Estimation of the Disturbing Potential Components and Comparison with GPS and Astrogeodetic Data

The optimal combination of surface gravity data with the OSU86F geopotential model (GM) complete to degree and order 360 is studied in a North-American test area. Experiments using gravity data and different truncations of the geopotential expansion are carried out in order to obtain for absolute geoidal heights an accuracy close to 0.40m and for relative geoidal heights 2–3 ppm. These results have been derived by comparing the computed gravimetric geoidal heights and corresponding heights derived from GPS. The same GM is employed with and without the additional use of gravity and height data in a second test area (Greece) in order to predict components of the deflections of the vertical. The results indicate an accuracy better than 2“. Conclusions for optimal combination of the 360x360 GM with regional gravity data and topographic heights are drawn and are verified numerically by the prediction of different quantities related to the gravity field.