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Some considerations on significance analysis for deformation detection via frequentist and Bayesian tests / F. Sacerdote in Journal of geodesy, vol 84 n° 4 (April 2010)  

Public [article]  inJournal of geodesy > vol 84 n° 4 (April 2010) . - pp 233 - 242 Titre : Some considerations on significance analysis for deformation detection via frequentist and Bayesian tests Type de document : Article/Communication Auteurs : F. Sacerdote, Auteur ; N. Cazzaniga, Auteur ; V. Tornatore, Auteur Année de publication : 2010 Article en page(s) : pp 233 - 242 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse de données [Termes IGN] classification bayesienne [Termes IGN] déformation géométrique Résumé : (Auteur) The Bayesian approach to significance testing, that makes use of prior information, has been studied in the last years, particularly to allow the detection of deformations which are small with respect to measurement errors from repeated surveys. Some investigations showed up to now that, under particular conditions concerning both the parameters of the prior distribution and the structure of the control network, Bayesian tests give stronger results than tests based on the frequentist approach, with regard to the detectability of deformations. In the present paper, after illustrating the essential developments and the most relevant results of previous works, new analytical developments and numerical simulations are carried out, to illustrate some critical aspects and advantages of the frequentist and Bayesian methods. It is shown, starting from simple examples involving only Gaussian and truncated Gaussian distributions and from a simplified formulation of the prior deformation model, that the testing procedures based on the frequentist approach, which do not introduce any a priori information, are in many cases of practical interest insensitive to internal consistencies of the displacements (e.g., to the fact that they have a common direction). It is also illustrated that the introduction of prior information, even in a non Bayesian context, more easily allows the detection of little displacements. Besides it is noted that in some cases Bayesian tests detect displacements in the presence of observed non-coherent movements, even if prior probability densities describing coherent movements are introduced. Copyright Springer Numéro de notice : A2010-151 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-009-0360-z Date de publication en ligne : 09/12/2009 En ligne : https://doi.org/10.1007/s00190-009-0360-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30346 [article]

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A case study of using Raman lidar measurements in high-accuracy GPS applications / Pierre Bosser in Journal of geodesy, vol 84 n° 4 (April 2010)  

Public [article]  inJournal of geodesy > vol 84 n° 4 (April 2010) . - pp 251 - 265 Titre : A case study of using Raman lidar measurements in high-accuracy GPS applications Type de document : Article/Communication Auteurs : Pierre Bosser , Auteur ; Olivier Bock , Auteur ; Christian Thom , Auteur ; Jacques Pelon, Auteur ; Pascal Willis , Auteur Année de publication : 2010 Article en page(s) : pp 251 - 265 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] diffusion de Raman [Termes IGN] lidar Raman [Termes IGN] positionnement par GPS [Termes IGN] propagation du signal [Termes IGN] propagation troposphérique [Termes IGN] vapeur d'eau Résumé : (Auteur) This paper investigates the impact of rapid small-scale water vapor fluctuations on GPS height determination. Water vapor measurements from a Raman lidar are used for documenting the water vapor heterogeneities and correcting GPS signal propagation delays in clear sky conditions. We use data from four short observing sessions (6 h) during the VAPIC experiment (15 May–15 June 2004). The retrieval of wet delays from our Raman lidar is shown to agree well with radiosonde retrievals (bias and standard deviation (SD) were smaller than 1 and 2.8 mm, respectively) and microwave radiometers (from two different instruments, bias was 6.0/-6.6 mm and SD 1.3/3.8 mm). A standard GPS data analysis is shown to fail in accurately reproducing fast zenith wet delay (ZWD) variations. The ZWD estimates could be improved when mean post-fit phase residuals were removed. Several methodologies for integrating zenith lidar observations into the GPS data processing are also presented. The final method consists in using lidar wet delays for correcting a priori the GPS phase observations and estimating a scale factor for the lidar wet delays jointly with the GPS station position. The estimation of this scale factor allows correcting for a mis-calibration in the lidar data and provides in the same way an estimate of the Raman lidar instrument constant. The agreement of this constant with an independent determination using radiosonde data is at the level of 1–4%. The lidar wet delays were derived by ray-tracing from zenith pointing measurements: further improvement in GPS positioning is expected from slant path lidar measurements that would properly account for water vapor anisotropy. Copyright Springer Numéro de notice : A2010-152 Affiliation des auteurs : IGN+Ext (1940-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-009-0362-x Date de publication en ligne : 24/12/2009 En ligne : https://doi.org/10.1007/s00190-009-0362-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30347 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2010041	MANQUANT	Revue	Centre de documentation	Indéterminé	Disponible