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Multi-dimensional B-spline modeling of spatio-temporal Ionospheric signals / C. Zeilhofer (2008)

Public Titre : Multi-dimensional B-spline modeling of spatio-temporal Ionospheric signals Type de document : Monographie Auteurs : C. Zeilhofer, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2008 Collection : DGK - A Sous-collection : Theoretische Geodäsie num. 123 Importance : 86 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-8203-8 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] B-Spline [Termes IGN] décomposition [Termes IGN] géodésie spatiale [Termes IGN] ionosphère [Termes IGN] modélisation 3D [Termes IGN] signal GPS [Termes IGN] traitement du signal Index. décimale : 24.20 Traitement du signal Résumé : (Auteur) Nowadays, ionospheric phenomena can be monitored globally from data of various satellite missions with an unprecedented accuracy. In many applications, like modeling the equatorial anomaly, regional processes are of special interest. To study regional phenomena multi-dimensional mathematical tools may be applied. In this report a regional multi-dimensional representation based on quadratic B-splines is derived and applied to spatio-temporal data sets. At first the theory of a multiscale analysis is introduced, i.e. the decomposition of signals into a smoother version arid a number of detail signals for the 1-dimensional case. To develop a multiscale analysis we introduce B-splines as scaling functions. The corresponding base functions, i.e. the B-spline wavelets can be computed via the so-called two-scale relations from the scaling functions. Series coefficients of the B-spline expansion can be computed by evaluating inner products using the dual base functions or by applying parameter estimation procedures. To generalize a 1-dimensional B-spline representation to the multi-dimensional case tensor product techniques are used. A data compression algorithm is derived from the multiscale analysis, i.e. we gain a tool to handle huge digital data sets. In our applications we decompose ionospheric functions, e.g. the electron density or the vertical total electron content, into a reference part and an unknown correction term. We apply our approach regionally to the correction term, i.e. we expand it in a multi-dimensional series expansion in terms of B-splines. Since our observations are located rather unbalanced with respect to space and time finer structures are modelable only in regions with a sufficient number of observation sites. The multiscale analysis derived from the wavelet analysis allows monitoring the ionospheric signals at different resolution levels. Numéro de notice : 15413 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62713

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
15413-01	24.20	Livre	Centre de documentation	Physique	Disponible
15413-02	24.20	Livre	Centre de documentation	Physique	Disponible