Centre de documentation
scientifique

Dépouillements

Transformation model selection by multiple hypotheses testing / Rüdiger Lehmann in Journal of geodesy, vol 88 n° 12 (December 2014)  

Public [article]  inJournal of geodesy > vol 88 n° 12 (December 2014) . - pp 1117 - 1130 Titre : Transformation model selection by multiple hypotheses testing Type de document : Article/Communication Auteurs : Rüdiger Lehmann, Auteur Année de publication : 2014 Article en page(s) : pp 1117 - 1130 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse comparative [Termes IGN] modèle de Gauss-Markov [Termes IGN] transformation de coordonnées Résumé : (Auteur) Transformations between different geodetic reference frames are often performed such that first the transformation parameters are determined from control points. If in the first place we do not know which of the numerous transformation models is appropriate then we can set up a multiple hypotheses test. The paper extends the common method of testing transformation parameters for significance, to the case that also constraints for such parameters are tested. This provides more flexibility when setting up such a test. One can formulate a general model with a maximum number of transformation parameters and specialize it by adding constraints to those parameters, which need to be tested. The proper test statistic in a multiple test is shown to be either the extreme normalized or the extreme studentized Lagrange multiplier. They are shown to perform superior to the more intuitive test statistics derived from misclosures. It is shown how model selection by multiple hypotheses testing relates to the use of information criteria like AICc and Mallows’ Cp , which are based on an information theoretic approach. Nevertheless, whenever comparable, the results of an exemplary computation almost coincide. Numéro de notice : A2014-567 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0747-3 Date de publication en ligne : 24/07/2014 En ligne : https://doi.org/10.1007/s00190-014-0747-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74753 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2014121	SL	Revue	Centre de documentation	Revues en salle	Disponible

Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere / Denise Dettmering in Journal of geodesy, vol 88 n° 12 (December 2014)  

Public [article]  inJournal of geodesy > vol 88 n° 12 (December 2014) . - pp 1131 - 1143 Titre : Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere Type de document : Article/Communication Auteurs : Denise Dettmering, Auteur ; Marco Limberger, Auteur ; M. Schmidt, Auteur Année de publication : 2014 Article en page(s) : pp 1131 - 1143 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] données DORIS [Termes IGN] électron [Termes IGN] ionosphère [Termes IGN] teneur totale en électrons Résumé : (Auteur) The Doppler orbitography and radiopositioning integrated by satellite (DORIS) system was originally developed for precise orbit determination of low Earth orbiting (LEO) satellites. Beyond that, it is highly qualified for modeling the distribution of electrons within the Earth’s ionosphere. It measures with two frequencies in L-band with a relative frequency ratio close to 5. Since the terrestrial ground beacons are distributed quite homogeneously and several LEOs are equipped with modern receivers, a good applicability for global vertical total electron content (VTEC) modeling can be expected. This paper investigates the capability of DORIS dual-frequency phase observations for deriving VTEC and the contribution of these data to global VTEC modeling. The DORIS preprocessing is performed similar to commonly used global navigation satellite systems (GNSS) preprocessing. However, the absolute DORIS VTEC level is taken from global ionospheric maps (GIM) provided by the International GNSS Service (IGS) as the DORIS data contain no absolute information. DORIS-derived VTEC values show good consistency with IGS GIMs with a RMS between 2 and 3 total electron content units (TECU) depending on solar activity which can be reduced to less than 2 TECU when using only observations with elevation angles higher than 50∘ . The combination of DORIS VTEC with data from other space-geodetic measurement techniques improves the accuracy of global VTEC models significantly. If DORIS VTEC data is used to update IGS GIMs, an improvement of up to 12% can be achieved. The accuracy directly beneath the DORIS satellites’ ground-tracks ranges between 1.5 and 3.5 TECU assuming a precision of 2.5 TECU for altimeter-derived VTEC values which have been used for validation purposes. Numéro de notice : A2014-568 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0748-2 Date de publication en ligne : 26/07/2014 En ligne : https://doi.org/10.1007/s00190-014-0748-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74755 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2014121	SL	Revue	Centre de documentation	Revues en salle	Disponible

Deformation analysis of the Lake Urmia causeway (LUC) embankments in northwest Iran: insights from multi-sensor interferometry synthetic aperture radar (InSAR) data and finite element modeling (FEM) / Roghayeh Shamshiri in Journal of geodesy, vol 88 n° 12 (December 2014)  

Public [article]  inJournal of geodesy > vol 88 n° 12 (December 2014) . - pp 1171 - 1185 Titre : Deformation analysis of the Lake Urmia causeway (LUC) embankments in northwest Iran: insights from multi-sensor interferometry synthetic aperture radar (InSAR) data and finite element modeling (FEM) Type de document : Article/Communication Auteurs : Roghayeh Shamshiri, Auteur ; Mahdi Motag, Auteur ; Marzieh Baes, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 1171 - 1185 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] analyse diachronique [Termes IGN] déformation d'édifice [Termes IGN] digue [Termes IGN] interferométrie différentielle [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] surveillance d'ouvrage Résumé : (Auteur) This paper presents deformation analysis of Lake Urmia causeway (LUC) embankments in northwest Iran using observations from interferometry synthetic aperture radar (InSAR) and finite element model (FEM) simulation. 58 SAR images including 10 ALOS, 30 Envisat and 18 TerraSAR-X are used to assess settlement of the embankments during 2003–2013. The interferometric dataset includes 140 differential interferograms which are processed using InSAR time series technique of small baseline subset approach. The results show a clear indication of large deformation on the embankments with peak amplitude of > 50 mm/year in 2003–2010, increasing to >80 mm/year in 2012–2013 in the line of sight (LOS) direction from ground to the satellite. 2D decomposition of InSAR observations from Envisat and ALOS satellites that overlap in the years 2007–2010 shows that the rate of the vertical settlement and horizontal motion is not uniform along the embankments; Both eastern and western embankments show significant vertical motion, while horizontal motion plays a more significant role in eastern embankment than western embankment. The InSAR results are then used to simulate deformation using FEM at two cross-sections at the distance of 4 and 9 km from the most western edge of the LUC for which detailed stratigraphy data are available. Results suggest that consolidation due to dissipation of excess pore pressure in embankments can satisfactory predict settlement of the LUC embankments. Our numerical modeling indicates that nearly half of the consolidation since the construction time of the causeway 30 years ago has been done. Numéro de notice : A2014-569 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0752-6 Date de publication en ligne : 02/09/2014 En ligne : https://doi.org/10.1007/s00190-014-0752-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74756 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2014121	SL	Revue	Centre de documentation	Revues en salle	Disponible

Detecting discontinuities in GNSS coordinate time series with STARS: case study, the Bologna and Medicina GPS sites / Sara Bruni in Journal of geodesy, vol 88 n° 12 (December 2014)  

Public [article]  inJournal of geodesy > vol 88 n° 12 (December 2014) . - pp 1203 - 1214 Titre : Detecting discontinuities in GNSS coordinate time series with STARS: case study, the Bologna and Medicina GPS sites Type de document : Article/Communication Auteurs : Sara Bruni, Auteur ; Susanna Zerbini, Auteur ; Fabio Raicich, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 1203 - 1214 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées géodésiques [Termes IGN] coordonnées GPS [Termes IGN] discontinuité [Termes IGN] données GNSS [Termes IGN] série temporelle Résumé : (Auteur) Global navigation satellite systems (GNSS) data are a fundamental source of information for achieving a better understanding of geophysical and climate-related phenomena. However, discontinuities in the coordinate time series might be a severe limiting factor for the reliable estimate of long-term trends. A methodological approach has been adapted from Rodionov (Geophys Res Lett 31:L09204, 2004; Geophys Res Lett 31:L12707, 2006) and from Rodionov and Overland (J Marine Sci 62:328–332, 2005) to identify both the epoch of occurrence and the magnitude of jumps corrupting GNSS data sets without any a priori information on these quantities. The procedure is based on the Sequential t test Analysis of Regime Shifts (STARS) (Rodionov in Geophys Res Lett 31:L09204, 2004). The method has been tested against a synthetic data set characterized by typical features exhibited by real GNSS time series, such as linear trend, seasonal cycle, jumps, missing epochs and a combination of white and flicker noise. The results show that the offsets identified by the algorithm are split into 48% of true-positive, 28% of false-positive and 24% of false-negative events. The procedure has then been applied to GPS coordinate time series of stations located in the southeastern Po Plain, in Italy. The series span more than 15 years and are affected by offsets of different nature. The methodology proves to be effective, as confirmed by the comparison between the corrected GPS time series and those obtained by other observation techniques. Numéro de notice : A2014-570 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0754-4 Date de publication en ligne : 24/08/2014 En ligne : https://doi.org/10.1007/s00190-014-0754-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74757 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2014121	SL	Revue	Centre de documentation	Revues en salle	Disponible