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Auteur Pascal Willis
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DORIS and GPS monitoring of the Gavdos calibration site in Crete / Pascal Willis in Advances in space research, vol 51 n° 8 (April 2013)
[article]
Titre : DORIS and GPS monitoring of the Gavdos calibration site in Crete Type de document : Article/Communication Auteurs : Pascal Willis , Auteur ; Stelios Mertikas, Auteur ; Donald F. Argus, Auteur ; Olivier Bock , Auteur Année de publication : 2013 Projets : Gavdos / Article en page(s) : pp 1438 - 1447 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] correction troposphérique
[Termes IGN] Crète (île)
[Termes IGN] étalonnage des données
[Termes IGN] GAMIT
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] modèle météorologique
[Termes IGN] positionnement par DORIS
[Termes IGN] positionnement par GPS
[Termes IGN] retard troposphérique zénithal
[Termes IGN] série temporelleRésumé : (auteur) Due to its specific geographical location as well as its geodetic equipment (DORIS, GNSS, microwave transponder and tide gauges), the Gavdos station in Crete, Greece is one of the very few sites around the world used for satellite altimetry calibration. To investigate the quality of the Gavdos geodetic coordinates and velocities, we analyzed and compared here DORIS and GPS-derived results obtained during several years of observations. The DORIS solution is the latest ignwd11 solution at IGN, expressed in ITRF2008, while the GPS solution was obtained using the GAMIT software package. Current results show that 1–2 mm/yr agreement can be obtained for 3-D velocity, showing a good agreement with current geophysical models. In particular, the agreement obtained for the vertical velocity is around 0.3–0.4 mm/yr, depending on the terrestrial reference frame. As a by-product of these geodetic GPS and DORIS results, Zenith Tropospheric Delays (ZTDs) estimations were also compared in 2010 between these two techniques, and compared to ECMWF values, showing a 6.6 mm agreement in dispersion without any significant difference between GPS and DORIS (with a 97.6% correlation), but with a 13–14 mm agreement in dispersion when comparing to ECMWF model (with only about 90% correlation for both techniques). These tropospheric delay estimations could also provide an external calibration of the tropospheric correction used for the geophysical data of satellite altimetry missions. Numéro de notice : A2013-798 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2012.08.006 En ligne : http://dx.doi.org/10.1016/j.asr.2012.08.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80125
in Advances in space research > vol 51 n° 8 (April 2013) . - pp 1438 - 1447[article]A new velocity field for Africa from combined GPS and DORIS space geodetic solutions : Contribution to the definition of the African Reference Frame (AFREF) / E. Saria in Journal of geophysical research : Solid Earth, vol 118 n° 4 (April 2013)
[article]
Titre : A new velocity field for Africa from combined GPS and DORIS space geodetic solutions : Contribution to the definition of the African Reference Frame (AFREF) Type de document : Article/Communication Auteurs : E. Saria, Auteur ; Eric Calais, Auteur ; Zuheir Altamimi , Auteur ; Pascal Willis , Auteur ; H. Farah, Auteur Année de publication : 2013 Article en page(s) : pp 1677 - 1697 Note générale : bibliographie Langues : Anglais (eng) Résumé : (auteur) We analyzed 16 years of GPS and 17 years of Doppler orbitography and radiopositioning integrated by satellite (DORIS) data at continuously operating geodetic sites in Africa and surroundings to describe the present-day kinematics of the Nubian and Somalian plates and constrain relative motions across the East African Rift. The resulting velocity field describes horizontal and vertical motion at 133 GPS sites and 9 DORIS sites. Horizontal velocities at sites located on stable Nubia fit a single plate model with a weighted root mean square residual of 0.6 mm/yr (maximum residual 1 mm/yr), an upper bound for plate-wide motions and for regional-scale deformation in the seismically active southern Africa and Cameroon volcanic line. We confirm significant southward motion ( ∼ 1.5 mm/yr) in Morocco with respect to Nubia, consistent with earlier findings. We propose an updated angular velocity for the divergence between Nubia and Somalia, which provides the kinematic boundary conditions to rifting in East Africa. We update a plate motion model for the East African Rift and revise the counterclockwise rotation of the Victoria plate and clockwise rotation of the Rovuma plate with respect to Nubia. Vertical velocities range from − 2 to +2 mm/yr, close to their uncertainties, with no clear geographic pattern. This study provides the first continent-wide position/velocity solution for Africa, expressed in International Terrestrial Reference Frame (ITRF2008), a contribution to the upcoming African Reference Frame (AFREF). Except for a few regions, the African continent remains largely under-sampled by continuous space geodetic data. Efforts are needed to augment the geodetic infrastructure and openly share existing data sets so that the objectives of AFREF can be fully reached. Numéro de notice : A2013-796 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1002/jgrb.50137 Date de publication en ligne : 04/03/2013 En ligne : http://dx.doi.org/10.1002/jgrb.50137 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80072
in Journal of geophysical research : Solid Earth > vol 118 n° 4 (April 2013) . - pp 1677 - 1697[article]vol 51 n° 8 - April 2013 - Satellite altimetry calibration and deformation monitoring using GNSS (Bulletin de Advances in space research) / Pascal Willis
[n° ou bulletin]
Titre : vol 51 n° 8 - April 2013 - Satellite altimetry calibration and deformation monitoring using GNSS Type de document : Périodique Auteurs : Pascal Willis , Éditeur scientifique Année de publication : 2013 Langues : Français (fre) Numéro de notice : sans Affiliation des auteurs : LASTIG LAREG (2012-mi2018) Nature : Numéro de périodique nature-HAL : DirectOuvrColl/Actes En ligne : https://www.sciencedirect.com/journal/advances-in-space-research/vol/51/issue/8 Format de la ressource électronique : URL bulletin Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=26661 [n° ou bulletin]Satellite altimetry calibration and deformation monitoring using GNSS / Pascal Willis in Advances in space research, vol 51 n° 8 (April 2013)
[article]
Titre : Satellite altimetry calibration and deformation monitoring using GNSS Type de document : Article/Communication Auteurs : Pascal Willis , Auteur Année de publication : 2013 Article en page(s) : pp 1283 - 1283 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] données altimétriques
[Termes IGN] données GNSS
[Termes IGN] surveillance géologiqueRésumé : (Auteur) Global change is of key scientific interest, and satellite altimetry recently became a major tool to provide information on sea level on a continuous and worldwide basis. However, any error in the radar altimeter data, and more specifically any error in the altimeter drift, would directly map as an undetected error in the derived mean sea level trend. This explains why satellite altimeter calibration is such an important metrological challenge for all satellite missions such as Jason-2 (US/France), Cryosat-2 (Europe), HY-2A (China), and many others.
On January 20–21, 2011, an international meeting was organized in Chania, Crete, on the following theme: “satellite altimetry calibration and deformation monitoring with GNSS”. Due to the importance of the scientific problems discussed during this meeting and to recent new methods proposed for altimeter calibration, the idea of a Special Issue in Advances in Space Research was proposed. An international call for participation was issued shortly after, and 27 manuscripts were submitted from authors from six different countries. All manuscripts went through the standard peer-review process for ASR with a minimum of two referees for each paper.
Many topics were addressed for this Special Issue: satellite altimeter calibration using dedicated GPS receivers, tide gauges or buoys, calibration sites, calibration on lakes or rivers, coastal altimetry, and crustal deformation using GPS techniques.
We thank the contribution of each author and extend our gratitude to all the referees; those who agreed to be identified by name are listed at the end of this issue.Numéro de notice : A2013-838 Affiliation des auteurs : LASTIG LAREG (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2013.01.004 Date de publication en ligne : 11/01/2013 En ligne : https://doi.org/10.1016/j.asr.2013.01.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91300
in Advances in space research > vol 51 n° 8 (April 2013) . - pp 1283 - 1283[article]Report of the IGN/JPL analysis center 2012 / Pascal Willis (2013)
Titre : Report of the IGN/JPL analysis center 2012 Type de document : Chapitre/Contribution Auteurs : Pascal Willis , Auteur Editeur : Toulouse : International Doris Service, IDS Année de publication : 2013 Importance : pp 58 - 60 Langues : Anglais (eng) Numéro de notice : H2012-012 Affiliation des auteurs : LAREG (1991-2011) Nature : Chapître / contribution nature-HAL : ChRappRech DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101413 Calibration of wet tropospheric delays in GPS observation using Raman lidar measurements / Pierre Bosser (2012)PermalinkEstimating horizontal tropospheric gradients in DORIS data processing: preliminary results / Pascal Willis (2012)PermalinkRecent improvements in DORIS data processing at IGN in view of ITRF2008, the IGNWD08 Solution / Pascal Willis (2012)PermalinkReport of the IGN/JPL analysis center 2011 / Pascal Willis (2012)PermalinkMulti-technique comparison of troposphere zenith delays and gradients during CONT08 / Kamil Teke in Journal of geodesy, vol 85 n° 7 (July 2011)PermalinkEvidence for a slow subsidence of the Tahiti Island from GPS, DORIS, and combined satellite altimetry and tide gauge sea level records / Abdelali Fadil in Comptes rendus : Géoscience, vol 343 n° 5 (May 2011)PermalinkAnalyse conjointe lidar Raman-GPS pour l'estimation de la composante verticale en GPS / Pierre Bosser in Bulletin d'information scientifique et technique de l'IGN, n° 77 (avril 2011)PermalinkScientific applications of Galileo and other Global Navigation Satellite Systems (II) Preface / Pascal Willis in Advances in space research, vol 47 n° 5 (1 March 2011)PermalinkPermalinkPermalinkAn inter-comparison of zenith tropospheric delays derived from DORIS and GPS data / Olivier Bock in Advances in space research, vol 46 n° 12 (15/12/2010)PermalinkDORIS/SLR POD modeling improvements for Jason-1 and Jason-2 / Nikita P. Zelensky in Advances in space research, vol 46 n° 12 (15/12/2010)PermalinkIDS contribution to ITRF2008 / Jean-Jacques Valette in Advances in space research, vol 46 n° 12 (15/12/2010)PermalinkPreface [to DORIS: Precise orbit determination and applications to the Earth sciences] / Pascal Willis in Advances in space research, vol 46 n° 12 (15/12/2010)PermalinkRefining DORIS atmospheric drag estimation in preparation of ITRF2008 / Marie-Line Gobinddass in Advances in space research, vol 46 n° 12 (15/12/2010)PermalinkTowards development of a consistent orbit series for TOPEX, Jason-1, and Jason-2 / Franck G. Lemoine in Advances in space research, vol 46 n° 12 (15/12/2010)PermalinkImproved constraints on models of glacial isostatic adjustment: A review of the contribution of ground-based geodetic observations / Matt A. King in Surveys in Geophysics, vol 31 n° 5 (September 2010)PermalinkPrecision orbit determination standards for the Jason series of altimeter missions / L. Cerri in Marine geodesy, vol 33 suppl 1 (August 2010)PermalinkContributions of the French Institut Géographique National (IGN) to the International DORIS Service / Pascal Willis in Advances in space research, vol 45 n° 12 (15/06/2010)PermalinkPreface [to DORIS: Scientific applications in geodesy and geodynamics] / Pascal Willis in Advances in space research, vol 45 n° 12 (15/06/2010)Permalink
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