顾及TDB参数改正的BDS-2/BDS-3 PPP性能分析

Performance Research of BDS-2/BDS-3 PPP Considering TDB Parameter Correction

北斗三号(BDS-3)虽然建成,但是能够提供精密星历的BDS-3卫星仍然偏少,且接收机等固件支持BDS-3信号需要有一个升级的过程,因此,联合应用北斗二号(BDS-2)和BDS-3对于提升导航定位性能仍具有现实意义。BDS-3和BDS-2之间存在时间延迟偏差(TDB),但在精密单点定位研究中仍未考虑TDB的影响,是否需要估计和改正仍需研究验证。为此,本文对比了改正TDB参数前后的PPP位置精度和收敛速度,选取6个MGEX站的24 h观测数据进行分析验证,实验结果表明估计并改正TDB参数影响后,静态位置误差由4.21 cm减小到3.87 cm,收敛时间由49.4 min变为55.3 min,动态位置误差东北天方向的误差由0.39、0.42和0.70 cm减小为0.41、0.33和0.17 cm,天向精度提升明显。BDS内部存在TDB影响,TDB参数与接收机类型有关,同一类型接收机TDB参数数值大小相近,且表现出近似的演化规律。本文研究结果为提高BDS-2和BDS-3联合精密单点定位精度提供了有益的参考。

Although the Beidou-3(BDS-3)has been built,there are still few BDS-3 satellites that can provide precise ephemeris,and receivers need to be upgraded to support BDS-3 signals,so the joint application of BDS-2 and BDS-3 is still of great significance for improving navigation and positioning performance.There is a time delay bias(TDB)between BDS-3 and BDS-2,but the impact of TDB is still not considered in the precise point positioning research,and whether it needs to be estimated and corrected still needs to be verified by research.For this reason,this paper compares the PPP position accuracy and convergence speed after correcting the TDB parameters.Six MGEX stations with the 24 h observation data are selected for analysis and verification.The results show that after estimating and correcting the influence of TDB parameters,the static position error is reduced from 4.21 cm to 3.87 cm,the convergence time is changed from 49.4 min to 55.3 min,and the dynamic position error in the northeast direction error is reduced from 0.39 cm,0.42 cm,and 0.70 cm to 0.41 cm,0.33 cm and 0.17 cm,the up-direction accuracy has improved significantly.Also,it is confirmed that TDB does exist inside the BDS.The parameters are related to the receiver type.The values of TDB parameters are similar,and show similar evolutionary laws.The research results of this paper provide reference for improving the precise point positioning accuracy of BDS-2 and BDS-3.