Evaluation for BDSBAS Single-Frequency Service Assisted by Data Authentication

The standardization process of Satellite-Based Augmentation System (SBAS) data authentication is in progress, and the BeiDou Satellite-Based Augmentation System (BDSBAS) is approaching official commissioning. This paper preliminarily assesses the performance of BDSBAS subsequent to the addition of the authentication service, leveraging actual collected data and conducting experiments and analyses with data from ten observation sites over a single day. In accordance with the extant authentication model, a one-day simulation of authentication messages was simulated on October 28, 2024. The findings reveal that the authentication service functions properly. When the message loss rate is 0.001, the authentication-related metrics, specifically the Authentication Error Rate (AER), Authentication Latency (AL), and Time Between Authentication (TBA), increase marginally by 0.15%, 0.0088 seconds, and 0.0088 seconds, respectively. The SBAS-related indicators before and after authentication were contrasted and validated, with the data comprising that from eight International GNSS Service (IGS) stations and two stations at Beihang University. Regarding positioning accuracy evaluation, the accuracy of each site under Single Point Positioning (SPP), SBAS-augmented positioning, and authenticated SBAS-augmented positioning was appraised. The positioning accuracy changes very little after adding the authentication service. After the authentication service is added, the protection level of these sites is increased to some extent. The IGS stations and the Vision Hotel Roof station possess near 100% availability. Even under authentication, the availability complies with the 99% to 99.9999% requirements of LPV - 200. In the message loss scenario, the availability coverage area after authentication has a more obvious downward trend. The current experimental results show that BDSBAS can support the implementation of authentication service and has little impact on the original performance of the system.