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Accounting for spatiotemporal correlations of GNSS coordinate time series to estimate station velocities / Clément Benoist in Journal of geodynamics, vol 135 (April 2020)  

Public [article]  inJournal of geodynamics > vol 135 (April 2020) . - n° 101693 Titre : Accounting for spatiotemporal correlations of GNSS coordinate time series to estimate station velocities Type de document : Article/Communication Auteurs : Clément Benoist , Auteur ; Xavier Collilieux , Auteur ; Paul Rebischung , Auteur ; Zuheir Altamimi , Auteur ; Olivier Jamet , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur ; Liliane Bel, Auteur Année de publication : 2020 Projets : GEODESIE / Coulot, David Article en page(s) : n° 101693 Note générale : bibliographie This study contributes to the IdEx Université de Paris ANR-18-IDEX-0001. It is partly supported by the Agence Nationale de la Recherche (ANR) project « Geodesie » ANR-16-CE01-0001. This is IPGP contribution number 4120. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes descripteurs IGN] corrélation [Termes descripteurs IGN] covariance [Termes descripteurs IGN] données spatiotemporelles [Termes descripteurs IGN] repère de référence terrestre conventionnel [Termes descripteurs IGN] série temporelle [Termes descripteurs IGN] vitesse Résumé : (auteur) It is well known that GNSS permanent station coordinate time series exhibit time-correlated noise. Spatial correlations between coordinate time series of nearby stations are also long-established and generally handled by means of spatial filtering techniques. Accounting for both the temporal and spatial correlations of the noise via a spatiotemporal covariance model is however not yet a common practice. We demonstrate in this paper the interest of using such a spatiotemporal covariance model of the stochastic variations in GNSS time series in order to estimate long-term station coordinates and especially velocities. We provide a methodology to rigorously assess the covariances between horizontal coordinate variations and use it to derive a simple exponential spatiotemporal covariance model for the stochastic variations in the IGS repro2 station coordinate time series. We then use this model to estimate station velocities for two selected datasets of 10 time series in Europe and 11 time series in the USA. We show that coordinate prediction as well as velocity determination from short time series are improved when using this spatiotemporal model, as compared with the case where spatiotemporal correlations are ignored. Numéro de notice : A2020-460 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jog.2020.101693 date de publication en ligne : 13/01/2020 En ligne : https://doi.org/10.1016/j.jog.2020.101693 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95385 [article]

Comparative analysis of different atmospheric surface pressure models and their impacts on daily ITRF2014 GNSS residual time series / Zhao Li in Journal of geodesy, vol 94 n°4 (April 2020)  

Public [article]  inJournal of geodesy > vol 94 n°4 (April 2020) . - n° 42 Titre : Comparative analysis of different atmospheric surface pressure models and their impacts on daily ITRF2014 GNSS residual time series Type de document : Article/Communication Auteurs : Zhao Li, Auteur ; Chen Wu, Auteur ; Tonie M. van Dam, Auteur ; Paul Rebischung , Auteur ; Zuheir Altamimi , Auteur Année de publication : 2020 Projets : 1-Pas de projet / Article en page(s) : n° 42 Note générale : bibliographie This research is supported by the National Key Research and Development Program of China (Project 2016YFB0502101), the European Commission/Research Grants Council (RGC) Collaboration Scheme sponsored by the Research Grants Council of Hong Kong Special Administrative Region, China (Project No. E-PolyU 501/16), and the National Science Foundation for Distinguished Young Scholars of China (Grant No. 41525014). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] coefficient de corrélation [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] International Terrestrial Reference Frame [Termes descripteurs IGN] modèle atmosphérique [Termes descripteurs IGN] pression atmosphérique [Termes descripteurs IGN] radar JPL [Termes descripteurs IGN] série temporelle [Termes descripteurs IGN] station GNSS Résumé : (auteur) To remove atmospheric pressure loading (ATML) effect from GNSS coordinate time series, surface pressure (SP) models are required to predict the displacements. In this paper, we modeled the 3D ATML surface displacements using the latest MERRA-2 SP grids, together with four other products (NCEP-R-1, NCEP-R-2, ERA-Interim and MERRA) for 596 globally distributed GNSS stations, and compared them with ITRF2014 residual time series. The five sets of ATML displacements are highly consistent with each other, particularly for those stations far away from coasts, of which the lowest correlations in the Up component for all the four models w.r.t MERRA-2 become larger than 0.91. ERA-Interim-derived ATML displacement performs best in reducing scatter of the GNSS height for 90.3% of the stations (89.3% for NCEP-R-1, 89.1% for NCEP-R-2, 86.4% for MERRA and 85.1% for MERRA-2). We think that this may be possibly due to the 4D variational data assimilation method applied. Considering inland stations only, more than 96% exhibit WRMS reduction in the Up direction for all five models, with an average improvement of 3–4% compared with the original ITRF2014 residual time series before ATML correction. Most stations (> 67%) also exhibit horizontal WRMS reductions based on the five models, but of small magnitudes, with most improvements (> 76%) less than 5%. In particular, most stations in South America, South Africa, Oceania and the Southern Oceans show larger WRMS reductions with MERRA-2, while all other four SP datasets lead to larger WRMS reduction for the Up component than MERRA-2 in Europe. Through comparison of the daily pressure variation from the five SP models, we conclude that the bigger model differences in the SP-induced surface displacements and their impacts on the ITRF2014 residuals for coastal/island stations are mainly due to the IB correction based on the different land–sea masks. A unique high spatial resolution land–sea mask should be applied in the future, so that model differences would come from only SP grids. Further research is also required to compare the ATML effect in ice-covered and high mountainous regions, for example the Qinghai–Tibet Plateau in China, the Andes in South America, etc., where larger pressure differences between models tend to occur. Numéro de notice : A2020-159 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01370-y date de publication en ligne : 20/03/2020 En ligne : https://doi.org/10.1007/s00190-020-01370-y Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94813 [article]

Vertical land motion in the Southwest and Central Pacific from available GNSS solutions and implications for relative sea levels / Valérie Ballu in Geophysical journal international, vol 218 n° 3 (September 2019)  

Public [article]  inGeophysical journal international > vol 218 n° 3 (September 2019) . - pp 1537 - 1551 Titre : Vertical land motion in the Southwest and Central Pacific from available GNSS solutions and implications for relative sea levels Type de document : Article/Communication Auteurs : Valérie Ballu, Auteur ; Médéric Gravelle, Auteur ; Guy Wöppelmann, Auteur ; Olivier de Viron, Auteur ; Paul Rebischung , Auteur ; Mélanie Becker, Auteur ; Pierre Sakic-Kieffer, Auteur Année de publication : 2019 Projets : STORISK / Duvat, Virginie Article en page(s) : pp 1537 - 1551 Note générale : bibliographie This work was supported by CNES through the TOSCA program and the French research agency (Agence Nationale de la Recherche, ANR) under the STORISK project (NR-15-CE03-0003) Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] changement du niveau de la mer [Termes descripteurs IGN] déformation verticale de la croute terrestre [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] incertitude géométrique [Termes descripteurs IGN] Pacifique ouest [Termes descripteurs IGN] Pacifique Sud [Termes descripteurs IGN] série temporelle Résumé : (auteur) Coastal populations are impacted by relative sea level variations, which consist both of absolute sea level variations and of vertical land motions. This paper focuses on the Southwest and Central Pacific region, a recognized vulnerable region to sea level rise and where a large range of vertical land motion dynamics is observed. We analyse vertical displacement rates obtained from Global Navigation Satellite Systems (GNSS) by different analysis centres. We study the role played by modelled parameters, such as step discontinuities (due to equipment changes, earthquakes, etc.), in the position time-series analysis. We propose a new modelling approach based on a joint inversion of GNSS position time-series from different analysis centres. The final uncertainty on the vertical land motion rates is estimated as a combination of the uncertainty due to the GNSS data processing itself and the uncertainty due to the stability of the reference frame in which the GNSS data are expressed. We find that the dominant trend in the Southwest and Central Pacific is a moderate subsidence, with an average rate of −1.1 mm yr–1, but significant variations are observed, with displacement rates varying from an uplift of 1.6 ± 0.3 mm yr–1 to a subsidence of −5.4 ± 0.3 mm yr–1. Taking into account the geodynamic context, we assess, for each station, the relevance of current estimates of linear vertical displacement rate and uncertainty for forecasting future coastal sea levels. Numéro de notice : A2019-634 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggz247 date de publication en ligne : 27/05/2019 En ligne : https://doi.org/10.1093/gji/ggz247 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95452 [article]

IX Hotine-Marussi Symposium on Mathematical Geodesy. Review of reference frame representations for a deformable Earth / Zuheir Altamimi (2019)  

Public Titre de série : IX Hotine-Marussi Symposium on Mathematical Geodesy Titre : Review of reference frame representations for a deformable Earth Type de document : Chapitre/Contribution Auteurs : Zuheir Altamimi , Auteur ; Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur Congrès : IAG 2018, 9th Hotine-Marussi Symposium on Mathematical Geodesy (18 - 22 juin 2018; Rome, Italie), Commanditaire Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2019 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 151 Projets : 2-Pas d'info accessible - article non ouvert / Importance : pp 51 - 56 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes descripteurs IGN] coordonnées GPS [Termes descripteurs IGN] erreur systématique [Termes descripteurs IGN] International Terrestrial Reference Frame [Termes descripteurs IGN] série temporelle Résumé : (auteur) Our planet Earth is constantly deforming under the effects of geophysical processes that cause linear and nonlinear displacements of the geodetic stations upon which the International Terrestrial Reference Frame (ITRF) is established. The ITRF has traditionally been defined as a secular (linear) frame in which station coordinates are described by piecewise linear functions of time. Nowadays, some particularly demanding applications however require more elaborate reference frame representations that can accommodate non-linear displacements of the reference stations. Two such types of reference frame representations are reviewed: the usual linear frame enhanced with additional parametric functions such as seasonal sine waves, and non-parametric time series of quasi-instantaneous reference frames. After introducing those two reference frame representations, we briefly review the systematic errors present in geodetic station position time series. We finally discuss the practical issues raised by the existence of these systematic errors for the implementation of both types of non-linear reference frames. Numéro de notice : H2019-007 Affiliation des auteurs : UMR IPGP-Géod (2020- ) Thématique : POSITIONNEMENT Nature : Chapître / contribution nature-HAL : ChOuvrScient DOI : 10.1007/1345_2019_66 date de publication en ligne : 17/05/2019 En ligne : https://doi.org/10.1007/1345_2019_66 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95512

The International Terrestrial Reference Frame: lessons from ITRF2014 / Zuheir Altamimi in Rendiconti Lincei. Scienze Fisiche e Naturali, vol 29 suppl 1 (June 2018)  

Public [article]  inRendiconti Lincei. Scienze Fisiche e Naturali > vol 29 suppl 1 (June 2018) . - 6 p. Titre : The International Terrestrial Reference Frame: lessons from ITRF2014 Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Paul Rebischung , Auteur ; Laurent Métivier , Auteur ; Xavier Collilieux , Auteur Congrès : Satellite Geodetic Positioning for Geosciences 2017 (8 mars 2017; Accademia Nazionale dei Lincei, Rome, Italie), Commanditaire Année de publication : 2018 Article en page(s) : 6 p. Note générale : bibliographie This contribution is the written, peer-reviewed version of a paper presented at the Conference “Satellite Geodetic Positioning for Geosciences”, held at the Accademia Nazionale dei Lincei in Rome on March 8, 2017 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes descripteurs IGN] International Terrestrial Reference Frame [Termes descripteurs IGN] repère de référence Résumé : (auteur) We review the progress and continuous improvements being made since more than 30 years in the determination and development of the International Terrestrial Reference Frame (ITRF). We present the modeling innovations introduced in the ITRF2014 elaboration, mainly (1) the estimation of the annual and semi-annual signals embedded in the time series of station coordinates provided by the four space geodesy techniques, and (2) the incorporation of post-seismic deformation (PSD) models for sites subject to major earthquakes. We recall the rank deficiency problem in the ITRF combination model that is related to the specification of the ITRF defining parameters. We evaluate the precision and accuracy of the main ITRF2014 geodetic and geophysical products using some key performance indicators. We address some scientific questions of space geodesy contribution, via ITRF2014 results, to understand geophysical processes that affect the Earth system, such as earthquake displacements, tectonic motions and loading effects. We evaluate in particular the performance of estimating periodic signals versus applying a non-tidal atmospheric loading model. A particular emphasis is devoted to the level of agreement between techniques in terms of seasonal signals, frame physical parameters (origin and scale) and consistency with terrestrial local ties at co-location sites. Main conclusions are then drawn to guide and improve our analysis and combination strategy for future ITRF developments. Numéro de notice : A2018-202 Affiliation des auteurs : LAREG (avant 2012) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s12210-017-0660-9 date de publication en ligne : 21/12/2017 En ligne : https://doi.org/10.1007/s12210-017-0660-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89935 [article]

Assessment of the possible contribution of space ties on-board GNSS satellites to the terrestrial reference frame / Sara Bruni in Journal of geodesy, vol 92 n° 4 (April 2018)  

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Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series / Kristel Chanard in Journal of geophysical research : Solid Earth, vol 123 n° 4 (April 2018)  

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Bruit de scintillation dans les séries temporelles de positions GNSS / Paul Rebischung (2018) 

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Comparing non-linear geocenter motion derived from GNSS and SLR observations corrected for loading and thermoelastic deformation / Kristel Chanard (2018)

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Comparison of the seasonal displacement parameters estimated in the ITRF2014 processing, what can we learn? / Xavier Collilieux (2018)

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Coordinate kinematic models in the International Terrestrial Reference Frame releases / Xavier Collilieux (2018)

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Déformation saisonnière de la Terre / Kristel Chanard (2018) 

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IGS International GNSS Service technical report 2017. IGS Reference frame working group technical report 2017 / Paul Rebischung (2018) 

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ITRF and seasonal station motions / Zuheir Altamimi (2018)

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ITRF: Three decades of research and development, current status and future plans / Zuheir Altamimi (2018)

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