Two different methods for the combined computation of the quasigeoid are compared in a test area in Germany. Both methods are based on the remove-restore technique and use the global geopotential model EGM96, point gravity data with a spacing of a few km, a digital terrain model and GPS/levelling control points (with a spacing of about 25 km).In method I the global model is combined first with the gravity and terrain data using the least squares spectral combination technique with integral formulas. The resulting height anomalies are given in a 1.0 ’x 1.5’grid. Then a smooth corrector surface is developed from the GPS/levelling data by least squares collocation, using a signal and a trend component.The second method (II) is based on a common adjustment of the EGM96 reduced gravity and height anomaly observations using point masses and appropriate weight relations. The point masses are arranged at a depth of 10 km, 30 km and 200 km, and in hilly areas also at a depth of 5 km.Both techniques are compared from the methodological and numerical point of view. The results are discussed and show an agreement at the cm level.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Investigation of different methods for the combination of gravity and GPS/levelling data
- Springer Berlin Heidelberg