体测绘卫星和激光测高仪的误差特性,即测绘相机定位精度受外方位角元素影响比较大,激光测高仪高程精度受角元素影响相对较小。然后,论证了用激光测高仪提高定位精度的可行性。在相同的卫星平台定向辅助数据下,激光测高仪高程精度要比测绘相机高得多,可以作为高程约束提高定位精度。最后,应用光束法平差原理对激光测高数据作为高程约束进行了仿真试验。结果表明,加入激光测高数据可将双线阵立体测绘卫星的高程精度由8.0m提高到约3.5m。此方法可为实现全球无控制点测绘提供一定参考。

Study on Improving Positioning Accuracy of Mapping Satellite Using Laser Altimeter

Positioning of dual liner array stereo mapping satellite demands exterior orientation elements with high accuracy,but setting control points will take high cost,and there is a lack of control points in the world.Using laser altimeter is a method to solve these problems.The paper analyzes the error features of dual liner array stereo mapping satellite and laser altimeter,namely,exterior orientation angle elements have greater influence on mapping camera than on laser altimeter.Then the paper demonstrates the feasibility of improving positioning accuracy using laser altimeter.Under the auxiliary data of the same satellite platform,elevation accuracy of laser altimeter is higher than that of mapping camera,and data of laser altimeter can be used as elevation control to improve positioning accuracy.Finally a simulation aerotriangulation experiment using laser data as elevation control points shows that the positioning accuracy of mapping satellite is improved from 8.0m to about 3.5m.The study can be as a reference for mapping without control point in the world,