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The ionosphere : effects, GPS modeling and the benefits for space geodetic techniques / Manuel Hernández-Pajares in Journal of geodesy, vol 85 n° 12 (December 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 12 (December 2011) . - pp 887 - 907 Titre : The ionosphere : effects, GPS modeling and the benefits for space geodetic techniques Type de document : Article/Communication Auteurs : Manuel Hernández-Pajares, Auteur ; M. Juan, Auteur ; Jaume Sanz, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 887 - 907 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] données GNSS [Termes IGN] données GPS [Termes IGN] ionosphère [Termes IGN] modèle ionosphérique [Termes IGN] perturbation ionosphérique [Termes IGN] propagation du signal [Termes IGN] qualité du signal [Termes IGN] signal GNSS [Termes IGN] signal GPS [Termes IGN] surveillance [Termes IGN] teneur totale en électrons Résumé : (Auteur) The main goal of this paper is to provide a summary of our current knowledge of the ionosphere as it relates to space geodetic techniques, especially the most informative technology, global navigation satellite systems (GNSS), specifically the fully deployed and operational global positioning system (GPS). As such, the main relevant modeling points are discussed, and the corresponding results of ionospheric monitoring are related, which were mostly computed using GPS data and based on the direct experience of the authors. We address various phenomena such as horizontal and vertical ionospheric morphology in quiet conditions, traveling ionospheric disturbances, solar flares, ionospheric storms and scintillation. Finally, we also tackle the question of how improved knowledge of ionospheric conditions, especially in terms of an accurate understanding of the distribution of free electrons, can improve space geodetic techniques at different levels, such as higher-order ionospheric effects, precise GNSS navigation, single-antenna GNSS orientation and real-time GNSS meteorology. Numéro de notice : A2011-501 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0508-5 Date de publication en ligne : 11/09/2011 En ligne : https://doi.org/10.1007/s00190-011-0508-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31395 [article]

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The international reference ionosphere today and in the future / Dieter Bilitza in Journal of geodesy, vol 85 n° 12 (December 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 12 (December 2011) . - pp 909 - 920 Titre : The international reference ionosphere today and in the future Type de document : Article/Communication Auteurs : Dieter Bilitza, Auteur ; L. Mckinnel, Auteur ; Bodo Reinisch, Auteur ; T. Fuller-Rowell, Auteur Année de publication : 2011 Article en page(s) : pp 909 - 920 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] International Reference Ionosphere [Termes IGN] ionosphère [Termes IGN] modèle empirique [Termes IGN] modèle ionosphérique [Termes IGN] teneur totale en électrons Résumé : (Auteur) The international reference ionosphere (IRI) is the internationally recognized and recommended standard for the specification of plasma parameters in Earth’s ionosphere. It describes monthly averages of electron density, electron temperature, ion temperature, ion composition, and several additional parameters in the altitude range from 60 to 1,500 km. A joint working group of the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) is in charge of developing and improving the IRI model. As requested by COSPAR and URSI, IRI is an empirical model being based on most of the available and reliable data sources for the ionospheric plasma. The paper describes the latest version of the model and reviews efforts towards future improvements, including the development of new global models for the F2 peak density and height, and a new approach to describe the electron density in the topside and plasmasphere. Our emphasis will be on the electron density because it is the IRI parameter most relevant to geodetic techniques and studies. Annual IRI meetings are the main venue for the discussion of IRI activities, future improvements, and additions to the model. A new special IRI task force activity is focusing on the development of a real-time IRI (RT-IRI) by combining data assimilation techniques with the IRI model. A first RT-IRI task force meeting was held in 2009 in Colorado Springs. We will review the outcome of this meeting and the plans for the future. The IRI homepage is at http://www.IRI.gsfc.nasa.gov. Numéro de notice : A2011-502 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0427-x Date de publication en ligne : 10/11/2011 En ligne : https://doi.org/10.1007/s00190-010-0427-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31396 [article]

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Validation of international reference ionosphere models using in situ measurements from GRACE K-band ranging system and CHAMP planar Langmuir probe / C. Lee in Journal of geodesy, vol 85 n° 12 (December 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 12 (December 2011) . - pp 921 - 929 Titre : Validation of international reference ionosphere models using in situ measurements from GRACE K-band ranging system and CHAMP planar Langmuir probe Type de document : Article/Communication Auteurs : C. Lee, Auteur ; S. Han, Auteur ; Dieter Bilitza, Auteur ; J. Chung, Auteur Année de publication : 2011 Article en page(s) : pp 921 - 929 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse comparative [Termes IGN] analyse diachronique [Termes IGN] atmosphère solaire [Termes IGN] bande K [Termes IGN] données CHAMP [Termes IGN] données GRACE [Termes IGN] International Reference Ionosphere [Termes IGN] modèle ionosphérique [Termes IGN] teneur totale en électrons [Termes IGN] zone équatoriale [Termes IGN] zone polaire Résumé : (Auteur) The in situ measurements of electron contents from GRACE K-band (dual-frequency) ranging system and CHAMP planar Langmuir probe were used to validate the international reference ionosphere (IRI) models. The comparison using measurements from year 2003 to 2007 shows a general agreement between data and the model outputs. The improvement in the newer IRI model (IRI-2007) is evident with the measurements from the GRACE satellites orbiting at the higher altitude. We present the comparison between the models and data comprehensively for various cases in solar activity, local time, season, and latitude. The IRI models do not well predict the electron density in the years 2006 and later, when the solar activity is extremely low. The IRI models generally overestimate the electron density during local winter while they underestimate during local summer. In the equatorial region, the large difference at local sunrise lasts for all years and all seasons. The IRI models do not perform well in predicting the anomaly in the polar region such as the Weddell Sea Anomaly. These discrepancies are likely due to smoothed (12-month averaged) solar activity indices used in the IRI models and due to insufficient spherical harmonic representation not able to capture small spatial scales. In near future, further improvement on the IRI models is expected by assimilating those in situ satellite data by implementing higher resolution (spatial and temporal) parameterizations. Numéro de notice : A2011-503 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0442-6 Date de publication en ligne : 30/11/2019 En ligne : https://doi.org/10.1007/s00190-011-0442-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31397 [article]

Exemplaires(1)

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Combination of different space-geodetic observations for regional ionosphere modeling / D. Dettmering in Journal of geodesy, vol 85 n° 12 (December 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 12 (December 2011) . - pp 989 - 998 Titre : Combination of different space-geodetic observations for regional ionosphere modeling Type de document : Article/Communication Auteurs : D. Dettmering, Auteur ; M. Schmidt, Auteur ; Robert Heinkelmann, Auteur ; Manuela Seitz, Auteur Année de publication : 2011 Article en page(s) : pp 989 - 998 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse combinatoire (maths) [Termes IGN] B-Spline [Termes IGN] correction ionosphérique [Termes IGN] ionosphère [Termes IGN] modèle ionosphérique [Termes IGN] teneur totale en électrons Résumé : (Auteur) Most of the space-geodetic observation techniques can be used for modeling the distribution of free electrons in the Earth’s ionosphere. By combining different techniques one can take advantage of their different spatial and temporal distributions as well as their different observation characteristics and sensitivities concerning ionospheric parameter estimation. The present publication introduces a procedure for multi-dimensional ionospheric modeling. The model consists of a given reference part and an unknown correction part expanded in terms of B-spline functions. This approach is used to compute regional models of Vertical Total Electron Content (VTEC) based on the International Reference Ionosphere (IRI 2007) and GPS observations from terrestrial Global Navigation Satellite System (GNSS) reference stations, radio occultation data from Low Earth Orbiters (LEOs), dual-frequency radar altimetry measurements, and data obtained by Very Long Baseline Interferometry (VLBI). The approach overcomes deficiencies in the climatological IRI model and reaches the same level of accuracy than GNSS-based VTEC maps from IGS. In areas without GNSS observations (e.g., over the oceans) radio occultations and altimetry provide valuable measurements and further improve the VTEC maps. Moreover, the approach supplies information on the offsets between different observation techniques as well as on their different sensitivity for ionosphere modeling. Altogether, the present procedure helps to derive improved ionospheric corrections (e.g., for one-frequency radar altimeters) and at the same time it improves our knowledge on the Earth’s ionosphere. Numéro de notice : A2011-504 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0423-1 Date de publication en ligne : 10/11/2011 En ligne : https://doi.org/10.1007/s00190-010-0423-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31398 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2011121	RAB	Revue	Centre de documentation	En réserve L003	Disponible