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Revisit the calibration errors on experimental slant total electron content (TEC) determined with GPS / Wenfeng Nie in GPS solutions, vol 22 n° 3 (July 2018)  

Public [article]  inGPS solutions > vol 22 n° 3 (July 2018) Titre : Revisit the calibration errors on experimental slant total electron content (TEC) determined with GPS Type de document : Article/Communication Auteurs : Wenfeng Nie, Auteur ; Tianhe Xu, Auteur ; Adria Rovira-Garcia, Auteur ; José Miguel Juan Zornoza, Auteur ; Jaume Sanz, Auteur ; Guillermo Gonzalez-Casado, Auteur ; Chen Wu, Auteur ; Guochang Xu, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] code GPS [Termes IGN] coordonnées GPS [Termes IGN] erreur systématique [Termes IGN] étalonnage des données [Termes IGN] station permanente [Termes IGN] teneur totale en électrons Mots-clés libres : differential code bias Résumé : (Auteur) The calibration errors on experimental slant total electron content (TEC) determined with global positioning system (GPS) observations is revisited. Instead of the analysis of the calibration errors on the carrier phase leveled to code ionospheric observable, we focus on the accuracy analysis of the undifferenced ambiguity-fixed carrier phase ionospheric observable determined from a global distribution of permanent receivers. The results achieved are: (1) using data from an entire month within the last solar cycle maximum, the undifferenced ambiguity-fixed carrier phase ionospheric observable is found to be over one order of magnitude more accurate than the carrier phase leveled to code ionospheric observable and the raw code ionospheric observable. The observation error of the undifferenced ambiguity-fixed carrier phase ionospheric observable ranges from 0.05 to 0.11 total electron content unit (TECU) while that of the carrier phase leveled to code and the raw code ionospheric observable is from 0.65 to 1.65 and 3.14 to 7.48 TECU, respectively. (2) The time-varying receiver differential code bias (DCB), which presents clear day boundary discontinuity and intra-day variability pattern, contributes the most part of the observation error. This contribution is assessed by the short-term stability of the between-receiver DCB, which ranges from 0.06 to 0.17 TECU in a single day. (3) The remaining part of the observation errors presents a sidereal time cycle pattern, indicating the effects of the multipath. Further, the magnitude of the remaining part implies that the code multipath effects are much reduced. (4) The intra-day variation of the between-receiver DCB of the collocated stations suggests that estimating DCBs as a daily constant can have a mis-modeling error of at least several tenths of 1 TECU. Numéro de notice : A2018-372 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0753-7 Date de publication en ligne : 26/06/2018 En ligne : https://doi.org/10.1007/s10291-018-0753-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90766 [article]

Accuracy of ionospheric models used in GNSS and SBAS: methodology and analysis / Adria Rovira-Garcia in Journal of geodesy, vol 90 n° 3 (March 2016)  

Public [article]  inJournal of geodesy > vol 90 n° 3 (March 2016) . - pp 229 - 240 Titre : Accuracy of ionospheric models used in GNSS and SBAS: methodology and analysis Type de document : Article/Communication Auteurs : Adria Rovira-Garcia, Auteur ; José Miguel Juan, Auteur ; Jaume Sanz, Auteur ; Guillermo Gonzalez-Casado, Auteur ; D. Ibáñez, Auteur Année de publication : 2016 Article en page(s) : pp 229 - 240 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] caractérisation [Termes IGN] données GNSS [Termes IGN] modèle ionosphérique [Termes IGN] phase GNSS Résumé : (auteur) The characterization of the accuracy of ionospheric models currently used in global navigation satellite systems (GNSSs) is a long-standing issue. The characterization remains a challenging problem owing to the lack of sufficiently accurate slant ionospheric determinations to be used as a reference. The present study proposes a methodology based on the comparison of the predictions of any ionospheric model with actual unambiguous carrier-phase measurements from a global distribution of permanent receivers. The differences are separated as hardware delays (a receiver constant plus a satellite constant) per day. The present study was conducted for the entire year of 2014, i.e. during the last solar cycle maximum. The ionospheric models assessed are the operational models broadcast by the global positioning system (GPS) and Galileo constellations, the satellite-based augmentation system (SBAS) (i.e. European Geostationary Navigation Overlay System (EGNOS) and wide area augmentation system (WAAS)), a number of post-process global ionospheric maps (GIMs) from different International GNSS Service (IGS) analysis centres (ACs) and, finally, a more sophisticated GIM computed by the research group of Astronomy and GEomatics (gAGE). Ionospheric models based on GNSS data and represented on a grid (IGS GIMs or SBAS) correct about 85 % of the total slant ionospheric delay, whereas the models broadcasted in the navigation messages of GPS and Galileo only account for about 70 %. Our gAGE GIM is shown to correct 95 % of the delay. The proposed methodology appears to be a useful tool to improve current ionospheric models. Numéro de notice : A2016-248 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0868-3 Date de publication en ligne : 29/10/2015 En ligne : https://doi.org/10.1007/s00190-015-0868-3 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80755 [article]

A worldwide ionospheric model for fast precise point positioning / Adria Rovira-Garcia in IEEE Transactions on geoscience and remote sensing, vol 53 n° 8 (August 2015)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 53 n° 8 (August 2015) . - pp 4596 - 4604 Titre : A worldwide ionospheric model for fast precise point positioning Type de document : Article/Communication Auteurs : Adria Rovira-Garcia, Auteur ; José Miguel Juan, Auteur ; Jaume Sanz, Auteur ; Guillermo Gonzalez-Casado, Auteur Année de publication : 2015 Article en page(s) : pp 4596 - 4604 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] correction ionosphérique [Termes IGN] modèle ionosphérique [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] résolution d'ambiguïté [Termes IGN] temps réel [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) Fast precise point positioning (Fast-PPP) is a satellite-based navigation technique using an accurate real-time ionospheric modeling to achieve high accuracy quickly. In this paper, an end-to-end performance assessment of Fast-PPP is presented in near-maximum Solar Cycle conditions; from the accuracy of the Central Processing Facility corrections, to the user positioning. A planetary distribution of permanent receivers including challenging conditions at equatorial latitudes, is navigated in pure kinematic mode, located from 100 to 1300 km away from the nearest reference station used to derive the ionospheric model. It is shown that satellite orbits and clocks accurate to few centimeters and few tenths of nanoseconds, used in conjunction with an ionosphere with an accuracy better than 1 Total Electron Content Unit (16 cm in L1) reduce the convergence time of dual-frequency Precise Point Positioning, to decimeter-level (3-D) solutions. Horizontal convergence times are shortened 40% to 90%, whereas the vertical components are reduced by 20% to 60%. A metric to evaluate the quality of any ionospheric model for Global Navigation Satellite System is also proposed. The ionospheric modeling accuracy is directly translated to mass-market single-frequency users. The 95th percentile of horizontal and vertical accuracies is shown to be 40 and 60 cm for single-frequency users and 9 and 16 cm for dual-frequency users. The tradeoff between the formal and actual positioning errors has been carefully studied to set realistic confidence levels to the corrections. Numéro de notice : A2015-389 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2015.2402598 En ligne : https://doi.org/10.1109/TGRS.2015.2402598 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76869 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-2015081	RAB	Revue	Centre de documentation	En réserve L003	Disponible

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]

Exemplaires(1)

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