IGU实时精密星历预推轨道精度分析

Precision analysis of predicted orbit on IGU real-time precise ephemeris

为了满足实时精密单点定位对卫星轨道坐标精度和实时性的要求，分析了IGU实时精密星历的预推轨道精度，计算出各个预推时刻的轨道误差值，进而得到预推时间与轨道精度的近似函数关系式．对31d的IGU星历数据进行统计分析，得到GPS卫星预推3—9h的轨道精度指标及不同Block类型的GPS卫星轨道精度，进而判断IGU星历能否满足精密单点定位的需求．研究结果表明：预推4h和8h卫星轨道误差值分别为5．0cm和6．5cm，且误差值与预推时间呈近似一次函数关系；对于不同类型的卫星，轨道精度存在差异，其中Block1IA类型的3颗卫星PRN04，RN08，RN09的轨道精度最低，剔除这3颗卫星后，轨道精度最大可提高10．64％．

In order to meet the requirements of the accuracy and real-time of the satellite orbit coor- dinates for real-time precise point positioning （PPP）, the accuracy of the predicted orbit from the in- ternational GNSS service ultra-rapid （IGU） real-time precise ephemeris is analyzed. The orbit error at every prediction time is calculated, and the approximate relationship between prediction time and