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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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Characteristics of the BDS-3 multipath effect and mitigation methods using precise point positioning / Ran Lu in GPS solutions, vol 26 n° 2 (April 2022)  

Public [article]  inGPS solutions > vol 26 n° 2 (April 2022) . - n° 41 Titre : Characteristics of the BDS-3 multipath effect and mitigation methods using precise point positioning Type de document : Article/Communication Auteurs : Ran Lu, Auteur ; Wen Chen, Auteur ; Chenglong Zhang, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 41 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] constellation BeiDou [Termes IGN] correction du trajet multiple [Termes IGN] modèle stochastique [Termes IGN] orbite géostationnaire [Termes IGN] orbite terrestre [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement ponctuel précis [Termes IGN] répétabilité [Termes IGN] trajet multiple Résumé : (auteur) Multipath effect is one of the main challenges of precise point positioning (PPP) in complex environments. Nowadays, the BeiDou global navigation satellite system (BDS-3) constellation was fully operational. We evaluated the multipath characteristics of BDS-3 open-service signals. The results indicate that the B2a signal had the best anti-multipath performance, and B1C signal had the worst capability. Since BDS-3 satellites with different orbital types have different orbital repeat time, the traditional method based on multipath time-domain repeatability is complicated to alleviate the multipath error on BDS-3 satellites. In contrast, the multipath spatial-domain repeatability method does not need to calculate the orbital repeat times and is only related to the position of the satellite in the sky. It has the advantages of simple algorithm and easy implementation. We selected a multipath hemispherical map (MHM) and a MHM based on trend-surface analysis (T-MHM) to evaluate the effects of BDS-3 PPP multipath correction. The positioning results for the inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites, which were separately modeled and corrected, are slightly better than those obtained when they were modeled and corrected together. Compared with the uncorrected multipath, the positioning accuracy of B1I/B3I and B1C/B2a ionospheric-free (IF) combinations using the MHM can be improved by 52.7% and 51.6% and the convergence time can be shortened by 48.6% and 57.5%, respectively. The positioning accuracy of B1I/B3I and B1C/B2a IF combinations using the T-MHM can be improved by 67% and 66.9% and the convergence time can be shortened by 69.3% and 76.5%, respectively. The T-MHM introduces trend-surface analysis to model the spatial variation of the multipath inside the grid, which effectively alleviates high-frequency and low-frequency multipath. This study is of great significance for further improvements to the application of BDS-3 in complex environments. Numéro de notice : A2022-106 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-022-01227-1 Date de publication en ligne : 24/01/2022 En ligne : https://doi.org/10.1007/s10291-022-01227-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99606 [article]

Influence of street reference data on geocoding quality / P. Zandbergen in Geocarto international, vol 26 n° 1 (February 2011)  

Public [article]  inGeocarto international > vol 26 n° 1 (February 2011) . - pp 35 - 47 Titre : Influence of street reference data on geocoding quality Type de document : Article/Communication Auteurs : P. Zandbergen, Auteur Année de publication : 2011 Article en page(s) : pp 35 - 47 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] base de données d'adresses [Termes IGN] données localisées de référence [Termes IGN] exhaustivité des données [Termes IGN] Floride (Etats-Unis) [Termes IGN] géocodage par adresse postale [Termes IGN] précision du positionnement [Termes IGN] répétabilité [Termes IGN] réseau routier Résumé : (Auteur) Repeatability of street geocoding was characterized in terms of completeness and positional accuracy by using different street network datasets to geocode the same address input file. Match rates were highest for local street centrelines followed by StreetMap USA 2005 and TIGER 2000 data. Positional accuracy was highest for local street centrelines, while StreetMap USA 2005 and TIGER 2000 were nearly identical. Rural addresses were geocoded less accurately than urban addresses. Multi-family residential and commercial, institutional or industrial addresses were geocoded less accurately than urban single family residential addresses. The enhancement of TIGER 2000 data by commercial firms resulted in higher match rates but not in improved positional accuracy. The study has also highlighted the unique nature of multi-family and non-residential addresses in terms of the quality of their street geocoded locations. When such addresses are of specific interest alternatives to traditional street geocoding may need to be considered. Numéro de notice : A2011-035 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2010.537374 Date de publication en ligne : 04/12/2010 En ligne : https://doi.org/10.1080/10106049.2010.537374 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30816 [article]

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Fundamental principles of deformation measurement / N. Hazelton in SaLIS Surveying and land information science, vol 69 n° 2 (Summer 2009)

Public [article]  inSaLIS Surveying and land information science > vol 69 n° 2 (Summer 2009) . - pp 89 - 98 Titre : Fundamental principles of deformation measurement Type de document : Article/Communication Auteurs : N. Hazelton, Auteur Année de publication : 2009 Article en page(s) : pp 89 - 98 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Topographie [Termes IGN] auscultation d'ouvrage [Termes IGN] déformation d'édifice [Termes IGN] échantillon [Termes IGN] instrument de mesure [Termes IGN] mesurande [Termes IGN] norme ISO [Termes IGN] répétabilité [Termes IGN] topométrie de précision Résumé : (auteur) Deformation measurement surveys are often undertaken without a proper understanding of the fundamental principles and standards that relate to such work. In this paper, five fundamental principles are outlined: understanding the underlying processes, repeatability and reproducibility of results, measurement system design, stability of marks, and sampling frequency. A number of the relevant national and international standards are cited. Some examples of good and bad practice are given. Copyright SaLIS Numéro de notice : A2009-331 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83709 [article]

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