The Carmel Mountains Precise Geoid

This paper presents the final results of a pilot-project, for mapping an accurate geoid of the State of Israel. The purpose of the project was to develop a feasible methodology, assemble all necessary data, design and test field procedures and finally to work out a suitable analysis algorithm, including the respective computer programs. The project was funded and supported by the Survey of Israel over a period of five years between 1994 and 1999. An area of about 600-sq. km on and around the Carmel Mountains served as a field laboratory and proving ground. The ultimate goal was to render a geoid map of the pilot area with a one-sigma accuracy of 4 cm. The geoid map was compiled from three independent data sources that complement each other: (a) Measured geoid undulations (indirectly- by GPS and trigonometric leveling) at a network of control points. The network density was set intentionally high by a factor of three to four in order to provide means for testing the quality of the map. (b) A global gravity model of the highest order available. Over the years 1994-1999 a number of gravity models were used, beginning with OSU'91, followed by EGM'9