2013—2015年BDS空间信号测距误差的精度评估

Accuracy assessment of BDS signal-in-space range errors in 2013—2015

基于武汉大学发布的精密星历,计算2013年1月至2015年9月北斗广播星历的轨道、钟差和空间信号测距误差,并对其进行统计分析评估。结果表明:北斗卫星的径向精度总体上优于0.7 m、法向精度总体上优于1.4 m,且无明显的长期变化趋势;在切向精度上,倾斜地球同步轨道和中轨道优于2.1 m,高轨道的切向精度已从14 m左右提升至8 m左右;北斗高轨道、倾斜地球同步轨道、中轨道的钟差精度分别为6.3 ns,4.7 ns,4.3 ns;所有卫星的钟差精度总体上优于6 ns;所有卫星的空间信号误差精度总体上优于2 m,从长期来看,中轨道卫星的空间信号误差精度较为稳定;倾斜地球同步轨道和高轨道卫星的空间信号误差精度存在一定的波动。

Based on precise ephemeris provided by Wuhan University,BDS（ Bei Dou navigation satellite system） broadcast ephemeris errors were computed over the past three years from January 2013 to September 2015. The orbit errors,clock errors,and SISREs（ signal-in-space user range errors） are presented and analyzed in different time periods for assessment. Results show that the radial accuracy of overall BDS satellites is less than 0. 7 m and the normal accuracy of that is less than 1. 4 m. Additionally,no obviously long term trends are found in both radial and normal errors. In term of along-track errors,the accuracies of IGSO（ inclined geo synchronous orbit） and MEO（ medium earth orbit） satellites are all less than 2. 1 m and the along-track accuracy of GEO（ geosynchronous earth orbit） is improved from 14 m to 8 m. The clock accuracies of GEO,IGSO and MEO are 6. 3 ns,4. 7 ns and 4. 3 ns respectively,and the clock accuracies of all satellites are more than 6 ns. The SISREs of all satellites are generally less than 2 m,and the SISREs of MEO satellites are relatively stable over the past 3 years. However,IGSO SISREs and GEO SISREs have some fluctuations in certain level.