AFRGDB_V2.0: The Gravity Database for the Geoid Determination in Africa

International Symposium on Advancing Geodesy in a Changing World - International Association of Geodesy Symposia ◽

10.1007/1345_2018_29 ◽

2018 ◽

pp. 61-70 ◽

Cited By ~ 4

Author(s):

Hussein A. Abd-Elmotaal ◽

Kurt Seitz ◽

Norbert Kühtreiber ◽

Bernhard Heck

Keyword(s):

Geoid Determination ◽

Gravity Database

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Surface Gravity Information of Nepal and its Role in Gravimetric Geoid Determination and Refinement

Journal on Geoinformatics, Nepal ◽

10.3126/njg.v9i1.39689 ◽

2010 ◽

pp. 41-46

Author(s):

Niraj Manandhar

Keyword(s):

Accurate Method ◽

Geoid Determination ◽

Surface Gravity ◽

Gravimetric Geoid ◽

First Order ◽

Height Determination ◽

Gravity Database ◽

Gravity Network ◽

Regional Gravimetric Geoid

This paper describes proposed first order gravity network which was almost abandoned and existing gravity database that has to be preserved and advocates about its importance in the determination of regional gravimetric geoid of the country. Since GPS is in full phase operation and adopted as an efficient and accurate method in position and height determination the paper also elaborates how all its three components can be taken into consideration.

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Comparison of remove-compute-restore and least squares modification of Stokes' formula techniques to quasi-geoid determination over the Auvergne test area

Journal of Geodetic Science ◽

10.2478/v10156-011-0024-9 ◽

2012 ◽

Vol 2 (1) ◽

pp. 53-64 ◽

Cited By ~ 15

Author(s):

H. Yildiz ◽

R. Forsberg ◽

J. Ågren ◽

C. Tscherning ◽

L. Sjöberg

Keyword(s):

Least Squares ◽

Gravity Data ◽

Test Area ◽

Geoid Determination ◽

Geopotential Model ◽

Low Degree ◽

Residual Terrain Modelling ◽

The Alps ◽

Stokes Formula ◽

Regional Geoid Determination

Comparison of remove-compute-restore and least squares modification of Stokes' formula techniques to quasi-geoid determination over the Auvergne test areaThe remove-compute-restore (RCR) technique for regional geoid determination implies that both topography and low-degree global geopotential model signals are removed before computation and restored after Stokes' integration or Least Squares Collocation (LSC) solution. The Least Squares Modification of Stokes' Formula (LSMS) technique not requiring gravity reductions is implemented here with a Residual Terrain Modelling based interpolation of gravity data. The 2-D Spherical Fast Fourier Transform (FFT) and the LSC methods applying the RCR technique and the LSMS method are tested over the Auvergne test area. All methods showed a reasonable agreement with GPS-levelling data, in the order of a 3-3.5 cm in the central region having relatively smooth topography, which is consistent with the accuracies of GPS and levelling. When a 1-parameter fit is used, the FFT method using kernel modification performs best with 3.0 cm r.m.s difference with GPS-levelling while the LSMS method gives the best agreement with GPS-levelling with 2.4 cm r.m.s after a 4-parameter fit is used. However, the quasi-geoid models derived using two techniques differed from each other up to 33 cm in the high mountains near the Alps. Comparison of quasi-geoid models with EGM2008 showed that the LSMS method agreed best in term of r.m.s.

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