Analysis of Recent Global Geopotential Models Over the Croatian Territory

Independent quality control of the national geoid model HRG2000 was performed using 65 control points, obtained through the realization of EUVN and EUVN_DA projects and the Croatian fundamental gravity network. Ellipsoidal heights and positions of the control points are precisely determined by GNSS measurements while the geodetic heights are obtained by geometric levelling. The latest geoid model HRG2000 is related to the old vertical system. The analysis indicated the need for a new improved national geoid model which has to be connected to the new vertical system HVRS71. As preparation, and as first step, an analysis of the global geopotential models was made, using eleven recent CHAMP and/or GRACE global models. The statistics of the differences between GNSS/levelling height anomalies (zeta HVRS71) and corresponding anomalies obtained from global geopotential models (zeta MODEL) shows that EGM2008 model is most suitable at this moment. Another interesting fact is that all global models are approximately 93 cm above the new Croatian vertical datum.