北斗三号空间信号测距误差评估与对比分析

Evaluation and comparative analysis of BDS-3 signal-in-space range error

北斗三号作为我国自主建设的全球卫星导航系统,其本身性能水平以及与其他卫星导航系统的性能对比情况,对后续推广应用具有重要影响。为此,本文以空间信号测距误差(signal-in-space range error,SISRE)作为系统关键性能指标,以GFZ提供的多系统精密轨道钟差作为标准,给出了卫星轨道、卫星钟差、SISRE的比对评估方法,并以2020年1—3月共3个月的实测数据,验证了北斗三号相对北斗二号的精度改进情况,并重点分析了北斗三号与GPS、Galileo、GLONASS之间的性能对比关系。结果表明:无论是卫星轨道还是卫星钟差,北斗三号的精度水平相对北斗二号都有了明显提高;北斗三号卫星轨道在R、T、N方向精度分别达到0.07、0.30、0.26 m,在4个全球系统中处于最优水平;卫星钟差精度达到1.83 ns,基本与GPS系统持平,优于GLONASS,但还略差于Galileo;在空间信号测距误差方面,如果仅考虑轨道误差,北斗三号SISRE(orb)平均达到0.08 m,紧随其后,Galileo达到0.26 m,GPS达到0.57 m,GLONASS达到0.98 m。如果综合考虑轨道和钟差误差,北斗三号SISRE平均达到0.50 m,稍逊于Galileo的0.38 m,略优于GPS的0.58 m,明显好于GLONASS的2.35 m。

BDS-3 is a global satellite navigation system independently built by China.Its performance level and performance comparison with other satellite navigation systems have an important impact on the follow-up promotion and application.In this paper,the signal in space range error(SISRE)is used as a key performance index of the system.Taking the multi-system precise orbit and clock offset provided by GFZ as the standard,the comparison and evaluation method of satellite orbit,satellite clock offset and SISRE is given.Based on the measured data of three months from January to March 2020,the accuracy improvement of BDS-3 relative to BDS-2 is verified,and the performance comparison between BDS-3,GPS,Galileo and GLONASS is analyzed emphatically.The results show that the accuracy level of BDS-3 is significantly higher than that of BDS-2 both in satellite orbit and in satellite clock offset.The orbit accuracy of BDS-3 in the R,T and N direction is 0.07 m,0.30 m and 0.26 m respectively,which is at the optimal level among the four global systems.The satellite clock offset accuracy is 1.83 ns,which is basically the same as that of GPS,superior to GLONASS,but slightly worse than Galileo.In terms of the signal in space range error,if only orbit error is considered,BDS-3 SISRE(orb)is averagely 0.08 m.Next,Galileo SISRE(orb)is 0.26 m,GPS SISRE(orb)is 0.57 m,and GLONASS SISRE(orb)is 0.98 m.If the orbit and clock error are considered comprehensively,the average SISRE of BDS-3 is 0.50 m,which is slightly lower than 0.38 m of Galileo,better than 0.58 m of GPS,and significantly better than 2.35 m of GLONASS.