嫦娥三号着陆器精确定位与精度分析

An Analysis of Precise Positioning and Accuracy of the CE-3 Lunarlander Soft Landing

嫦娥三号成功实施月球软着陆,对着陆器实施精确定位是开展科学数据分析的基本要求。本文首先描述了月球着陆器定位的精确观测建模与统计定位方法,然后使用嫦娥三号着陆器现有测量数据进行了定位计算,利用月球高程模型和光学图像数据计算位置对定位结果进行了比较。结果表明,着陆器计算位置与高程模型的高程方向差异为4.5m,与光学图像解算的三维位置差异小于100m。最后,基于协方差分析理论,分析了当前测量条件下的着陆器定位能力,结果表明测距数据的系统偏差是制约定位精度的主要因素,如果能消除测距系统偏差,可以实现10m定位精度。

In December,2013,the Chinese lunar lander Chang＇E-3made a soft landing on the Moon successfully.Its precision positioning is a basic requirement in the analysis of scientific data.In this paper,the modeling of the precise observation equation and the statistical positioning method are first described briefly.Second,using the limited tracking data of the lander,the statistical positioning of the lander was performed and the positioning accuracy analyzed by three different methods.The results indicate that the determined altitude of the lander was approximately 4.5 mdifferent from the latest lunar topographical model.Compared with the lander location observed from the lunar reconnaissance orbiter camera,there is a deviation less than 100 min the three dimensions.We subsequeently analyze the positioning ability under current tracking conditions using the covariance analysis theory.These results show that the systematic error in the ranging data was the main limiting factor that restricts lander positioning accuracy,and an accuracy of 10 m positioning solution may be obtained if this bias is removed.