ADAPTED REFERENCE ELLIPSOID FOR THE NWL-8D GEODETIC PARAMETER SOLUTION.
NAVAL WEAPONS LAB DAHLGREN VA
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An adapted reference ellipsoid is developed for geodetic parameter solutions with application to the NWL-8D Solution. Mean sea level geoid is defined by a suitably chosen equi-potential surface of the gravity field resulting from the geodetic parameter solution under consideration. Starting from a corresponding world-wide geoid height table which is based on one of the standard reference ellipsoids, a two-parameter solution for the ellipsoid parameters determines that ellipsoid which minimizes the area weighted sum of the squares of the geoid heights. Included are a detailed description of the two-parameter solution, a related computer program formulation and numerical data which concern the NWL-8D solution as well as the associated geoid heights above both the Kaula ellipsoid and the adapted NWL-8D ellipsoid. Also discussed is an alternative approach to the ellipsoid determination. This interprets the first two expansion coefficients of the earths gravity potential as numbers which carry, implicity, the information necessary to specify a meaningful adapted ellipsoid which is essentially identical to the one derived earlier. Both methods result in an ellipsoid of a 6378.144 km and 1f 298.234. The parameters of the initial Kaula ellipsoid were a 6378.165 km and 1f 298.300. The semimajor axis of the adapted ellipsoid is thus twenty-one meters smaller than that of the Kaula ellipsoid. Due to the increase in flattening of the new ellipsoid over the Kaula ellipsoid, the separation of the two ellipsoids amounts to only five meters at the poles. Author