Author(s): P. Sterzai; F. Coren; M. Maso; N. Creati; I. Marson
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Abstract: The geoid is considered the natural shape of the Earth and is physically described as the equipotential surface of the Earth gravity field. It coincides to the mean s. l. over the sea whereas over continental areas it is represented by an imaginary surface modulated by the distribution of masses inside the Earth (Marussi, 1985). The geoid is a fundamental reference surface for many geophysical and geodetic applications. The widespread use of GPS receivers with modern data measurement systems needs the accurate knowledge of the geoid undulation. The most important aspect related to the geoid is the possibility to retrieve from systems that measure only ellipsoidal elevations (as GPS) geopotential elevations and therefore express an elevation as referenced to the “mean sea level”. Geoid also plays an important role in high accuracy inertial navigation and generally it represents the base to make the conversion from the geodetic GPS reference system, usually WGS84, to a local reference one. The accuracy of the separation between ellipsoidal and orthometric height depends on the resolution of the local geoid. The “Autorita di Bacino dei Fiumi dell’Alto Adriatico” (North Adriatic Rivers Authority – ADBVE) and the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (National Institute of Oceanography and Geophysical - OGS) developed a new high resolution local geoid, named ADBVE2006, that covers the Veneto and Friuli Venezia Giulia region and the northern Adriatic Sea since known local geoid models have low resolution an are not suited for local hydraulic and generally hydrologic modelling.
Year: 2007