Efficient Regional Geoid Computations from Airborne and Surface Gravimetry Data: A Case Study

Abstract

Regarding the rapidly growing airborne gravimetric database worldwide, an investigation to study efficient and stable geoid computations based on this type of data was assessed to be important. The efficiency and quality of results for different approaches and combinations with surface data are discussed. The data sets used are: 1) Airborne gravimetry in the Skagerrak acquired during the AGMASCO EU-project (MAS3-CT95-0014), 2) Marine gravity data in the Skagerrak extracted from the BGI database, 3) UEGN94 absolute gravimetric network data. The methods applied on these data sets to compute a regional geoid are: 1) collocation; 2) collocation with regularization; 3) approximation by radial multipole potentials, including point mass potentials. The concluding results of the investigation are: 1) collocation with regularization provides more accurate results than the standard collocation method using the same reproducing kernel, 2) higher stability of solutions is achieved by including absolute gravimetric network data, 3) the approximation by radial multipole potentials is recommended especially for fast computations of the geoid from airborne data without loss of accuracy. Comparisons of all achieved solutions of this study with the geoid model for the European Nordic countries show a good agreement (mean deviation similar to 0.5 cm; rms 5 - 6 cm). This noise level corresponds to an estimated geoid accuracy of better than 10 cm for the Skagerrak.