Assessment of Solar Radiation Pressure Models for BDS-3 MEO Navigation Satellites

Precise orbit products of BeiDou Navigation Satellite System (BDS) are the primary prerequisite to provide high-quality positioning, navigation and timing services. As the dominating satellite type in BDS-3 constellation, the orbit accuracy of Medium Earth Orbit (MEO) satellite mainly depends on geometric observation conditions and the quality of dynamic models. In recent years, the growing number of global BDS monitoring stations greatly enhance the geometric pattern for BDS-3 MEO satellites. However, solar radiation pressure (SRP) of BDS-3 MEO satellites is still under investigation and the SRP models adopted by analysis centers in the International GNSS Service (IGS) are different from each other. Based on International GNSS Monitoring and Assessment System (iGMAS) BeiDou analysis center of Tongji University, this paper comprehensively evaluates six SRP models (e.g., ECOM1, ECOM2, ECOM1 with a prior Box-wing model, ECOM2 with a prior Box-wing model, ECOM1 with an empirical force model, ECOM2 with an empirical force model) that commonly used for BDS-3 MEO satellites. The results indicate that compared with ECOM1 model, ECOM2 model can reduce orbit overlap error by 5.02% when satellites are out of earth eclipse. Moreover, ECOM2 model can effectively reduce the orbit overlap error in spite of a low solar elevation angle. As for satellite laser ranging residuals of BeiDou-3 MEO satellites, ECOM1 model with an empirical force model performs better. The average orbit bias in radial direction is 0.63–2.51 cm and the standard deviation is 2.68–3.16 cm, which is decreased by 7.76%–26.97% comparing with other five models. Furthermore, the orbit products resolved by this paper is better than orbit products provided by GFZ and WUM in radial direction.