Multipath remains one of the major challenges in high-precision GNSS positioning. The multipath hemispherical map (MHM) based on satellites’ location repeatability in space is a popular method to mitigate GNSS multipath effects, but its performance depends on the availability of sufficient satellite orbital tracks in the skyplot. For instance, for BDS-3 medium Earth orbiters and Galileo satellites with 7-day and 10-day orbital repeat times, respectively, the skyplot of their orbital tracks will be too sparse to cover the shifting orbital tracks on the succeeding days, if only a few days of observations are used to construct MHMs. In this study, we establish an interoperable MHM using the overlap frequency signals of GPS, Galileo and BDS-3 (i.e., GPS L1/L5, Galileo E1/E5a and BDS-3 B1C/B2a). We compared the performance of GPS/Galileo/BDS-3 MHM (i.e., MP_GEC) and single-constellation MHMs (i.e., MP_G, MP_E and MP_C). The mean reduction rates of the L1/E1/B1C and L5/E5a/B2a carrier-phase residuals for the MP_GEC applied to GPS, Galileo and BDS-3 are 36% and 48%, respectively, which are 10–30% points larger compared to the MP_G, MP_E and MP_C. The MP_GEC constructed using 4 days of observations reduced the Galileo RMS positioning errors by 26%, 31% and 29% for the east, north, and up components, respectively, showing improvements of about 16, 18 and 17% points compared to the MP_E, and even approaching the RMS errors of the MP_E constructed using 10 days of observations. The results show that the interoperable GPS/Galileo/BDS-3 MHM is able to improve the spatial resolution, modeling efficiency and correction performance in mitigating multipath effects for high-precision GNSS positioning.

多路径仍然是高精度 GNSS 定位的主要挑战之一。基于卫星在空间中的位置重复性的多径半球地图 (MHM) 是减轻 GNSS 多径效应的常用方法，但其性能取决于星空图中是否有足够的卫星轨道。例如，对于分别具有 7 天和 10 天轨道重复时间的 BDS-3 中地球轨道飞行器和伽利略卫星，其轨道的星空图将过于稀疏，无法覆盖随后几天的移动轨道，如果仅几天的观察用于构建 MHM。在本研究中，我们利用GPS、伽利略和BDS-3（即GPS L1/L5、伽利略E1/E5a和BDS-3 B1C/B2a）的重叠频率信号建立了可互操作的MHM 。我们比较了 GPS/Galileo/BDS-3 MHM（即MP_GEC）和单星座 MHM（即MP_G、MP_E 和 MP_C）的性能。 MP_GEC应用于GPS、Galileo和BDS-3的L1/E1/B1C和L5/E5a/B2a载波相位残差的平均降低率分别为36%和48%，比原来高出10-30%与 MP_G、MP_E 和 MP_C 相比。使用 4 天的观测构建的 MP_GEC 将东、北和向上分量的伽利略 RMS 定位误差分别减少了 26%、31% 和 29%，与 MP_E 相比分别提高了约 16%、18% 和 17% ，甚至接近使用 10 天的观察构建的 MP_E 的 RMS 误差。结果表明，可互操作的GPS/Galileo/BDS-3 MHM能够提高高精度GNSS定位的空间分辨率、建模效率和减轻多径效应的校正性能。