月球探测器定轨误差分量协方差分析

Covariance Analysis of Orbit-determination Error Components for Lunar Probe

基于测量量的数学模型,推导环月探测器状态矢量的信息阵,建立定轨误差RTN分量的误差方程和协方差矩阵,给出了测距、测速、时延和时延率的测量误差对定轨误差RTN分量影响的数值关系。根据中国探月工程实际轨道测量数据精度和测站/基线分布情况,计算分析了2种环月轨道位置速度误差RTN分量的影响因素和误差水平。利用嫦娥-1、2月球探测器实际定轨结果,验证了分析方法的有效性。该方法对中国探月工程二期任务动力下降初始定轨误差RTN分量计算具有参考意义。

Based on measurement models of the tracking data including ranging, range rate, inter- ferometric delay and delay rate, the information array of lunar probe＇s state vector is presented. Error equations and covariance matrixes for RTN components of orbit-determination error are de- rived. The numerical relation between RTN components of error and the measurement accuracy are calculated for lunar orbit. According to measurement error and station/baseline distribution in the China lunar exploration program, the influence and level of error factors are analyzed and calcu- lated for RTN components of errors in the position and velocity for various lunar orbits. The or- bit-determination results using measurement data of Chang＇e-1 and Chang＇e-2 probes validate this analysis method, which will be as an important reference for RTN components of errors in the lunar decent initial orbit in the second phase of China lunar exploration program.