顾及轨道误差BDS/GPS实时钟差融合估计的观测权函数设计

Observation Weight Function Design for Fusing BDS/GPS Data to Estimate the Real-time Clock with Regard to the Orbit Errors

实时钟差产品是高精度广域差分位置服务(亚米级、分米级、厘米级)的基础产品,本文针对BDS/GPS轨道精度差异,设计了一种顾及轨道精度差异观测权函数,优化了实时钟差估计的随机模型,在此基础上基于非差法实现了BDS/GPS联合的实时钟差估计。采用MGEX和iGMAS跟踪站的实时观测数据进行实时钟差解算,并与iGMAS产品综合中心提供的事后精密钟差产品进行了比较分析。结果表明:基于该方法估计的钟差精度对单GPS、单BDS和BDS/GPS融合都有提高,其中BDS钟差精度整体较GPS更为显著,提高幅度约12.8%,其中IGSO/MEO更为突出,提高幅度约20%,验证了方法的有效性。

The real-time clock product is one of the basis products for wide-area positioning service of high precision.Considering the difference between BDS orbit precision and GPS precision,we design a new observation weight function,in order to optimize the stochastic model of real time BDS/GPS clock estimation.The BDS/GPS observations of 78 MGEX global stations and 2iGMAS stations were collected to generate the real time clock,and then the calculation results were compared with the final iGMAS precise clock product in two strategies(the old stochastic model and the new stochastic model).Itshowsthatthemethodbasedtheproposed stochastic model can improve the precision of satellite clock about 9%for GPS and 10%for BDS.