中文摘要：

以CHAMP卫星的GPS观测资料为例,分析GPS精密星历、钟差、卫星相位中心改正、相对论效应和GPS卫星空间几何分布等各类误差对定轨的影响。分析结果表明：不同数据处理中心的GPS轨道相差很小,对LEO卫星定轨影响可以忽略不计。同一数据中心的相邻历元间的钟差变化很小,为1～2 cm,不同数据中心的钟差改正数差异较大;GPS卫星钟差改正精度优于5 ns。

英文摘要：

In the un-differential phase kinematic precise orbit determination from satellite-borne GPS data,besides ionospheric delay,multi-path effect,relativistic effect and phase center offset,LEO satellite orbit accuracy is prone to be affected by GPS precise ephemeris from different data centers,spatial geometric distribution of GPS satellite and so on.Taking satellite-borne GPS observations on CHAMP satellite as example,we analyze error effect on kinematic precise orbit determination from GPS precise ephemeris,satellite clock bias,phase center offset,relativistic effect and GPS satellite geometric distribution,and achive some helpful results,the main ones are as follows.1）The difference among the GPS orbits obtained from different data processing centers are small.2）The clock error changes between neighboring epochs of the some data centers are small,1-2 cm and the differences of the correction clock error of different data center are large.3）The accuracy of the clock error correction of GPS satellite is better than 5 ns.