A Calibration Algorithm of Ultra-rapid Orbit Boundary Discontinuity based on Adaptive Orbital Arc Length

The precise ultra-rapid orbit is a prerequisite to providing accurate Positioning, Navigation and Timing (PNT) service. There are the orbit boundary discontinuities (OBDs) in adjacent ultra-rapid orbits. The OBD will decrease the accuracy of the positioning service at the orbit boundary. The traditional time-weighted calibration algorithm based on the fixed orbital arc length depends on the broadcast latter orbit, which cannot meet the requirement of the real-time application. By assigning the weights of overlapping orbits according to time, an adaptive calibration algorithm is proposed to correct the latter orbit. The evaluation results have shown that the OBD calibration accuracy and the orbit accuracy loss are improved 12.27% and 9.87%, respectively. The OBD verification results have shown that the PPP accuracy at the boundary is improved 5%. It is confirmed that the OBD can be improved effectively based on the adaptive calibration algorithm, which can be applied for the real-time PPP.