Centimeter-Level Real-Time Orbit Determination and Accuracy Analysis of LEO Satellite with POD4LEO Software

High precision and low delay satellite orbits are the key requirements for many Earth observation missions today. This paper briefly introduces the development of precision orbit determination of low orbit satellites, and the opportunities brought by GNSS satellite-based enhancement service for real-time centimeter-level orbit determination of low orbit satellites, then analyzes the orbit accuracy and clock error accuracy of current satellite-based enhancement real-time products, and then introduces the mathematical model of precision orbit determination of low orbit satellites with simplified dynamics real-time filtering solution in detail. At last, the Sentinel-3A satellite GPS observation data for 10 days were used to simulate the in-orbit mode by POD4LEO software. The results show that, compared with the scientific orbit provided by the European Copernicus Center, the RMS of the computed orbit in the radial, tangential, normal and three-dimensional directions are 2.5 cm, 2.5 cm, 2.0 cm and 4.1 cm respectively, and the SISRE caused by the orbital error is about 3.0 cm. The effectiveness and feasibility of the real-time orbit determination method proposed in this paper and the developed software are verified, which has practical significance in the future low orbit navigation enhanced satellite or other low orbit satellite engineering applications.