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contenu dans Reference frames for applications in geosciences, Proceedings of IAG Symposium REFAG 2010 / Zuheir Altamimi (2013)
Titre : Time-correlated GPS noise dependency on data time period Type de document : Article/Communication Auteurs : Alvaro Santamaria Gomez, Auteur ; Marie-Noëlle Bouin , Auteur ; Xavier Collilieux , Auteur ; Guy Wöppelmann , Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2013 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 138 Conférence : REFAG 2010, Reference Frames for Applications in Geosciences, IAG symposium 04/10/2010 08/10/2010 Champs-sur-Marne France Proceedings Springer Importance : pp 119 - 124 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse diachronique
[Termes IGN] bruit (théorie du signal)
[Termes IGN] filtrage du bruit
[Termes IGN] positionnement par GPS
[Termes IGN] série temporelleRésumé : (Auteur) GPS position time series contain time-correlated noise. The estimated parameters using correlated time series data, as station velocities, are then more uncertain than if the time series data were uncorrelated. If the level of the time-correlated noise is not taken into account, the estimated formal uncertainties will be smaller. By estimating the type and amplitude of the noise content in time series, more realistic formal uncertainties can be assessed. However, time-correlated noise amplitude is not constant in long time series, but depends on the time period of the time series data. Older time series data contain larger time-correlated noise amplitudes than newer time series data. This way, shorter time series with older data time period exhibit time-correlated noise amplitudes similar to the whole time series. This paper focuses on the source of the time-correlated noise amplitude decrease from older to newer time series period data. The results of several tested sources are presented. Neither the increasing ambiguity fixation rate, nor the increasing number of tracking stations, nor the increasing number of observed satellites are likely the source of the noise reduction. The quality improvement of the equipment of both tracking network and constellation is likely the main source of the correlated noise evolution. Numéro de notice : C2010-015 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-32998-2_19 Date de publication en ligne : 27/11/2012 En ligne : http://dx.doi.org/10.1007/978-3-642-32998-2_19 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65070
Titre : Auvergne dataset: Testing several geoid computation methods Type de document : Article/Communication Auteurs : Pierre Valty , Auteur ; Henri Duquenne (1948-2010) , Auteur ; Isabelle Panet , 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 465 - 472 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altitude
[Termes IGN] analyse de données
[Termes IGN] anomalie de pesanteur
[Termes IGN] Auvergne
[Termes IGN] formule de Stokes
[Termes IGN] levé gravimétrique
[Termes IGN] quasi-géoïdeRésumé : (auteur) In 2004, the French Institut Géographique National (IGN), upon the request of the steering committee of the European Gravity and Geoid Project, prepared a dataset to test geoid computation methods. It consists of a set of about 240,000 gravity points, three digital terrestrial models (an accurate one, a low-resolution one and a filtered one) and 75 GPS/levelling points to evaluate the quality of the computed geoid models (Duquenne, A data set to test geoid computation methods. In: Dergisi H (eds.), Proceedings of the 1st international symposium of the international gravity field service “gravity field of the earth”, pp 61–65, 2006). In this paper, we compared the following geoid computation methods using the Auvergne dataset: the remove-compute-restore method using the unmodified Stokes’ kernel, the deterministic (Wong and Gore) and stochastic (KTH) modifications of Stokes’ kernel. For each method, we tested different choices of the parameters (radius of integration of Stokes’ anomalies, degree of modification of Stokes’ kernel, radius of integration of terrain effect, etc.). We analysed the results in order to find out which method performs the best and how the geoid modelling method impacts the results, considering the presence of errors in the dataset. The question that this work intends to answer is whether we should put our efforts rather on the theoretical investigations of geoid modelling methodologies, or on the acquisition of gravity measurements. Numéro de notice : C2009-032 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-20338-1_56 Date de publication en ligne : 16/07/2011 En ligne : https://doi.org/10.1007/978-3-642-20338-1_56 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91509 Calibration of wet tropospheric delays in GPS observation using Raman lidar measurements / Pierre Bosser (2012)
Titre : Calibration of wet tropospheric delays in GPS observation using Raman lidar measurements Type de document : Article/Communication Auteurs : Pierre Bosser , Auteur ; Christian Thom , Auteur ; Olivier Bock , Auteur ; Jacques Pelon, Auteur ; Pascal Willis , 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 795 - 800 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données GPS
[Termes IGN] données lidar
[Termes IGN] étalonnage des données
[Termes IGN] humidité de l'air
[Termes IGN] lidar Raman
[Termes IGN] retard troposphériqueRésumé : (auteur) Water vapor measurements from a Raman lidar developed conjointly by the IGN and the LATMOS/CNRS are used for documenting the water vapor heterogeneities and correcting GPS signal propagation delays in clear sky conditions. We use data from four 6 h-observing sessions during the VAPIC experiment (15 May–15 June 2004). The retrieval of zenith wet delays (ZWDs) from our Raman lidar is shown to agree well with radiosonde (0.6 ± 2.5 mm) and microwave radiometers (−6.6 ± 1.2 and 6.0 ± 3.8 mm) retrievals. ZWDs estimated from GPS data present a good consistency too (−2.0 ± 2.7 mm) but they are still shown to not represent properly the fast evolutions with high frequency variations correlation about 0.12. Part of the errors is also due to multipath and antenna phase center variations. Within this framework, methodologies for integrating of zenith lidar observations into the GPS processing are described. They include also a correction for multipath and antenna phase center variation. The best results are obtained when the lidar ZWDs are used for a priori correcting the GPS phase observations: discrepancies between lidar and GPS estimates are then reduced to −1.1 ± 1.4 mm. It is shown also that mapping function derived from the lidar vertical profiles performs nearly as well as the VMF1 mapping function. Numéro de notice : C2009-033 Affiliation des auteurs : LOEMI+Ext (1985-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-20338-1_100 Date de publication en ligne : 26/07/2011 En ligne : https://doi.org/10.1007/978-3-642-20338-1_100 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91511 Comparison of regional and global GNSS positions, velocities and residual time series / Juliette Legrand (2012)
Titre : Comparison of regional and global GNSS positions, velocities and residual time series Type de document : Article/Communication Auteurs : Juliette Legrand, Auteur ; Nicolas Bergeot, Auteur ; Carine Bruyninx, Auteur ; Guy Wöppelmann , Auteur ; Alvaro Santamaria Gomez, Auteur ; Marie-Noëlle Bouin , Auteur ; Zuheir Altamimi , 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 95 - 103 Format : 16 x 24 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] European Terrestrial Reference Frame
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] résidu
[Termes IGN] retard troposphérique zénithal
[Termes IGN] série temporelleRésumé : (auteur) More than 10 years (1996–2008) of weekly GPS solutions of 299 globally distributed stations have been used to quantify the impact of the reference frame definition and especially the size of the network on the estimated station positions, velocities, and residual position time series. For that purpose, weekly regional solutions (covering the European region) and global solutions have been respectively stacked to obtain regional and global station positions, velocities, and residual position time series. In both cases, the estimated long-term solutions have been tied to the ITRF2005 under minimal constraints using a selected set of reference stations. This study shows that: (1) regional position and velocity solutions can present biases with respect to each other and to global solutions, while in comparison, global solutions are much more stable; (2) the obtained residual position time series are affected by the size of the network with significantly reduced periodic signals in the regional networks, e.g. a 27% reduction of the annual signals in the height component. Numéro de notice : C2009-063 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-20338-1_12 Date de publication en ligne : 26/07/2011 En ligne : https://doi.org/10.1007/978-3-642-20338-1_12 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102021 A dense global velocity field based on GNSS observations: Preliminary Results / Carine Bruyninx (2012)
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 Estimating horizontal tropospheric gradients in DORIS data processing: preliminary results / Pascal Willis (2012)PermalinkFlexible dataset combination and modelling by domain decomposition approaches / Isabelle Panet (2012)PermalinkImproved GPS data analysis strategy for tide gauge benchmark monitoring / Alvaro Santamaria Gomez (2012)PermalinkOcean Loading in Brittany, Northwest France: Impact of the GPS Analysis Strategy / Joëlle Nicolas (2012)PermalinkRecent improvements in DORIS data processing at IGN in view of ITRF2008, the IGNWD08 Solution / Pascal Willis (2012)PermalinkPermalinkPermalinkAssessment of a numerical method for computing the spherical harmonic coefficients of the gravitational potential of a constant density polyhedron / Olivier Jamet (2010)PermalinkGravity, Geoid and Earth Observation, IAG Commission 2 Gravity Field, Chania, Crete, Greece, 23-27 June 2008 / Stelios Mertikas (2010)PermalinkPermalinkPermalinkImpact of the network effect on the origin and scale: case study of Satellite Laser Ranging / Xavier Collilieux (2009)PermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalink