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IDS contribution to ITRF2008 / Jean-Jacques Valette in Advances in space research, vol 46 n° 12 (15/12/2010)
[article]
Titre : IDS contribution to ITRF2008 Type de document : Article/Communication Auteurs : Jean-Jacques Valette, Auteur ; Franck G. Lemoine, Auteur ; Pascale Ferrage, Auteur ; Philippe Yaya, Auteur ; Zuheir Altamimi , Auteur ; Pascal Willis , Auteur ; Laurent Soudarin, Auteur Année de publication : 2010 Article en page(s) : pp 1614 - 1632 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] correction troposphérique
[Termes IGN] données DORIS
[Termes IGN] DORIS
[Termes IGN] géocentre
[Termes IGN] International DORIS Service
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] modèle de géopotentiel
[Termes IGN] orbitographie
[Termes IGN] orientation de la TerreRésumé : (Auteur) For the first time, the International DORIS Service (IDS) has produced a technique level combination based on the contributions of seven analysis centers (ACs), including the European Space Operations Center (ESOC), Geodetic Observatory Pecny (GOP), Geoscience Australia (GAU), the NASA Goddard Space Flight Center (GSFC), the Institut Géographique National (IGN), the Institute of Astronomy, Russian Academy of Sciences (INASAN, named as INA), and CNES/CLS (named as LCA). The ACs used five different software packages to process the DORIS data from 1992 to 2008, including NAPEOS (ESA), Bernese (GOP), GEODYN (GAU, GSC), GIPSY/OASIS (INA), and GINS (LCA). The data from seven DORIS satellites, TOPEX/Poseidon, SPOT-2, SPOT-3, SPOT-4, SPOT-5, Envisat and Jason-1 were processed and all the analysis centers produced weekly SINEX files in either variance–covariance or normal equation format. The processing by the analysis centers used the latest GRACE-derived gravity models, forward modelling of atmospheric gravity, updates to the radiation pressure modelling to improve the DORIS geocenter solutions, denser parameterization of empirically determined drag coefficients to improve station and EOP solutions, especially near the solar maximum in 2001–2002, updated troposphere mapping functions, and an ITRF2005-derived station set for orbit determination, DPOD2005. The CATREF software was used to process the weekly AC solutions, and produce three iterations of an IDS global weekly combination. Between the development of the initial solution IDS-1, and the final solution, IDS-3, the ACs improved their analysis strategies and submitted updated solutions to eliminate troposphere-derived biases in the solution scale, to reduce drag-related degradations in station positioning, and to refine the estimation strategy to improve the combination geocenter solution. An analysis of the frequency content of the individual AC geocenter and scale solutions was used as the basis to define the scale and geocenter of the IDS-3 combination. The final IDS-3 combination has an internal position consistency (WRMS) that is 15 to 20 mm before 2002 and 8 to 10 mm after 2002, when 4 or 5 satellites contribute to the weekly solutions. The final IDS-3 combination includes solutions for 130 DORIS stations on 67 different sites of which 35 have occupations over 16 years (1993.0–2009.0). The EOPs from the IDS-3 combination were compared with the IERS 05 C04 time series and the RMS agreement was 0.24 mas and 0.35 mas for the X and Y components of polar motion. The comparison to ITRF2005 in station position shows an agreement of 6 to 8 mm RMS in horizontal and 10.3 mm in height. The RMS comparison to ITRF2005 in station velocity is at 1.8 mm/year on the East component, to 1.2 mm/year in North component and 1.6 mm/year in height. Numéro de notice : A2010-566 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2010.05.029 Date de publication en ligne : 02/06/2010 En ligne : https://doi.org/10.1016/j.asr.2010.05.029 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30758
in Advances in space research > vol 46 n° 12 (15/12/2010) . - pp 1614 - 1632[article]On secular geocenter motion: The impact of climate changes / Laurent Métivier in Earth and planetary science letters, vol 296 n° 3-4 (August 2010)
[article]
Titre : On secular geocenter motion: The impact of climate changes Type de document : Article/Communication Auteurs : Laurent Métivier , Auteur ; Marianne Greff-Lefftz, Auteur ; Zuheir Altamimi , Auteur Année de publication : 2010 Article en page(s) : pp 360 - 366 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] changement climatique
[Termes IGN] eau de fonte
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] mouvement du géocentre
[Termes IGN] système de référence mondialRésumé : (auteur) We investigate the impact of recent climate changes on the long-term displacement of the Center of Figure (CF) of the Earth (also defined as the geocenter in our convention) with respect to the Center of Mass of the whole Earth (CM). The two realizations of the International Terrestrial Reference System (ITRS), entitled ITRF2000 and ITRF2005, present a difference of 1.8 mm/yr between the velocities of their respective frame origins, suggesting an acceleration of the geocenter towards the North Pole. We investigate if such a displacement could be explained by geophysical phenomena, such as the present ice melting and the sea level rise. Using published observations on ice caps and glaciers, we calculated the range of geocenter motion that may occur today. We found that the global ice melting induces long-term displacements of the geocenter mainly along the Z-axis, toward the North Pole. The geocenter velocity is today between 0.3 and 0.7–0.8 mm/yr and has doubled during last decade with the recent acceleration of ice melting. Combining with Greff-Lefftz (2000) results on post-glacial rebound, we conclude that a present secular geocenter velocity of 1 mm/yr is possible. However, the recent increase of the geocenter velocity cannot explain the difference observed between the two last realizations of the ITRS. Our results comfort the previous conclusions about ITRF2000 and ITRF2005 and the pre-analysis of ITRF2008 data, suggesting that the large Z-translation rate between the ITRS realizations is probably due to an imprecise ITRF2000 origin. Finally, we show that determining precisely the geocenter velocity would give a new type of information that may be useful to more precisely constrain mass exchanges associated with climate changes. Numéro de notice : A2010-615 Affiliation des auteurs : IGN+Ext (1940-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.epsl.2010.05.021 Date de publication en ligne : 29/06/2010 En ligne : https://doi.org/10.1016/j.epsl.2010.05.021 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86682
in Earth and planetary science letters > vol 296 n° 3-4 (August 2010) . - pp 360 - 366[article]Analyse des séries temporelles SLR du géocentre et des EOP basées sur les mesures des satellites LAGEOS1/2 et Starlette / Bachir Gourine in Bulletin des sciences géographiques, n° 25 (juin 2010)
[article]
Titre : Analyse des séries temporelles SLR du géocentre et des EOP basées sur les mesures des satellites LAGEOS1/2 et Starlette Type de document : Article/Communication Auteurs : Bachir Gourine, Auteur ; Salem Kahlouche, Auteur ; Boualem Ghezali, Auteur Année de publication : 2010 Article en page(s) : pp 2 - 13 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] données TLS (télémétrie)
[Termes IGN] élément d'orientation externe
[Termes IGN] géocentre
[Termes IGN] Lageos
[Termes IGN] série temporelle
[Termes IGN] Starlette
[Termes IGN] télémétrie laser sur satellite
[Termes IGN] varianceRésumé : (Auteur) L'objectif de cet article est d'étudier l'impact des mesures laser (SLR) du satellite bas Starlette dans la détermination précise des produits geodésiques (EOP et géocentre), sur une période de 14 ans (1993-2007). Les résultats ont montré que la précision sur les trois composantes de la translation (Mouvement du géocentre), est de l'ordre de 4 à 5 mm pour les solutions LAGEOS1/2 et Starlette, respectivement. Concernant les EOP, les écarts-types des solutions LAGEOS1/2 et Starlette sont respectivement de l'ordre de 0.14 et 0.20 mas (~4-6mm) en coordonnées du pôle, et de 0.01 et 0.02 ms (~5-10 mm) en temps (UTI et LOD). L'analyse des résultats est basée d'une part, sur l'analyse fréquentielle, et d'autre part, sur l'étude du bruit des séries temporelles des paramètres d'intérêt. Des termes saisonniers sont estimés, de l'ordre de quelques mm, sur les composantes du géocentre en comparaison avec des modèles géodynamiques. Le type de bruit dominant est le bruit blanc, avec un niveau de l'ordre de 2mm. Le signal périodique des EOP est décomposé en termes interannuel, annuel et courtes périodes. Le bruit de scintillation est le bruit caractérisant des séries temporelles des EOP avec un niveau de l'ordre de 4 et 15 mm en coordonnées du pôle et en LOD, respectivement, pour la solution Starlette. Numéro de notice : A2010-576 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30767
in Bulletin des sciences géographiques > n° 25 (juin 2010) . - pp 2 - 13[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 253-2010011 RAB Revue Centre de documentation En réserve L003 Disponible The angular velocities of the plates and the velocity of Earth's centre from space geodesy / Donald F. Argus in Geophysical journal international, vol 180 n° 3 (March 2010)
[article]
Titre : The angular velocities of the plates and the velocity of Earth's centre from space geodesy Type de document : Article/Communication Auteurs : Donald F. Argus, Auteur ; Richard G. Gordon, Auteur ; Michael B. Heflin, Auteur ; Chopo Ma, Auteur ; Richard J. Eanes, Auteur ; Pascal Willis , Auteur ; W. Richard Peltier, Auteur ; Susan E. Owen, Auteur Année de publication : 2010 Article en page(s) : pp 913 - 960 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] tectonique des plaques
[Termes IGN] vitesse angulaireRésumé : (auteur) Using space geodetic observations from four techniques (GPS, VLBI, SLR and DORIS), we simultaneously estimate the angular velocities of 11 major plates and the velocity of Earth's centre. We call this set of relative plate angular velocities GEODVEL (for GEODesy VELocity).
Plate angular velocities depend on the estimate of the velocity of Earth's centre and on the assignment of sites to plates. Most geodetic estimates of the angular velocities of the plates are determined assuming that Earth's centre is fixed in an International Terrestrial Reference Frame (ITRF), and are therefore subject to errors in the estimate of the velocity of Earth's centre. In ITRF2005 and ITRF2000, Earth's centre is the centre of mass of Earth, oceans and atmosphere (CM); the velocity of CM is estimated by SLR observation of LAGEOS's orbit. Herein we define Earth's centre to be the centre of mass of solid Earth (CE); we determine the velocity of CE by assuming that the portions of plate interiors not near the late Pleistocene ice sheets move laterally as if they were part of a rigid spherical cap. The GEODVEL estimate of the velocity of CE is likely nearer the true velocity of CM than are the ITRF2005 and ITRF2000 estimates because (1) no phenomena can sustain a significant velocity between CM and CE, (2) the plates are indeed nearly rigid (aside from vertical motion) and (3) the velocity of CM differs between ITRF2005 and ITRF2000 by an unacceptably large speed of 1.8 mm yr−1. The velocity of Earth's centre in GEODVEL lies between that of ITRF2000 and that of ITRF2005, with the distance from ITRF2005 being about twice that from ITRF2000. Because the GEODVEL estimates of uncertainties in plate angular velocities account for uncertainty in the velocity of Earth's centre, they are more realistic than prior estimates of uncertainties.
GEODVEL differs significantly from all prior global sets of relative plate angular velocities determined from space geodesy. For example, the 95 per cent confidence limits for the angular velocities of GEODVEL exclude those of REVEL (Sella et al.) for 34 of the 36 plate pairs that can be formed between any two of the nine plates with the best-constrained motion. The median angular velocity vector difference between GEODVEL and REVEL is 0.028° Myr−1, which is up to 3.1 mm yr−1 on Earth's surface. GEODVEL differs the least from the geodetic angular velocities that Altamimi et al. determine from ITRF2005. GEODVEL's 95 per cent confidence limits exclude 11 of 36 angular velocities of Altamimi et al., and the median difference is 0.015° Myr−1.
GEODVEL differs significantly from nearly all relative plate angular velocities averaged over the past few million years, including those of NUVEL-1A. The difference of GEODVEL from updated 3.2 Myr angular velocities is statistically significant for all but two of 36 angular velocities with a median difference of 0.063° Myr−1. Across spreading centres, eight have slowed down while only two have sped up. We conclude that plate angular velocities over the past few decades differ significantly from the corresponding angular velocity averaged over the past 3.2 Myr.Numéro de notice : A2010-656 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1365-246X.2009.04463.x Date de publication en ligne : 01/03/2010 En ligne : https://doi.org/10.1111/j.1365-246X.2009.04463.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91734
in Geophysical journal international > vol 180 n° 3 (March 2010) . - pp 913 - 960[article]Documents numériques
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The angular velocities of the plates ... - pdf éditeurAdobe Acrobat PDF Estimation of crustal vertical movements with GPS in a geocentric frame, within the framework of the TIGA project / Alvaro Santamaria Gomez (2010)
Titre : Estimation of crustal vertical movements with GPS in a geocentric frame, within the framework of the TIGA project Titre original : Estimation des mouvements verticaux de l'écorce terrestre par GPS dans un repère géocentrique, dans le cadre du projet TIGA Type de document : Thèse/HDR Auteurs : Alvaro Santamaria Gomez, Auteur ; Marie-Noëlle Bouin , Directeur de thèse ; Guy Wöppelmann , Directeur de thèse Editeur : Paris, Meudon et Nançay : Observatoire de Paris Année de publication : 2010 Importance : 225 p. Format : 21 x 30 cm Note générale : Bibliographie
Doctoral dissertation of the Observatoire de Paris, speciality Astronomy and Astrophysics, geodesy mention in Paris on October 11th 2010Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] déformation de la croute terrestre
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] marégraphe
[Termes IGN] niveau moyen des mers
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] série temporelleIndex. décimale : THESE Thèses et HDR Résumé : (Auteur) Long-term sea-level variations are provided today only by tide gauge measurements. However, these variations are contaminated by vertical long-term movements of the Earth crust. In order to obtain absolute sea-level variations, vertical movements at tide gauges can be now monitored by GPS.
The research work carried out was centered around the methodological study to improve the estimation of vertical velocities of a global GPS network co-located with tide gauges. We devised an optimal distribution of GPS stations which greatly improved the processing performance. This original procedure also allowed us to extend the analyzed data period. We obtained and exported station positions, satellite orbits, Earth orientation parameters, and apparent geocenter motion estimates to be combined by the International GNSS Service (IGS). The coupled effect of periodic signals and discontinuities on the estimated velocities was highlighted, showing the need to estimate both parameters in a consistent and rigorous way. The realistic velocity uncertainties were analyzed in depth taking into account the time-correlated noise content in the data. The noise content analysis led to the confirmation that temporal correlation of homogeneously reprocessed time series is dependent on data epoch. This way, we demonstrated that noise content in long GPS time series is mainly driven by the noise level of older data. However, to get the smallest formal velocity uncertainty, we still needed to use all the data available. The estimated velocity uncertainty was shown to agree with velocity differences with respect to the incoming new terrestrial reference frame, the ITRF2008.Note de contenu : Introduction
PART I. CONTEXT
1. Coastal sea level change and vertical land movements
1.1. Sea level observations
1.2. Long-term sea level rise estimation
1.3. Vertical movements at tide gauges
2. International efforts to monitor tide gauge benchmarks
2.1. First steps
2.2. The TIGA Pilot Project.
2.3. The University of La Rochelle TIGA Analysis Center
PART II. METHODOLOGY
3. GPS processing strategy definition
3.1. Testing the antenna modeling impact.
3.2. Tropospheric modeling test
3.3. Sub-network distribution
3.4. Other changes
3.5. Summary
4. Combination and products.
4.1. ULR3 combination procedure
4.2. ULR4 combination procedure
4.3. Comparison between ULR3 and ULR4 combination procedures
4.4. Summary
5. Vertical velocity field estimation.
5.1. Offsets, discontinuities and outliers
5.2. Seasonal signals
5.3. Datum selection
5.4. Summary
6. Vertical velocity field uncertainty
6.1. Noise effect on velocity uncertainties
6.2. Noise analysis methodology
6.3. Noise analysis procedure
6.4. Stochastic noise model selection
6.5. Reference frame uncertainty
6.6. Summary
PART III. RESULTS
7. ULR4 products
7.1. Frame transformation parameters
7.2. Terrestrial frame
7.3. Earth orientation parameters
7.4. Orbits
7.5. Summary
8. Vertical velocity field.
8.1. Selection of the stations in the ULR4 velocity field
8.2. Comparison of ULR3 and ULR4 vertical velocity fields
8.3. Comparison with multi-technique vertical velocity fields
8.4. Comparison with the ITRF2008 vertical velocity field
8.5. Sea level application
8.6. Summary
Conclusion and perspectivesNuméro de notice : 10447 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de doctorat : Astronomie et astrophysique. Géodésie : Observatoire de Paris : 2010 Organisme de stage : LAREG (IGN) nature-HAL : Thèse DOI : sans En ligne : https://hal.science/tel-00686823 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=45140 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 10447-01 THESE Livre Centre de documentation Thèses Disponible 10447-02 THESE Livre Centre de documentation Thèses Disponible Etude des erreurs systématiques liées à la détermination du géocentre par les mesures DORIS / Marie-Line Gobinddass (2010)PermalinkGeocenter variations derived from GPS tracking of the GRACE satellites / Z. Kang in Journal of geodesy, vol 83 n° 10 (October 2009)PermalinkEffect of the satellite laser ranging network distribution on geocenter motion estimation / Xavier Collilieux in Journal of geophysical research : Solid Earth, Vol 114 n° B4 (April 2009)PermalinkIntroduction aux systèmes de références terrestres / Xavier Collilieux (2009)PermalinkAnalyse des séries temporelles de positions des stations de géodésie spatiale : application au repère international de référence terrestre (ITRF) / Xavier Collilieux (2008)PermalinkDORIS satellite phase center determination and consequences on the derived scale of the Terrestrial Reference Frame / Pascal Willis in Advances in space research, vol 39 n° 10 (May 2007)PermalinkGeocentre motion measured with DORIS and SLR, and predicted by geophysical models / Martine Feissel-Vernier in Journal of geodesy, vol 80 n° 8-11 (November 2006)PermalinkSystematic errors in the Z-geocenter derived using satellite tracking data: a case study from SPOT-4 DORIS data in 1998 / Pascal Willis in Journal of geodesy, vol 79 n° 10-11 (February 2006)PermalinkIGS reference frames: status and future improvements / Jim Ray (2004)PermalinkPermalink