An analysis of BDS-3 real-time PPP: Time transfer, positioning, and tropospheric delay retrieval

Abstract

With the development of China’s BDS-3, more studies focused on its performance in precise point positioning (PPP), mainly in post-processing mode. This study conducts a comprehensive investigation of BDS-3 real-time PPP with Centre National d’Etudes Spatiales (CNES) real-time products (SSRA00CNE0) from the perspective of time transfer, positioning, and tropospheric delay retrieval. First, the availability and accuracy of BDS-3 real-time products were evaluated over 41 days. The product availability was about 80%. The accuracy of BDS-3 satellite orbit were 0.060, 0.115 and 0.065 m in the radial, along-track, and cross-track component. In addition, the standard deviation (STD) of satellite clock difference was 0.455 ns. Afterwards, precise time transfer, positioning, and Zenith troposphere delay (ZTD) estimation derived from BDS-3 real-time PPP were assessed with 7-day processing. The root mean square (RMS) of smoothed residuals is 0.020 ns, while it is 0.001 ns for BDS-3 PPP with WUM final products for time transfer. Furthermore, the RMS values of positioning errors derived from real-time static BDS-3 PPP positioning were 0.021, 0.010, and 0.03 m in the east (E), north (N), and up (U) component, respectively. Moreover, the RMS of ZTD estimation is 9.9 mm, which is comparable to GPS real-time PPP solutions.