Uncombined precise orbit and clock determination of GPS and BDS-3

Abstract

There is increasing concern about the uncombined (UC) observation model in the field of global navigation satellite system (GNSS). Based on the global positioning system (GPS) and the third-generation BeiDou navigation satellite system (BDS-3), this study processed the UC precision orbit determination (POD) for single and dual systems. First, a UC observation model suitable for multi-GNSS POD was derived, and the ionospheric-free (IF) combination observation model was presented. Although the ambiguity parameters of UC and IF strategies were different after reparameterization, the difference could be removed when processing ambiguity resolution, and the equivalence was proved theoretically. To demonstrate the accuracy of BDS-3 orbits fully, the observation data of approximately 1 month were selected for determining the precise orbit for global positioning system (GPS) only, BDS-3 only, and GPS/BDS-3 systems based on the UC and IF models. The orbit precision of BDS-3 satellites was validated by using metrics, including comparison with precision products released by Wuhan University, orbit boundary discontinuity, and satellite laser ranging (SLR) residuals. The results show that the orbit accuracies of the IF and UC models are almost the same, the difference in orbits is approximately several millimeters, and the clock difference is within 0.01 ns. The GPS/BDS-3 combined solution shows better accuracy compared to other solutions. The average accuracies in the R and 3D directions are approximately 4 and 15 cm, and the clock standard deviation is approximately 0.2 ns compared to external orbit product. The root mean square of SLR residuals is approximately 4 cm.

Advances in satellite atomic clock technologies for the GNSS

“…The observed value used in the clock estimation is normally taken from the pseudorange and phase observations together. In different time synchronization algorithms, delays are handled differently, resulting in different characteristics of the estimated satellite clock offset (Zeng et al 2020).…”

Ground-Based GNSS Precipitable Water Vapor Retrieval With the BeiDou B2B Service

“…After its service, precise orbit determination [14][15][16], satellite clock offset estimation [17][18][19], tropospheric delay estimation [20], precise positioning [21][22][23][24] and time transfer [25][26][27][28], are studied. For precise applications, two representative technologies are Real-time Kinematic (RTK) and PPP [29].…”

A precise positioning method for global navigation satellite system based on BDS/GPS fusion

“…In the pursuit of improving the precise positioning accuracy of observation points, researchers have embarked on exploring the precise positioning method of GNSS integrating multiple systems, which bears great significance. On the one hand, it can avoid the interference of a single system and enhance the application effect of the system [8][9] ; on the other hand, increasing the number of satellites can improve the signal acquisition ability and positioning accuracy. However, due to the different spatio-temporal references of different systems, the data processing difficulty of fusing multiple systems increases accordingly.…”