Real-Time Precise Orbit Determination of BDS/GNSS: Method and Service

Multi-GNSS (Global Navigation Satellite System) precise orbit determination and prediction is the prerequisite of high-precision real-time precise positioning. To improve the efficiency of ultra-rapid orbit solution and prediction precision in multi-GNSS, this paper proposes a collocation method based on block recursive least squares. The proposed method can combine post estimation with real-time filtering orbit determination by ① relaxing and connecting kinetics and geometry parameters, and ② transferring and recurring orbit status parameters. In addition, this method increases the efficiency of GNSS orbit solution and shortens the orbit updating time. Furthermore, experimental result verifies the reliability and effectiveness of our proposed method. Our orbit precisions are superior to the precisions of ultra-rapid GPS orbits provided by international GNSS service (IGS) and German Research Centre for Geosciences. The results show that, for quad-constellation (GPS/GLONASS/Galileo/BDS) precise orbit determination by 120 ground observation stations, our method is able to realize one-hour updating and provides service with 30 minutes delay. The 3D root mean squares of available parts in GPS/GLONASS/Galileo/BDS real-time orbit are 2.8 cm, 8.5 cm, 5.0 cm and 11.5 cm(IGSO/MEO), respectively. At present, one-hour updating for multi-GNSS orbits and real-time service system have been provided, and compared with previous three-hour and six-hour updating orbit, the precision has been improved by 20% to 40%.