关键词: 多级完好性监测策略, 北斗卫星导航系统, 北斗星基增强系统, 先进接收机自主完好性监测, 接收机自主完好性监测

Abstract: Abstract: In July 2020, the construction of the BeiDou Satellite-Based Augmentation System (BDSBAS) was completed, providing single-frequency and dual-frequency augmentation services compliant with International Civil Aviation Organization (ICAO) standards to users in China and surrounding regions. Addressing issues such as uneven augmentation service performance and integrity holes caused by severe ionospheric effects in southern China and the incomplete GPS L5 constellation, this paper investigates an airborne multi-level integrity monitoring strategy. We propose a combined strategy integrating BDSBAS, Advanced Receiver Autonomous Integrity Monitoring (ARAIM), and Receiver Autonomous Integrity Monitoring (RAIM). For precision approaches, RAIM verification is conducted when dual-frequency BDSBAS is active; otherwise, the system falls back to V-ARAIM or single-frequency BDSBAS for integrity support. For en-route and non-precision phases, the unavailability of dual-frequency BDSBAS triggers a progressive switch to H-ARAIM, single-frequency BDSBAS, or RAIM. This strategy ultimately improves the continuity of integrity services and avoids performance degradation. This strategy was validated through field vehicle tests and airborne flight tests. Results show that under normal conditions, the multi-level integrity monitoring strategy can achieve APV-I service level integrity monitoring. Compared with single integrity monitoring methods, the proposed strategy increases the proportion of effective navigation epochs by up to 0.36% and improves user navigation integrity monitoring availability by 6.84%. The multi-level integrity monitoring algorithm provides more continuous and stable integrity monitoring performance. This study provides revision ideas for incorporating BeiDou into international standards, and offers a technical foundation as well as data support for promoting the application of BeiDou in civil aviation.

Key words: Multi-level integrity monitoring strategy, BDS, BDSBAS, ARAIM, RAIM