LEO增强的GPS、Galileo、BDS-3非差PPP模糊度固定性能分析

Performance analysis of undifferenced PPP ambiguity resolution with LEO enhanced GPS,Galileo,BDS-3

本文主要研究了GPS、Galileo、北斗三号(BeiDou-3 Global Satellite Navigation System,BDS-3)的未校准相位延迟(uncalibrated phase delays,UPD)稳定性以及低地球轨道(low earth orbit,LEO)增强的非差精密单点定位(precise point positioning,PPP)模糊度固定.基于全球分布的126个测站2022年001—007共一周的观测数据进行GPS、Galileo、BDS-3的UPD估计分析.宽巷UPD每天作为一组常数估计,窄巷UPD每15 min作为一组常数估计.结果表明:宽巷UPD在一周之内具有较好的稳定性,平均标准差小于0.05周;窄巷UPD在一天之内具有较好的稳定性,平均标准差小于0.06周.使用估计的UPD产品进行PPP模糊度固定并对其性能进行分析,GPS、Galileo、 BDS-3各系统静态PPP的平均收敛时间分别由20.75 min、 23.78 min、 30.60 min缩短至10.69 min、18.27 min、24.80 min;平均模糊度固定率分别为90.41%、77.22%、67.21%;东(east,E)、北(north,N)、天顶(up,U)三个方向均方根误差(root mean square error,RMSE)的平均值分别由(1.59 cm、0.91 cm、3.30 cm)、(1.58 cm、0.93 cm、3.24 cm)、(1.61 cm、0.98 cm、3.39 cm)减小至(0.90 cm、0.89 cm、2.98 cm)、(1.33 cm、0.85 cm、2.90 cm)、(1.47 cm、1.18 cm、2.94 cm).利用仿真的LEO星座观测数据,研究不同LEO卫星数量的增强效果,当LEO可视卫星数量愈多时,增强效果愈加显著,当LEO可视卫星数量为10颗时,GPS、Galileo、BDS-3各系统的静态PPP固定解的平均收敛时间分别由10.69 min、18.27 min、24.80 min缩短至1.53 min、1.71 min、1.94 min;模糊度固定率分别由90.41%、77.22%、67.51%提高至93.43%、79.99%、72.00%.

This paper focused on the stability of uncalibrated phase delays(UPD) of GPS,Galileo,BDS-3,and the low earth orbit(LEO) augmented undifferenced precise point positioning(PPP) ambiguity resolution.Based on the observation data of 126 global distributed MGEX stations of 7 days from 001 to 007in 2022 were employed for UPDs estimation of GPS,Galileo,BDS-3.Wide-lane UPDs were estimated as a set of constants every day and narrow-lane UPDs were estimated as a set of constants every 15 minutes.The results showed that the wide-lane UPSs had good stability within one week,and the average standard deviation was less than 0.05 cycles.The narrow-lane UPDs had good stability within 1 day,and the average standard deviation was less than 0.06 cycles.Using the estimated UPDs products for PPP AR and analyzing their performance,the average convergence time of GPS,Galileo and BDS-3 was shortened from 20.75 min,23.78 min,30.60 min to 10.69 min,18.27 min,24.80 min,respectively,and the average ambiguity fix rates were 90.41%,77.22% and 67.21%,respectively.The average value of root-mean square error(RMSE) in the east,north and up components decreased from(1.59 cm,0.91 cm,3.30 cm),(1.58 cm,0.93 cm,3.24 cm),(1.61 cm,0.98 cm,3.39 cm) to(0.90 cm,0.89 cm,2.98 cm),(1.33 cm,0.85 cm,2.90 cm) and(1.47 cm,1.18 cm,2.94 cm),respectively.Using the simulated LEO constellation observation data,the enhancement effect of different number of LEO satellites was studied,and the enhancement effect became more significant when the number of LEO visible satellites is more.When the number of LEO visible satellites was 10,the average convergence time of GPS,Galileo and BDS-3 were improved from 10.69 min,18.27 min,24.80 min to 1.53 min,1.71 min,1.94 min,and average ambiguity fixing rates were improved from 90.41%,77.22%,67.51% to93.43%,79.99%,72.00%,respectively.