Combination of GPS/leveling and the gravimetric geoid by using the thin plate spline interpolation technique via finite element method

Abstract

The purpose of this paper is to develop an improved local geoid model for Hungary combining GPS and leveling height data with a local gravimetric geoid model, via corrector surface, which accounts for datum inconsistencies, long-wavelength geoid errors and vertical network distortions. The improved model is the so-called GPS-gravimetric geoid, which can be constructed by adding the corrector surface to the original gravimetric geoid. The corrector surface can be represented by means of a Thin Plate Spline Interpolation (TPSI) and finite element solution. In this work 194 GPS/leveling points with a local gravimetric geoid were used to calculate the corrector surface and the combined geoid model. To estimate the realistic error of the solution 110 GPS/ leveling points were used as external control points. Attention is called to the importance of the homogeneous distribution of the GPS/leveling data. The mean accuracy of geoid heights of the used 110 control stations was 1–2 cm after the surface fitting.