______________________________________________________________________________________________________________ HRVATSKI GEODETSKI INSTITUT. Savska 41/XVI, 10144 Zagreb, p.p. 19, tel: +385 1 6312 400, fax: +385 1 6312 410, hgi@cgi.hr, www.cgi.hr 1 CURRENT STATUS OF GRAVITY MEASUREMENTS IN THE REPUBLIC OF CROATIA WITH THE FUNDAMENTAL GRAVITY NETWORK FINALIZATION PROJECT* *the paper was presented as poster at the IUGG Symposium in Perugia, 2th to 13th July, 2007. Ilija Grgić 1 , Maro Lučić 2 , Mihajla Liker 3 , Tomislav Bašić 4 , Bojan Barišić 5 , Marija Repanić 6 1 Croatian Geodetic Institute, Zagreb (e-mail:ilija.grgic@cgi.hr) 2 Croatian Geodetic Institute, Zagreb (e-mail:maro.lucic@cgi.hr) 3 Croatian Geodetic Institute, Zagreb (e-mail:mihajla.liker@cgi.hr) 4 Croatian Geodetic Institute, Zagreb (e-mail:tomislav.basic@cgi.hr) 5 Croatian Geodetic Institute, Zagreb (e-mail:bojan.barisic@cgi.hr) 6 Croatian Geodetic Institute, Zagreb (e-mail:marija.repanic@cgi.hr) ABSTRACT: The Fundamental Gravity Network (FGN) is foundation for all national gravity measurements. This network consists of 42 points: 6 absolute gravity points (0. Order Gravity Network) and 36 relative gravity points (I. Order Gravity Network). Further densification of FGN will be carried out by the lower order networks (II. Order Gravity Network). Fundamental gravity points should be homogeneously spaced over the whole state. In some large countries the distance between gravity points can be more than few hundred kilometres. Like the other geodetic networks in the Republic of Croatia, gravity network also followed the trend of connecting at the European level. The result of this trend was UNIGRACE project. Six absolute gravity points have been established (0. Order Gravity Network) during two phases of UNIGRACE project. These points provided reference for all other gravity works in Croatia. After the finalization of UNIGRACE project the main preconditions for gravity network of the first order, which leans on established six absolute stations, were accomplished. In the year 2000 revision of inherited gravity network of the first order was started. The revision showed that 25 old points could be used for the new, I. order, gravity network. Also, 11 new I. order gravity points were stabilized. With the 11 new I. order gravity points the frame for the Fundamental Gravity Network has been founded, that comprises 36 points. The gravity measurements have been performed during year 2003. After processing and measurement adjustment, the gravity value at each point has been obtained. Levelling connection of the absolute and first order gravity points at the national levelling network benchmarks was not performed. Also, the position of gravity points in respect to existing geodetic network stayed unknown. Quality positional and height definition of gravity points is necessary for calculating different corrections, which are needed for processing gravimetric measurements. By implementation of the FGN Finalization Project, along with already finalized projects, the modern gravity foundation for the Republic of Croatia will be established.