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Validation of a corner reflector installation at Côte d’Azur multi-technique geodetic observatory / Xavier Collilieux in Advances in space research, vol 70 n° 2 (15 July 2022)  

Public [article]  inAdvances in space research > vol 70 n° 2 (15 July 2022) . - pp 360 - 370 Titre : Validation of a corner reflector installation at Côte d’Azur multi-technique geodetic observatory Type de document : Article/Communication Auteurs : Xavier Collilieux , Auteur ; Clément Courde, Auteur ; Bénédicte Fruneau , Auteur ; Mourad Aimar, Auteur ; Guillaume Schmidt, Auteur ; Isabelle Delprat, Auteur ; Marie-Amélie Defresne, Auteur ; Damien Pesce, Auteur ; Fabien Bergerault, Auteur ; Guy Wöppelmann , Auteur Année de publication : 2022 Projets : Université de Paris / Clerici, Christine Article en page(s) : pp 360 - 370 Note générale : bibliographie This study contributes to the IdEx Université de Paris ANR-18-IDEX-0001. It was supported by the Programme National GRAM INSAROME of CNRS/INSU with INP and IN2P3 co-funded by CNES but also by BQR-OCA. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] coin réflecteur [Termes IGN] constellation Sentinel [Termes IGN] Global Geodetic Observing System [Termes IGN] image radar moirée [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] observatoire astronomique Résumé : (auteur) We present the procedure we followed to design an artificial corner reflector (CR) at the Calern site of Côte d’Azur Observatory (France). Although still few in number, such reflectors are an integral part of the Global Geodetic Observing System (GGOS) infrastructure. They can be used as a stable radar target in SAR images to connect local InSAR deformation maps to the global Terrestrial Reference Frame and for SAR absolute determination. During a test phase, the orientation of the CR was changed in order to be aligned toward all possible orbits of Sentinel-1A/1B satellites. On the different SAR images, the CR exhibits a high backscattering signal, and provides a Signal-to-Clutter Ratio larger than 26 dB. Since December 2018, the CR is specifically oriented toward the relative orbit 88. It is clearly detected as a PS in our InSAR analyses and as expected, the standard deviation of displacement measured on the CR is lower than on surrounding PS. A first local survey was performed to locate precisely this CR with respect to the existing geodetic instruments and annual campaigns have been carried out since then to insure its stability over time. Numéro de notice : A2022-337 Affiliation des auteurs : ENSG+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2022.04.050 Date de publication en ligne : 29/04/2022 En ligne : https://doi.org/10.1016/j.asr.2022.04.050 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100694 [article]

Analysis of IGS repro3 station position time series [diaporama] / Paul Rebischung (2021)  

Public contenu dans Earth and Space Science Open Archive ESSOAr / American Geophysical Union (2019)   Titre : Analysis of IGS repro3 station position time series [diaporama] Type de document : Article/Communication Auteurs : Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Zuheir Altamimi , Auteur ; Kristel Chanard , Auteur Editeur : Washington DC [Etats-Unis] : Earth and Space Science Open Archive ESSOAr Année de publication : 2021 Conférence : AGU 2021 Fall Meeting 13/12/2021 17/12/2021 New Orleans and virtual Louisiane - Etats-Unis Importance : 30 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse spectrale [Termes IGN] déformation de la croute terrestre [Termes IGN] effet de charge [Termes IGN] International Terrestrial Reference Frame [Termes IGN] série temporelle Résumé : (auteur) The IGS contribution to ITRF2020, based on the third IGS reprocessing campaign (repro3), comprises daily position estimates for 1905 globally distributed GNSS stations. As an essential step of the ITRF2020 preparation, a detailed analysis of the IGS repro3 station position time series has been carried out, including identification of offsets, modeling of post-seismic displacements, confrontation with deformation predicted by geophysical loading models, and characterization of systematic and random errors. This presentation covers the different aspects of this analysis, the methods used and the lessons learned. Numéro de notice : C2021-070 Affiliation des auteurs : UMR IPGP-Géod (2020- ) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : 10.1002/essoar.10509008.1 Date de publication en ligne : 06/12/2021 En ligne : https://doi.org/10.1002/essoar.10509008.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99607

Are there detectable common aperiodic displacements at ITRF co-location sites? / Maylis Teyssendier de la Serve (2021)  

Public contenu dans Earth and Space Science Open Archive ESSOAr / American Geophysical Union (2019)   Titre : Are there detectable common aperiodic displacements at ITRF co-location sites? Type de document : Article/Communication Auteurs : Maylis Teyssendier de la Serve , Auteur ; Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Zuheir Altamimi , Auteur ; Laurent Métivier , Auteur Editeur : Washington DC [Etats-Unis] : Earth and Space Science Open Archive ESSOAr Année de publication : 2021 Projets : 1-Pas de projet / Clerici, Christine Conférence : AGU 2021 Fall Meeting 13/12/2021 17/12/2021 New Orleans and virtual Louisiane - Etats-Unis Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] co-positionnement [Termes IGN] déformation de la croute terrestre [Termes IGN] International Terrestrial Reference Frame [Termes IGN] résidu [Termes IGN] série temporelle Résumé : (auteur) Nowadays, the time evolution of ITRF station positions is described by piece-wise linear models extended with exponential and logarithmic functions to account for post-seismic displacements. The ITRF2020 will also account for seasonal deformation by means of annual and semi-annual sine waves. However, part of the Earth’s surface deformation is not captured by those deterministic functions, such as inter-annual hydrological loading deformation, or high-frequency atmospheric loading deformation. To account for such aperiodic displacements, a reference frame in the form of a time series could be considered. This would require aperiodic motions of the different space geodetic stations to be tied in a common frame by means of co-motion constraints. The relevance of such constraints is however debatable. Indeed, common aperiodic movements between co-located space geodetic stations have thus far not been evidenced. This presentation describes the comparison of station position time series from the different space geodetic techniques in order to highlight whether or not common aperiodic movements can be detected at co-location sites. Those time series are extracted from the solutions provided by the techniques international services for the ITRF2014. They are first carefully aligned to a common reference frame in order to minimize differential network effect. Then, they are cleaned from linear, post-seismic and periodic signals (including seasonal deformation and technique systematic errors). Residual time series from co-located stations are finally confronted with each other. Numéro de notice : C2021-069 Affiliation des auteurs : UMR IPGP-Géod (2020- ) Thématique : POSITIONNEMENT Nature : Poster nature-HAL : Poster-avec-CL DOI : 10.1002/essoar.10509118.1 Date de publication en ligne : 06/12/2021 En ligne : https://doi.org/10.1002/essoar.10509118.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99604

Review of Reference Frame Representations for a Deformable Earth / Zuheir Altamimi (2021)  

Public Titre : Review of Reference Frame Representations for a Deformable Earth Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Paul Rebischung , Auteur ; Xavier Collilieux , Auteur ; Laurent Métivier , Auteur ; Kristel Chanard , Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2021 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 151 Conférence : IAG 2018, 9th Hotine-Marussi Symposium on Mathematical Geodesy 18/06/2018 22/06/2018 Rome Italie Proceedings Springer Importance : pp 51 - 56 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] erreur systématique [Termes IGN] International Terrestrial Reference Frame [Termes IGN] repère de référence [Termes IGN] station de référence [Termes IGN] système de référence géodésique 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 : C2018-076 Affiliation des auteurs : LASTIG LAREG (2012-mi2018) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/1345_2019_66 Date de publication en ligne : 17/05/2019 En ligne : http://dx.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=91473

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, Université de Paris / Clerici, Christine Article en page(s) : n° 101693 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] corrélation [Termes IGN] covariance [Termes IGN] données spatiotemporelles [Termes IGN] repère de référence terrestre conventionnel [Termes IGN] série temporelle [Termes 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 : Géodésie+Ext (mi2018-2019) 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]

A breakpoint detection in the mean model with heterogeneous variance on fixed time-intervals / Olivier Bock in Statistics and Computing, vol 29 n° 1 (February 2020)  

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2014 Hartebeesthoek co-location survey reprocessing report / Jean-Michaël Muller (2020) 

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Description and evaluation of DTRF2014, JTRF2014 and ITRF2014, ch. 3. ITRS Center evaluation of DTRF2014 and JTRF2014 with respect to ITRF2014 / Zuheir Altamimi (2020)  

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A factor model approach for the joint segmentation with between‐series correlation / Xavier Collilieux in Scandinavian Journal of Statistics, vol 46 n° 3 (September 2019)  

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InSAR Corner Cube at GRSM [diaporama] / Mourad Aimar (2019)  

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A quelles altitudes se trouvent les horloges atomiques de l'observatoire de Paris ? / Xavier Collilieux in XYZ, n° 156 (septembre - novembre 2018)

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

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Apport de la prise en compte de la dépendance spatiotemporelle des séries temporelles de positions GNSS à l’estimation d’un système de référence / Clément Benoist (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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