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Asymmetric tropospheric delays from numerical weather models for UT1 determination from VLBI Intensive sessions on the baseline Wettzell–Tsukuba / Johannes Böhm in Journal of geodesy, vol 84 n° 5 (May 2010)  

Public [article]  inJournal of geodesy > vol 84 n° 5 (May 2010) . - pp 319 - 325 Titre : Asymmetric tropospheric delays from numerical weather models for UT1 determination from VLBI Intensive sessions on the baseline Wettzell–Tsukuba Type de document : Article/Communication Auteurs : Johannes Böhm , Auteur ; T. Hobiger, Auteur ; R. Ichikawa, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 319 - 325 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] interférométrie à très grande base [Termes IGN] Japon [Termes IGN] ligne de base [Termes IGN] modèle atmosphérique [Termes IGN] propagation troposphérique [Termes IGN] temps universel [Termes IGN] Wettzell Résumé : (Auteur) One-baseline 1-h Very Long Baseline Interferometry (VLBI) Intensive sessions are carried out every day to determine Universal Time (UT1). Azimuthal asymmetry of tropospheric delays around the stations is usually ignored and not estimated because of the small number of observations. In this study we use external information about the asymmetry for the Intensive sessions between Tsukuba (Japan) and Wettzell (Germany), which are carried out on Saturdays and Sundays (1) from direct ray-tracing for each observation at Tsukuba and (2) in the form of linear horizontal north and east gradients every 6 h at both stations. The change of the UT1 estimates is at the 10 us level with maximum differences of up to 50 us, which is clearly above the formal uncertainties of the UT1 estimates (between 5 and 20 us). Spectral analysis reveals that delays from direct ray-tracing for the station Tsukuba add significant power at short periods (1–2 weeks) w.r.t. the state-of-the-art approach, and comparisons with length-of-day (LOD) estimates from Global Positioning System (GPS) indicate that these ray-traced delays slightly improve the UT1 estimates from Intensive sessions. Numéro de notice : A2010-184 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0370-x Date de publication en ligne : 05/03/2010 En ligne : https://doi.org/10.1007/s00190-010-0370-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30379 [article]

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Verbesserung des Datenmanagements in inhomogenen rechnernetzen geodätischer Messeinrichtungen auf des Basis von Middleware und Dateisystemen am Beispiel der Fundamentalstation Wettzell / A. Neidhardt (2005)

Public Titre : Verbesserung des Datenmanagements in inhomogenen rechnernetzen geodätischer Messeinrichtungen auf des Basis von Middleware und Dateisystemen am Beispiel der Fundamentalstation Wettzell Titre original : [Amélioration de la gestion des données dans l'organisation des mesures géodésiques des réseaux informatiques non homogènes sur la base de logiciels intermédiaires et de systèmes de datums, par exemple à la station fondamentale de Wettzell] Type de document : Monographie Auteurs : A. Neidhardt, Auteur Editeur : Francfort sur le Main : Bundesamt für Kartographie und Geodäsie Année de publication : 2005 Collection : Mitteilungen des Bundesamtes für Kartographie und Geodäsie, ISSN 1436-3445 num. 37 Importance : 378 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-89888-915-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] CORBA [Termes IGN] échange de données informatisé [Termes IGN] jeu de données localisées [Termes IGN] station GPS [Termes IGN] station permanente [Termes IGN] traitement de données GNSS [Termes IGN] Wettzell [Termes IGN] XML Index. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) Geodetic observatories for space techniques are the fundament for global reference systems since the beginning of space geodesy. The producing of data by these area-wide distributed, permanent data acquisition sites is therefore a main part. However, the requirements increase. A higher amount of measured data have to be transported to the analysing centres without long lasting down times during a more and more reduced time period. Interferences in these data workflows would cause affects in the continuity of the generated time series. Because of the fact that the main interest for the geodesists applies to the measured geodetic data the aspect of administration and availability for that geodetic data is being more or less underrated. Properly working information processing facilities are supposed to be simply existent. But meanwhile the historically crown systems reach their self set limits. This fact was the cause for a project study defined at the research and development program 2001 to 2005 by the German Research Group for Satellite Geodesy (Forschungsgruppe Satellitengeodasie (FGS)) with the challenge to analyze the data management basically. This defines the frame of the present work, which is an interdisciplinary approach affecting geodesy as well as computer science. Found ideas are applied to the current situation at the geodetic observatory at Wettzell as an exemplary realization. A profound analysis showed, that the problems are more basical than they were written at the studies notification. The used transfer mechanisms and flows cause a remarkable amount of unstableness. The incrementally accomplished generalisation of the collected information leaded to a three step method, which addresses the abstraction of problem categories and their technical realization. A basic element is therefore the creation of a reliable, flexible, transparent and stable transfer mechanism. The developed Extended CORBA File Transfer (ECFT) offers most of the criteria for quality of service, which are not or only partially existent in current solutions. And when they are offered they are restricted by system borders. Concurrency control, state driven processing, error or fault management and a flexible system architecture with hidden technical attributes are only a few elements of the new system. With it geodetic data can be transported as well in local area networks as over world wide existing nets. At least the next step deals with the data handling itself. The originally wished creation of a consistent meta data set was not really considered as reasonable. External procurements and historically given parts would hardly be integrated with this regulation. The present work keeps the individuality of data and their formats instead and offers a homogeneous transformation possibility by defining a description language based on the Extensible Markup Language (XML). This method for conversions of semi-structured and structured data formats can be seen as unique at the moment, because all other techniques uses the abilities of foreign programming languages to convert the original data into a markup set. With the created constructs in the present work any geodetic data sets can be transformed into any wished format. The final step of the three phases of abstraction creates a superordinated configuration for the currently existing conditions at the geodetic observatory Wettzell. The classification into manageable administration zones with dedicated competencies and their structured interaction over flexible interface access points with a hierarchically structured data processing workflow combines all of the so far developed ideas to a harmonical unit. The specific character of the present work is therefore especially given by the strong reference to technical realizations. Main focus always laid on a real implementation of the theories and strategies. So the strict compliance of a software process was selected for the structure of the present work. Because of that the developed parts will also be enhanced partially for specific application sets after the ending of this work, e.g. for the new Satellite Observing System Wettzell (SOS-W). Numéro de notice : 13315 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54963

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Beiträge zum J.J. Baeyer-symposium, Berlin-Köpenick, 05-06 November 1994 / H. Seeger (1996)

Public Titre : Beiträge zum J.J. Baeyer-symposium, Berlin-Köpenick, 05-06 November 1994 Titre original : [Contributions au symposium J.J. Baeyer, Berlin] Type de document : Actes de congrès Auteurs : H. Seeger, Éditeur scientifique Congrès : J.J. Baeyer-symposium (5 - 6 novembre 1994; Köpenick, Berlin, Allemagne), Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1996 Collection : DGK - E Sous-collection : Geschichte und Entwicklung der Geodäsie num. 029 Importance : 179 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie ancienne [Termes IGN] Bessel, Friedrich [Termes IGN] dix-neuvième siècle [Termes IGN] géodésie ancienne [Termes IGN] Wettzell Numéro de notice : 10254 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Actes Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=34496

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10254-01	CG.94	Livre	Centre de documentation	Congrès	Disponible