Initial performance assessment of the single-frequency (SF) service with the BeiDou satellite-based augmentation system (BDSBAS)

The BeiDou satellite-based augmentation system (BDSBAS) is expected to provide single-frequency (SF) service through B1C signals for users in Chinese mainland and the surrounding areas, in accordance with the standards of the International Civil Aviation Organization (ICAO). The SF service of the BDSBAS is designed to augment both GPS and GLONASS with the performances meeting the requirements of approach with vertical guidance (APV-I), and initial SF service has been provided for test since July 2020. To comprehensively assess the performance of the SF service before its official application to civil aviation users, experiments were conducted with data collected at more than 30 stations all over the BDSBAS service area during the year of operation to June 30, 2021. With the BDSBAS corrections being applied, the average 95th percentiles of horizontal and vertical positioning errors are improved by 45.7% and 41.9% to 1.45 m and 2.77 m, respectively. The horizontal and vertical availabilities of the BDSBAS are 99.98% and 99.89%, respectively, and no risky event of integrity occurs throughout the year. The BDSBAS has generally achieved stable operation and has the capacity to routinely provide single-frequency positioning service as designed. According to the standards of the ICAO, the SF service with the BDSBAS is able to satisfy the positioning accuracy requirement of APV-I operation and has the potential to meet the requirements on availability and integrity.