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Towards reliable velocities of permanent GNSS stations / Janusz Bogusz in Reports on geodesy and geoinformatics, vol 100 (May 2016)
[article]
Titre : Towards reliable velocities of permanent GNSS stations Type de document : Article/Communication Auteurs : Janusz Bogusz, Auteur ; Anna Klos, Auteur ; Marta Gruszczynska, Auteur ; Maciej Gruszczynski, Auteur Année de publication : 2016 Article en page(s) : pp 17 - 26 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse de spectre singulier
[Termes IGN] analyse en composantes principales
[Termes IGN] bruit (théorie du signal)
[Termes IGN] coordonnées GNSS
[Termes IGN] série temporelle
[Termes IGN] station permanente
[Termes IGN] vitesse
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) In the modern geodesy the role of the permanent station is growing constantly. The proper treatment of the time series from such station lead to the determination of the reliable velocities. In this paper we focused on some pre-analysis as well as analysis issues, which have to be performed upon the time series of the North, East and Up components and showed the best, in our opinion, methods of determination of periodicities (by means of Singular Spectrum Analysis) and spatio-temporal correlations (Principal Component Analysis), that still exist in the time series despite modelling. Finally, the velocities of the selected European permanent stations with the associated errors determined following power-law assumption in the stochastic part is presented.
In this paper we preliminary discuss methods for collecting raster data in a geodatabase by processing open multi-temporal and multi-scale satellite data aimed at retrieving indicators for land degradation phenomenon (i.e. land cover/land use analysis, vegetation indices, trend analysis, etc.). Then we describe a methodology for designing a WebGIS framework in order to disseminate information through maps for territory monitoring. Basic WebGIS functions were extended with the help of POSTGIS database and OpenLayers libraries. Geoserver was customized to set up and enhance the website functions developing various advanced queries using PostgreSQL and innovative tools to carry out efficiently multi-layer overlay analysis. The end-product is a simple system that provides the opportunity not only to consult interactively but also download processed remote sensing data.Numéro de notice : A2016-645 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/rgg-2016-0003 En ligne : http://dx.doi.org/10.1515/rgg-2016-0003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81851
in Reports on geodesy and geoinformatics > vol 100 (May 2016) . - pp 17 - 26[article]
Titre : GPS time-variable seasonal signals modeling Type de document : Mémoire Auteurs : Qiang Chen, Auteur Editeur : Stuttgart : University of Stuttgart Année de publication : 2015 Importance : 65 p. Format : 21 x 30 cm Note générale : bibliographie
mémoire de master, Université de StuttgartLangues : Anglais (eng) Descripteur : [Termes IGN] analyse comparative
[Termes IGN] analyse de spectre singulier
[Termes IGN] compensation par moindres carrés
[Termes IGN] données GPS
[Termes IGN] filtrage du bruit
[Termes IGN] filtre de Kalman
[Termes IGN] oscillation
[Termes IGN] série temporelle
[Termes IGN] variation saisonnière
[Vedettes matières IGN] Traitement de données GNSSIndex. décimale : MX Mémoires divers Résumé : (auteur) Seasonal signals (annual plus semi-annual) in GPS time series are of great importance for understanding the evolution of regional mass, i.e. ice and hydrology. Conventionally these signals (annual and semi-annual) are derived by least-squares fitting of harmonic terms with a constant amplitude and phase. In reality, however, such seasonal signals are modulated, i.e. they will have a time-variable amplitude and phase. Recently, Davis et al. (2012) proposed a Kalman filter based approach to capture the stochastic seasonal behavior of geodetic time series. In this study, a non-parametric approach, singular spectrum analysis (SSA) is introduced. It uses time domain data to extract information from short and noisy time series without prior knowledge of the dynamics affecting the time series. A prominent benefit is that obtained trends are not necessarily linear and extracted oscillations can be amplitude and phase modulated. In this work, the capability of SSA for analyzing time-variable seasonal signals from GPS time series is investigated. We also compare SSA-based results to two model-based results, i.e. least-squares analysis and Kalman filtering. Our results show that singular spectrum analysis could be a viable and complementary tool for exploring modulated oscillations from GPS time series. Based on the SSA-derived seasonal signals, we look into the effects of the input noise variances in the framework of Kalman filtering. Two Kalman filtering based approaches with different process noise models are compared over 79 GPS sites. We find that the basic Kalman filtering technique with the input noise model suggested by Davis et al. (2012) turns out to be optimal. Numéro de notice : 17348 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Mémoire masters divers En ligne : http://dx.doi.org/10.18419/opus-8824 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83707 Singular spectrum analysis of global mean sea level variations / S. Khelifa in Bulletin des sciences géographiques, n° 26 (octobre 2011)
[article]
Titre : Singular spectrum analysis of global mean sea level variations Type de document : Article/Communication Auteurs : S. Khelifa, Auteur ; M. Belbachir, Auteur ; M. Hadad, Auteur Année de publication : 2011 Article en page(s) : pp 17 - 22 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altimétrie satellitaire par radar
[Termes IGN] altitude
[Termes IGN] analyse de spectre singulier
[Termes IGN] hauteurs de mer
[Termes IGN] montée du niveau de la mer
[Termes IGN] niveau moyen des mers
[Termes IGN] série temporelle
[Termes IGN] variation temporelleRésumé : (Auteur) Le thème développé à travers cet article porte sur l'analyse des séries temporelles d'anomalies moyennes de hauteur de la mer (MSLA) d'altimétrie spatiale par le spectre singulier (SSA). Le but de cette étude est de caractériser et de quantifier la variabilité à long terme du niveau de la mer. Les données utilisées lors du traitement sont constituées d'une série hebdomadaire d'anomalies moyennes de hauteur de la mer issues des satellites d'altimétrie spatiale, conduite entre 1993 et 2009. Les résultats obtenus ont montré que la SAA est bien adaptée pour l'extraction simultanée de la tendance non linéaire et des signaux saisonniers contenus dans les séries temporelles MSLA. La tendance, le signal annuel et semi annuel représentent respectivement 93.36%, 6.01 % et 0.34% du signal total. La tendance estimée de 2.88 mm/an de niveau global de la mer est similaire aux récents résultats publiés par AVISO Altimétrie sur la tendance de niveau global de la mer qui est d'environs 2.92 mm/an. Numéro de notice : A2011-499 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31393
in Bulletin des sciences géographiques > n° 26 (octobre 2011) . - pp 17 - 22[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 253-2011011 RAB Revue Centre de documentation En réserve L003 Disponible Seasonal variations of vertical crustal motion in Australia observed by joint analysis of GPS and GRACE / Hao Wang in Geomatics and Information Science of Wuhan University, vol 47 n° 2 (February 2022)
[article]
Titre : Seasonal variations of vertical crustal motion in Australia observed by joint analysis of GPS and GRACE Type de document : Article/Communication Auteurs : Hao Wang, Auteur ; Jianping Yue, Auteur ; Yunfei Xiang, Auteur Année de publication : 2022 Article en page(s) : pp 197 - 207 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse de spectre singulier
[Termes IGN] Australie
[Termes IGN] déformation verticale de la croute terrestre
[Termes IGN] données GPS
[Termes IGN] données GRACE
[Termes IGN] transformation en ondelettes
[Termes IGN] variation saisonnièreRésumé : (auteur) Objectives There are obvious seasonal variations in the GPS height time series, which affect the improvement of precision and can be corrected by both mathematical modelling and geophysical mechanisms. Compared to least square fitting, singular spectrum analysis (SSA) can extract random seasonal signals effectively through signal reconstruction, which is unaffected by the assumed sinusoidal waves. According to the elastic loading theory, the gravity recovery and climate experiment (GRACE) can be used to calculate the vertical surface displacement caused by changes in terrestrial water storage. Methods This paper mainly studies the feasibility of correcting the seasonal variations in GPS heights using SSA and GRACE inversion results. The height time series of 27 GPS stations in Australia with a time span of from 5 to 10 years were chosen and combined with GRACE simultaneous inversions. Results Because the spatial resolutions of GRACE are coarse and the loading displacement is much more sensitive to near-field mass changes than far-field ones, the amplitudes of GRACE-inferred hydrological loading deformations are significantly smaller than GPS. The weighted root mean square (WRMS) are reduced at 22 stations after GRACE-inferred displacement corrections, and the correlation coefficients between deformations estimated by GPS and GRACE range from 0.12 to 0.78 with a mean value of 0.43, indicating that GPS and GRACE results have good consistency and correlation. SSA is used to extract the annual signals of vertical displacements derived from GPS and GRACE, and contribution rates of singular spectral variance of annual signals are 21.60% and 34.48%, respectively, expressing that annual signals are the main components of GRACE-inferred results. Geographical climatic conditions have a significant impact on the consistency of annual signals derived from GPS and GRACE. Compared with the arid areas in central and western Australia, the amplitude and phase of annual signals derived from GPS and GRACE are more consistent in the northern region with seasonal rainfall. Furthermore, cross wavelet transform (XWT) finds that the vertical displacement series derived from GPS and GRACE of each station have a significant resonance period of one year. The circular average phase angles of GPS/GRACE at the period closet to 1 cycle per year (cpy) outside the cone of influence range from -74.03° to 67.23°. The mean XWT-based semblances range from 0.28 to 0.99 with an average value of 0.79, showing that there is a significant positive correlation between the annual variations derived from GPS and GRACE. Conclusions Overall, GRACE-inferred deformations can explain the annual variations of GPS-derived displacements, particularly in areas with high hydrological loading. It is possible to correct the annual signals of GPS heights by GRACE inversions, but the effect is not as good as the SSA-filtered annual signals. Numéro de notice : A2022-150 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.13203/j.whugis20190282 Date de publication en ligne : 05/02/2022 En ligne : http://dx.doi.org/10.13203/j.whugis20190282 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100109
in Geomatics and Information Science of Wuhan University > vol 47 n° 2 (February 2022) . - pp 197 - 207[article]An effective toolkit for the interpolation and gross error detection of GPS time series / X. Wang in Survey review, vol 48 n° 348 (May 2016)
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Titre : An effective toolkit for the interpolation and gross error detection of GPS time series Type de document : Article/Communication Auteurs : X. Wang, Auteur ; Y. Cheng, Auteur ; S. Wu, Auteur ; K. Zhang, Auteur Année de publication : 2016 Article en page(s) : pp 202 - 211 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse de spectre singulier
[Termes IGN] coordonnées GPS
[Termes IGN] détection d'erreur
[Termes IGN] interpolation
[Termes IGN] modèle de simulation
[Termes IGN] série temporelle
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) As data gaps and gross errors inevitably exist in GPS time series, robust detection and interpolation procedures are needed to obtain a uniform time series for various geospatial studies and applications. The use of traditional methods for this purpose is usually based on some improper assumptions, which are not derived based on the real properties of the data. Moreover, different interpolation methods may need to be investigated for interpolation for various gaps with different types and amount of missing data. These make the interpolation for missing data not easy. To address the issue of mentioned above, in this study, a data-analysis method named singular spectrum analysis (SSA) for missing data is assessed for reconstructing a reliable model from unevenly sampled time series without the need for any a priori knowledge of the time series data. In this method, the interpolation and detection of gross errors are carried out in one go along with the reliable reconstructed model. Both simulation data and real GPS data testing results showed that this was an efficient method for interpolation and gross error detection. Numéro de notice : A2016-276 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/1752270615Y.0000000023 En ligne : http://doi.org/10.1179/1752270615Y.0000000023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80830
in Survey review > vol 48 n° 348 (May 2016) . - pp 202 - 211[article]Hydrologically-driven crustal stresses and seismicity in the New Madrid seismic zone / Timothy J. Craig in Nature communications, vol 8 (2017)PermalinkOn the application of Monte Carlo singular spectrum analysis to GPS position time series / Seyed Mohsen Khazraei in Journal of geodesy, vol 93 n° 9 (September 2019)PermalinkStudy on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models / Artur Lenczuk in Journal of applied geodesy, vol 14 n° 4 (October 2020)PermalinkData-adaptive spatio-temporal filtering of GRACE data / Paoline Prevost in Geophysical journal international, vol 219 n° 3 (December 2019)PermalinkLong-term prediction of polar motion using a combined SSA and ARMA model / Y. Shen in Journal of geodesy, vol 92 n° 3 (March 2018)PermalinkQuantifying the correlation between the MEI and LOD variations by decomposing LOD with singular spectrum analysis / Karine Le Bail (2014)Permalink