Centre de documentation
scientifique

Dépouillements

GPS network monitors the Western Alp's deformation over a five-year period: 1993-1998 / Christophe Vigny in Journal of geodesy, vol 76 n° 2 (February 2002)  

Public [article]  inJournal of geodesy > vol 76 n° 2 (February 2002) . - pp 63 - 76 Titre : GPS network monitors the Western Alp's deformation over a five-year period: 1993-1998 Type de document : Article/Communication Auteurs : Christophe Vigny, Auteur ; J. Chery, Auteur ; Thierry Duquesnoy , Auteur ; et al., Auteur Année de publication : 2002 Article en page(s) : pp 63 - 76 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Alpes occidentales [Termes IGN] déformation de la croute terrestre [Termes IGN] montagne [Termes IGN] positionnement par GPS [Termes IGN] surveillance géologique [Termes IGN] tectonique [Termes IGN] triangulation (topologie) Résumé : (Auteur) The Western Alps are among the best studied collisional belts with both detailed structural mapping and also crustal geophysical investigations such as the ECORS and EGT seismic profile. By contrast, the present-day kinematics of the belt is still largely unknown due to small relative motions and the insufficient accuracy of the triangulation data. As a consequence, several tectonic problems still remain to be Occidental Alps, the repartition of the deformation between the Alpine tectonic units, and the relation between deformation and rotation across the Alpine arc. In order to address these problems, the GPS ALPES group, made up of French, Swiss and Italian research organizations, has achieved the first large-scale GPS surveyed in 1993 and 1998 with a minimum observation of 3 days at each site. GPS data processing has been done by three independent teams using different soft-ware. The different solutions have horizontal repeat-abilities (N-E) of 4-7 min in 1993 and 2-3 mm in 1998 and compare at the 3-5-mm level in position and 2-mm/yr level in velocity. A comparison of 1993 and 1998 coordinates shows that residual velocities of the GPS marks are generally smaller than 2 mm/yr, precluding a detailed tectonic interpretation of the differential motions. However, these data seem to suggest that the N-S compression of the Western Alps is quite mild (less than 2 mm/yr) compared to the global convergence between the African and Eurasian plate (6 mm/yr). This implies that the shortening must be accomodated elsewhere by the deformation of the Maghrebids and/ or by rotations of Mediterranean microplates. Also, EW velocity components analysis supports the idea that E-W extension exists, as already suggested by recent structural and seismotectonic data interpretation Numéro de notice : A2002-018 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-001-0231-8 En ligne : https://doi.org/10.1007/s00190-001-0231-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21935 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-02021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Stochastic assessment of GPS carrier phase measurements for precise static relative positioning / J. Wang in Journal of geodesy, vol 76 n° 2 (February 2002)  

Public [article]  inJournal of geodesy > vol 76 n° 2 (February 2002) . - pp 95 - 104 Titre : Stochastic assessment of GPS carrier phase measurements for precise static relative positioning Type de document : Article/Communication Auteurs : J. Wang, Auteur ; Chalermchon Satirapod, Auteur ; Chris Rizos, Auteur Année de publication : 2002 Article en page(s) : pp 95 - 104 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] mesurage de phase [Termes IGN] modèle stochastique [Termes IGN] positionnement différentiel [Termes IGN] positionnement par GPS [Termes IGN] positionnement statique [Termes IGN] variable aléatoire Résumé : (Auteur) Global positioning system (GPS) carrier phase measurements are used in all precise static relative positioning applications. The GPS carrier phase measurements are generally processed using the least-squares method, for which both functional and stochastic models need to be carefully defined. Whilst the functional model for precise GPS positioning is well documented in the literature, realistic stochastic modelling for the GPS carrier phase measurements is still both a controversial topic and a difficult task to accomplish in practice. The common practice of assuming that the raw GPS measurements are statistically independent in space and time, and have the same accuracy, is certainly not realistic. Any mis-specification in the stochastic model will inevitably lead to unreliable positioning results. A stochastic assessment procedure has been developed to take into account the heteroscedastic, space- and timecorrelated error structure of the GPS measurements. Test results indicate that the reliability of the estimated positioning results is improved by applying the developed stochastic assessment procedure. In addition, the quality of ambiguity resolution can be more realistically evaluated. Numéro de notice : A2002-019 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-001-0225-6 En ligne : https://doi.org/10.1007/s00190-001-0225-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21936 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-02021	RAB	Revue	Centre de documentation	En réserve L003	Disponible