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Performance of 6 different global navigation satellite system receivers at low latitude under moderate and strong scintillation / E.R. de Paula in Earth and space science, vol 8 n° 2 (February 2021)
[article]
Titre : Performance of 6 different global navigation satellite system receivers at low latitude under moderate and strong scintillation Type de document : Article/Communication Auteurs : E.R. de Paula, Auteur ; A.R.F. Martinon, Auteur ; A.O. Moraes, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° e2020EA001314 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Brésil
[Termes IGN] correction ionosphérique
[Termes IGN] phase GNSS
[Termes IGN] positionnement par GNSS
[Termes IGN] récepteur GNSS
[Termes IGN] scintillation
[Termes IGN] signal GNSSRésumé : (auteur) After sunset, in the equatorial regions ionospheric plasma irregularities are generated due to the generalized Rayleigh‐Taylor instability. Under favorable conditions these irregularities develop in the equatorial region while mapping along the magnetic field lines giving rise to large plasma depletion structures called Equatorial Plasma Bubbles with embedded smaller structures on their walls. The global navigation satellite system (GNSS) L1 band frequency is sensitive to irregularities of the size of 300–400 m in the first Fresnel zone, which cause scattering and diffraction of the signal and produce amplitude and/or phase scintillation. Severe scintillation of GNSS signals can in turn cause loss of lock of the receiver code and/or carrier loops. As a result, GNSS navigation and positioning solution can be adversely affected by the ionospheric scintillation. There are multiple GNSS receivers designed to monitor scintillations. These receivers are based on different hardware designs and use different methodologies to process the raw data. When using simultaneous data from different GNSS scintillation monitors it is important to evaluate and compare their performances under similar scintillation conditions. The scintillation monitoring techniques may be useful for many applications that use GNSS signal. The aim of this work is to evaluate the performance of six different GNSS receivers located at São José dos Campos (23.1°S, 45.8°W, dip latitude 17.3°S) during moderate and strong scintillation activity. The amplitude (S4) and phase (σϕ) scintillation indexes from these receivers were analyzed and compared for the nights February 20–21 and November 27–28, 2013. Numéro de notice : A2021-255 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1029/2020EA001314 Date de publication en ligne : 29/12/2020 En ligne : https://doi.org/10.1029/2020EA001314 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97281
in Earth and space science > vol 8 n° 2 (February 2021) . - n° e2020EA001314[article]A practical method for calculating reliable integer float estimator in GNSS precise positioning / Xianwen Yu in Survey review, Vol 53 n° 377 (February 2021)
[article]
Titre : A practical method for calculating reliable integer float estimator in GNSS precise positioning Type de document : Article/Communication Auteurs : Xianwen Yu, Auteur ; Siqi Xia, Auteur ; Wang Gao, Auteur Année de publication : 2021 Article en page(s) : pp 97 - 107 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] estimateur
[Termes IGN] matrice
[Termes IGN] positionnement par GNSS
[Termes IGN] précision du positionnement
[Termes IGN] résolution d'ambiguïté
[Termes IGN] varianceRésumé : (auteur) To overcome the problem that a fixed estimator is contaminated by a system error for the ambiguity be misjudged in the GNSS precise positioning, a reliable integer float estimator is recommended. Accordingly, the method for determining a finite number of integer vectors based on a given reliability probability is proposed, the formula for calculating the variance matrix of the recommended estimator is derived, and the judgment method of the estimator’s availability is proposed. The detailed process and the effect of the method are also demonstrated using examples to facilitate user application. Numéro de notice : A2021-193 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2020.1718268 Date de publication en ligne : 29/01/2020 En ligne : https://doi.org/10.1080/00396265.2020.1718268 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97127
in Survey review > Vol 53 n° 377 (February 2021) . - pp 97 - 107[article]Benefits from a multi-receiver architecture for GNSS RTK positioning and attitude determination / Xiao Hu (2021)
Titre : Benefits from a multi-receiver architecture for GNSS RTK positioning and attitude determination Type de document : Thèse/HDR Auteurs : Xiao Hu, Auteur ; Christophe Macabiau, Directeur de thèse ; Paul Thevenon, Directeur de thèse Editeur : Toulouse : Université de Toulouse Année de publication : 2021 Importance : 217 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse en vue de l'obtention du Doctorat de l'Université de Toulouse délivré par l'institut National Polytechnique de ToulouseLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] capteur d'orientation
[Termes IGN] dégradation du signal
[Termes IGN] erreur de mesure
[Termes IGN] filtre de Kalman
[Termes IGN] mesurage de phase
[Termes IGN] milieu urbain
[Termes IGN] modèle stochastique
[Termes IGN] orientation de véhicule
[Termes IGN] phase GNSS
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] récepteur GPS
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GNSS
[Termes IGN] trajet multipleIndex. décimale : THESE Thèses et HDR Résumé : (auteur) Precise positioning with a stand-alone GPS receiver or using differential corrections is known to be strongly degraded in an urban or sub-urban environment due to frequent signal masking, strong multipath effect, frequent cycle slips on carrier phase, etc. The objective of this Ph.D. thesis is to
explore the possibility of achieving precise positioning with a low-cost architecture using multiple installed low-cost single-frequency receivers with known geometry whose one of them is RTK positioned w.r.t an external reference receiver. This setup is thought to enable vehicle attitude determination and RTK performance amelioration. In this thesis, we firstly proposed a method that includes an array of receivers with known geometry to enhance the performance of the RTK in different environments. Taking advantage of the attitude information and the known geometry of the installed array of receivers, the improvement of some internal steps of RTK w.r.t an external reference receiver can be achieved. The navigation module to be implemented in this work is an Extended Kalman Filter (EKF). The performance of a proposed two-receiver navigation architecture is then studied to quantify the improvements brought by the measurement redundancy. This concept is firstly tested on a simulator in order to validate the proposed algorithm and to give a reference result of our multi-receiver system’s performance. The pseudo-range measurements and carrier phase measurements mathematical models are implemented in a realistic simulator. Different
scenarios are conducted, including varying the distance between the 2 antennas of the receiver array, the satellite constellation geometry, and the amplitude of the noise measurement, in order to determine the influence of the use of an array of receivers. The simulation results show that our multi-receiver RTK system w.r.t an external reference receiver is more robust to noise and degraded satellite geometry, in terms of ambiguity fixing rate, and gets a better position accuracy under the same conditions when compared with the single receiver system. Additionally, our method achieves a relatively accurate estimation of the attitude of the vehicle which provides additional information beyond the positioning. In order to optimize our processing, the correlation of the measurement errors affecting observations taken by our array of receivers has been determined. Then, the performance of our real-time single frequency cycle-slip detection and repair algorithm has been assessed. These two investigations yielded important information so as to tune our Kalman Filter. The results obtained from the simulation made us eager to use actual data to verify and improve our multi-receiver RTK and attitude system. Tests based on real data collected around Toulouse, France, are used to test the performance of the whole methodology, where different scenarios are conducted, including varying the distance between the 2 antennas of the receiver array as well as the environmental conditions (open sky, suburban, and constrained urban environments). The thesis also tried to take advantage of a dual GNSS constellation, GPS and Galileo, to further strengthen the position solution and the reliable use of carrier phase measurements. The results show that our multi-receiver RTK system is more robust to degraded GNSS environments. Our experiments correlate favorably with our previous simulation results and further support the idea of using an array of receivers with known geometry to improve the RTK performance.Note de contenu : 1- Introduction
2- GNSS functional and stochastic model
3- GNSS-based precise positioning and attitude estimation
4- Proposed multi-receiver architecture for GNSS precise positioning and attitude estimation
5- Simulation results and performance analysis
6- real data tests and results
7- Conclusions and perspectivesNuméro de notice : 15216 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de Doctorat : Informatique et Télécommunications : Toulouse : 2021 Organisme de stage : ENAC-LAB DOI : sans En ligne : https://hal.science/tel-03506304/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100473 Copula-based modeling of dependence structure in geodesy and GNSS applications: case study for zenith tropospheric delay in complex terrain / Roya Mousavian in GPS solutions, vol 25 n° 1 (January 2021)
[article]
Titre : Copula-based modeling of dependence structure in geodesy and GNSS applications: case study for zenith tropospheric delay in complex terrain Type de document : Article/Communication Auteurs : Roya Mousavian, Auteur ; Christof Lorenz, Auteur ; Masoud Mashhadi Hossainali, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 12 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] corrélation croisée normalisée
[Termes IGN] dissymétrie
[Termes IGN] données GNSS
[Termes IGN] Europe centrale
[Termes IGN] modèle atmosphérique
[Termes IGN] prévision météorologique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] série temporelleRésumé : (auteur) Modeling and understanding the statistical relationships between geophysical quantities is a crucial prerequisite for many geodetic applications. While these relationships can depend on multiple variables and their interactions, commonly used scalar methods like the (cross) correlation are only able to describe linear dependencies. However, particularly in regions with complex terrain, the statistical relationships between variables can be highly nonlinear and spatially heterogeneous. Therefore, we introduce Copula-based approaches for modeling and analyzing the full dependence structure. We give an introduction to Copula theory, including five of the most widely used models, namely the Frank, Clayton, Ali-Mikhail-Haq, Gumbel and Gaussian Copula, and use this approach for analyzing zenith tropospheric delays (ZTDs). We apply modeled ZTDs from the Weather and Research Forecasting (WRF) model and estimated ZTDs through the processing of Global Navigation Satellite System (GNSS) data and evaluate the pixel-wise dependence structures of ZTDs over a study area with complex terrain in Central Europe. The results show asymmetry and nonlinearity in the statistical relationships, which justifies the application of Copula-based approaches compared to, e.g., scalar measures. We apply a Copula-based correction for generating GNSS-like ZTDs from purely WRF-derived estimates. Particularly the corrected time series in the alpine regions show improved Nash–Sutcliffe efficiency values when compared against GNSS-based ZTDs. The proposed approach is therefore highly suitable for analyzing statistical relationships and correcting model-based quantities, especially in complex terrain, and when the statistical relationships of the analyzed variables are unknown. Numéro de notice : A2021-007 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-01044-4 Date de publication en ligne : 02/11/2020 En ligne : https://doi.org/10.1007/s10291-020-01044-4 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96297
in GPS solutions > vol 25 n° 1 (January 2021) . - n° 12[article]ESA UGI (Unified-GNSS-Ionosphere): An open-source software to compute precise ionosphere estimates / Raül Orús-Pérez in Advances in space research, vol 67 n° 1 (January 2021)
[article]
Titre : ESA UGI (Unified-GNSS-Ionosphere): An open-source software to compute precise ionosphere estimates Type de document : Article/Communication Auteurs : Raül Orús-Pérez, Auteur ; Bruno Nava, Auteur ; Juan M Parro-Jimenez, Auteur ; Anton Kashcheyev, Auteur Année de publication : 2021 Article en page(s) : pp 56 - 65 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] code source libre
[Termes IGN] logiciel libre
[Termes IGN] modèle ionosphérique
[Termes IGN] propagation ionosphériqueRésumé : (auteur) Ionospheric estimation is becoming more and more important for the new multifrequency positioning algorithms, since they can help to improve greatly the convergence time for acquiring a good positioning error. In this paper, an open source tool to estimate precise ionospheric estimates is presented, namely ESA UGI (Unified-GNSS-Ionosphere). The presentation is done jointly with a methodology to test ionospheric model using a modified NeQuick to generate synthetic data. The results with different option of the ESA UGI shows that it has a good performance below 1 TECU (Total Electron Content Units) in vTEC (vertical Total Electron Content) RMS (Root Mean Squared) for European networks, around 2 TECU in a well-covered African region and between 1 and 6 TECU globally with this synthetic data. It shows as well the capability of changing between different ionosphere models (voxel, multilayer and spherical harmonics) and configuration options. Finally, a test with uncombined PPP actual data is presented showing that instantaneous convergence below 30 cm in 3D RMS position error are achievable in a well sounded area in Europe. Numéro de notice : A2021-485 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.asr.2020.09.011 Date de publication en ligne : 19/09/2020 En ligne : https://doi.org/10.1016/j.asr.2020.09.011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97445
in Advances in space research > vol 67 n° 1 (January 2021) . - pp 56 - 65[article]PermalinkPermalinkGLONASS FDMA data for RTK positioning: a five-system analysis / Andreas Brack in GPS solutions, vol 25 n° 1 (January 2021)PermalinkPermalinkA new method for improving the performance of an ionospheric model developed by multi-instrument measurements based on artificial neural network / Wang Li in Advances in space research, vol 67 n° 1 (January 2021)PermalinkPerformance of miniaturized atomic clocks in static laboratory and dynamic flight environments / Ankit Jain in GPS solutions, vol 25 n° 1 (January 2021)PermalinkStatistical analysis of vertical land motions and sea level measurements at the coast / Kevin Gobron (2021)PermalinkPermalinkInclusion of GPS clock estimates for satellites Sentinel-3A/3B in DORIS geodetic solutions / Petr Štěpánek in Journal of geodesy, vol 94 n° 12 (December 2020)PermalinkReference system origin and scale realization within the future GNSS constellation “Kepler” / Susanne Glaser in Journal of geodesy, vol 94 n° 12 (December 2020)PermalinkAn advanced residual error model for tropospheric delay estimation / Szabolcs Rózsa in GPS solutions, Vol 24 n° 4 (October 2020)PermalinkEvolution of orbit and clock quality for real-time multi-GNSS solutions / Kamil Kazmierski in GPS solutions, Vol 24 n° 4 (October 2020)PermalinkInteger-estimable GLONASS FDMA model as applied to Kalman-filter-based short- to long-baseline RTK positioning / Pengyu Hou in GPS solutions, Vol 24 n° 4 (October 2020)PermalinkA low-cost integrated MEMS-based INS/GPS vehicle navigation system with challenging conditions based on an optimized IT2FNN in occluded environments / Elahe S. Abdolkarimi in GPS solutions, Vol 24 n° 4 (October 2020)PermalinkPython software tools for GNSS interferometric reflectometry (GNSS-IR) / Angel Martín in GPS solutions, Vol 24 n° 4 (October 2020)PermalinkBenefits of non-tidal loading applied at distinct levels in VLBI analysis / Matthias Glomsda in Journal of geodesy, vol 94 n° 9 (September 2020)PermalinkEstimation of frequency and duration of ionospheric disturbances over Turkey with IONOLAB-FFT algorithm / Secil Karatay in Journal of geodesy, vol 94 n° 9 (September 2020)PermalinkAn assessment of wide-lane ambiguity resolution methods for multi-frequency multi-GNSS precise point positioning / Viet Duong in Survey review, vol 52 n° 374 (August 2020)PermalinkEvaluation of single-frequency receivers for studying crustal deformation at the longitudinal Valley fault, eastern Taiwan / Horng-Yue Chen in Survey review, vol 52 n° 374 (August 2020)PermalinkGipsyX/RTGx, a new tool set for space geodetic operations and research / Willy I. Bertiger in Advances in space research, vol 66 n° 3 (1 August 2020)Permalink