Abstract:Using nearly 70 000 gravity observation data, SRTM topographic data and GNSS/leveling control points data from Hunan and nearby districts, the EIGEN-6C4 global gravity fields model is taken to be the reference gravity field. And the Stokes-Helmert approach and spherical cap harmonic analysis are conducted to construct the 2′×2′ resolution Hunan GNSS gravity geoid model(HNGG2017). The precision test shows that the external error range is ±0.022 m. Compared to the historic model, the error of the new model in north areas such as Changde Hanshou and southwest areas such as Yongzhou Jiangyong are significantly reduced.