北斗星基增强系统双频多星座服务覆盖范围评估

双频多星座（DFMC）服务已成为星基增强系统（SBAS）未来能力提升的重要方向之一，相关国际标准也将在2023年11月正式发布。北斗星基增强系统（BDSBAS）是全球范围内唯一持续播发DFMC增强服务测试信号的星基增强系统。在详细介绍SBAS DFMC服务可用性和保护级计算方法的基础上，利用实测的BDSBAS B2a增强电文对BDSBAS DFMC增强服务的一类垂向引导进近（APV-I）/垂向导航信标性能（LPV）和决断高度200英尺垂向导航信标性能（LPV-200）等级的服务覆盖率进行了初步评估。评估结果表明，当前BDSBAS DFMC增强服务能够实现对中国及周边广大区域的服务覆盖，且双系统（BeiDou navigation satellite system和global positioning system，BDS+GPS）增强服务的APV-I和LPV-200等级99%可用性覆盖率比单系统（BDS）增强服务的覆盖率分别提升16%和32%。

Dual-frequency multi-constellations service coverage evaluation of BeiDou satellite-based augmentation system

Dual-frequency multi-constellation (DFMC) service has become one of the important directions for future capability improvement of satellite-based augmentation systems (SBAS), and relevant international standards will be officially released in November 2023. The BeiDou satellite-based augmentation system (BDSBAS) is the only satellite-based augmentation system in the world that continuously advertises DFMC service test signals. Based on the detailed introduction of SBAS DFMC service availability and protection level calculation method, this paper uses the BDSBAS B2a message to evaluate the service coverage of BDSBAS DFMC service at approach and landing operations with vertical guidance I(APV-I)/localizer performance with vertical guidance(LPV)and localizer performance with vertical guidance-200ft(LPV-200) levels. The evaluation results show that the current BDSBAS DFMC service can achieve service coverage in China and surrounding areas, and the 99% availability coverage of APV-I and LPV-200 for dual-system (BDS+GPS) service increases by 16% and 32% respectively compared to the coverage of single-system (BDS).