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Identifying a low-frequency oscillation in Galileo IOV pseudorange rates / Daniele Borio in GPS solutions, vol 20 n° 3 (July 2016)
[article]
Titre : Identifying a low-frequency oscillation in Galileo IOV pseudorange rates Type de document : Article/Communication Auteurs : Daniele Borio, Auteur ; Ciro Gioia, Auteur ; Neil Mitchison, Auteur Année de publication : 2016 Article en page(s) : pp 363 - 372 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] étalonnage en vol
[Termes IGN] Galileo
[Termes IGN] horloge atomique
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] oscillateur
[Termes IGN] performance
[Termes IGN] vitesseRésumé : (Auteur) Galileo, the European global navigation satellite system, is in its in-orbit validation phase and the four satellites which have been available for some months now have allowed a preliminary analysis of the system performance. Previous studies have showed that Galileo will be able to provide pseudorange measurements more accurate than those provided by GPS. However, a similar improvement was not found for pseudorange rate observations in the velocity domain. This fact stimulated additional analysis of the velocity domain, and, in particular, an unintended oscillatory component was identified as the main error source in the velocity solution. The magnitude of such oscillation is less than 10 cm/s, and its period is in the order of few minutes. A methodology was developed to identify oscillatory components in the Galileo IOV pseudorange rate observables, and it was verified that the measurements from Galileo IOV PFM and Galileo IOV FM2 are affected by a small oscillatory disturbance. This disturbance stems from the architecture adopted for combining the frequency references provided by the two active clocks present in the Galileo satellites. The issue has been solved in Galileo IOV FM3 and Galileo IOV FM4, and the oscillatory component has been eliminated. We also propose a methodology for removing this unwanted component from the final velocity solution and for determining the performance that Galileo will be able to achieve. The analysis shows that Galileo velocity solution will provide a root-mean-square error of about 8 cm/s even in the limited geometry conditions achieved using only four satellites. This shows the potential of Galileo also in the determination of user velocity. Numéro de notice : A2016-630 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0443-7 En ligne : http://dx.doi.org/10.1007/s10291-015-0443-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81833
in GPS solutions > vol 20 n° 3 (July 2016) . - pp 363 - 372[article]Impacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation / Junbo Shi in Journal of geodesy, vol 89 n° 8 (August 2015)
[article]
Titre : Impacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation Type de document : Article/Communication Auteurs : Junbo Shi, Auteur ; Chaoqian Xu, Auteur ; Yihe Li, Auteur ; Yang Gao, Auteur Année de publication : 2015 Article en page(s) : pp 747-756 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] erreur corrélée au temps
[Termes IGN] horloge atomique
[Termes IGN] orbite précise
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] retard troposphérique zénithal
[Termes IGN] temps réel
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Global Positioning System (GPS) has become a cost-effective tool to determine troposphere zenith total delay (ZTD) with accuracy comparable to other atmospheric sensors such as the radiosonde, the water vapor radiometer, the radio occultation and so on. However, the high accuracy of GPS troposphere ZTD estimates relies on the precise satellite orbit and clock products available with various latencies. Although the International GNSS Service (IGS) can provide predicted orbit and clock products for real-time applications, the predicted clock accuracy of 3 ns cannot always guarantee the high accuracy of troposphere ZTD estimates. Such limitations could be overcome by the use of the newly launched IGS real-time service which provides ∼5 cm orbit and 0.2–1.0 ns (an equivalent range error of 6–30 cm) clock products in real time. Considering the relatively larger magnitude of the clock error than that of the orbit error, this paper investigates the effect of real-time satellite clock errors on the GPS precise point positioning (PPP)-based troposphere ZTD estimation. Meanwhile, how the real-time satellite clock errors impact the GPS PPP-based troposphere ZTD estimation has also been studied to obtain the most precise ZTD solutions. First, two types of real-time satellite clock products are assessed with respect to the IGS final clock product in terms of accuracy and precision. Second, the real-time GPS PPP-based troposphere ZTD estimation is conducted using data from 34 selected IGS stations over three independent weeks in April, July and October, 2013. Numerical results demonstrate that the precision, rather than the accuracy, of the real-time satellite clock products impacts the real-time PPP-based ZTD solutions more significantly. In other words, the real-time satellite clock product with better precision leads to more precise real-time PPP-based troposphere ZTD solutions. Therefore, it is suggested that users should select and apply real-time satellite products with better clock precision to obtain more consistent real-time PPP-based ZTD solutions. Numéro de notice : A2015-374 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0811-7 Date de publication en ligne : 04/04/2015 En ligne : https://doi.org/10.1007/s00190-015-0811-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76852
in Journal of geodesy > vol 89 n° 8 (August 2015) . - pp 747-756[article]The clock at the center of the universe / Gavin Schrock in xyHt, vol 2015 n° 6 (June 2015)
[article]
Titre : The clock at the center of the universe Type de document : Article/Communication Auteurs : Gavin Schrock, Auteur Année de publication : 2015 Article en page(s) : pp 31 - 35 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] chronométrie
[Termes IGN] Global Positioning System
[Termes IGN] horloge atomique
[Termes IGN] temps universel coordonnéRésumé : (éditeur) To provide precise global time that's critical to our digital world, the United States Naval Observatory serves as the major node in a world-wide array of synchronized atomic clocks Numéro de notice : A2015-955 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT/SOCIETE NUMERIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79848
in xyHt > vol 2015 n° 6 (June 2015) . - pp 31 - 35[article]Estimating the short-term stability of in-orbit GNSS clocks : Following launch on GEO/GSO satellites / Dhaval Upadhyay in Inside GNSS, vol 10 n° 3 (May - June 2015)
[article]
Titre : Estimating the short-term stability of in-orbit GNSS clocks : Following launch on GEO/GSO satellites Type de document : Article/Communication Auteurs : Dhaval Upadhyay, Auteur ; Kriti Khatri, Auteur ; et al., Auteur Année de publication : 2015 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] éphémérides de satellite
[Termes IGN] horloge atomique
[Termes IGN] orbite géostationnaireRésumé : (éditeur) An engineering team proposes a method for determining the time of atomic clocks onboard satellites in geosynchronous and geostationary orbits when precise ephemeris data from ground monitoring stations are unavailable during initial checkout following launch. Numéro de notice : A2015-252 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://www.insidegnss.com/node/4503 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76296
in Inside GNSS > vol 10 n° 3 (May - June 2015)[article]Stochastic modeling of high-stability ground clocks in GPS analysis / Kang Wang in Journal of geodesy, vol 87 n° 5 (May 2013)
[article]
Titre : Stochastic modeling of high-stability ground clocks in GPS analysis Type de document : Article/Communication Auteurs : Kang Wang, Auteur ; Markus Rothacher, Auteur Année de publication : 2013 Article en page(s) : pp 427 - 437 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] horloge atomique
[Termes IGN] modèle stochastique
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation troposphérique
[Termes IGN] signal GPS
[Termes IGN] stabilité
[Termes IGN] temps atomique internationalRésumé : (Auteur) In current global positioning system (GPS) applications, receiver clocks are typically estimated epoch-wise in the data analyses even for clocks with high performance like Hydrogen-masers (H-maser). Applying an appropriate clock model for high-stability receiver clocks should, in view of the strong correlation between the station height and the clock parameters, significantly improve the positioning results. Recent experiments have shown that modeling the deterministic behavior of high-quality receiver clocks can improve the kinematic precise point positioning considerably. In this paper, well-behaving ground clocks are studied in detail applying constraints between subsequent and near-subsequent clock parameters. The influence of different weights for these relative clock constraints on the positioning quality, especially on the height, is investigated. For excellent clocks, an improvement of up to a factor of 3 can be obtained for the repeatability of the kinematic height estimates. This may be essential to detect small but sudden changes in the vertical component (e.g., caused by earthquakes). Troposphere zenith path delays (ZPD) are also heavily correlated with the receiver clock estimates and station heights. All these parameters are usually estimated simultaneously. We show that the use of relative clock constraints allows for a higher time resolution of the ZPD estimates (smaller than 2 h) without compromising the quality of the kinematic height estimates. Numéro de notice : A2013-253 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0616-5 Date de publication en ligne : 19/03/2013 En ligne : https://doi.org/10.1007/s00190-013-0616-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32391
in Journal of geodesy > vol 87 n° 5 (May 2013) . - pp 427 - 437[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2013051 SL Revue Centre de documentation Revues en salle Disponible Le positionnement par satellites et les maths / Jonathan Chenal in Tangente, n° 151 (mars-avril 2013)PermalinkPerformance of real-time precise point positioning / Junping Chen in Marine geodesy, vol 36 n° 1 (January - March 2013)PermalinkTime, atomics clocks and relativistic geodesy / Enrico Mai (2013)PermalinkGalileo, un système global de positionnement par satellites / Jonathan Chenal (2012)PermalinkDe la relativité au GPS / P. Spagnou (2012)PermalinkPrecise point positioning with GPS: A new approach for positioning, atmospheric studies, and signal analysis / Rodrigo Figueiredo Leandro (2009)PermalinkGalileo / François Barlier (2008)PermalinkTime for GIOVE-A: the onboard rubidium clock experiment / J. Hahn in GPS world, vol 18 n° 5 (May 2007)PermalinkGPS : Theory, algorithms and applications / Guochang Xu (2003)PermalinkUn système de positionnement Galileo / Academie de marine (2003)PermalinkNew IGS clock products: a global time transfer assessment / Jim Ray in GPS world, vol 13 n° 11 (November 2002)PermalinkContributions to GPS studies / Chris Rizos (1990)PermalinkUntersuchung zum rationellen Einsatz des GPS in kleinräumigen Netzen / H.J. Euler (1990)PermalinkZeit und Frequenzen im Meßverfahren der Geodäsie / W. Schlüter (1988)PermalinkGeodetic positioning using a Global Positioning System of satellites / P.J. Fell (1980)PermalinkLa mesure précise du temps / B. Decaux (1959)Permalink