ASSESSMENT OF RECENT GLOBAL GRAVITY FIELD MODELS BY GNSS/LEVELLING DATA

This paper focuses on making a comparing of GNSS/Levelling data and data obtained from global geopotential models. For comparison, geoid undulations obtained by GNSS/Levelling method and geoid undulations obtained from global geopotential models have been used. As global geopotential models, SGG-UGM-2, XGM2019e_2159, GO_CONS_GCF_2_TIM_R6e, ITSG-Grace2018s, EIGEN-GRGS.RL04.MEAN-FIELD, GOCO06s, GO_CONS_GCF_2_TIM_R6, GO_CONS_GCF_2_DIR_R6 global gravity field models are used. The data sets used in the development of the models are altimetry, satellite (e.g., GRACE, GOCE, LAGEOS), ground data (e.g., terrestrial, shipborne and airborne measurements) and topography. The differences between the geoid undulations obtained from the GNSS/Levelling method and the geoid undulations obtained from the global geoid models have been taken. Some statistical criteria for these differences have been calculated. These criteria, such as smallest, biggest, average, standard deviation, Square Mean RMS statistical values of deviations between GNSS/Levelling geoid and global geopotential models, are taken into consideration when comparing the models. According to the comparison, the global gravity field model that best fits the GNSS/Levelling is selected.