针对我国难以全球建站实现全球连续监测, 以及当前全球卫星导航系统 (GNSS)精密定位收敛速度慢的难题, 提出一种基于低轨全球通信星座的全球导航增强系统。该系统不需独立建设, 可与低轨通信星座融合发展。低轨卫星既可作为“天基监测站”, 又可作为“导航信息源”。结合正在发展的低轨鸿雁全球通信系统进行仿真分析, 作为“天基监测站”时, 通过配置高精确度GNSS接收机, 采用“地面区域监测网+天基全球监测网”的观测体制, 实现中高轨导航卫星与低轨通信卫星的联合精密定轨与钟差确定; 作为“导航信息源”时, 可降低几何精确度因子 (GDOP)值和缩短精密单点定位首次收敛时间, 相比只利用北斗单系统, 在收敛时间方面具有显著优势, 收敛时间从 30 min缩短到 5 min以内。

In view of the difficulty of BeiDou Navigation Satellite System(BDS) global continuous monitoring and the long convergence time of Global Navigation Satellite System(GNSS) precision positioning, a global navigation augmentation system based on Low Earth Orbit(LEO) communication constellation is proposed. The system can be developed together with the LEO communication system, and needn’t build a new system. The LEO satellites can jointly determine the precise orbits and clock errors of GNSS satellites and LEO satellites with the data from the mounted high precision GNSS monitoring receiver and the ground based monitoring stations. When served as navigation information broadcasting sources, besides the precise orbit, precise clock error, and integrity augmentation information, an additional navigation augmentation signal is broadcasted to realize Global Precise Point Positioning(GPPP) with sub-meter level of positioning precision in dynamic mode and sub-decimeter level of precision in static mode. The convergence time of precise point positioning is cut from 30 min(using a GNSS system alone) to less than 5 min(using a GNSS system together with the LEO global navigation augmentation system).