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Towards reliable velocities of permanent GNSS stations / Janusz Bogusz in Reports on geodesy and geoinformatics, vol 100 (May 2016)  

Public [article]  inReports on geodesy and geoinformatics > vol 100 (May 2016) . - pp 17 - 26 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 GNSS Résumé : (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 [article]

Spatio-temporal filtering for determination of common mode error in regional GNSS networks / Janusz Bogusz in Open geosciences, vol 7 n° 1 (January 2015)  

Public [article]  inOpen geosciences > vol 7 n° 1 (January 2015) . - pp 140 - 148 Titre : Spatio-temporal filtering for determination of common mode error in regional GNSS networks Type de document : Article/Communication Auteurs : Janusz Bogusz, Auteur ; Maciej Gruszczynski, Auteur ; Mariusz Figurski, Auteur ; Anna Klos, Auteur Année de publication : 2015 Article en page(s) : pp 140 - 148 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] erreur de positionnement [Termes IGN] EUPOS [Termes IGN] filtrage spatiotemporel [Termes IGN] Pologne [Termes IGN] positionnement par GNSS [Termes IGN] série temporelle Résumé : (auteur) The spatial correlation between different stations for individual components in the regional GNSS networks seems to be significant. The mismodelling in satellite orbits, the Earth orientation parameters (EOP), largescale atmospheric effects or satellite antenna phase centre corrections can all cause the regionally correlated errors. This kind of GPS time series errors are referred to as common mode errors (CMEs). They are usually estimated with the regional spatial filtering, such as the "stacking". In this paper, we show the stacking approach for the set of ASG-EUPOS permanent stations, assuming that spatial distribution of the CME is uniform over the whole region of Poland (more than 600 km extent). The ASG-EUPOS is a multifunctional precise positioning system based on the reference network designed for Poland. We used a 5- year span time series (2008-2012) of daily solutions in the ITRF2008 from Bernese 5.0 processed by the Military University of Technology EPN Local Analysis Centre (MUT LAC). At the beginning of our analyses concerning spatial dependencies, the correlation coefficients between each pair of the stations in the GNSS network were calculated. This analysis shows that spatio-temporal behaviour of the GPS-derived time series is not purely random, but there is the evident uniform spatial response. In order to quantify the influence of filtering using CME, the norms L1 and L2 were determined. The values of these norms were calculated for the North, East and Up components twice: before performing the filtration and after stacking. The observed reduction of the L1 and L2 norms was up to 30% depending on the dimension of the network. However, the question how to define an optimal size of CME-analysed subnetwork remains unanswered in this research, due to the fact that our network is not extended enough. Numéro de notice : A2015-439 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/geo-2015-0021 En ligne : https://doi.org/10.1515/geo-2015-0021 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77039 [article]