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Gavdos /
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Gavdos
titre complet :
Establishment of an absolute sea level monitoring and altimeter calibration facility on the isle of Gavdos, south of the island of Crete, Greece
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Affiner la recherche Interroger des sources externesDORIS and GPS monitoring of the Gavdos calibration site in Crete / Pascal Willis in Advances in space research, vol 51 n° 8 (April 2013)
Titre : DORIS and GPS monitoring of the Gavdos calibration site in Crete Type de document : Article/Communication Auteurs : Pascal Willis 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]
Titre : Geodetic mobile solar spectrometer [GEMOSS] Type de document : Thèse/HDR Auteurs : Alexander Somieski, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2005 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 68 Projets : Gavdos / Importance : 205 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-11-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rayonnement électromagnétique
[Termes IGN] campagne d'expérimentation
[Termes IGN] positionnement par GPS
[Termes IGN] propagation troposphérique
[Termes IGN] spectromètre
[Termes IGN] spectroscopie
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] troposphèreIndex. décimale : 24.30 Rayonnement électromagnétique Résumé : (Auteur) The goal of this work was to develop a portable prototype of a solar spectrometer for the determination of tropospheric water vapor with a high precision as needed for geodetic applications. It was realized in the construction of the "GEodetic MObile Solar Spectrometer" (GEMOSS), which allows the simultaneous measurement of numerous single vibrational-rotational absorption lines in the wide wavelength range between 728 nm and 915 nm.
In order to achieve the wide wavelength range and the envisaged high measurement accuracy, a new optical layout of a high-resolution echelle spectrograph was applied. Furthermore, its instrumental characteristics were determined and considered in the analysis and simulation of the spectrum. Therefore, investigations were carried out concerning hardware requirements, appropriate spectral intervals, stabilization of the wavelength scale, determination of the apparatus function and stray light. In addition to the theoretical aspects of molecular absorption and emission in Earth's atmosphere, the meteorological model, ray tracing and the current state of molecular spectroscopie databases were examined. Furthermore, an algorithm for retrieving the integrated precipitable water vapor (PW) from GEMOSS spectra was developed. It is based on the "Differential Optical Absorption Spectroscopy" (DOAS) and includes the simulation of synthetic solar spectra. For the simulation the line strength parameters of H20 absorption lines were taken frorn the molecular spectroscopie database by the European Space Agency (ESA). Although the line strength parameters, which have a large impact on the accuracy of the simulated spectra and the retrieved PW, were improved during the last years, they still reveal significant errors. The wide spectral range of GEMOSS enables the accurate correction of those parameters using solar spectra measured at atmospheric conditions controlled by radiosonde soundings and a water vapor radiometer (WVR). For this purpose, a dedicated campaign was carried out at the meteorological station at Payerne (Switzerland) in May and June 2004. CEMOSS and a co-located WVR were deployed next to a Global Positioning Systern (GPS) receiver of the Automated GPS Network of Switzerland (AGNES). The acquired dataset was utilized to improve line strength parameters of 69 individual transitions of the H20 molecule between 732 mn and 906 nm.
In order to validate the performance of GEMOSS, a long-term series of PW was acquired at ETH Hönggerberg where a permanent GPS station (AGNES) is operated. With the utilization of up to 40 selected H20 absorption lines measured at the same time, an accuracy of the PW of 0.5 kg/m can be achieved. The comparison between GEMOSS and GPS revealed that GPS over-estimated the PW during the summer 2003 by about 2-3 kg/m . The same discrepancies were observed at Payerne in 2004 by comparing the GPS results with GEMOSS, WVR and radiosondes.
In the framework of the EU-project "GAVDOS", GEMOSS was operated under the track of the altimeter satellite Jason at Rethimnon (Crete, Greece) and at Fiskardo on the island of Kefalonia (Greece) in January and September in 2003. The highly precise PW measurements of GEMOSS were used to calibrate the on-board microwave radiometer of Jason (JMR). The integrated water vapor content which was simultaneously determined by GEMOSS and JMR agree at the 0.3-0.4 kg/m level. On the basis of these promising results GEMOSS can be considered as a novel portable tool for space-borne radiometer calibration and it will be deployed for further calibration of Jason in the future.Numéro de notice : 13265 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-004930678 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-68.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54946 Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 13265-01 24.30 Livre Centre de documentation Physique Disponible 13265-02 24.30 Livre Centre de documentation Physique Disponible
Titre : FTLRS support to the Gavdos project: tracking and positioning Type de document : Article/Communication Auteurs : Philippe Berio, Auteur ; Pierre Exertier, Auteur ; F. Pierron, Auteur ; J. Weick, Auteur ; David Coulot Editeur : Greenbelt : International Laser Ranging Service ILRS Année de publication : 2004 Conférence : IWLR 2004, 14th international workshop on laser ranging 07/06/2004 11/06/2004 San Fernando Espagne OA proceedings Projets : Gavdos / Importance : 7 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Station laser ultra-mobileRésumé : (auteur) In 2002, the FTLRS system performed a very successful six months campaign in Corsica for the altimeter calibration (CAL/VAL) of the JASON-1 satellite. The results have been presented on last laser workshop in Washington. After a short period of maintenance, this mobile station was again engaged in 2003 in the framework of the European GAVDOS project. The primary objective of this project is the establishment of an absolute sea level monitoring and altimeter calibration facility on the isle of GAVDOS, south of the island of Crete, Greece. The GAVDOS project will determine consistently and reliably (1) the altimeter biases and drifts for each satellite altimetric missions (TOPEX/Poseidon, JASON] , ENVISAT, ...) and (2) the bias among different missions. It will also determine the mean sea level and the earth's tectonic deformation field in the region of Crete. The FTLRS was set up in Crete (from April to October 2003 with a two month stop in July and August to avoid too warm days) in order to provide accurate data for altimeter calibrations, orbit validations and accurate positioning. In this talk, we will present the observational balance sheet of the FTLRS Crete campaign and the positioning results obtained with a combination of LAGEOS -1, -2, STELLA, and STARLETTE observations. This solution will be compared to a GPS one. Numéro de notice : C2004-045 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103032 Documents numériques
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