Annual Variation Analysis and Forecasting Model of DCB Parameters for BDS Satellites

Abstract

The accuracy and stability of differential code bias (DCB) parameters are important to the timing and positioning service performance. According to the actual observation data of Beidou navigation satellite system (BDS) from 2013 to 2015, DCB₁₂ parameters and DCB₁₃ parameters of BDS satellites are analyzed, and the long-term statistical results of DCB parameters of different types of satellites are given. The annual standard deviation of the DCB parameters of GEO satellites with good observation conditions is 0.3 ns. The statistical standard deviation of most IGSO satellites DCB parameters are less than 0.4 ns, and the statistical standard deviation of MEO satellite’s DCB are about 0.5 ns. The annual statistical results show that the average DCB parameter of the BDS satellites has an annual slow change of 0.3 ns. The polynomial fitting method was used to forecast the long-term trend of DCB parameters. The results show that the mean annual variation trend of DCB parameters of BDS satellites is similar to that of GPS satellites, but the BDS satellite DCB parameter stability is 0.5 ns, which is affected by the regional distribution of the measurement stations and the poor data quality of some receivers, which has a large gap with the GPS satellite DCB parameters provided by the IGS ionosphere center (30-days stability better than 0.1 ns).