基于测距观测的静地卫星定轨精度分析

Covariance Analysis of Range-Based Orbit Determination for Geostationary Satellite

在卫星动力法定轨的协方差分析基础上,提出了一种针对地球静止轨道(GEO)卫星的简化定轨精度分析方法。根据GEO卫星的线性化状态转移方程,通过设定地面跟踪网坐标和卫星星下点经度计算叠加矩阵,由观测弧长和采样间隔直接计算定轨精度评定公式中的主要部分。公式扩展后,能比较各种系统误差源对定轨精度的影响,并将影响较大的作为附加参数纳入估计过程并重新评价定轨精度。用该法对10 m定轨精度的测距跟踪网优化设计和测距偏差对定轨精度的影响特性进行分析的结果表明,测量系统中的系统性误差可能以近20的放大倍率传播到卫星沿迹方向和法向,且不能通过自校准测距常值偏差提高定轨精度。

An approximate algorithm of orbit determination error analysis for geostationary （GEO） satellite was presented based on the covariance analysis of dynamic orbit determination in this paper. The superposition matrix was computed by setting coordinate of ground tracking net and satellite ground longitude according to the linear state transfer equation of GEO satellite. The main part of the evaluation equation for orbit determination accuracy was calculated by observation arc and sampling interval. The effects of various system errors on orbit determining accuracy would be compared after the equation extended. The severe ones could be as the additional factors which added into estimation, and the orbit determining accuracy was revalued, The analysis result of the effect of range tracking net optimal design and ranging error with 10 m accuracy on the orbit determining error showed that the system error in measuring system would be propagated into trace and normal direction with 20 times amplified. The orbit determining accuracy would not be improved by self-calibration of constant error in ranging.