Comparative analysis of real-time PPP time transfer performance of BDS-3 based on SSR/PPP-B2b corrections

The BeiDou Navigation Satellite System (BDS) precise point positioning (PPP) service, PPP-B2b, is broadcasted by BDS-3 geostationary earth orbit (GEO) satellites, which provides high-precision positioning and timing services to users in China and neighboring regions. This paper presents an analysis of real-time PPP time transfer experiments utilizing PPP-B2b corrections from BDS-3 satellites and compares the results with real-time time transfer performance based on the state space representation (SSR) corrections broadcast by the International Global Navigation Satellite System Service Data Center of Wuhan University. PPP-B2b/SSR corrections were applied to the broadcast ephemeris to derive precise satellite positions and clock biases. The BDS-3 B1I + B3I and B1C + B2a combinations were analyzed under short baseline conditions using real-time PPP processing software. The results demonstrated that the standard deviation (STD) of real-time PPP time transfer for the B1C + B2a dual-frequency combination of BDS-3 using PPP-B2b/SSR corrections were consistently below 0.2 ns, while the STD for the B1I + B3I dual-frequency combination remained under 0.3 ns. The 10 000 s Allan Deviations for all combinations were better than 1.322 × 10−14. The findings confirmed that the PPP-B2b of BDS-3 is capable of achieving sub-nanosecond time transfer, comparable to SSR-based methods. PPP-B2b is more accessible and offers a broader range of applications compared to SSR, making it suitable for long-term, reliable real-time time transfer operations in network-restricted environments.