The multipath error is considered to be the most limiting factor for high precision positioning applications. The sidereal filtering (SF) method can be used to mitigate the multipath error in the observation domain, and it has been successfully applied in the multipath mitigation in global positioning systems (GPS) and regional BeiDou navigation satellite systems (BDS2). However, there are few reports on the SF method in other systems. The performance of the SF method relies on the explicit orbit repeat periods of satellites in diverse systems or even different types of constellations. It is therefore inconvenient to utilize the SF method for multi-GNSS multipath error mitigation. Alternatively, a space domain multipath error reduction method, which establishes the multi-point hemispherical grid model (MHGM) using the residuals of the double-differenced carrier phase observations in the ambiguity-fixed period, has been modified. It is an integrated model for multi-GNSS, without considering the diversity of different systems and constellations. To compare the performance of MHGM and SF from a multi-GNSS point of view, the determination method of orbit repeat periods via the broadcast ephemerides is summarized, and the SF method is extended to the global BeiDou navigation satellite system (BDS3) and Galileo navigation satellite system. Further test results show that the performance of MHGM and SF are comparable from the perspective of root mean squares (RMS) and the power spectrum analysis of double-differenced residuals, as well as the static positioning results. This implies that the space domain MHGM can obtain similar correction effects as the SF method in the observation domain, but the former is more flexible for modeling with various systems’ data. In addition, the established MHGM using the data of multi orbit periods demonstrates a better performance compared with that of only one orbit period, and an average improvement of 13.1% in the RMS of the double-differenced residuals can be achieved.

中文翻译：

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Multi-GNSS的多径误差融合建模方法

多径误差被认为是高精度定位应用的最大限制因素。恒星滤波（SF）方法可用于减轻观测域的多径误差，已成功应用于全球定位系统（GPS）和区域性北斗卫星导航系统（BDS2）的多径抑制。然而，在其他系统中关于SF方法的报道很少。SF 方法的性能依赖于不同系统甚至不同类型星座中卫星的明确轨道重复周期。因此，将SF方法用于多GNSS多径误差缓解是不方便的。或者，一种空间域多径误差减少方法，修改了使用模糊度固定期间双差分载波相位观测的残差建立多点半球网格模型（MHGM）。它是多GNSS的综合模型，没有考虑不同系统和星座的多样性。为了从多GNSS的角度比较MHGM和SF的性能，总结了通过广播星历确定轨道重复周期的方法，并将SF方法扩展到全球北斗卫星导航系统（BDS3）和伽利略导航卫星系统。进一步的测试结果表明，从均方根（RMS）和双差分残差的功率谱分析以及静态定位结果来看，MHGM和SF的性能具有可比性。这意味着空间域 MHGM 在观测域可以获得与 SF 方法类似的校正效果，但前者对于各种系统的数据建模更灵活。此外，使用多轨道周期数据建立的MHGM与仅一个轨道周期相比表现出更好的性能，并且双差分残差的RMS平均提高了13.1%。