Calibration/validation of GOCE data by terrestrial torsion balance observations
One promising method for the external validation and calibration of the upcoming GOCE satellite mission data is the use of ground gravity field data continued upward to satellite altitude. There is a unique situation for Hungary in this respect since surface gravity gradients are available at 20143 points over an approximately 48700 km2 area, measured by the classical E6tv6s torsion balance. The concept of this contribution is to test the usability of these point gravity gradient observations for upward continuation to the GOCE satellite orbit in combination with different geopotential models and other gravity field information.
The computations are based on the least squares collocation method and the direct numerical integration of the torsion balance data. For the latter method, the spectral combination technique and the classical integration kernels are considered. Furthermore, various other data sources, such as the Tzz gravity gradients based on the gravity and terrain data collected within the frame of the European Geoid Project, are utilized for comparisons.
Besides the comparisons between the different satellite gravity gradient computations, an error analysis of the results is presented.
KeywordsGOCE vertical gravity gradients upward continuation Eötvös’ torsion balance
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