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Analyse und Vergleich unterschiedlicher Modelle der dreidimensionalen Geodäsie / U. Klein (1997)

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Titre :	Analyse und Vergleich unterschiedlicher Modelle der dreidimensionalen Geodäsie
Titre original :	[Analyse et comparaison de différents modèles de la géodésie tridimensionnelle]
Type de document :	Thèse/HDR
Auteurs :	U. Klein, Auteur
Editeur :	Munich : Bayerische Akademie der Wissenschaften
Année de publication :	1997
Collection :	DGK - C
Sous-collection :	Dissertationen num. 479
Importance :	123 p.
Format :	21 x 30 cm
ISBN/ISSN/EAN :	978-3-7696-9519-9
Note générale :	Bibliographie
Langues :	Allemand (ger)
Descripteur :	[Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] données GPS [Termes IGN] équation linéaire [Termes IGN] géodésie tridimensionnelle [Termes IGN] levé gravimétrique [Termes IGN] potentiel de pesanteur terrestre [Termes IGN] quantité discrète
Index. décimale :	30.40 Géodésie physique
Résumé :	(Auteur) The dependence of geodetic observables on the gravity field yields an interaction between the deter-mination of the figure of the earth, of the position of points on its surface, and of the gravity field. The determination of both components must be seen as a uniform problem which is denoted by inte-grated geodesy. It is characterized by the combination of all possible available geometric and physical observables. The main problem within the integrated adjustment is that the dependence of the various observations on the gravity potential function has a different structure. The observables depend either on the gravity potential itself or on its derivatives. The problem of how to treat the function-dependent parameters in the adjustment leads to different approaches of the integrated geodesy. In the discrete approach the functionals of the gravity field are considered as discrete deterministic quantities disregarding their common dependence on the underlying function. In every point the coordinates, the disturbing potential and its derivatives have to be estimated as discrete unknowns. The pure geometrical approach is a particular case of this approach if we consider the astronomical coordinates as parameters in the gravity field. The computed reference potential and its derivatives are the result of a previous data analysis and they are therefore the outcome of random variables which differ from the corresponding true values. So the observations are not the only available information for the model parameter. The prior estimates will be introduced as pseudo-observations of the corresponding parameters affected by errors. This approach is called model with prior information. In the analytical approach the unknown disturbing potential is modeled as a deterministic function depending on a finite set of unknown discrete parameters. As simple base functions the potentials of point masses can be used. The masses and the positions of the point masses have to be estimated in the adjustment. An emphasis of this work is the detailed analysis of the listed approaches. Several aspects will be treated. The comprehensive description of the basis is followed by the classification of previous pub--lications. The disposable observations are not sufficient for the clear determination of the choosen geometrical and physical parameters. Therefore a comprehensive rank defect analysis is carried out with the linearized observation equations. The practical applicability of the approaches will be investi--gated with a three-dimensional example. Some information about the sensitivity of the observations referring to the determined quantities and the accessible accuracies is given. The comparison of the approaches is concentrated essentially to the quality of the determination of coordinates and to the question, how the particular observables affect the determination of the different groups of parameters. The horizontal position of points is mainly determined by GPS observations, measurements of distance or horizontal direction. Zenith distances and GPS observations contribute to the determination of the vertical position of points. Measurements of gravity and potential differences do not influence the determination of the coordinates. The parameters of the gravity field, which are choosen in the different approaches, are determined exclusively by the physical observations. Beside the analysis and the comparison of the approaches remains another important aspect. It has to be determined how the geometry of the net is influenced by the type of treating the functionals of the gravity field. The results of this investigation lead to the conclusion that the type of treating the functionals of the gravity field does not affect the geometry of the net. Concerning the quality of the determination of coordinates the analysed approaches can be considered as equivalent.
Numéro de notice :	28011
Affiliation des auteurs :	non IGN
Thématique :	POSITIONNEMENT
Nature :	Thèse étrangère
Permalink :	https://documentation.ensg.eu/index.php?lvl=notice_display&id=63358

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
28011-01	30.40	Livre	Centre de documentation	Géodésie	Disponible
28011-02	30.40	Livre	Centre de documentation	Géodésie	Disponible

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