GNSS精密卫星钟差实时估计与分析

Real-time Estimation and Analysis of GNSS Precision Satellite Clock Error

随着精密单点定位(PPP)技术的发展,对卫星轨道和钟差改正精度的要求不断提升。卫星钟差实时估计已经成为影响PPP实时解算重要因素之一。采用全球选取均匀分布的53个监测站进行四系统联合估计,同时对四系统实时钟差估计模型、相关误差改正及解算流程进行了说明。对比分析了当前IGS各中心发布的事后精密钟差精度,利用IGS事后精密钟差产品对自解算钟差结果进行了评估,结果显示GPS卫星钟差精度大部分在0.2 ns以下,北斗GEO卫星钟差精度偏大,在0.6 ns~1 ns之间,IGSO/MEO在0.4 ns~0.6 ns左右,GLONASS卫星钟差精度在0.2 ns~0.4 ns左右,Galileo卫星精度优于0.2 ns,解算耗时满足5 s更新需求。

With the development of Precision Point Positioning(PPP)technology,the requirements for satellite orbit and clock correction accuracy continue to increase.The real-time estimation of the satellite clock error has become one of the important factors affecting the real-time PPP calculation.In this paper,53 monitoring stations uniformly distributed around the world are selected for the four-system joint estimation.This article describes the four-system real-time difference estimation model,related error correction and solution process.A comparative analysis of the accuracy of the post-precision clock error released by the current IGS centers,and the use of IGS post-precision clock products to evaluate the self-calculated clock error results,the results show that most of the GPS satellite clock error accuracy is below 0.2ns,the clock error accuracy of Beidou GEO satellite is relatively large,between 0.6ns~1ns,IGSO/MEO is about 0.4ns~0.6ns,GLONASS satellite clock error accuracy is about 0.2ns~0.4ns,and Galileo satellite accuracy is better than 0.2ns.Clock error calculation takes time to meet 5s update requirements.