10.5880/isg.2018.003 eng dataset GFZ German Research Centre for Geosciences datapub@gfz-potsdam.de http://www.gfz-potsdam.de Helmholtz-Centre Potsdam - GFZ German Research Centre for Geosciences Helmholtz-Centre Potsdam - GFZ German Research Centre for Geosciences pointOfContact 2021-11-26 urn:ogc:def:crs:EPSG:4326 The Belgian hybrid quasi-geoid: hBG18 2021-11-26 revision 2018 creation doi:10.5880/isg.2018.003 Slobbe, Cornelis Delft University of Technology, Delft, The Netherlands author Klees, Roland Delft University of Technology, Delft, The Netherlands author Farahani, Hassan H. Institute of Geodesy, University of Stuttgart, Germany author Huisman, Lennard Kadaster, Apeldoorn, The Netherlands author Alberts, Bas Rijkswaterstaat Centrale Informatievoorziening, Delft, The Netherlands author Voet, Pierre National Geographic Institute, Brussels, Belgium author De Doncker, Filip National Geographic Institute, Brussels, Belgium author GFZ Data Services publisher hBG2018 is the hybrid quasi-geoid model for Belgium, including both the Belgian mainland and the Exclusive Economic Zone. The hBG18 quasi-geoid heights are referred to the ETRS89/GRS80 ellipsoid. It is computed using radar altimetry data, terrestrial gravity anomalies, airborne gravity disturbances, and shipboard gravity anomalies. The quasi-geoid computation is based on the remove-compute-restore procedure. The long-wavelength signal content in the data is reduced by removing the contribution of the GOCO05S global gravity field model complete to degree 280. At the very short wavelengths, residual terrain modelling (RTM) is applied to the shipboard, terrestrial and airborne gravity datasets using EuroDEM as input data. The residual disturbing potential is parameterized over the target area using Spherical Radial Basis Functions (SRBF). The SRBF coefficients and bias parameters for the sets of gravity anomalies and disturbances are estimated using weighted least-squares with regularization, assuming white noise. To support the exploitation of the hBG2018 gravimetric quasi-geoid for the conversion of GNSS derived heights to the TAW/DNG height system, several post-processing steps were applied. First, as the TAW/DNG height system is a mean-tide height system (i.e., mean-tide crust = zero crust over mean-tide geoid) the quasi-geoid was transformed from the zero-tide to the mean tide system. Thereafter, a corrector surface (also called 'innovation function') has been estimated from the differences between the geometric quasi-geoid at 3707 GNSS/leveling points and the gravimetric quasi-geoid. This surface also accounts for the difference between the fictitious datum point of the gravimetric hBG18 and the datum point of the TAW/DNG. Finally, the transformation from the tide-free permanent tide system adopted in the GNSS community and the mean-tide system adopted in TAW/DNG, has been applied. hBG18 replaces hBG03 as the official Belgian model since August 1, 2018. The geoid model is provided in ISG format 2.0 (ISG Format Specifications), while the file in its original data format is available at the model ISG webpage. Verbeurgt, Jeffrey National Geographic Institute, Brussels, Belgium jeffrey.verbeurgt@ngi.be pointOfContact ISG Staff International Service for the Geoid (ISG) isg@polimi.it http://www.isgeoid.polimi.it/ informtion pointOfContact Geodesy Geoid model ISG Spherical Radial Basis Functions Belgium EARTH SCIENCE > SOLID EARTH > GEODETICS > GEOID CHARACTERISTICS EARTH SCIENCE > SOLID EARTH > GRAVITY/GRAVITATIONAL FIELD > GRAVITY NASA/GCMD Earth Science Keywords publication CC BY 4.0 CC BY 4.0 10.1029/2018JB016470 DOI IsDocumentedBy 10.1007/s00190-010-0406-2 DOI References 10.5194/essd-13-1653-2021 DOI References http://www.isgeoid.polimi.it/ URL References https://www.isgeoid.polimi.it/Geoid/format_specs.html URL IsDocumentedBy eng geoscientificInformation Hybrid quasi-geoid model hBG18 1 7 48.5 52.5 http://doi.org/10.5880/isg.2018.003 WWW:LINK-1.0-http--link Data Access - DOI Data Access - DOI information