分步北斗三频部分模糊度解算方法

随着月球探索进入一个新的时代，为确保未来月球任务的实时高精度定位，大幅提高登月航天器的自主性，且减少对地球基站的依赖，选取合适的轨道构建月球导航星座，并且实现月球导航星座与地球GNSS的通信链路同步尤为重要。为评估月球导航星座轨道中卫星接收GNSS信号的性能，首先对椭圆形月球冻结轨道(ELFO)、近直线晕轨道(NRHO)、顺行圆形轨道(PCO)和低月球轨道(LLO)4种轨道进行仿真。然后基于天线方向图等指标仿真了GNSS卫星信号，并依据主旁瓣波束宽度和载噪比等仿真结果评估了4种不同轨道卫星对GNSS的可见性。结果表明，NRHO和ELFO对GNSS星座有较好的可视效果，最高可见时间占比达99.57%，保障了绝大部分时间内能够稳定接收GNSS信号，有助于实现月球导航星座轨道卫星的轨道和时钟校正，并保证轨道的定位性能。

Stepwise Beidou triple-frequency partial ambiguity resolution method

As the era of lunar exploration dawns anew, to ensure real-time, high-precision positioning for future lunar missions, significantly enhance the autonomy of lunar spacecraft and reduce their dependence on Earth-based stations, it is particularly important to select suitable orbits for constructing a lunar navigation constellation and achieve synchronization of communication links between the lunar navigation constellation and the Earth''s GNSS. To assess the performance of satellites receiving GNSS signals in lunar navigation constellation orbits, simulations of four types of orbits—elliptical lunar frozen orbit (ELFO), near-rectilinear halo orbit (NRHO), prograde circular orbit (PCO) and low lunar orbit (LLO)—are conducted.Along with simulations of GNSS satellite signals based on antenna pattern metrics,the visibility of GNSS by satellites in these four types of orbits is evaluated based on simulation results such as main and side lobe beam width and signal-to-noise ratio. Results show that NRHO and ELFO orbits provide better visibility of the GNSS constellation, with the highest visibility time proportion reaching 99.57%. This ensures stable reception of GNSS signals for the majority of the time, facilitating the correction of orbit and clock of lunar navigation constellation satellites and guaranteeing positioning performance of the orbit.