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Assessment of geocenter motion estimates from the IGS second reprocessing / Yifang Ma in GPS solutions, vol 24 n° 2 (April 2020)  

Public [article]  inGPS solutions > vol 24 n° 2 (April 2020) . - n° 55 Titre : Assessment of geocenter motion estimates from the IGS second reprocessing Type de document : Article/Communication Auteurs : Yifang Ma , Auteur ; Paul Rebischung , Auteur ; Zuheir Altamimi , Auteur ; Weiping Jiang, Auteur Année de publication : 2020 Projets : 3-projet - voir note / Article en page(s) : n° 55 Note générale : bibliographie This study is supported by the National Science Fund for Distinguished Young Scholars (No. 41525014) and the National Key R&D Program of China (No. 2018YFC15036). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse comparative [Termes IGN] données TLS (télémétrie) [Termes IGN] International Terrestrial Reference Frame [Termes IGN] mouvement du géocentre [Termes IGN] série temporelle [Termes IGN] variation saisonnière [Termes IGN] variation temporelle Résumé : (auteur) We investigate geocenter motion time series derived from the combined solutions and six individual analysis center (AC) solutions of the International GNSS Service (IGS) second reprocessing campaign using the network shift approach, in terms of noise content, long-term trends, periodic and aperiodic variations. We assess these GNSS geocenter motion estimates by comparison with independent estimates from satellite laser ranging (SLR). The GNSS geocenter time series exhibit correlated noise which is better represented by a white plus power–law noise model in the X and Y directions, and by a white plus first-order autoregressive (or generalized Gauss–Markov) noise model in the Z direction. The GNSS geocenter time series include expected seasonal variations, but also spurious draconitic signals, particularly in the Z direction. GNSS annual geocenter motion estimates are in reasonable agreement with SLR estimates in the X and Y directions. In the Z direction, however, the annual signals derived from the IGS solutions disagree with SLR estimates, except for three particular ACs. This suggests that the different orbit modeling strategies used by these ACs may constitute an improvement over the conventional strategy employed by the other ACs. The background noise in GNSS and SLR geocenter time series finally appears to be correlated, suggesting that it might partly reflect real, aperiodic geocenter motion. Numéro de notice : A2020-838 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-0968-2 Date de publication en ligne : 10/03/2020 En ligne : https://doi.org/10.1007/s10291-020-0968-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98264 [article]

GPS-derived geocenter motion from the IGS second reprocessing campaign / Liansheng Deng in Earth, Planets and Space, vol 71 (2019)  

Public [article]  inEarth, Planets and Space > vol 71 (2019) . - n° 74 Titre : GPS-derived geocenter motion from the IGS second reprocessing campaign Type de document : Article/Communication Auteurs : Liansheng Deng, Auteur ; Zhao Li, Auteur ; Na Wei, Auteur ; Yifang Ma , Auteur ; Hua Chen, Auteur Année de publication : 2019 Article en page(s) : n° 74 Note générale : bibloigraphie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] campagne d'observations [Termes IGN] mouvement du géocentre [Termes IGN] télémétrie laser sur satellite Résumé : (auteur) GPS data processing methods and theories are under continuous refinement in the past 30 years. Using the latest products is supposed to provide more stable and reliable geocenter estimates. In this paper, geocenter estimates from deformation inversion approach with new observations of IGS second data reprocessing campaign (IG2) are investigated. Results indicate that our IG2-derived geocenter motion estimates agree well with solutions from network approach for SLR. The truncated degree 5 exhibits the highest consistency between GPS-inverted geocenter estimates and the SLR results in both annual amplitudes and phases. Then, the GPS-derived geocenter motions are compared with results from other different approaches. We find that except for a discrepancy in the annual phase estimates of Z component, geocenter motions predicted with the IG2 data are in line with those based on other techniques. In addition, the effects of the translational parameters and the comparison with the IGS first data reprocessing campaign (IG1)-estimated geocenter motions are investigated, and results demonstrate that the translation parameters should be estimated when inversing the geocenter motion with the newly IG2 solutions and the advantage of the IG2 data reprocessing over the previous IG1 efforts. Finally, we address the impacts of post-seismic effects and the missing ocean data on the IG2-derived solutions. After removing the stations affected by large earthquakes, the amplitudes of Y component become higher, but the annual phases of the Y component become far away from the SLR solutions. Comparisons of the equivalent water height from the IG2-estimated coefficients and the solutions from the estimation of the circulation and climate of the ocean indicate that the differences between the two types of solutions vary with different truncated degrees, and the consistency is getting worse and worse with the truncated degree grows. Further researches still need to be done to invert surface mass variation coefficients from various combinations of GPS observations, ocean models and other datasets. Numéro de notice : A2019-669 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1186/s40623-019-1054-2 Date de publication en ligne : 05/07/2019 En ligne : https://doi.org/10.1186/s40623-019-1054-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99940 [article]

Influences of environmental loading corrections on the nonlinear variations and velocity uncertainties for the reprocessed global positioning system height time series of the crustal movement observation network of China / Peng Yuan in Remote sensing, vol 10 n° 6 (June 2018)    

Public [article]  inRemote sensing > vol 10 n° 6 (June 2018) Titre : Influences of environmental loading corrections on the nonlinear variations and velocity uncertainties for the reprocessed global positioning system height time series of the crustal movement observation network of China Type de document : Article/Communication Auteurs : Peng Yuan, Auteur ; Zhao Li, Auteur ; Weiping Jiang, Auteur ; Yifang Ma , Auteur ; Wu Chen, Auteur ; Nico Sneeuw, Auteur Année de publication : 2018 Projets : 1-Pas de projet / Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse en composantes principales [Termes IGN] champ de vitesse [Termes IGN] Chine [Termes IGN] coordonnées GPS [Termes IGN] correction géométrique [Termes IGN] données GPS [Termes IGN] réseau de surveillance géophysique [Termes IGN] série temporelle [Termes IGN] station permanente Résumé : (auteur) Mass redistribution of the atmosphere, oceans, and terrestrial water storage generates crustal displacements which can be predicted by environmental loading models and observed by the Global Positioning System (GPS). In this paper, daily height time series of 235 GPS stations derived from a homogeneously reprocessed Crustal Movement Observation Network of China (CMONOC) and corresponding loading displacements predicted by the Deutsche GeoForschungsZentrum (GFZ) are compared to assess the effects of loading corrections on the nonlinear variations of GPS time series. Results show that the average root mean square (RMS) of vertical displacements due to atmospheric, nontidal oceanic, hydrological, and their combined effects are 3.2, 0.6, 2.7, and 4.0 mm, respectively. Vertical annual signals of loading and GPS are consistent in amplitude but different in phase systematically. The average correlation coefficient between loading and GPS height time series is 0.6. RMS of the GPS height time series are reduced by 20% on average. Moreover, an investigation of 208 CMONOC stations with observing time spans of ~4.6 years shows that environmental loading corrections lead to an overestimation of the GPS velocity uncertainty by about 1.4 times on average. Nevertheless, by using a common mode component filter through principal component analysis, the dilution of velocity precision due to environmental loading corrections can be compensated. Numéro de notice : A2018-658 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/rs10060958 Date de publication en ligne : 15/06/2018 En ligne : https://doi.org/10.3390/rs10060958 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93811 [article]

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