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A new algebraic solution for transforming Cartesian to geodetic coordinates / Jia-Chun Guo in Survey review, vol 55 n° 389 (March 2023)  

Public [article]  inSurvey review > vol 55 n° 389 (March 2023) . - pp 169 - 177 Titre : A new algebraic solution for transforming Cartesian to geodetic coordinates Type de document : Article/Communication Auteurs : Jia-Chun Guo, Auteur ; Wenbin Shen, Auteur Année de publication : 2023 Article en page(s) : pp 169 - 177 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] calcul algébrique [Termes IGN] coordonnées cartésiennes [Termes IGN] coordonnées géodésiques [Termes IGN] système de coordonnées [Termes IGN] transformation de coordonnées Résumé : (auteur) An exact and stable algebraic solution based on solving a quartic equation with respect to the cosine function of the reduced latitude is proposed to transform Cartesian into geodetic coordinates. The unique proper root of the equation appropriate to the transformation is chosen from all possible roots by rigorous analyses and the singular region of the transformation that in which there at least one component of the geodetic coordinates is indeterminate or non-single-valued characteristics are determined strictly. The new algorithm does not need any approximation and the instability problems incurred in other algebraic solutions are overcome. For practical applications, the algorithm performs comparably to that of [Vermeille, H., 2011. An analytical method to transform geocentric into geodetic coordinates. Journal of geodesy, 85 (2), 105–117.] and shows a certain superiority in the singular disc over Vermeille's algorithm. Numéro de notice : A2023-135 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2022.2071055 Date de publication en ligne : 24/05/2022 En ligne : https://doi.org/10.1080/00396265.2022.2071055 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102686 [article]

Determination of the orthometric height difference based on optical fiber frequency transfer technique / Anh The Hoang in Geodesy and Geodynamics, vol 12 n° 6 (November 2021)  

Public [article]  inGeodesy and Geodynamics > vol 12 n° 6 (November 2021) . - pp 405 - 412 Titre : Determination of the orthometric height difference based on optical fiber frequency transfer technique Type de document : Article/Communication Auteurs : Anh The Hoang, Auteur ; Ziyu Shen, Auteur ; Wenbin Shen, Auteur Année de publication : 2021 Article en page(s) : pp 405 - 412 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes IGN] altimétrie [Termes IGN] altitude orthométrique [Termes IGN] coefficient de géopotentiel [Termes IGN] fibre optique [Termes IGN] fréquence [Termes IGN] précision centimétrique Mots-clés libres : optical fiber frequency transfer Résumé : (auteur) The development of remote frequency transfer techniques, especially the appearance of optical clocks with unprecedented stability, has prompted geoscientists to study their applications in geodesy. Using remote frequency transfer technique, by frequency comparison of two optical clocks at two points P and Q connected by optical fibers, one can measure the signal's frequency shift between them, and the geopotential difference between them can be determined based on the gravity frequency shift equation. Given the orthometric height of P, the orthometric height of Q can be determined. Since the present stability of the optical clock has achieved 1 × 10−18 or better and comparing the frequency transfer via optical fiber provides stability at 10−19 level, the optical clock network enables determining the orthometric height at centimeter-level. This study provides a formulation to determine the height difference at one-centimeter level between two points on the ground based on the optical fiber frequency transfer technique. Numéro de notice : A2021-945 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.geog.2021.08.003 Date de publication en ligne : 22/09/2021 En ligne : https://doi.org/10.1016/j.geog.2021.08.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99757 [article]

Ionospheric and receiver DCB-constrained multi-GNSS single-frequency PPP integrated with MEMS inertial measurements / Zhouzheng Gao in Journal of geodesy, vol 91 n° 11 (November 2017)  

Public [article]  inJournal of geodesy > vol 91 n° 11 (November 2017) . - pp 1351 – 1366 Titre : Ionospheric and receiver DCB-constrained multi-GNSS single-frequency PPP integrated with MEMS inertial measurements Type de document : Article/Communication Auteurs : Zhouzheng Gao, Auteur ; Maorong Ge, Auteur ; Wenbin Shen, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 1351 – 1366 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] coordonnées GNSS [Termes IGN] erreur instrumentale [Termes IGN] erreur systématique [Termes IGN] filtre de Kalman [Termes IGN] GNSS en mode différentiel [Termes IGN] GPS-INS [Termes IGN] intégration de données [Termes IGN] perturbation ionosphérique [Termes IGN] positionnement ponctuel précis [Termes IGN] récepteur monofréquence [Termes IGN] retard ionosphèrique Résumé : (Auteur) Single-frequency precise point positioning (SF-PPP) is a potential precise positioning technique due to the advantages of the high accuracy in positioning after convergence and the low cost in operation. However, there are still challenges limiting its applications at present, such as the long convergence time, the low reliability, and the poor satellite availability and continuity in kinematic applications. In recent years, the achievements in the dual-frequency PPP have confirmed that its performance can be significantly enhanced by employing the slant ionospheric delay and receiver differential code bias (DCB) constraint model, and the multi-constellation Global Navigation Satellite Systems (GNSS) data. Accordingly, we introduce the slant ionospheric delay and receiver DCB constraint model, and the multi-GNSS data in SF-PPP modular together. In order to further overcome the drawbacks of SF-PPP in terms of reliability, continuity, and accuracy in the signal easily blocking environments, the inertial measurements are also adopted in this paper. Finally, we form a new approach to tightly integrate the multi-GNSS single-frequency observations and inertial measurements together to ameliorate the performance of the ionospheric delay and receiver DCB-constrained SF-PPP. In such model, the inter-system bias between each two GNSS systems, the inter-frequency bias between each two GLONASS frequencies, the hardware errors of the inertial sensors, the slant ionospheric delays of each user-satellite pair, and the receiver DCB are estimated together with other parameters in a unique Kalman filter. To demonstrate its performance, the multi-GNSS and low-cost inertial data from a land-borne experiment are analyzed. The results indicate that visible positioning improvements in terms of accuracy, continuity, and reliability can be achieved in both open-sky and complex conditions while using the proposed model in this study compared to the conventional GPS SF-PPP. Numéro de notice : A2017-706 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1029-7 En ligne : https://doi.org/10.1007/s00190-017-1029-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88087 [article]