A method for mitigating GNSS multipath effect based on multi-point hemispherical grid model

Multipath effect is related to the observational environment of stations, and cannot be eliminated or mitigated by differential algorithm. It is a major factor affecting accuracy and reliability in GPS signal processing. This paper proposes a method to mitigate the multipath effect—MHGM (Multi-point Hemispherical Grid Model). The method divides the hemisphere centered on each station into a grid, and estimates the multipath error at the station based on parametrization of the grid points, which can be applied to different kinds of hardware and software system of GPS data processing and observation environment. The experimental results in this paper show that, MHGM multipath error modeling based on data from observations made improvements in the mean RMS of double-differenced observation residuals averaging about 71.3%, an average increase of 26.9% compared with the traditional sidereal filtering method, the positioning results of 1.7 mm in level and 3.0 mm in altitude are obtained for static observation using real-time kinematic relative positioning mode. MHGM proposed in this paper also can used to assess orientation of error sources around the station, giving guidance which may assist in the physical elimination of sources of multipath error.