Proposal of Gravity Calibration Line of the Republic of Croatia

The paper depicts proposal of gravity calibration line of the Republic of Croatia and auxiliary vertical calibration line. Particularly, the paper leys down procedures of relative gravity meter calibration and gives relevant mathematical foundation, with respect to relative gravity meters used for fundamental gravity survey in the Republic of Croatia. The accuracy of relative gravity meter calibration has been analysed. Furthermore, present calibration line has been examined. At last, proposal of new gravity calibration line of the Republic of Croatia, which is horizontal, but partly vertical also, is given, as well as auxiliary vertical calibration line. In accordance, gravity calibration line should comprise two absolute and one intermediate relative gravity station. As extreme stations, locations in Eakovec (or alternatively Zabok) and Gospie are foreseen. Predicted gravity range amounts 2993 mu ms(-2) (or alternatively 2755 mu ms(-2)), with transport time of 3 hours on highway (or alternatively 2 and a half). Furthermore, auxiliary vertical calibration line should comprise two absolute stations: one on mountain Medvednica near Zagreb and other in Zabok. Predicted gravity range amounts 1720 mu ms(-2), with transport time of 45 minutes on district road. Proposal should provide significant increase in calibration accuracy of relative gravity meters.