Modeling BDS pseudorange variations and models assessment

We present an analysis of the satellite-induced pseudorange variations based on multipath combination observables from the Chinese BeiDou Navigation Satellite System. With the main focus on refinement of the current correction models, we propose a new method to model the pseudorange variations for each satellite in the inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) and develop individual models of each satellite by differencing observables between epochs. We conduct experiments to evaluate correctness and effectiveness of the developed models. The performances of different correction models are compared and analyzed using the Hatch–Melbourne–Wübbena (HMW) observable. Numerical results show that: (1) for individual IGSO and MEO satellite, the developed correction models can make an improvement of approximately 20%, compared to the current correction models. For satellite C08, a maximum improvement of 43% can be achieved at low elevation angles of less than 10°. (2) For IGSO and MEO satellites, there are remarkable improvements using our models when the elevation angle is lower than 20° or higher than 60°; the improvements are more than 30% and nearly 25%, respectively.