北斗卫星钟差近实时估计模型及其实现

Function Model of Near Time Estimation of BDS Clock Difference and Its Implementation

为更快地获取高可靠性、高精度的天顶对流层延迟,提出了选择历元间差分与非差组合模型为函数模型,对BDS/GPS钟差参数采用近实时方式进行估计。为此,从全球范围内均匀选取45个MGEX跟踪站,使用GFZ的超快速轨道产品为钟差估计提供初始轨道信息,并以事后产品为参考值。试验结果表明,GPS实时钟差的精度优于0.06 ns,略低于事后钟差估计精度,三类BDS卫星的实时钟差估计精度均在0.04~0.08 ns,其中GEO卫星的准实时钟差精度略低于IGSO和MEO卫星,满足近实时天顶对流层延迟估计的需求。

In order to obtain high reliability and accuracy of zenith tropospheric delay more quickly, the paper proposes a parameter estimation method.The method chooses epoch-differenced and undifferenced function model and estimates BDS/GPS satellites clock difference using the near time way. 45 MGEX tracking stations distributed globally are selected. Initial orbit information of clock difference estimation used the ultra rapid orbit products released by GFZ and used post products as reference values.The experimental results show that the accuracy of GPS satellite clock difference is better than 0.06 ns, and three kinds of BDS satellites clock difference are between 0.04 ~ 0.08 ns, which is a little worse than Global Positioning System （GPS）. Apparently, the estimated BDS clock difference meets the demands of computing quasi real-time zenith troposphere delay.