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Accurate gravimetry at the BIPM watt balance site / Z. Jiang (2014)  

Public contenu dans Earth on the Edge: Science for a Sustainable Planet / Chris Rizos (2014)   Titre : Accurate gravimetry at the BIPM watt balance site Type de document : Article/Communication Auteurs : Z. Jiang, Auteur ; Vojtech Pálinkáš, Auteur ; Olivier Francis, Auteur ; S. Merlet, Auteur ; Henri Baumann, Auteur ; Matthias Becker, Auteur ; Philippe Jousset, Auteur ; J. Makinen, Auteur ; H.R. Schulz, Auteur ; K.U. Kessler-Schulz, Auteur ; S. Svitlov, Auteur ; Alain Coulomb , Auteur ; L. Tisserand, Auteur ; H. Hu, Auteur ; Ch. Rothleitner, Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2014 Conférence : IAG 2011, General Assembly 28/06/2011 02/07/2011 Melbourne Australie Proceedings Springer Importance : pp 371 - 376 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] gravimètre [Termes IGN] gravimètre absolu [Termes IGN] gravimétrie [Termes IGN] métrologie Résumé : (auteur) Accurate gravity measurements were made to support the International Bureau of Weights and Measures (BIPM) watt balance (WB) project in association with the eighth International Comparison of Absolute Gravimeters (ICAG-2009) and the accompanying Relative Gravity Campaign (RGC-2009) at the BIPM in 2009. The goal of WB project is to determine the Planck constant h for the realization of a new definition of the kilogram. The accurate value of free fall acceleration g is crucial for the precise determination of h. During the formal ICAG-2009 and the RGC-2009, four absolute and six relative gravimeters took part in the WB gravity campaign. The results can therefore be converted to the international reference of the ICAG results, i.e., they are SI-traceable. The WB gravity network is a regular 3D grid over the site in the WB laboratory that serves to evaluate gravity acceleration at the test mass centre of the future WB setup. The local Earth tide parameters were determined by analyzing a 6 months record of a gPhone spring-type gravimeter. These parameters, together with the atmospheric and polar motion corrections, enable precise prediction of the instantaneous values of the acceleration of free fall required by the WB experiment with an accuracy reaching 5 μGal. In addition, repeated precise levelling has been carried out to monitor the stability of the WB pillar. Numéro de notice : C2011-092 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-37222-3_49 Date de publication en ligne : 06/10/2013 En ligne : http://dx.doi.org/10.1007/978-3-642-37222-3_49 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102738

Absolute airborne gravimetry / Henri Baumann (2005)  

Public Titre : Absolute airborne gravimetry Type de document : Thèse/HDR Auteurs : Henri Baumann, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2005 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 69 Importance : 142 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-12-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] accélération [Termes IGN] étude de faisabilité [Termes IGN] GPS-INS [Termes IGN] gravimètre absolu [Termes IGN] gravimétrie aérienne [Termes IGN] traitement de données Index. décimale : 30.42 Gravimétrie Résumé : (Auteur) This work consists of a feasibility study of a first stage prototype airborne absolute gravimeter system. In contrast to relative systems, which are using spring gravimeters, the measurements acquired by absolute systems are uncorrelated and the instrument is not suffering from problems like instrumental drift, frequency response of the spring and possible variation of the calibration factor. The major problem we had to resolve were to reduce the influence of the non-gravitational accelerations included in the measurements. We studied two different approaches to resolve it: direct mechanical filtering, and post-processing digital compensation. The first part of the work describes in detail the different mechanical passive filters of vibrations, which were studied and tested in the laboratory and later in a small truck in movement. For these tests as well as for the airborne measurements an absolute gravimeter FG5-L from Micro-G Ltd was used together with an Inertial navigation system Litton-200, a vertical accelerometer EpiSensor, and GPS receivers for positioning. These tests showed that only the use of an optical table gives acceptable results. However, it is unable to compensate for the effects of the accelerations of the drag free chamber. The second part describes the strategy of the data processing. It is based on modeling the perturbing accelerations by means of GPS, EpiSensor and INS data. In the third part the airborne experiment is described in detail, from the mounting in the aircraft and data processing to the different problems encountered during the evaluation of the quality and accuracy of the results. In the part of data processing the different steps conducted from the raw apparent gravity data and the trajectories to the estimation of the true gravity are explained. A comparison between the estimated airborne data and those obtained by ground upward continuation at flight altitude allows to state that airbome absolute gravimetry is feasible and has a spatial resolution comparable to the one of the relative airborne gravimetry. For a wavelength on the order of 11 km the mean value of the resolution of the estimated gravity is 9.7 mGal. Finally some suggestions are formulated for the improvement of the system which should simplify its use, increase the accuracy and reduce its price. Numéro de notice : 13266 Affiliation des auteurs : non IGN Autre URL associée : http://dx.doi.org/10.3929/ethz-a-004701048 Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD thesis : Géodésie et photogrammétrie : ETH Zurich : 2005 DOI : 10.3929/ethz-a-004701048 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-69.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54947

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
13266-01	30.42	Livre	Centre de documentation	Géodésie	Disponible
13266-02	30.42	Livre	Centre de documentation	Géodésie	Disponible