Geopotential Models Evaluation in Algeria Using Stochastic Method, GPS/Leveling and Topographic Data
Authors: M. A. Meslem
For precise geoid determination, we use a reference field to subtract long and medium wavelength of the gravity field from observations data when we use the remove-compute-restore technique. Therefore, a comparison study between considered models should be made in order to select the optimal reference gravity field to be used. In this context, two recent global geopotential models have been selected to perform this comparison study over Northern Algeria. The Earth Gravitational Model (EGM2008) and the Global Gravity Model (GECO) conceived with a combination of the first model with anomalous potential derived from a GOCE satellite-only global model. Free air gravity anomalies in the area under study have been used to compute residual data using both gravity field models and a Digital Terrain Model (DTM) to subtract the residual terrain effect from the gravity observations. Residual data were used to generate local empirical covariance functions and their fitting to the closed form in order to compare their statistical behaviors according to both cases. Finally, height anomalies were computed from both geopotential models and compared to a set of GPS levelled points on benchmarks using least squares adjustment. The result described in details in this paper regarding these two models has pointed out a slight advantage of GECO global model globally through error degree variances comparison and ground-truth evaluation.Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 665
 EGM Development Team (2008) Description of files related to the EGM2008 Global Gravitational Model, US National Geospatial-Intelligence Agency (NGA) EGM2008 Development Team http://earth-info.nga.mil/GrandG/wgs84/gravitymod/egm2008/.
 Gilardoni, M., Reguzzoni, M., Sampietro, D. (2016). GECO: a global gravity model by locally combining GOCE data and EGM2008. Studia Geophysica et Geodaetica, 60, 228-247.
 H. Moritz, 1980. Advanced Physical Geodesy, H. Press, Karlsruhe-Tundridge Wells.
 C. C. Tscherning, Geophysical Institute, University of Copenhagen, Haraldsgage 6, DK-2200 Copenhagen N. Mathematical and statistical methods in physical geodesy, Spring semester 1991. Revised July 1992.
 Forsberg and P. Knudsen, Gravsoft – A System for Geodetic Gravity Field Modelling. C. C. Tscherning, Department of Geophysics, Juliane Maries Vej 30, DK-2100 Copenhagen N. R. Kort og Matrikelstyrelsen, Rentemestervej 8, DK-2400 Copenhagen NV.
 M. A. Meslem, A gravimetric quasi-geoid evaluation in the Northern region of Algeria using EGM96 and GPS/Levelling, Jan. 2005. Newton Bulletin, IGS at DICA Politecnico di Milano – P.za Leonardo da Vinci, 32 – 20133 Milano (Italy).
 H. Moritz, 2015. Classical Physical Geodesy, H. Press, Karlsruhe-Tundridge Wells.
 H. Moritz, 1967. Physical Geodesy, H. Press, Karlsruhe-Tundridge Wells.
 G. Fotopoulos, C. Kotsakis, M. G. Sideris, Evaluation of Geoid Models and Their use in combined GPS/Levelling/Geoid Height Network, Department of Geomatics Engineering, The University of Calgary, 2500 University Drive N. W. Calgary, Alberta, Canada.