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A generalized theory of the figure of the Earth : on the global dynamical flattening / Chenjun Liu in Journal of geodesy, vol 93 n° 3 (March 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 3 (March 2019) . - pp 319 - 331 Titre : A generalized theory of the figure of the Earth : on the global dynamical flattening Type de document : Article/Communication Auteurs : Chenjun Liu, Auteur ; Chengli Huang, Auteur ; Yu Liu, Auteur ; Mian Zhang, Auteur Année de publication : 2019 Article en page(s) : pp 319 - 331 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes descripteurs IGN] aplatissement [Termes descripteurs IGN] croute terrestre [Termes descripteurs IGN] isostasie [Termes descripteurs IGN] manteau terrestre [Termes descripteurs IGN] moment d'inertie [Termes descripteurs IGN] noyau terrestre [Termes descripteurs IGN] rotation de la Terre Résumé : (Auteur) A generalized theory of the figures of the Earth’s interior to a third-order precision of ellipticity is proposed in accompanying paper in which all the odd degree and nonzero order spherical harmonic terms are included. As both the direct and indirect contributions of the asymmetric crust are included, this theory makes a significant improvement for calculating the asymmetric equilibrium figures of the real Earth comparing with the traditional theories which can only deal with the ideal symmetric Earth. The principal moments of inertia (PMOI: A, B, C) and global dynamical flattening (H) are important quantities in studying the rotating Earth. Precession and gravity observations give observation value of H (Hobs≈1/305.4559) with very high precision, while its theoretical calculated value (Htheory≈1/308.5) from traditional theories and a starting symmetric Earth model (like PREM model) is about 1% less than Hobs. Using the new theory in accompanying paper and replacing the homogeneous outermost crust and oceanic layers in PREM with CRUST1.0 model, we recalculate the equilibrium figures of the Earth’s interior and finally get new values of PMOI and Htheory (≈1/304.7167) whose consistency with Hobs are significantly improved to 0.24%. Furthermore, the asymmetric figures of some interesting boundaries, like inner core boundary, core-mantle boundary, are also given as by-products of this work as these boundaries’ figures are key input for studies of their topographic effect on global rotation and geodynamics, like nutation, normal modes, especially like free core nutation. Numéro de notice : A2019-151 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1163-x date de publication en ligne : 22/06/2018 En ligne : https://doi.org/10.1007/s00190-018-1163-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92490 [article]

Influence of subdaily model for polar motion on the estimated GPS satellite orbits / Natalia Panafidina in Journal of geodesy, vol 93 n° 2 (February 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 2 (February 2019) . - pp 229 - 240 Titre : Influence of subdaily model for polar motion on the estimated GPS satellite orbits Type de document : Article/Communication Auteurs : Natalia Panafidina, Auteur ; Urs Hugentobler, Auteur ; Manuela Seitz, Auteur Année de publication : 2019 Article en page(s) : pp 229 - 240 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] analyse diachronique [Termes descripteurs IGN] élément orbital [Termes descripteurs IGN] erreur systématique [Termes descripteurs IGN] International Terrestrial Reference Frame [Termes descripteurs IGN] marée océanique [Termes descripteurs IGN] mouvement du géocentre [Termes descripteurs IGN] mouvement du pôle [Termes descripteurs IGN] orbite [Termes descripteurs IGN] positionnement par GPS [Termes descripteurs IGN] rotation de la Terre [Termes descripteurs IGN] satellite GPS [Termes descripteurs IGN] traitement du signal Résumé : (auteur) In this contribution, it is shown that GPS orbits are able to absorb some diurnal signals in polar motion. The arising implications for the influence of the subdaily pole model on GPS solutions are discussed. Two signals in polar motion can be absorbed by GPS orbits: a retrograde signal with a period of a sidereal day (23 h 56 min 4 s) and a prograde signal with a period matching the revolution period of the GPS satellites in the terrestrial reference frame (23 h 55 min 56 s). We show that the retrograde signal contributes to the absolute orientation of the orbital planes in space and the prograde signal, due to coincidence of its period with the period of revolution of the GPS satellites, contributes to the position of the geocenter for each individual satellite. It is known from previous studies that there are systematic differences between orbital parameters from GPS solutions computed with different subdaily pole models. We show in this paper that this behavior can be explained by the absorption effects in 1-day GPS orbits. Diurnal signals cannot be spectrally separated over a time interval of 1 day. Adjustment of any diurnal prograde or retrograde signal to a subdaily pole time series given by a subdaily model over 24 h will lead to an estimated signal with a nonzero amplitude. Thus, any subdaily pole model used in the processing of space geodetic observations contains a part which corresponds numerically to the discussed prograde signal and a part which corresponds to the retrograde diurnal signal. Different pole models show different amplitudes of the diurnal signals which will be absorbed by the orbits. As a result, GPS orbits computed with different subdaily pole models have systematically different orientation and position in space. Using 1-day GPS solutions over a time span of 13 years (1994–2007), we show that the systematic variations in orbit position and orientation caused by individual tidal terms in polar motion can be well predicted and explained by the suggested mechanism. Numéro de notice : A2019-080 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1153-z date de publication en ligne : 24/05/2018 En ligne : https://doi.org/10.1007/s00190-018-1153-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92198 [article]

Consistent realization of celestial and terrestrial reference frames / Younghee Kwak in Journal of geodesy, vol 92 n° 9 (September 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 9 (September 2018) . - pp 1047 - 1061 Titre : Consistent realization of celestial and terrestrial reference frames Type de document : Article/Communication Auteurs : Younghee Kwak, Auteur ; Mathis Blossfeld, Auteur ; Ralf Schmid, Auteur ; Detlef Angermann, Auteur ; Michael Gerstl, Auteur ; Manuela Seitz, Auteur Année de publication : 2018 Article en page(s) : pp 1047 - 1061 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes descripteurs IGN] cohérence des données [Termes descripteurs IGN] erreur systématique inter-systèmes [Termes descripteurs IGN] International Terrestrial Reference Frame [Termes descripteurs IGN] paramètres d'orientation de la Terre [Termes descripteurs IGN] point de liaison (géodésie) [Termes descripteurs IGN] système de référence céleste Résumé : (Auteur) The Celestial Reference System (CRS) is currently realized only by Very Long Baseline Interferometry (VLBI) because it is the space geodetic technique that enables observations in that frame. In contrast, the Terrestrial Reference System (TRS) is realized by means of the combination of four space geodetic techniques: Global Navigation Satellite System (GNSS), VLBI, Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite. The Earth orientation parameters (EOP) are the link between the two types of systems, CRS and TRS. The EOP series of the International Earth Rotation and Reference Systems Service were combined of specifically selected series from various analysis centers. Other EOP series were generated by a simultaneous estimation together with the TRF while the CRF was fixed. Those computation approaches entail inherent inconsistencies between TRF, EOP, and CRF, also because the input data sets are different. A combined normal equation (NEQ) system, which consists of all the parameters, i.e., TRF, EOP, and CRF, would overcome such an inconsistency. In this paper, we simultaneously estimate TRF, EOP, and CRF from an inter-technique combined NEQ using the latest GNSS, VLBI, and SLR data (2005–2015). The results show that the selection of local ties is most critical to the TRF. The combination of pole coordinates is beneficial for the CRF, whereas the combination of ΔUT1 results in clear rotations of the estimated CRF. However, the standard deviations of the EOP and the CRF improve by the inter-technique combination which indicates the benefits of a common estimation of all parameters. It became evident that the common determination of TRF, EOP, and CRF systematically influences future ICRF computations at the level of several μas. Moreover, the CRF is influenced by up to 50 μas if the station coordinates and EOP are dominated by the satellite techniques. Numéro de notice : A2018-458 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1130-6 date de publication en ligne : 12/03/2018 En ligne : https://doi.org/10.1007/s00190-018-1130-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91055 [article]

Future global SLR network evolution and its impact on the terrestrial reference frame / Alexander Kehm in Journal of geodesy, vol 92 n° 6 (June 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 6 (June 2018) . - pp 625 – 635 Titre : Future global SLR network evolution and its impact on the terrestrial reference frame Type de document : Article/Communication Auteurs : Alexander Kehm, Auteur ; Mathis Blossfeld, Auteur ; Erricos C. Pavlis, Auteur ; Florian Seitz, Auteur Année de publication : 2018 Article en page(s) : pp 625 – 635 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] données TLS (télémétrie) [Termes descripteurs IGN] International Terrestrial Reference Frame [Termes descripteurs IGN] paramètres d'orientation de la Terre [Termes descripteurs IGN] télémétrie laser sur satellite Résumé : (Auteur) Satellite laser ranging (SLR) is an important technique that contributes to the determination of terrestrial geodetic reference frames, especially to the realization of the origin and the scale of global networks. One of the major limiting factors of SLR-derived reference frame realizations is the datum accuracy which significantly suffers from the current global SLR station distribution. In this paper, the impact of a potential future development of the SLR network on the estimated datum parameters is investigated. The current status of the SLR network is compared to a simulated potential future network featuring additional stations improving the global network geometry. In addition, possible technical advancements resulting in a higher amount of observations are taken into account as well. As a result, we find that the network improvement causes a decrease in the scatter of the network translation parameters of up to 24%, and up to 20% for the scale, whereas the technological improvement causes a reduction in the scatter of up to 27% for the translations and up to 49% for the scale. The Earth orientation parameters benefit by up to 15% from both effects. Numéro de notice : A2018-152 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1083-1 date de publication en ligne : 09/11/2017 En ligne : https://doi.org/10.1007/s00190-017-1083-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89765 [article]

Long-term prediction of polar motion using a combined SSA and ARMA model / Y. Shen in Journal of geodesy, vol 92 n° 3 (March 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 3 (March 2018) . - pp 333 - 343 Titre : Long-term prediction of polar motion using a combined SSA and ARMA model Type de document : Article/Communication Auteurs : Y. Shen, Auteur ; Jinyun Guo, Auteur ; X. Liu, Auteur ; Qiaoli Kong, Auteur ; Linxi Guo, Auteur ; Li Wang, Auteur Année de publication : 2018 Article en page(s) : pp 333 - 343 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] analyse de spectre singulier [Termes descripteurs IGN] analyse en composantes principales [Termes descripteurs IGN] modèle de simulation [Termes descripteurs IGN] mouvement du pôle Mots-clés libres : modèle ARMA Résumé : (Auteur) To meet the need for real-time and high-accuracy predictions of polar motion (PM), the singular spectrum analysis (SSA) and the autoregressive moving average (ARMA) model are combined for short- and long-term PM prediction. According to the SSA results for PM and the SSA prediction algorithm, the principal components of PM were predicted by SSA, and the remaining components were predicted by the ARMA model. In applying this proposed method, multiple sets of PM predictions were made with lead times of two years, based on an IERS 08 C04 series. The observations and predictions of the principal components correlated well, and the SSA + ARMA model effectively predicted the PM. For 360-day lead time predictions, the root-mean-square errors (RMSEs) of PMx and PMy were 20.67 and 20.42 mas, respectively, which were less than the 24.46 and 24.78 mas predicted by IERS Bulletin A. The RMSEs of PMx and PMy in the 720-day lead time predictions were 28.61 and 27.95 mas, respectively. Numéro de notice : A2018-061 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1065-3 En ligne : https://doi.org/10.1007/s00190-017-1065-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89397 [article]

Dependency of geodynamic parameters on the GNSS constellation / Stefano Scaramuzza in Journal of geodesy, vol 92 n° 1 (January 2018)  

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Hydrological excitation of polar motion by different variables from the GLDAS models / Malgorzata Winska in Journal of geodesy, vol 91 n° 12 (December 2017)  

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Basic Earth's Parameters as estimated from VLBI observations / Ping Zhu in Geodesy and Geodynamics, vol 8 n° 6 (November 2017)  

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IGS polar motion measurement accuracy / Jim Ray in Geodesy and Geodynamics, vol 8 n° 6 (November 2017)    

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Analysis of decade-long time series of GPS-based polar motion estimates at 15-min temporal resolution / Aurore E. Sibois in Journal of geodesy, vol 91 n° 8 (August 2017)  

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A global terrestrial reference frame from simulated VLBI and SLR data in view of GGOS / Susanne Glaser in Journal of geodesy, vol 91 n° 7 (July 2017)  

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The extension of the parametrization of the radio source coordinates in geodetic VLBI and its impact on the time series analysis / Maria Karbon in Journal of geodesy, vol 91 n° 7 (July 2017)  

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Multivariate analysis of GPS position time series of JPL second reprocessing campaign / AliReza Amiri-Simkooei in Journal of geodesy, vol 91 n° 6 (June 2017)  

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GRACE era variability in the Earth's oblateness: a comparison of estimates from six different sources / Thierry Meyrath in Geophysical journal international, vol 208 n° 2 (February 2017)  

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On the consistency of the current conventional EOP series and the celestial and terrestrial reference frames / Santiago Belda in Journal of geodesy, vol 91 n° 2 (February 2017)  

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