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Titre : Modelling and Inversion of High Precision Gravity Data Type de document : Thèse/HDR Auteurs : E. Lewi, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - C Sous-collection : Dissertationen num. 471 Importance : 145 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9511-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur local
[Termes IGN] Darmstadt
[Termes IGN] gradient de gravitation
[Termes IGN] levé gravimétrique
[Termes IGN] lissage de données
[Termes IGN] matrice
[Termes IGN] problème inverse
[Termes IGN] tour (bâtiment)Index. décimale : 30.42 Gravimétrie Résumé : (Auteur) In this work, the scope of the present day gravity data acquisition, processing and interpretational technique in using weak signal gravity anomalies, to study mass distributions, has been tested. To carry out this test, measurements were taken in Darmstadt and Bremen. The study in these areas, that encompasses the different stages of gravity data measurement, analysis and modelling procedures, has led to the development of some new methods and algorithms. The survey in Darmstadt was aimed at recovering the shape, location and density of two Rain Water Reservoirs, from measured gravity data. On the other hand the survey in Bremen was aimed at computing the vertical component of the gravity gradient within the "Drop Tower Bremen".
At first, the implementation of a spectral analysis technique in choosing a sampling interval that avoided aliasing effects was discussed and demonstrated, using the data in the Darmstadt survey area. The simulation of data, for this analysis, was partially carried out using an algorithm that can compute the gravitational attraction of cylindrically shaped bodies. This algorithm, which has reduced the well-known problem in computing the gravitational attraction of vertical cylinders on points that lie outside the axis of symmetry, is developed based on an existing theoretical relationship. The effectiveness of this algorithm was also tested in modelling the effect of the different steal and concrete structures in the "Drop Tower Bremen". Besides this, the need to apply a modified terrain correction procedure for data measured at a certain height above the surface of the ground has been shown.
One of the major findings of this study, is the development of a trend analysis method that makes use of the polynomial fitting technique. This technique is advantageous in its capability to suppress the role of the residual in determining the trend surface. Especially its capability to incorporate a priori information about the trend surface enables the modelling procedure to focus on the trend surface only. In addition, the method estimates the densities for the Bouguer and terrain reductions in an environment where all other effects, other than the elevation dependant term, are modelled using different polynomial terms. In conjunction with this, the role of anomalous gradient effect in gravity data interpretation has been discussed and its effect in the Darmstadt survey area has been analysed.
The other major finding of the present study is the development of a three-dimensional gravity inversion technique. This method makes use of diagonal weighting matrices to reduce the need for large computer memory and to save large computational time. Besides this, the use of a priori information together with a regularization method that depends on the misfit between the measured and model data iteratively, leads to the desired stable solution. Based on this three-dimensional gravity inversion method, a software which can be used for different applications has been developed. The test made on simulated data and the field gravity data, in the Darmstadt survey area, showed the effectiveness of the method both in error-free and error contaminated data. The test made on error-free data, simulated by simple shape three-dimensional models, particularly showed the capability of the method in recovering the causative body using a minimal amount of a priori information. The inversion of measured gravity data taken from the Darmstadt survey area showed not only the effectiveness of the inversion method but also the ability of the present day gravity data interpretation technique in analysing weak signal gravity anomalies.
The comparison of the upward continued gravity data and that measured at different heights of the "Drop Tower Bremen" confirmed the validity of Newton's inverse square law, within the accuracy of the survey. Moreover, through the use of this comparison between the measured and analytically continued gravity data, the vertical component of the gravity gradient has been computed with high accuracy. In general, the study in both the Darmstadt and Bremen survey areas showed that the gravity method, if effectively used, can serve as a tool in locating mass distributions, even if these masses generate only weak signal gravity anomalies.Numéro de notice : 28023 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63370 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28023-01 30.42 Livre Centre de documentation Géodésie Disponible 28023-02 30.42 Livre Centre de documentation Géodésie Disponible Zuordnung von raumbezogenen Daten, am Beispiel der Datenmodelle ATKIS und GDF / Volker Walter (1997)
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Titre : Zuordnung von raumbezogenen Daten, am Beispiel der Datenmodelle ATKIS und GDF Titre original : [Classement de données spatiales, par exemple le modèle de données ATKIS et GDF] Type de document : Thèse/HDR Auteurs : Volker Walter, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - C Sous-collection : Dissertationen num. 480 Importance : 130 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9520-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] base de données ATKIS
[Termes IGN] cohérence géométrique
[Termes IGN] données vectorielles
[Termes IGN] format GDF
[Termes IGN] information sémantique
[Termes IGN] intégration de données
[Termes IGN] modèle conceptuel de données localiséesNuméro de notice : 28010 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Thèse étrangère DOI : sans En ligne : https://www.ifp.uni-stuttgart.de/dokumente/Dissertationen/walter.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63357 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28010-01 37.10 Livre Centre de documentation Géomatique Disponible 28010-02 37.10 Livre Centre de documentation Géomatique Disponible
Titre : Zur Analyse und Optimierung von Transportnetzen Titre original : [Sur l'analyse et l'optimisation des réseaux de transport] Type de document : Thèse/HDR Auteurs : R. Röder, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - C Sous-collection : Dissertationen num. 484 Importance : 151 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9524-3 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] algorithme du simplexe
[Termes IGN] matrice
[Termes IGN] métrique
[Termes IGN] optimisation (mathématiques)
[Termes IGN] relation topologique
[Termes IGN] réseau de transport
[Termes IGN] théorie des graphesNuméro de notice : 28008 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63355 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28008-01 37.20 Livre Centre de documentation Géomatique Disponible 28008-02 37.20 Livre Centre de documentation Géomatique Disponible Zur präzisen Berechnung der Oberflächenkräfte eines erdgebundenen Satelliten auf Basis der Hill-Variablen. Ein quasi-universelles Bahnintegrationsprogramm / K. Arfa-Kaboodvand (1997)
Titre : Zur präzisen Berechnung der Oberflächenkräfte eines erdgebundenen Satelliten auf Basis der Hill-Variablen. Ein quasi-universelles Bahnintegrationsprogramm Titre original : [Vers une estimation précise de la force des superficies d'un satellite terrestre sur la base des variables de Hill : un programme d'intégration d'orbite quasi-universel] Type de document : Thèse/HDR Auteurs : K. Arfa-Kaboodvand, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - C Sous-collection : Dissertationen num. 476 Importance : 75 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9516-8 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] équation de Hill
[Termes IGN] International Terrestrial Reference System
[Termes IGN] mécanique orbitale
[Termes IGN] orbitographie
[Termes IGN] perturbation orbitale
[Termes IGN] système de référence géodésiqueNuméro de notice : 28014 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63361 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28014-01 21.10 Livre Centre de documentation Technologies spatiales Disponible 28014-02 21.10 Livre Centre de documentation Technologies spatiales Disponible Analyse und Numerik überbestimmter Randwertprobleme in der Physikalischen Geodäsie / M. Hirsch (1996)
Titre : Analyse und Numerik überbestimmter Randwertprobleme in der Physikalischen Geodäsie Titre original : [Analyse et problème de valeur aux limites numériques surdéterminées en géodésie physique] Type de document : Thèse/HDR Auteurs : M. Hirsch, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1996 Collection : DGK - C Sous-collection : Dissertationen num. 453 Importance : 154 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 3-7696-9596-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Aristoteles
[Termes IGN] modèle mathématique
[Termes IGN] problème des valeurs limitesIndex. décimale : 30.40 Géodésie physique Résumé : (Auteur)The determination of the Earth gravity field is a primary objective of geodesy. In order to solve this task, gravity values must be available in global covering and high density; till now this condition is only insufficiently fulfilled. Therefore, great expectations are focused on new developed observation technologies realizing high precision measurements of gravity or gravitational field signals on moved platforms (airplanes, satellites). These processes promise strongly improved qualitative and quantitative information about the gravity field. Moreover, they are much more effective than traditional methods.
This study deals with suitable mathematical modelling of two of these new measurement methods: airborne gravimetry and satellite gradiometry. In particular, the combination between already available gravity information and new observations in a consistent model is investigated. Overdetermined boundary value problems are used for a mathematical description of this task. In contrast to the classical geodetic boundary value problem, the solution of these problems is not uniquely determinable. The sought quantities rather have to be estimated in function spaces. For this reason, the well known BLUE principle was expanded in order to apply it in infinite dimensional spaces. The direct parameter estimation in the overdetermined boundary value problem is not possible, since the equation types are different while the BLUE principle requires an identical equation type. Therefore, a transformation into a homogenous system of integral equations using the theory of pseudodifferential operators (PDO) has to be performed.
Starting from a general formulation of the overdetermined boundary value problem, two special problems are studied; a linear fixed problem to model the local determination of the gravity field by means of airborne gravimetry, and a nonlinear free boundary value problem, describing the global determination of the gravitational field by means of satellite gradiometry. The solution of the nonlinear problem is based upon an imbedding technique by Hormander. Using this imbedding technique the problem can be decomposed into a sequence of linear boundary value problems with the same structure.
In order to be able to solve the problems with an uniform procedure, the problems are transformed in systems of PDO-equations and interpreted as an analogy to the Gauss-Markov-Model. Inversion-free solution formulae are derived for optimal estimation of the sought potential in the space and frequency domains. Using assumptions about stochastic properties of measurement noise, error formulae, describing expected accuracy of the solution, can be obtained.
In order to verify derived solutions, numerical studies are carried out, which can be divided into the following two parts:
In the first part, an overdetermined boundary value problem in local formulation is investigated. This problem is applied for modelling the stabilized downward continuation of airborne gravimeter data. Using three numerical experiments, the possibility of achieving the stabilization of continuation process without a smoothing of the measurements can be proved. This means that the overdetermined boundary value problem is an alternative to the usually applied Tikhonov's regularization, also in numerical case.
The second part discusses the numerical studies of an overdetermined boundary value problem, which has been formulated to determine the global gravitational field in high resolution. First, the numerical experiments are described. This description explains the simulation of the satellite gradiometry mission ARISTOTELES, the data reduction to given boundary surfaces and the error modelling. In the sequel, the successful numerical verification of the derived estimation formulae is covered. A detailed graphical representation illustrates the accuracy potential of the satellite gradiometry data. Further on, analyses of the influence of the polar data gaps and of the aliasing effect are carried out. The obtained results are compared with the results of other authors.Numéro de notice : 28036 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63383 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28036-01 30.40 Livre Centre de documentation Géodésie Disponible 28036-02 30.40 Livre Centre de documentation Géodésie Disponible Aufbau eines operablen inertialen Vermessungssystems zur Online-Verarbeitung in der Geodäsie auf Basis eines kommerziellen Strapdown Inertialsystems / O. Heinze (1996)
PermalinkPermalinkEin hybrides System in der Geodäsie. Einsatz des NAVSTAR GPS mit dem Strapdown-Inertial-Navigations- system LASERNAV II für kinematische Punktbestimmung und Orientierung / Wolfgang Söhne (1996)
PermalinkEin neuer Ansatz zur kartographischen Verdrängung auf der Grundlage eines mechanischen Federmodells / Joachim Bobrich (1996)
PermalinkEntwicklung eines Meßsystems zur automatischen polaren Objekterfassung am Beispiel der Bauaufnahme / P. Buchmann (1996)
PermalinkEntwicklung und Erprobung eines abbildenden Laseraltimeters für den Flugeinsatz unter Verwendung des Mehrfrequenz- Phasenvergleichsverfahrens / C. Hug (1996)
PermalinkEntwicklung und Erprobung eines Positionierungssystems für den lokalen Anwendungsbereich / C. Ziegler (1996)
PermalinkPermalinkPermalinkGenauigkeitssteigerung bei kurzzeit-statischen und kinematischen Satellitenmessungen bis hin zur Echtzeitanwendung / M. Gianniou (1996)
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