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Investigation of different methods for the combination of gravity and GPS/levelling data

  • H. Denker
  • W. Torge
  • G. Wenzel
  • J. Ihde
  • U. Schirmer
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 121)

Abstract

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.

Keywords

Geoid levelling gravity GPS 

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References

  1. Denker, H. (1998): Evaluation and improvement of the EGG97 quasigeoid model for Europe by GPS and levelling data. Second Cont. Workshop on the Geoid in Europe, Rep. Finn. Geod. Inst. 98:4, 53–61, Masala, 1998.Google Scholar
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Copyright information

© SPringer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • H. Denker
    • 1
  • W. Torge
    • 1
  • G. Wenzel
    • 1
  • J. Ihde
    • 2
  • U. Schirmer
    • 2
  1. 1.Institut für Erdmessung (IfE)Universität HannoverHannoverGermany
  2. 2.Bundesamt für Kartographie and Geodäsie, Außenstelle LeipzigLeipzigGermany

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