Improved stochastic modeling of multi-GNSS single point positioning with additional BDS-3 observations

Abstract

The accuracy of Global Navigation Satellite System (GNSS) observations is affected by many factors, such as different systems, frequencies, carriers and pseudoranges, all of which also vary with different situations. Therefore, it is challenging to establish an accurate stochastic model for multi-GNSS positioning in theory, particularly for the additional BeiDou-3 Global Navigation Satellite System (BDS-3). In practical applications, the real stochastic model needs to be estimated based on the characteristics of the observations themselves. We evaluated the influence of BDS-3 on the positioning results using 46 sites distributed around the world and proposed an improved stochastic model for multi-GNSS single point positioning (SPP) based on the least-squares variance component estimation (LS-VCE). The results show that when the BDS-3 observations are added, the positioning precision and accuracy are significantly improved. By using the improved LS-VCE method in GPS/BDS dual system positioning, the accuracy of E, N and U directions are 0.373, 0.498 and 1.044 m, respectively, when compared to the traditional method with 0.502, 0.533 and 1.333 m. The proposed stochastic model improves the multi-GNSS SPP accuracy without significantly increasing the calculation time. Furthermore, reliable results are obtained for all epochs with the improved LS-VCE model.