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Assessment of VRS performances of the Algerian-CORS-network / Takka Elhadi in Bulletin des sciences géographiques, vol 27 n° 1 (2023)    

Public [article]  inBulletin des sciences géographiques > vol 27 n° 1 (2023) . - pp 25 - 33 Titre : Assessment of VRS performances of the Algerian-CORS-network Type de document : Article/Communication Auteurs : Takka Elhadi, Auteur ; Touabet Touabet, Auteur ; Boudrassene Abdennour, Auteur Année de publication : 2023 Article en page(s) : pp 25 - 33 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] Algérie [Termes IGN] disponibilité des données [Termes IGN] intégrité des données [Termes IGN] performance [Termes IGN] précision du positionnement [Termes IGN] répétabilité [Termes IGN] réseau géodésique local [Termes IGN] réseau géodésique permanent [Termes IGN] station de référence Résumé : (auteur) The Algerian Continuously Operating Reference Stations Network, so-called AL-CORS-Net, is deployed to provideNRTK services based onVRS method using Geo++GNSMART software.This paper investigates VRS performance in terms ofprecision, availability, integrity, Time-to-Fix-Ambiguity (TTFA), repeatability and PDOP.Several survey sessions were performed at different sites in the north of Algeria during October 2021 to January 2022. The results revealed good performance indicators; the precision was in the order of 1.3 cm in the horizontal component and about 2.2 cm in the vertical (at 1 sigma). The VRS solution's availability was 97.25%, its integrity was 98.8% in the horizontal and 94.9% in the vertical, and the TTFA ranged from a few seconds to a few minutes. The VRS measurements' repeatability presented similar measurement results throughout time. High satellite numbers have been tracked, their geometry (PDOP) was ideal. Numéro de notice : A2023-090 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : https://www.asjp.cerist.dz/en/downArticle/213/27/1/216928 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103152 [article]

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A fast satellite selection algorithm for multi-GNSS marine positioning based on improved particle swarm optimisation / Xiaoguo Guan in Survey review, vol 54 n° 387 (November 2022)  

Public [article]  inSurvey review > vol 54 n° 387 (November 2022) . - pp 554 - 565 Titre : A fast satellite selection algorithm for multi-GNSS marine positioning based on improved particle swarm optimisation Type de document : Article/Communication Auteurs : Xiaoguo Guan, Auteur ; Hongzhou Chai, Auteur ; Guorui Xiao, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 554 - 565 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] combinaison linéaire ponderée [Termes IGN] itération [Termes IGN] milieu marin [Termes IGN] optimisation par essaim de particules [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] précision du positionnement Résumé : (auteur) This paper introduces an improved particle swarm optimisation algorithm (IPSO), to select satellites rapidly in multi-GNSS marine positioning. The traditional particle swarm optimisation (PSO) may be trapped into local optimisation. To avoid the disadvantage, the proposed algorithm uses linear inertia weight factor and two functions of the immune system, i.e. the memory function and the self-regulatory function. Several experiments are carried out by adopting real survey data collected by the SiNan receiver that is installed on the Snow Dragon scientific research ship during the 9th China Arctic expedition. Compared with the minimum Geometric dilution of precision (GDOP) method, PSO and IPSO significantly reduce the computing time (96.25% and 95.61%). The variance of IPSO is 0.063, which is much lower than that of PSO (0.087). As for the positioning accuracy, the IPSO can reach the centimetre level in the kinematics condition. Numéro de notice : A2022-831 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2021.1991175 Date de publication en ligne : 31/10/2021 En ligne : https://doi.org/10.1080/00396265.2021.1991175 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102017 [article]

Regularized integer least-squares estimation: Tikhonov’s regularization in a weak GNSS model / Zemin Wu in Journal of geodesy, vol 96 n° 4 (April 2022)  

Public [article]  inJournal of geodesy > vol 96 n° 4 (April 2022) . - n° 22 Titre : Regularized integer least-squares estimation: Tikhonov’s regularization in a weak GNSS model Type de document : Article/Communication Auteurs : Zemin Wu, Auteur ; Shaofeng Bian, Auteur Année de publication : 2022 Article en page(s) : n° 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] méthode des moindres carrés [Termes IGN] phase GNSS [Termes IGN] positionnement par GNSS [Termes IGN] régularisation de Tychonoff [Termes IGN] résolution d'ambiguïté Résumé : (auteur) The strength of the GNSS precise positioning model degrades in cases of a lack of visible satellites, poor satellite geometry or uneliminated atmospheric delays. The least-squares solution to a weak GNSS model may be unreliable due to a large mean squared error (MSE). Recent studies have reported that Tikhonov’s regularization can decrease the solution’s MSE and improve the success rate of integer ambiguity resolution (IAR), as long as the regularization matrix (or parameter) is properly selected. However, there are two aspects that remain unclear: (i) the optimal regularization matrix to minimize the MSE and (ii) the IAR performance of the regularization method. This contribution focuses on these two issues. First, the “optimal” Tikhonov’s regularization matrix is derived conditioned on an assumption of prior information of the ambiguity. Second, the regularized integer least-squares (regularized ILS) method is compared with the integer least-squares (ILS) method in view of lattice theory. Theoretical analysis shows that regularized ILS can increase the upper and lower bounds of the success rate and reduce the upper bound of the LLL reduction complexity and the upper bound of the search complexity. Experimental assessment based on real observed GPS data further demonstrates that regularized ILS (i) alleviates the LLL reduction complexity, (ii) reduces the computational complexity of determinate-region ambiguity search, and (iii) improves the ambiguity fixing success rate. Numéro de notice : A2022-262 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01585-7 Date de publication en ligne : 28/03/2022 En ligne : https://doi.org/10.1007/s00190-021-01585-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100251 [article]

LEO enhanced Global Navigation Satellite System (LeGNSS) for real-time precise positioning services / Bofeng Li in Advances in space research, vol 63 n° 1 (1 January 2019)  

Public [article]  inAdvances in space research > vol 63 n° 1 (1 January 2019) . - pp 73 - 93 Titre : LEO enhanced Global Navigation Satellite System (LeGNSS) for real-time precise positioning services Type de document : Article/Communication Auteurs : Bofeng Li, Auteur ; Haibo Ge, Auteur ; Maorong Ge, Auteur ; Liangwei Nie, Auteur ; Yunzhong Shen, Auteur ; Harald Schuh, Auteur Année de publication : 2019 Article en page(s) : pp 73 - 93 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] étude de faisabilité [Termes IGN] orbitographie [Termes IGN] positionnement ponctuel précis [Termes IGN] satellite de télécommunication [Termes IGN] simulation [Termes IGN] temps réel Mots-clés libres : LEO constellation enhanced GNSS Résumé : (Auteur) Global Navigation Satellite System (GNSS) has been widely used in many geosciences areas with its Positioning, Navigation and Timing (PNT) service. However, GNSS still has its own bottleneck, such as the long initialization period of Precise Point Positioning (PPP) without dense reference network. Recently, the concept of PNTRC (Positioning, Navigation, Timing, Remote sensing and Communication) has been put forward, where Low Earth Orbit (LEO) satellite constellations are recruited to fulfill diverse missions. In navigation aspect, a number of selected LEO satellites can be equipped with a transmitter to transmit similar navigation signals to ground users, so that they can serve as GNSS satellites but with much faster geometric change to enhance GNSS capability, which is named as LEO constellation enhanced GNSS (LeGNSS). As a result, the initialization time of PPP is expected to be shortened to the level of a few minutes or even seconds depending on the number of the LEO satellites involved. In this article, we simulate all the relevant data from June 8th to 14th, 2014 and investigate the feasibility of LeGNSS with the concentration on the key issues in the whole data processing for providing real-time PPP service based on a system configuration with fourteen satellites of BeiDou Navigation Satellite System (BDS), twenty-four satellites of the Global Positioning System (GPS), and sixty-six satellites of the Iridium satellite constellations. At the server-end, Precise Orbit Determination (POD) and Precise Clock Estimation (PCE) with various operational modes are investigated using simulated observations. It is found out that GNSS POD with partial LEO satellites is the most practical mode of LeGNSS operation. At the user-end, the Geometry Dilution Of Precision (GDOP) and Signal-In-Space Ranging Error (SISRE) are calculated and assessed for different positioning schemes in order to demonstrate the performance of LeGNSS. Centimeter level SISRE can be achieved for LeGNSS. Numéro de notice : A2019-175 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2018.08.017 Date de publication en ligne : 16/08/2018 En ligne : https://doi.org/10.1016/j.asr.2018.08.017 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92631 [article]

PPPH : a MATLAB-based software for multi-GNSS precise point positioning analysis / Berkay Bahadur in GPS solutions, vol 22 n° 4 (October 2018)  

Public [article]  inGPS solutions > vol 22 n° 4 (October 2018) Titre : PPPH : a MATLAB-based software for multi-GNSS precise point positioning analysis Type de document : Article/Communication Auteurs : Berkay Bahadur, Auteur ; Metin Nohutcu, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] données GNSS [Termes IGN] erreur en position [Termes IGN] horloge du récepteur [Termes IGN] Matlab [Termes IGN] positionnement ponctuel précis [Termes IGN] retard troposphérique zénithal [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) The integration of different GNSS constellations offers considerable opportunities to improve Precise Point Positioning (PPP) performance. Being aware of the limited number of the alternatives that utilize the potential advantages of the multi-constellation and multi-frequency GNSS, we developed a MATLAB-based GNSS analysis software, named PPPH. PPPH is capable of processing GPS, GLONASS, Galileo and BeiDou data, and forming their different combinations depending on user’s preference. Thanks to its user-friendly graphical interface, PPPH allows users to determine a variety of processing options and parameters. In addition to an output file including the estimated parameters for every single epoch, PPPH also presents several analyzing and plotting tools for evaluating the results, such as positioning error, tropospheric zenith total delay, receiver clock estimation, satellite number, dilution of precisions. On the other hand, we conducted experimental tests to both validate the performance of PPPH and assess the potential benefits of multi-GNSS on PPP. The results indicate that PPPH provides comparable PPP solution with the general standards and also contributes to the improvement of PPP performance with the integration of multi-GNSS. Consequently, we introduce a GNSS analysis software that is easy to use, has a robust performance and is open to progress with its modular structure. Numéro de notice : A2018-377 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0777-z Date de publication en ligne : 18/08/2018 En ligne : https://doi.org/10.1007/s10291-018-0777-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90781 [article]

Positioning stability improvement with inter-system biases on multi-GNSS PPP / Byung-Kyu Choi in Journal of applied geodesy, vol 12 n° 3 (July 2018)  

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Reference satellite selection method for GNSS high-precision relative positioning / Xiao Gao in Geodesy and Geodynamics, vol 8 n° 2 (March 2017)  

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A closed-form formula to calculate geometric dilution of precision (GDOP) for multi-GNSS constellations / Yunlong Teng in GPS solutions, vol 20 n° 3 (July 2016)  

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Visibility and geometry of global satellite navigation systems constellations / Jacek Januszewski in Artificial satellites, vol 50 n° 4 (December 2015)  

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Positioning configurations with the lowest GDOP and their classification / Shuqiang Xue in Journal of geodesy, vol 89 n° 1 (January 2015)  

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Effects of forest environment and survey protocol on GPS accuracy / Christian Piedallu in Photogrammetric Engineering & Remote Sensing, PERS, vol 71 n° 9 (September 2005)  

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Mapping Dilution of Precision (MDOP) and map-matched GPS / Geoffrey Blewitt in International journal of geographical information science IJGIS, vol 16 n° 1 (january 2002)  

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Geophysical distributions of occultations of GPS satellites viewed from a low Earth orbiting satellite / D.M. O'Brien (1998)

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Positionnement géodésique par satellites Doppler / Claude Boucher in Bulletin d'information de l'Institut géographique national, n° 34 (septembre 1977)

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Methodology and field tests of GDOP, a geodetic computation package for the short arc adjustment of satellite Doppler observations / Claude Boucher (12/10/1976)

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