Abstract
In geodesy, civil engineering and related fields high accuracy coordinate determination is needed, for that reason GNSS technologies plays important role. Transformation from GNSS derived ellipsoidal heights to orthometric or normal heights requires a high accuracy geoid or quasi-geoid model, respectively the accuracy of the currently used Latvian gravimetric quasi-geoid model LV'98 is 6–8 cm. The objective of this work was to calculate an improved quasi-geoid (QGeoid) for Latvia. The computation was performed by applying the DFHRS software. This paper discusses obtained geoid height reference surface, its comparisons to other geoid models, fitting point statistics and quality control based on independent measurements.
Highlights
The objective of this work was to calculate the QGgeoid height reference surface for Latvia
Comparisons were made between the geoid height reference surface obtained by using DFHRS software and European Gravimetric Geoid Model 1997 (EGG97), EGM2008, Eigen5c, Eigen6c, GOCE GO_CONS_GFC_2_DIR_R3 models, and between LV’98 and above mentioned regional and global models
High accuracy geoid height reference surface can be achieved by minimum number of observations (102 fitting points)
Summary
The objective of this work was to calculate the QGgeoid height reference surface for Latvia. The computation was performed by applying the DFHRS software of Karlsruhe University of Applied Sciences. The obtained geoid height reference surface was compared with Latvian gravimetric geoid model LV’98 which is broadly used by land surveyors for more than 10 years. It is based on gravimetric measurements, data digitized from gravimetric maps and satellite altimetry data over Baltic Sea, its computation was performed by applying GRAVSOFT software. Comparisons were made between the geoid height reference surface obtained by using DFHRS software and EGG97, EGM2008, Eigen5c, Eigen6c, GOCE GO_CONS_GFC_2_DIR_R3 models, and between LV’98 and above mentioned regional and global models. Appropriate transformation was applied because the global models are not fitted to national height system
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