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Auteur R. Fernandes |
Documents disponibles écrits par cet auteur (7)



EUREF’s contribution to national, European and global geodetic infrastructures / Johannes Ihde (2014)
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Titre : EUREF’s contribution to national, European and global geodetic infrastructures Type de document : Article/Communication Auteurs : Johannes Ihde, Auteur ; H. Habrich, Auteur ; M. Sacher, Auteur ; Wolfgang Söhne, Auteur ; Zuheir Altamimi , Auteur ; Elmar Brockmann, Auteur ; Carine Bruyninx, Auteur ; Alessandro Caporali, Auteur ; Jan Douša, Auteur ; R. Fernandes, Auteur ; Helmut Hornik, Auteur ; A. Kenyeres, Auteur ; M. Lidberg, Auteur ; J. Makinen, Auteur ; Markku Poutanen, Auteur ; G. Stangl, Auteur ; Joao Agria Torres, Auteur ; C. Völksen, Auteur
Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2014 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 139 Conférence : IAG 2011, General Assembly 28/06/2011 02/07/2011 Melbourne Australie Proceedings Springer Importance : pp 189 - 196 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] International Terrestrial Reference FrameRésumé : (auteur) The EUREF key infrastructures are the EUREF Permanent GNSS Network (EPN) and the Unified European Levelling Network (UELN). The EPN runs almost 250 Global Navigation Satellite System (GNSS) stations in a well organized environment and serves as the backbone of the realization of and access to the European Terrestrial Reference System (ETRS89) and as contribution to the densification of the International Terrestrial Reference Frame (ITRF2008). The upcoming European navigation system Galileo will be a big challenge for the EPN in sense of upgrading the station network. Almost half of the EPN stations are capable of streaming their data in real-time. To strengthen the robustness of the real-time data and product distribution two additional Ntrip broadcasters were set up at different premises in Europe. The EVRS and the ETRS89 have been adopted by the European Community as coordinate reference systems in INSPIRE for environmental policies, or policies and activities that have an impact on the environment. Numéro de notice : C2011-059 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-37222-3_24 Date de publication en ligne : 06/10/2013 En ligne : https://doi.org/10.1007/978-3-642-37222-3_24 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99600 Fast error analysis of continuous GNSS observations with missing data / M.S. Bos in Journal of geodesy, vol 87 n° 4 (April 2013)
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Titre : Fast error analysis of continuous GNSS observations with missing data Type de document : Article/Communication Auteurs : M.S. Bos, Auteur ; R. Fernandes, Auteur ; S. Williams, Auteur ; Luisa Bastos, Auteur Année de publication : 2013 Article en page(s) : pp 351 - 360 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] bruit (théorie du signal)
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] données GNSS
[Termes IGN] matrice de covariance
[Termes IGN] série temporelle
[Termes IGN] traitement de données GNSSRésumé : (Auteur) One of the most widely used method for the time-series analysis of continuous Global Navigation Satellite System (GNSS) observations is Maximum Likelihood Estimation (MLE) which in most implementations requires O(n3) operations for n observations. Previous research by the authors has shown that this amount of operations can be reduced to O(n2) for observations without missing data. In the current research we present a reformulation of the equations that preserves this low amount of operations, even in the common situation of having some missing data. Our reformulation assumes that the noise is stationary to ensure a Toeplitz covariance matrix. However, most GNSS time-series exhibit power-law noise which is weakly non-stationary. To overcome this problem, we present a Toeplitz covariance matrix that provides an approximation for power-law noise that is accurate for most GNSS time-series. Numerical results are given for a set of synthetic data and a set of International GNSS Service (IGS) stations, demonstrating a reduction in computation time of a factor of 10–100 compared to the standard MLE method, depending on the length of the time-series and the amount of missing data. Numéro de notice : A2013-218 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-012-0605-0 Date de publication en ligne : 02/12/2012 En ligne : https://doi.org/10.1007/s00190-012-0605-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32356
in Journal of geodesy > vol 87 n° 4 (April 2013) . - pp 351 - 360[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2013041 SL Revue Centre de documentation Revues en salle Disponible A dense global velocity field based on GNSS observations: Preliminary Results / Carine Bruyninx (2012)
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Titre : A dense global velocity field based on GNSS observations: Preliminary Results Type de document : Article/Communication Auteurs : Carine Bruyninx, Auteur ; Zuheir Altamimi , Auteur ; Matthias Becker, Auteur ; M. Craymer, Auteur ; L. Combrinck, Auteur ; A. Combrink, Auteur ; J.A. Dawson, Auteur ; R. Dietrich, Auteur ; R. Fernandes, Auteur ; Ramesh Govind, Auteur ; T.A. Herring, Auteur ; A. Kenyeres, Auteur ; R. King, Auteur ; C. Kreemer, Auteur ; David Lavallée, Auteur ; Juliette Legrand, Auteur ; L. Sánchez, Auteur ; R. Glenn Sellar, Auteur ; Z. Shen, Auteur ; Alvaro Santamaria Gomez, Auteur
Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2012 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 136 Conférence : IAG 2009 Symposium, Geodesy for Planet Earth 31/08/2009 04/09/2009 Buenos Aires Argentine Proceedings Springer Importance : pp 19 - 26 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de vitesse
[Termes IGN] coordonnées cartésiennes géocentriques
[Termes IGN] déformation verticale de la croute terrestre
[Termes IGN] réseau permanent EUREF
[Termes IGN] série temporelleRésumé : (auteur) In a collaborative effort with the regional sub-commissions within IAG sub-commission 1.3 “Regional Reference Frames”, the IAG Working Group (WG) on “Regional Dense Velocity Fields” (see http://epncb.oma.be/IAG) has made a first attempt to create a dense global velocity field. GNSS-based velocity solutions for more than 6,000 continuous and episodic GNSS tracking stations, were proposed to the WG in reply to the first call for participation issued in November 2008. The combination of a part of these solutions was done in a two-step approach: first at the regional level, and secondly at the global level. Comparisons between different velocity solutions show an RMS agreement between 0.3 and 0.5 mm/year resp. for the horizontal and vertical velocities. In some cases, significant disagreements between the velocities of some of the networks are seen, but these are primarily caused by the inconsistent handling of discontinuity epochs and solution numbers. In the future, the WG will re-visit the procedures in order to develop a combination process that is efficient, automated, transparent, and not more complex than it needs to be. Numéro de notice : C2009-062 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-20338-1_3 Date de publication en ligne : 01/01/2011 En ligne : https://doi.org/10.1007/978-3-642-20338-1_3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102020 Fast error analysis of continuous GPS observations / M. Bos in Journal of geodesy, vol 82 n° 3 (March 2008)
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Titre : Fast error analysis of continuous GPS observations Type de document : Article/Communication Auteurs : M. Bos, Auteur ; R. Fernandes, Auteur ; S. Williams, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 157 - 166 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] bruit blanc
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] données GPS
[Termes IGN] incertitude des données
[Termes IGN] série temporelleRésumé : (Auteur) It has been generally accepted that the noise in continuous GPS observations can be well described by a power-law plus white noise model. Using maximum likelihood estimation (MLE) the numerical values of the noise model can be estimated. Current methods require calculating the data covariance matrix and inverting it, which is a significant computational burden. Analysing 10 years of daily GPS solutions of a single station can take around 2 h on a regular computer such as a PC with an AMD AthlonTM 64 X2 dual core processor. When one analyses large networks with hundreds of stations or when one analyses hourly instead of daily solutions, the long computation times becomes a problem. In case the signal only contains power-law noise, the MLE computations can be simplified to a O(N log N) process where N is the number of observations. For the general case of power-law plus white noise, we present a modification of the MLE equations that allows us to reduce the number of computations within the algorithm from a cubic to a quadratic function of the number of observations when there are no data gaps. For time-series of three and eight years, this means in practise a reduction factor of around 35 and 84 in computation time without loss of accuracy. In addition, this modification removes the implicit assumption that there is no environment noise before the first observation. Finally, we present an analytical expression for the uncertainty of the estimated trend if the data only contains power-law noise. Copyright Springer Numéro de notice : A2008-167 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0165-x En ligne : https://doi.org/10.1007/s00190-007-0165-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29162
in Journal of geodesy > vol 82 n° 3 (March 2008) . - pp 157 - 166[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08031 RAB Revue Centre de documentation En réserve L003 Disponible 266-08032 RAB Revue Centre de documentation En réserve L003 Disponible Canada-wide maps of dominant tree species from remotely sensed and ground data / G. Pavlic in Geocarto international, vol 22 n° 3 (September - November 2007)
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Titre : Canada-wide maps of dominant tree species from remotely sensed and ground data Type de document : Article/Communication Auteurs : G. Pavlic, Auteur ; W. Chen, Auteur ; R. Fernandes, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 185 - 204 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Canada
[Termes IGN] carte de la végétation
[Termes IGN] données de terrain
[Termes IGN] feuillu
[Termes IGN] image SPOT-Végétation
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] PinophytaRésumé : (Auteur) Information on the spatial distribution of dominant tree species is important as input or validation data in large scale ecological studies, such as carbon budget estimation, biodiversity assessment, and vegetation dynamic modelling. We used a 1-km resolution land cover map of Canada produced from 1998 SPOT VGT satellite data as the base map. Fractions of coniferous needleleaf or deciduous broadleaf forests within each 1-km pixel were then estimated by developing relationships with climate using land-cover maps from Landsat images selected as a representative sample. The fraction of coniferous/deciduous forest within each 1-km pixel was further divided into dominant species fractions using species composition information at the sub-ecoregion level, derived from statistics in the Canadian Forest Inventory (CanFI 1991/94 version), from narrative descriptions of ecoregions, and from topographical data. A total of 17 Canada-wide maps of dominant tree species groups at 1 km-resolution were produced. The estimates of this study agree well with CanFI data at the ecoregion level where available, and show good correspondence with published range maps of Canadian tree species. Numéro de notice : A2007-461 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106040701201798 Date de publication en ligne : 16/08/2007 En ligne : https://doi.org/10.1080/10106040701201798 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28824
in Geocarto international > vol 22 n° 3 (September - November 2007) . - pp 185 - 204[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 059-07031 RAB Revue Centre de documentation En réserve L003 Disponible Landsat-7 ETM+ radiometric normalization comparison for northern mapping application / I. Olthof in Remote sensing of environment, vol 95 n° 3 (15/04/2005)
PermalinkApproaches to fractional land cover and continuous field mapping: a comparative assessment over the BOREAS [BOReal Ecosystem Atmosphere Study] study region / R. Fernandes in Remote sensing of environment, vol 89 n° 2 (30/01/2004)
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