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The height datum problem and the role of satellite gravity models / A. Gatti in Journal of geodesy, vol 87 n° 1 (January 2013)
[article]
Titre : The height datum problem and the role of satellite gravity models Type de document : Article/Communication Auteurs : A. Gatti, Auteur ; M. Reguzzoni, Auteur ; Giovanna Venuti, Auteur Année de publication : 2013 Article en page(s) : pp 15 - 22 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altitude normale
[Termes IGN] anomalie de pesanteur
[Termes IGN] données GOCE
[Termes IGN] données GRACE
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] erreur en altitude
[Termes IGN] erreur systématique
[Termes IGN] géoïde altimétrique
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] modèle de géopotentiel
[Termes IGN] niveau moyen des mers
[Termes IGN] réseau de nivellement
[Termes IGN] système de référence altimétriqueRésumé : (Auteur) Regional height systems do not refer to a common equipotential surface, such as the geoid. They are usually referred to the mean sea level at a reference tide gauge. As mean sea level varies (by +1 to 2 m) from place to place and from continent to continent each tide gauge has an unknown bias with respect to a common reference surface, whose determination is what the height datum problem is concerned with. This paper deals with this problem, in connection to the availability of satellite gravity missions data. Since biased heights enter into the computation of terrestrial gravity anomalies, which in turn are used for geoid determination, the biases enter as secondary or indirect effect also in such a geoid model. In contrast to terrestrial gravity anomalies, gravity and geoid models derived from satellite gravity missions, and in particular GRACE and GOCE, do not suffer from those inconsistencies. Those models can be regarded as unbiased. After a review of the mathematical formulation of the problem, the paper examines two alternative approaches to its solution. The first one compares the gravity potential coefficients in the range of degrees from 100 to 200 of an unbiased gravity field from GOCE with those of the combined model EGM2008, that in this range is affected by the height biases. This first proposal yields a solution too inaccurate to be useful. The second approach compares height anomalies derived from GNSS ellipsoidal heights and biased normal heights, with anomalies derived from an anomalous potential which combines a satellite-only model up to degree 200 and a high-resolution global model above 200. The point is to show that in this last combination the indirect effects of the height biases are negligible. To this aim, an error budget analysis is performed. The biases of the high frequency part are proved to be irrelevant, so that an accuracy of 5 cm per individual GNSS station is found. This seems to be a promising practical method to solve the problem. Numéro de notice : A2013-070 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-012-0574-3 Date de publication en ligne : 03/07/2012 En ligne : https://doi.org/10.1007/s00190-012-0574-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32208
in Journal of geodesy > vol 87 n° 1 (January 2013) . - pp 15 - 22[article]Réservation
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