Abstract: [Purposes] The quality of raw observations at reference stations is a critical factor in delivering high-precision services via the BeiDou ground-based augmentation system (BDS-GBAS),and a systemic quality analysis is of great significance for improving service accuracy and reliability.[Methods] This study analyzes observational data from five consecutive days at 110 domestic reference stations in the BDS-GBAS network.Using the Anubis software,we conduct data quality assessments in terms of completeness rate,cycle slips,multipath error,and carrier-to-noise ratio (C/No).[Findings]The results indicate that,91.8% of stations achieve a completeness rate above 85%; 99% of stations have a cycle slip rate (CSR)below 1 (per 1000); 99% of stations exhibit multipath error below 50 cm; 99% of stations have C/No above 40 dB·Hz,with the BDS system showing superior performance.We also identify a small number of anomalous stations,and propose possible causes and optimization suggestions based on station geographic location,antenna environment,etc.[Conclusions]The results confirm that the national BDS-GBAS network exhibits high overall observational quality.These findings provide important references for the layout,operational strategies,and data quality assurance of augmentation system reference stations.

Key words: BeiDou ground-based augmentation system, reference stations, Anubis, data quality, framework