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Ionosphere probing with simultaneous GNSS radio occultations / Viet-Cuong Pham in GPS solutions, vol 21 n° 1 (January 2017)
[article]
Titre : Ionosphere probing with simultaneous GNSS radio occultations Type de document : Article/Communication Auteurs : Viet-Cuong Pham, Auteur ; Jyh-Ching Juang, Auteur Année de publication : 2017 Article en page(s) : pp 101 - 109 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données GNSS
[Termes IGN] gradient ionosphèrique
[Termes IGN] inversion
[Termes IGN] occultation du signal
[Termes IGN] orbite basse
[Termes IGN] régularisation de Tychonoff
[Termes IGN] teneur totale en électronsRésumé : (Auteur) Radio occultation (RO) is a powerful technique for providing vertical profiles of refractivity, temperature, pressure, and water vapor of the neutral atmosphere and electron density of the ionosphere. The Abel inversion method which is based on the spherical symmetry assumption has been widely utilized to retrieve electron density profiles (EDPs) from RO measurements, which are available by observing Global Navigation Satellite System (GNSS) satellites from low-earth-orbit satellites. It is well known that the Abel inversion is subject to errors in the presence of ionospheric horizontal gradients. With the arrival of new navigation systems, the opportunities of establishing simultaneous GNSS RO events are increasing. We develop an improved Abel inversion technique that accounts for pairs of simultaneous RO events to relax the spherical symmetry assumption. Through the use of Tikhonov regularization, the problem is formulated so that numerical conditioning is improved and a priori information such as expected electron density, asymmetric factor, and vertical total electron content can be incorporated. Appropriate weighting can be determined to reflect the availability and quality of information. By balancing the reference data and measurements, the method thus paves a way for ionospheric probing in challenging geomagnetic conditions as both the EDP at the intersection and the horizontal gradients are retrieved. Simulation and experimental results are provided to show the effectiveness of the proposed method. The robustness and sensitivity of the proposed method are also assessed. Numéro de notice : A2017-014 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0501-1 Date de publication en ligne : 02/01/2016 En ligne : http://dx.doi./org/10.1007/s10291-015-0501-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83936
in GPS solutions > vol 21 n° 1 (January 2017) . - pp 101 - 109[article]Positional accuracy control in dense urban environment with low-cost receiver and multi-constellation GNSS / Yann Méneroux (2017)
Titre : Positional accuracy control in dense urban environment with low-cost receiver and multi-constellation GNSS Type de document : Article/Communication Auteurs : Yann Méneroux , Auteur ; Dinesh Manandhar, Auteur ; Saurav Ranjit, Auteur ; Guillaume Saint Pierre, Auteur ; Ryosuke Shibasaki, Auteur Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2017 Projets : 1-Pas de projet / Conférence : MGA 2017, 9th Multi-GNSS Asia Conference 09/10/2017 11/10/2017 Jakarta Indonésie Importance : 5 p. Note générale : bibliographie
références https://hal.archives-ouvertes.fr/hal-02193751Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] constellation
[Termes IGN] constellation BeiDou
[Termes IGN] constellation GLONASS
[Termes IGN] positionnement par GNSS
[Termes IGN] précision décimétrique
[Termes IGN] RTKLIBRésumé : (auteur) In this work, we investigate the effectiveness of a method leveraging multi-GNSS positioning with low-cost receiver to control the accuracy of a set of predefined points with short time acquisition and reduced sky view factor. Final accuracy is required to be sub-meter level. 20 positions located in Tokyo (Japan) have been observed for 6 minutes with a u-blox NEO M8T receiver and a L1-band antenna. Solutions have been computed with the free software RTKlib, for different combinations of satellite constellations. Eventually, we derived a probabilistic upper bound on the controlled points root mean square error (rmse) based on Rayleigh distribution and the central limit theorem. Results highlighted that completing GPS with one additional constellation may markedly reduce the predicted rmse as well as the convergence time. The gain in accuracy has been found to be more moderated when a maximal number of constellations is added, despite solution is reached much faster. We shall notice however that these findings may be dependent upon the selected mask angle for the computation. Some further analysis is also required to assess more precisely the respective contributions of GLONASS and Beidou systems in the overall enhancement. Numéro de notice : C2017-056 Affiliation des auteurs : LASTIG+Ext (2016-2019) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97092 Documents numériques
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Positional accuracy control ... - pdf auteurAdobe Acrobat PDF Assessment of vertical TEC mapping functions for space-based GNSS observations / Jiahao Zhong in GPS solutions, vol 20 n° 3 (July 2016)
[article]
Titre : Assessment of vertical TEC mapping functions for space-based GNSS observations Type de document : Article/Communication Auteurs : Jiahao Zhong, Auteur ; Jiuhou Lei, Auteur ; Xiankang Dou, Auteur ; Xinan Yue, Auteur Année de publication : 2016 Article en page(s) : pp 353 - 362 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] centroïde
[Termes IGN] coordonnées GNSS
[Termes IGN] hauteur de la couche ionosphérique
[Termes IGN] ionosphère
[Termes IGN] orbite basse
[Termes IGN] teneur totale en électrons
[Termes IGN] teneur verticale totale en électronsRésumé : (Auteur) The mapping function is commonly used to convert slant to vertical total electron content (TEC) based on the assumption that the ionospheric electrons concentrate in a layer. The height of the layer is called ionospheric effective height (IEH) or shell height. The mapping function and IEH are generally well understood for ground-based global navigation satellite system (GNSS) observations, but they are rarely studied for the low earth orbit (LEO) satellite-based TEC conversion. This study is to examine the applicability of three mapping functions for LEO-based GNSS observations. Two IEH calculating methods, namely the centroid method based on the definition of the centroid and the integral method based on one half of the total integral, are discussed. It is found that the IEHs increase linearly with the orbit altitudes ranging from 400 to 1400 km. Model simulations are used to compare the vertical TEC converted by these mapping functions and the vertical TEC directly calculated by the model. Our results illustrate that the F&K (Foelsche and Kirchengast) geometric mapping function together with the IEH from the centroid method is more suitable for the LEO-based TEC conversion, though the thin layer model along with the IEH of the integral method is more appropriate for the ground-based vertical TEC retrieval. Numéro de notice : A2016-629 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0444-6 En ligne : http://dx.doi.org/10.1007/s10291-015-0444-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81832
in GPS solutions > vol 20 n° 3 (July 2016) . - pp 353 - 362[article]Performance of real-time Precise Point Positioning using IGS real-time service / Mohamed Elsobeiey in GPS solutions, vol 20 n° 3 (July 2016)
[article]
Titre : Performance of real-time Precise Point Positioning using IGS real-time service Type de document : Article/Communication Auteurs : Mohamed Elsobeiey, Auteur ; Salim Al-Harbi, Auteur Année de publication : 2016 Article en page(s) : pp 565 - 571 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] correction du signal
[Termes IGN] horloge
[Termes IGN] international GPS service for geodynamics
[Termes IGN] orbite
[Termes IGN] positionnement ponctuel précis
[Termes IGN] temps réelRésumé : (Auteur) Until recently, the real-time IGS precise orbit and clock corrections were only available for the predicted part of the ultra-rapid solution. Whereas the accuracy of the ultra-rapid orbit is about 5 cm, the root mean square (RMS) of the respective satellite clock corrections is, unfortunately, about 3 ns (0.9 m). Hence, high accuracy Precise Point Positioning (PPP) applications can be achieved only in post-processing rather than in realtime. With the availability of the IGS real-time service (RTS), it becomes possible to obtain precise satellite orbit and satellite clock corrections in realtime with accuracy better than those of the ultra-rapid products. Recent research has shown that GPS IGS RTS products availability is at least 95 %, which makes it possible to perform real-time PPP with high accuracy. We study the performance of IGS RTS products in PPP by introducing a detailed description and analysis of IGS RTS products, describing the broadcasting of the IGS RTS orbit and clock corrections and their implementation as corrections to the broadcast ephemerides, and analyzing IGS RTS in PPP using several, randomly selected globally distributed IGS stations. It is shown that using IGS RTS products in real-time PPP can improve the solution RMS by about 50 % compared with the solution obtained from the predicted part of the IGS ultra-rapid products. Numéro de notice : A2016-635 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0467-z En ligne : http://dx.doi.org/10.1007/s10291-015-0467-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81837
in GPS solutions > vol 20 n° 3 (July 2016) . - pp 565 - 571[article]Stochastic modeling of triple-frequency BeiDou signals: estimation, assessment and impact analysis / Bofeng Li in Journal of geodesy, vol 90 n° 7 (July 2016)
[article]
Titre : Stochastic modeling of triple-frequency BeiDou signals: estimation, assessment and impact analysis Type de document : Article/Communication Auteurs : Bofeng Li, Auteur Année de publication : 2016 Article en page(s) : pp 593 – 610 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] données BeiDou
[Termes IGN] erreur instrumentale
[Termes IGN] modèle stochastique
[Termes IGN] orbite géostationnaire
[Termes IGN] positionnement par GNSS
[Termes IGN] récepteur trifréquence
[Termes IGN] résolution d'ambiguïtéRésumé : (auteur) Stochastic models are important in global navigation satellite systems (GNSS) estimation problems. One can achieve reliable ambiguity resolution and precise positioning only by use of a suitable stochastic model. The BeiDou system has received increased research focus, but based only on empirical stochastic models from the knowledge of GPS. In this paper, we will systematically study the estimation, assessment and impacts of a triple-frequency BeiDou stochastic model. In our estimation problem, a single-difference, geometry-free functional model is used to extract pure random noise. A very sophisticated structure of unknown variance matrix is designed to allow the estimation of satellite-specific variances, cross correlations between two arbitrary frequencies, as well as the time correlations for phase and code observations per frequency. In assessing the stochastic models, six data sets with four brands of BeiDou receivers on short and zero-length baselines are processed, and the results are compared. In impact analysis of stochastic model, the performance of integer ambiguity resolution and positioning are numerically demonstrated using a realistic stochastic model. The results from ultrashort (shorter than 10 m) and zero-length baselines indicate that BeiDou stochastic models are affected by both observation and receiver brands. The observation variances have been modeled by an elevation-dependent function, but the modeling errors for geostationary earth orbit (GEO) satellites are larger than for inclined geosynchronous satellite orbit (IGSO) and medium earth orbit (MEO) satellites. The stochastic model is governed by both the internal errors of the receiver and external errors at the site. Different receivers have different capabilities for resisting external errors. A realistic stochastic model is very important for achieving ambiguity resolution with a high success rate and small false alarm and for determining realistic variances for position estimates. To the best of our knowledge, this paper is the first comprehensive study on such stochastic models used specifically with BeiDou data. Numéro de notice : A2016-424 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0896-7 En ligne : http://dx.doi.org/10.1007/s00190-016-0896-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81318
in Journal of geodesy > vol 90 n° 7 (July 2016) . - pp 593 – 610[article]Absolute IGS antenna phase center model igs08.atx: status and potential improvements / Ralf Schmid in Journal of geodesy, vol 90 n° 4 (April 2016)PermalinkCODE’s new ultra-rapid orbit and ERP products for the IGS / Simon Lutz in GPS solutions, vol 20 n° 2 (April 2016)PermalinkInterferometric processing of Sentinel-1 TOPS Data / Néstor Yagüe-Martínez in IEEE Transactions on geoscience and remote sensing, vol 54 n° 4 (April 2016)PermalinkPrecise orbit determination based on raw GPS measurements / Norbert Zehentner in Journal of geodesy, vol 90 n° 3 (March 2016)PermalinkImproved ephemerides of natural satellites / Anonyme in Research*eu - results, n° 49 (February 2016)PermalinkPermalinkEléments de géodésie et de la théorie des moindres carrés / Abdelmajid Ben Hadj Salem (février 2016)PermalinkApplication d'algorithmes génétiques à la détermination d'orbites optimales pour GRASP / Arnaud Pollet in XYZ, n° 144 (septembre - novembre 2015)PermalinkSimulating the effects of quasar structure on parameters from geodetic VLBI / Stanislav S. Shabala in Journal of geodesy, vol 89 n° 9 (september 2015)PermalinkUsing lunar observations to validate in-flight calibrations of clouds and the earth's radiant energy system instruments / Janet L. Daniels in IEEE Transactions on geoscience and remote sensing, vol 53 n° 9 (September 2015)PermalinkUsing ionospheric corrections from the space-based augmentation systems for low earth orbiting satellites / Jeongrae Kim in GPS solutions, vol 19 n° 3 (July 2015)PermalinkThe impact of common versus separate estimation of orbit parameters on GRACE gravity field solutions / U. Meyer in Journal of geodesy, vol 89 n° 7 (July 2015)PermalinkEstimating 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)PermalinkAnalysis of orbital configurations for geocenter determination with GPS and low-Earth orbiters / Da Kuang in Journal of geodesy, vol 89 n° 5 (May 2015)PermalinkImpact of the atmospheric drag on Starlette, Stella, Ajisai, and Lares Orbits / Krzysztof Sosnica in Artificial satellites, vol 50 n° 1 (March 2015)PermalinkEvaluation and comparison of different radargrammetric approaches for Digital Surface Models generation from COSMO-SkyMed, TerraSAR-X, RADARSAT-2 imagery: Analysis of Beauport (Canada) test site / P. Capaldo in ISPRS Journal of photogrammetry and remote sensing, vol 100 (February 2015)PermalinkGalileo orbit determination using combined GNSS and SLR observations / Stefan Hackel in GPS solutions, vol 19 n° 1 (January 2015)PermalinkDetermination of precise satellite orbits and geodetic parameters using satellite laser ranging / Krzysztof Sosnica (2015)PermalinkPermalinkAssessment of observing time-variable gravity from GOCE GPS and accelerometer observations / Pieter N.A.M. Visser in Journal of geodesy, vol 88 n° 11 (November 2014)Permalink