摘要 利用精密星历产品对BDS-2和BDS-3广播星历的精度进行系统评估,进一步比较分析不同BDS-2和BDS-3卫星星座组合对单点定位的影响,提出一种基于SISRE(signal in space range error)的单点定位加权优化模型。实验结果表明,BDS-2星座中MEO、IGSO和GEO卫星广播星历轨道误差的RMS分别为2.404 m、3.030 m、12.574 m;BDS-3星座中MEO、IGSO卫星广播星历轨道误差的RMS约为0.5 m和0.8 m;对于SISRE,BDS-2平均优于2 m,BDS-3平均优于1 m;BDS-3配备H钟和Rb钟的卫星钟差及稳定性基本相同。同时单点定位结果表明,BDS-2/BDS-3 IGSO/MEO星座组合定位精度最高。利用提出的SISRE加权模型进行单点定位解算,定位精度在N、E、U方向的平均优化率分别为9.61%、18.55%、11.19%,平均总体优化率达到12.26%,证明了模型的有效性。
Abstract:We evaluate the precision of broadcast ephemeris of BDS-2 and BDS-3 using precise ephemeris products. We further compare and analyze the influence of different BDS-2 and BDS-3 constellation combinations on single point positioning(SPP). We propose a SPP weighted optimization model based on SISRE(signal in space range error). The experimental results show that the broadcast ephemeris orbit errors of MEO, IGSO and GEO satellites in BDS-2 constellation are 2.404 m, 3.030 m and 12.574 m respectively. The broadcast ephemeris orbit errors of MEO and IGSO satellites in BDS-3 are about 0.5 m and 0.8 m respectively. For SISRE, BDS-2 is on average better than 2 m and BDS-3 is on average better than 1 m. BDS-3 satellite clock error and stability with H clock and Rb clock are basically the same. At the same time, SPP results show that BDS-2/BDS-3 IGSO/MEO constellation combination has the highest positioning accuracy. The SISRE weighted model is used to solve the SPP, and the optimized positioning accuracy is 9.61%, 18.55%, and 11.19% respectively in the N,E,U directions, proving the effectiveness of the model.