Research and Performance Assessment of BDSBAS Time System Interoperability

Since each SBAS is constructed by different countries, the augmented GNSS constellation and the reference time are not the same, the compatibility and interoperability between SBAS time systems has been one of the important issues in the SBAS standard research of the International Civil Aviation Organization (ICAO). The contribution introduces the concept and research status of the SBAS network time (SNT), combined with the formulation of ICAO SBAS Standards and Recommended Practices (SAPRs), analyzes and studies SNT compatibility and interoperability issues, and presents the latest joint solution. On this basis, the ground sub-system of the BeiDou Satellite-Based Augmentation System (BDSBAS) was upgraded, and preliminary service performance assessment was carried out. The results show that the maximum deviations between the BDSBAS single-frequency (SF) SNT and dual-frequency multi-constellation (DFMC) SNT and the reference GNSS time reference are 37 ns and 0.17 μs, respectively, which meet the ICAO standards. The service performance basically conforms to the APV-I level requirements, which proves the feasibility and reliability of the interoperability of BDSBAS SNT.