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Titre : Korrektur stationsabhängiger Fehler bei GNSS Type de document : Thèse/HDR Auteurs : Andreas Knöpfler, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2015 Collection : DGK - C, ISSN 0065-5325 num. 744 Importance : 177 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5156-0 Note générale : bibliographie
akademisches Grades eines Doktor-Ingenieurs von der Fakultüt für Bauingenieur-, Geo- und Umweltwissenschaften des Karlsruher Instituts für TechnologieLangues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne GNSS
[Termes IGN] centre de phase
[Termes IGN] erreur systématique
[Termes IGN] étalonnage d'instrument
[Termes IGN] modèle d'erreur
[Termes IGN] positionnement ponctuel précis
[Termes IGN] positionnement statique
[Termes IGN] résidu
[Termes IGN] traitement de données GNSS
[Termes IGN] trajet multipleMots-clés libres : stacking map Index. décimale : 30.60 Géodésie spatiale Résumé : (auteur) Highly precise positioning techniques based on Global Navigation Satellite Systems (GNSS) have become a standard tool for numerous disciplines, benefitting from the continuous development of receiver equipment and the appearance of additional GNSS. In addition to the classical differential processing approach, the Precise Point Positioning (PPP) method is able to derive station coordinates with the same accuracy as a baseline setup, when sufficient observation time is available. The basis for PPP is the improved quality of external products for the GNSS data processing, for example the orbit and especially the satellite clock products of the International GNSS Service (IGS) and its analysis centers.
The increased usage of GNSS comes along with higher demands on accuracy. Therefore, the modelling of important error sources in GNSS is continuously upgraded. Intensive research led to a refinement of both the functional and the stochastic model in GNSS data processing in order to enable the correction of specific error components, for example the antenna behaviour or the tropospheric delay. Despite of the improvements in GNSS modelling, multipath effects still remain as a main error source in highly precise GNSS positioning. Within this work, stacking techniques are used to correct for multipath effects and further site dependent errors, for example residual errors in the calibration values of the receiving GNSS antenna. The method developed in this work is based on zero difference PPP residuals, which are accumulated over defined azimuth-elevation cells and over a fixed period of time (here: 10 d) and introduced as correction (so-called stacking maps) in a second PPP processing run. The main purpose of this approach aims for the improvement of data, recorded on continuously operating reference stations.
Within this work, two scenarios for the implementation of the corrections were investigated in detail: the combination of the stacking maps joined with the calibration information of the GNSS receiving antennas and in contrast to this approach the separate modelling of both aspects in a separate file. In order to check the effectivity of this method, the results (e.g., coordinates, residuals) before and after the introduction of the stacking maps were intensively analyzed. Within the second scenario (introduction of the correction in a separate file), the behaviour of the stacking maps over time was investigated by the analysis of so-called sliding stacking maps. Sliding stacking maps are generated as follows: calculation of a first stacking map from the residuals for example for day of year (DoY) 121 to 130 and introduction as correction for DoY 131, the next stacking map is computed from the residuals for DoY 122 to 131 and introduced for DoY 132 and so on. Especially sites with poor data quality show a significant improvement of the residual values after the implementation of stacked information. Furthermore, observations remain in the used data set, whereas they were eliminated in the processing without the introduction of stacking maps.
In addition, the necessity of expensive, site-dependent individual antenna calibration was checked. The focus was on the compensating level of the stacking approach with respect to unmodelled antenna effects based on the replacement of individual receiving antenna calibrations by type mean values of the IGS in combination with stacking maps. Therefore, data of selected sites were processed using both the existing individual antenna calibration sets and the IGS type mean values. In a second processing run, the calibration sets were introduced taking the corresponding stacking information into account. Differences in the phase center variations of the antennas can be corrected by the stacking maps. Discrepancies due to differences in the phase center offsets remain in the estimated site coordinates.Numéro de notice : 14920 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Géodésie : Karlsruhes Institut für Technologie : 2015 DOI : 10.5445/KSP/1000045959 En ligne : https://doi.org/10.5445/KSP/1000045959 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76931