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Real-time sea-level monitoring using Kalman filtering of GNSS-R data / Joakim Strandberg in GPS solutions, vol 23 n° 3 (July 2019)  

Public [article]  inGPS solutions > vol 23 n° 3 (July 2019) Titre : Real-time sea-level monitoring using Kalman filtering of GNSS-R data Type de document : Article/Communication Auteurs : Joakim Strandberg, Auteur ; Thomas Hobiger, Auteur ; Rüdiger Haas, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Nivellement [Termes descripteurs IGN] B-Spline [Termes descripteurs IGN] déformation de la croute terrestre [Termes descripteurs IGN] filtre de Kalman [Termes descripteurs IGN] glace de mer [Termes descripteurs IGN] marée terrestre [Termes descripteurs IGN] niveau de la mer [Termes descripteurs IGN] rapport signal sur bruit [Termes descripteurs IGN] réflectométrie par GNSS [Termes descripteurs IGN] temps réel Résumé : (auteur) Current GNSS-R (GNSS reflectometry) techniques for sea surface measurements require data collection over longer periods, limiting their usability for real-time applications. In this work, we present a new, alternative GNSS-R approach based on the unscented Kalman filter and the so-called inverse modeling approach. The new method makes use of a mathematical description that relates SNR (signal-to-noise ratio) variations to multipath effects and uses a B-spline formalism to obtain time series of reflector height. The presented algorithm can provide results in real time with a precision that is significantly better than spectral inversion methods and almost comparable to results from inverse modeling in post-processing mode. To verify the performance, the method has been tested at station GTGU at the Onsala Space Observatory, Sweden, and at the station SPBY in Spring Bay, Australia. The RMS (root mean square) error with respect to nearby tide gauge data was found to be 2.0 cm at GTGU and 4.8 cm at SPBY when evaluating the output corresponding to real-time analysis. The method can also be applied in post-processing, resulting in RMS errors of 1.5 cm and 3.3 cm for GTGU and SPBY, respectively. Finally, based on SNR data from GTGU, it is also shown that the Kalman filter approach is able to detect the presence of sea ice with a higher temporal resolution than the previous methods and traditional remote sensing techniques which monitor ice in coastal regions. Numéro de notice : A2019-198 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0851-1 En ligne : https://doi.org/10.1007/s10291-019-0851-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92653 [article]

The impact of solid Earth-tide model error on tropospheric zenith delay estimates and GPS coordinate time series / Fei Li in Survey review, vol 50 n° 361 (July 2018)  

Public [article]  inSurvey review > vol 50 n° 361 (July 2018) . - pp 355 - 363 Titre : The impact of solid Earth-tide model error on tropospheric zenith delay estimates and GPS coordinate time series Type de document : Article/Communication Auteurs : Fei Li, Auteur ; Jintao Lei, Auteur ; Chao Ma, Auteur ; Weifeng Hao, Auteur ; et al., Auteur Année de publication : 2018 Article en page(s) : pp 355 - 363 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] coordonnées GPS [Termes descripteurs IGN] erreur de modèle [Termes descripteurs IGN] marée terrestre [Termes descripteurs IGN] propagation du signal [Termes descripteurs IGN] retard troposphérique zénithal [Termes descripteurs IGN] série temporelle Résumé : (Auteur) Any unmodelled or mismodelled subdaily signals left in the model may not only affect the instantaneous site positions and the associated estimates, but also propagate into spurious seasonal signals, contaminating the daily coordinate time series. To demonstrate how subdaily ‘error’ in the modelling of the solid Earth-tide affects the estimates of tropospheric zenith total delay (ZTD) and how it propagates into long-period signal in the daily GPS time series, we analyse GPS observations collected between 2009 and 2013 for 13 sites in the coastal regions of Antarctica using the GAMIT/GLOBK 10.6 software. We find that ZTD differenced time series, with amplitude at 2 mm level, have inverse correlation with the input K1 correction, and the corresponding admittances range from 6% to 14%; Propagated spurious annual signals are evident in the vertical component of coordinate differenced time series, with amplitudes at the mm level and admittances of around 2–11%. Numéro de notice : A2018-444 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2016.1277657 date de publication en ligne : 12/01/2017 En ligne : https://doi.org/10.1080/00396265.2016.1277657 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91018 [article]

Bimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf / Denis Lombardi in Geophysical journal international, vol 206 n° 2 (August 2016)  

Public [article]  inGeophysical journal international > vol 206 n° 2 (August 2016) . - pp 1375 - 1381 Titre : Bimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf Type de document : Article/Communication Auteurs : Denis Lombardi, Auteur ; Lionel Benoit, Auteur ; Thierry Camelbeeck, Auteur ; Olivier Martin , Auteur ; Christophe Meynard, Auteur ; Christian Thom , Auteur Année de publication : 2016 Article en page(s) : pp 1375 - 1381 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] Antarctique [Termes descripteurs IGN] calotte glaciaire [Termes descripteurs IGN] coordonnées GPS [Termes descripteurs IGN] déformation de la croute terrestre [Termes descripteurs IGN] marée terrestre [Termes descripteurs IGN] séisme Résumé : (auteur) In Antarctica, locally grounded ice, such as ice rises bordering floating ice shelves, plays a major role in the ice mass balance as it stabilizes the ice sheet flow from the hinterland. When in direct contact with the ocean, the ice rise buttressing effect may be altered in response of changing ocean forcing. To investigate this vulnerable zone, four sites near the boundary of an ice shelf with an ice rise promontory in Dronning Maud Land, East-Antarctica were monitored for a month in early 2014 with new instruments that include both seismic and GPS sensors. Our study indicated that this transition zone experiences periodic seismic activity resulting from surface crevassing during oceanic tide-induced flexure of the ice shelf. The most significant finding is the observation of apparent fortnightly tide-modulated low-frequency, long-duration seismic events at the seaward front of the ice rise promontory. A basal origin of these events is postulated with the ocean water surge at each new spring tide triggering basal crevassing or basal slip on a local bedrock asperity. Detection and monitoring of such seismicity may help identifying ice rise zones vulnerable to intensified ocean forcing. Numéro de notice : A2016--191 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggw214 date de publication en ligne : 05/06/2016 En ligne : https://doi.org/10.1093/gji/ggw214 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91841 [article]

Optimized strategy for the calibration of superconducting gravimeters at the one per mille level / Michel Van Camp in Journal of geodesy, vol 90 n° 1 (January 2016)  

Public [article]  inJournal of geodesy > vol 90 n° 1 (January 2016) . - pp 91- 99 Titre : Optimized strategy for the calibration of superconducting gravimeters at the one per mille level Type de document : Article/Communication Auteurs : Michel Van Camp, Auteur ; Bruno Meurers, Auteur ; Olivier de Viron, Auteur ; Thomas Forbriger, Auteur Année de publication : 2016 Article en page(s) : pp 91- 99 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] étalonnage d'instrument [Termes descripteurs IGN] gravimètre absolu [Termes descripteurs IGN] gravimètre supraconducteur [Termes descripteurs IGN] marée terrestre Résumé : (auteur) This paper reports on different sources of errors that occur in the calibration process of a superconducting gravimeter (SG), determined by comparison with a ballistic absolute gravimeter (AG); some of them have never been discussed in the literature. We then provide methods to mitigate the impact of those errors, to achieve a robust calibration estimate at the http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq1_HTML.gif level. We demonstrate that a standard deviation at the level of http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq2_HTML.gif can be reached within 48 h by measuring at spring tides and by increasing the AG sampling rate. This is much shorter than what is classically reported in previous empirical studies. Measuring more than 5 days around a tidal extreme does not improve the precision in the calibration factor significantly, as the variation in the error as a function of 1/N−−√ does not apply, considering the decrease in signal amplitude due to the tidal modulation. However, we investigate the precision improvement up to 120 days, which can be useful if an AG is run continuously: at mid-latitude it would require 21 days to ensure a calibration factor at the http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq4_HTML.gif level with a 99.7 % confidence interval. We also show that restricting the AG measurement periods to tidal extrema can reduce instrument demand, while this does not affect the precision on the calibration factor significantly. Then, we quantify the effect of high microseismic noise causing aliasing in the AG time series. We eventually discuss the attenuation bias that might be induced by noisy time series of the SG. When experiments are performed at the http://static-content.springer.com/image/art%3A10.1007%2Fs00190-015-0856-7/MediaObjects/190_2015_856_IEq5_HTML.gif level, 7 are needed to ensure that the error in the calibration estimate will be at the 1 per mille level with a 99 % confidence. Numéro de notice : A2016-021 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://link.springer.com/article/10.1007/s00190-015-0856-7/fulltext.html Format de la ressource électronique : Url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79469 [article]

Earth rotation and geodynamics / Janusz Bogusz in Geodesy and cartography, vol 64 n° 2 (December 2015)  

Public [article]  inGeodesy and cartography > vol 64 n° 2 (December 2015) . - pp 201 - 242 Titre : Earth rotation and geodynamics Type de document : Article/Communication Auteurs : Janusz Bogusz, Auteur ; Alexander Brzezinski, Auteur ; Wieslaw Kosek, Auteur ; Jolanta Nastula, Auteur Année de publication : 2015 Article en page(s) : pp 201 - 242 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] champ géomagnétique [Termes descripteurs IGN] géodynamique [Termes descripteurs IGN] marée terrestre [Termes descripteurs IGN] Pologne [Termes descripteurs IGN] positionnement par GNSS [Termes descripteurs IGN] positionnement par télémétrie laser sur satellite [Termes descripteurs IGN] rotation de la Terre Résumé : (auteur) This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals with monitoring of geodynamic phenomena. It contains analysis of geodynamic networks of local, and regional scale using space (GNSS and SLR) techniques, Earth tides monitoring with gravimeters and water-tube hydrostatic clinometer, and the determination of secular variation of the Earth’ magnetic field. Numéro de notice : A2015--018 Thématique : POSITIONNEMENT Nature : Article En ligne : http://dx.doi.org/10.1515/geocart-2015-0013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80814 [article]

Revisiting the pole tide for and from satellite altimetry / Shailen Desai in Journal of geodesy, vol 89 n° 12 (december 2015)  

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Atmospheric effects on measurements of the Earth gravity field / Maria Karbon (2013)    

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Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series / D. Small in Journal of geodesy, vol 86 n° 4 (April 2012)  

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Modelos armonicos no lineales para series temporales geodéticas = Non-linear harmonic models for geodetic time series / P.A. Martinez-Ortiz (2011)

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Vertical crustalmotion derived from satellite altimetry and tide gauges, and comparisons with DORIS measurements / R. Ray in Advances in space research, vol 45 n° 12 (15/06/2010)

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Les marées terrestres, la dynamique du manteau et la sismicité / Laurent Métivier in Géomatique expert, n° 67 (01/02/2009)

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Mesure de la déformation de l'écorce terrestre par géodésie spatiale [diaporama] / Jérome Verdun (01/02/2006) 

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Le projet Litto3D / Laurent Louvart in Le monde des cartes, n° 186 (décembre 2005 - février 2006) 

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World-wide synthetic tide parameters for gravity and vertical and horizontal displacements / K.H. Zahran in Journal of geodesy, vol 79 n° 6-7 (September - October 2005)

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Atmosphärische und ozeanische Einflüsse auf die Rotation der Erde - Nummerische Untersuchungen mit einem dynamischen Erdsystemmodell / Florian Seitz (2004)

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