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Global ionosphere maps based on GNSS, satellite altimetry, radio occultation and DORIS / Peng Chen in GPS solutions, vol 21 n° 2 (April 2017)  

Public [article]  inGPS solutions > vol 21 n° 2 (April 2017) . - pp 639 – 650 Titre : Global ionosphere maps based on GNSS, satellite altimetry, radio occultation and DORIS Type de document : Article/Communication Auteurs : Peng Chen, Auteur ; Yi Bin Yao, Auteur ; Wanqiang Yao, Auteur Année de publication : 2017 Article en page(s) : pp 639 – 650 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées GNSS [Termes IGN] données altimétriques [Termes IGN] données DORIS [Termes IGN] ionosphère [Termes IGN] modèle ionosphérique [Termes IGN] occultation du signal [Termes IGN] radiooccultation [Termes IGN] teneur verticale totale en électrons Résumé : (auteur) Global ionosphere maps (GIMs) provided by the global navigation satellite systems (GNSS) data are essential in ionospheric research as the source of the global vertical total electron content (VTEC). However, conventional GIMs experience lower accuracy and reliability from uneven distribution of GNSS tracking stations, especially in ocean areas with few tracking stations. The orbits of ocean altimetry satellite cover vast ocean areas and can directly provide VTEC at nadir with two different wavelengths of radio waves. Radio occultation observations and the beacons of Doppler orbitography and radio positioning integrated by satellite (DORIS) are evenly distributed globally. Satellite altimetry, radio occultation and DORIS can compensate GNSS data in ocean areas, allowing a more accurate and reliable GIMs to be formed with the integration of these observations. This study builds GIMs with temporal intervals of 2 h by the integration of GNSS, satellite altimetry, radio occultation and DORIS data. We investigate the integration method for multi-source data and used the data in May 2013 to validate the effectiveness of integration. Result shows that VTEC changes by −11.0 to −7.0 TECU after the integration of satellite altimetry, radio occultation and DORIS data. The maximum root mean square decreases by 5.5 TECU, and the accuracy of GIMs in ocean areas improves significantly. Numéro de notice : A2017-216 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-016-0554-9 En ligne : http://dx.doi.org/10.1007/s10291-016-0554-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85089 [article]

GNSS interferometric radio occultation / Manuel Martín-Neira in IEEE Transactions on geoscience and remote sensing, vol 54 n° 9 (September 2016)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 54 n° 9 (September 2016) . - pp 5285 - 5300 Titre : GNSS interferometric radio occultation Type de document : Article/Communication Auteurs : Manuel Martín-Neira, Auteur Année de publication : 2016 Article en page(s) : pp 5285 - 5300 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] altimétrie [Termes IGN] autocorrélation [Termes IGN] autocorrélation spatiale [Termes IGN] diffusomètre [Termes IGN] estimation des paramètres [Termes IGN] interférométrie [Termes IGN] radiooccultation [Termes IGN] rapport signal sur bruit [Termes IGN] réflectométrie par GNSS [Termes IGN] signal GNSS Résumé : (Auteur) GNSS Reflectometry, Scatterometry and Radio Occultation aboard ISS is the mission concept under study within the European Space Agency. Its core payload consists of an interferometric GNSS-Reflectometry ocean altimeter/scatterometer which does not need to generate any clean replicas of the GNSS codes for its operation. This paper describes a new interferometric technique by which such payload could also perform radio occultation as an add-on, without requiring any additional hardware resources, like the generation of clean code replicas or a storage of them. Two possibilities are studied. The first one consists of performing the complex autocorrelation function of the received signal transmitted by a rising or setting GNSS satellite. The autocorrelation function is evaluated around time epochs that are multiples of the period of suitable codes found in the modulation of the navigation signals. Satellite discrimination has to be performed spatially, through the antenna pattern. The second possibility consists in acquiring the reference signal separately from the occultation event which, in turn, has two options depending upon the geometry at which the reference is recorded: zenithal and top of the atmosphere. The signal-to-noise ratio, the satellite discrimination, and the impact of clock errors are assessed. Numéro de notice : A2016-898 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2559944 En ligne : https://doi.org/10.1109/TGRS.2016.2559944 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83091 [article]

A technique for routinely updating the ITU-R database using radio occultation electron density profiles / Claudio Brunini in Journal of geodesy, vol 87 n° 9 (September 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 9 (September 2013) . - pp 813 - 823 Titre : A technique for routinely updating the ITU-R database using radio occultation electron density profiles Type de document : Article/Communication Auteurs : Claudio Brunini, Auteur ; Francisco Azpilicueta, Auteur ; Bruno Nava, Auteur Année de publication : 2013 Article en page(s) : pp 813 - 823 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] Formosat / COSMIC [Termes IGN] International Reference Ionosphere [Termes IGN] ionosphère [Termes IGN] mise à jour de base de données [Termes IGN] modèle ionosphérique [Termes IGN] orbite basse [Termes IGN] radiooccultation [Termes IGN] teneur totale en électrons [Termes IGN] trajectographie par GPS Résumé : (Auteur) Well credited and widely used ionospheric models, such as the International Reference Ionosphere or NeQuick, describe the variation of the electron density with height by means of a piecewise profile tied to the F2-peak parameters: the electron density, NmF2 , and the height, hmF2. Accurate values of these parameters are crucial for retrieving reliable electron density estimations from those models. When direct measurements of these parameters are not available, the models compute the parameters using the so-called ITU-R database, which was established in the early 1960s. This paper presents a technique aimed at routinely updating the ITU-R database using radio occultation electron density profiles derived from GPS measurements gathered from low Earth orbit satellites. Before being used, these radio occultation profiles are validated by fitting to them an electron density model. A re-weighted Least Squares algorithm is used for down-weighting unreliable measurements (occasionally, entire profiles) and to retrieve NmF2 and hmF2 values—together with their error estimates—from the profiles. These values are used to monthly update the database, which consists of two sets of ITU-R-like coefficients that could easily be implemented in the IRI or NeQuick models. The technique was tested with radio occultation electron density profiles that are delivered to the community by the COSMIC/FORMOSAT-3 mission team. Tests were performed for solstices and equinoxes seasons in high and low-solar activity conditions. The global mean error of the resulting maps—estimated by the Least Squares technique—is between 0.5*1010 and 3.6*1010 elec/m-3 for the F2-peak electron density (which is equivalent to 7 % of the value of the estimated parameter) and from 2.0 to 5.6 km for the height ( ~ 2 %). Numéro de notice : A2013-563 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0648-x Date de publication en ligne : 13/06/2013 En ligne : https://doi.org/10.1007/s00190-013-0648-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32699 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2013091	SL	Revue	Centre de documentation	Revues en salle	Disponible

vol 46 n° 11 Tome 1 - November 2008 - Special section on meteorology, climate, ionosphere, geodesy and reflections from the ocean surfaces: studies by radio occultation methods (Bulletin de IEEE Transactions on geoscience and remote sensing) / Geoscience and remote sensing society  

Public [n° ou bulletin]  est un bulletin de IEEE Transactions on geoscience and remote sensing / IEEE Geoscience and remote sensing society (Etats-Unis) (1986 -)   Titre : vol 46 n° 11 Tome 1 - November 2008 - Special section on meteorology, climate, ionosphere, geodesy and reflections from the ocean surfaces: studies by radio occultation methods Type de document : Périodique Auteurs : Geoscience and remote sensing society, Auteur Année de publication : 2008 Importance : 250 p. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Télédétection [Termes IGN] Formosat / COSMIC [Termes IGN] météorologie [Termes IGN] radiooccultation [Termes IGN] réflectance [Termes IGN] surface de la mer [Termes IGN] télédétection spatiale [Termes IGN] traitement d'image Numéro de notice : 065-0811A Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Numéro de périodique En ligne : http://ieeexplore.ieee.org/xpl/tocresult.jsp?isnumber=4685926&punumber=36 Format de la ressource électronique : URL sommaire Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=9541 [n° ou bulletin]

Contient

• Sea-surface polarization ratio from Envisat ASAR AP Data / H. Jonhsen in IEEE Transactions on geoscience and remote sensing, vol 46 n° 11 Tome 1 (November 2008)  

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-08111A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Weather Report : Meteorological applications of GNSS from space and on the ground / P. Poli in Inside GNSS, vol 3 n° 8 (November - December 2008)    

Public [article]  inInside GNSS > vol 3 n° 8 (November - December 2008) . - 10 p. ; pp 30 - 39 Titre : Weather Report : Meteorological applications of GNSS from space and on the ground Type de document : Article/Communication Auteurs : P. Poli, Auteur ; J. Pailleux, Auteur ; Véronique Ducrocq, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : 10 p. ; pp 30 - 39 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] changement climatique [Termes IGN] prévision météorologique [Termes IGN] propagation ionosphérique [Termes IGN] propagation troposphérique [Termes IGN] radiooccultation [Termes IGN] signal GNSS Résumé : (Auteur) Les auteurs de Météo-France et du CNES décrivent les techniques et applications qui utilisent le comportement de la propagation du signal GNSS au travers de l'atmosphère terrestre pour prédire le temps et surveiller le changement climatique. Numéro de notice : A2008-682 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://www.insidegnss.com/node/920 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33446 [article]

Documents numériques

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Satellite constellation with direct radio measurements for atmospheric studies : WATS mission case / G. Alberti in International Journal of Remote Sensing IJRS, vol 25 n° 18 (September 2004)  

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Single frequency processing of atmospheric radio occultations / M. De La Torre Juarez in International Journal of Remote Sensing IJRS, vol 25 n° 18 (September 2004)  

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Geophysical distributions of occultations of GPS satellites viewed from a low Earth orbiting satellite / D.M. O'Brien (1998)

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The application of spaceborne atmospheric limb sounding and global change monitoring / W.G. Melbourne (1994)

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