- 119 - STATUS OF EUVN AND EUVN_DA PROJECTS IN THE REPUBLIC OF CROATIA * Ilija Grgić, Bojan Barišić, Mihajla Liker ABSTRACT The EUVN points are represent one basic element of the European geodetic infrastructure. They serve as a control of the existing continental and national geoid solutions and for the estimation of height datum differences. After the first analysis, discrepancies between gravimetric geoid EGG97 and the point-wise EUVN geoid were detected due to errors in one of compared models. Croatian Geodetic Institute (CGI) received all materials related to EUVN project from the State Geodetic Administration. Analyse of the received materials shows that some height data, which have been sent to the EUREF- UELN data centre, were calculated using benchmarks whose heights are in different height datum. This paper represents discrepancies between EGG97 and EUVN after using uniform new official height datum in Croatia – HVRS71 and densification project EUVN_DA on the territory of the Republic of Croatia. KEYWORDS EUVN, EUVN_DA 1. INTRODUCTION EUVN project was completed in the year 2001 under the EUREF responsibility. It consists of almost 200 points, which represent one basic element of the European geodetic infrastructure. EUVN points serve as a control of the existing continental and national geoid solutions in ETRS89 and for the estimation of height datum differences. After the first analysis, discrepancies between gravimetric geoid EGG97 and the point-wise EUVN geoid were detected due to errors in one of compared models. On the Croatian territory discrepancy on only one point, HR05-Split, exceeds 50 cm and that point is marked as problematic (Kenyeres et al. 2002), Fig. 1.1. 0 10 20 30 50 100 km 40 +51cm +19cm 0cm +23cm +67cm +1cm +15cm +28cm <1dm >1dm Fig. 1.1. EGG97 and EUVN discrepancies on the territory of Croatia Need of solving these problems is recognised and defined in two EUREF resolutions: No. 3 (June 2000) and No. 4 (May 2001). Result is project of EUVN densification - EUVN_DA and its aim is solving the discrepancies problems and densification of EUVN points that will be used for sub-decimetre accuracy connection of different national height networks in Europe. In combination with new European * Predstavljeno na EUREF2005 simpoziju (Symposium of the IAG Subcommission for Europe – EUREF) održanom u Beču, Austria, 2.-5.6.2005. godine. Objavljeno u Zborniku radova Simpozija (u tisku).