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Resilient GNSS real-time kinematic precise positioning with inequality and equality constraints / Zhetao Zhang in GPS solutions, vol 27 n° 3 (July 2023)  

Public [article]  inGPS solutions > vol 27 n° 3 (July 2023) . - n° 116 Titre : Resilient GNSS real-time kinematic precise positioning with inequality and equality constraints Type de document : Article/Communication Auteurs : Zhetao Zhang, Auteur ; Yuan Li, Auteur ; Xiufeng He, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] contrainte d'intégrité [Termes IGN] positionnement cinématique en temps réel [Termes IGN] positionnement par GNSS [Termes IGN] précision du positionnement [Termes IGN] résolution d'ambiguïté Résumé : (auteur) How to conduct the GNSS real-time kinematic precise positioning in challenging environments is not an easy problem. The challenging environment mainly refers to frequent signal reflection, refraction, diffraction, and occlusion, inevitably introducing large positioning errors. We propose a resilient positioning method considering the inequality and equality constraints. Specifically, first, we introduce the functional and stochastic models of real-time kinematic (RTK) positioning, considering the impacts of challenging environments. Second, specific iterative procedures of resilient GNSS precise positioning method with inequality and equality constraints are proposed. In addition, a general form of inequality constraints in terms of coordinate components is given that is suitable for real-time kinematic situations. Four 24-h real datasets in canyon environments were collected to verify the performance of the proposed method. The results show that compared with the traditional RTK positioning without inequality constraints, the proposed method can improve the success rates of ambiguity resolution by 42.2% on average. Also, the positioning accuracy of fixed solutions can be improved significantly after applying the proposed method, where the root mean square errors can be reduced by 77.2% on average. Therefore, the proposed method can significantly improve success rates of ambiguity resolution and positioning accuracy, which is especially promising in challenging environments. Numéro de notice : A2023-213 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-023-01454-0 Date de publication en ligne : 26/04/2023 En ligne : https://doi.org/10.1007/s10291-023-01454-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103142 [article]

Performance analysis of cross-frequency Doppler-assisted carrier phase tracking / Dun Wang in GPS solutions, vol 27 n° 3 (July 2023)  

Public [article]  inGPS solutions > vol 27 n° 3 (July 2023) . - n° 105 Titre : Performance analysis of cross-frequency Doppler-assisted carrier phase tracking Type de document : Article/Communication Auteurs : Dun Wang, Auteur ; Shuangna Zhang, Auteur ; Tong Liu, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 105 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] bruit thermique [Termes IGN] erreur systématique interfréquence d'horloge [Termes IGN] fréquence [Termes IGN] méthode de Monte-Carlo [Termes IGN] modèle mathématique [Termes IGN] phase [Termes IGN] signal GNSS Résumé : (auteur) Using the Doppler frequency obtained from tracking a GNSS pilot signal to aid in tracking another signal modulated with higher rate navigation messages in a different frequency band can improve tacking robustness and lower the message demodulation threshold. Based on an analysis of received signal frequency coherence, a linearized mathematical model of the cross-frequency Doppler-assisted carrier phase tracking loop is built, a thermal noise jitter calculation equation for the assisted tracking loop is derived, and its dynamic stress response characteristics are examined. The loop design requirements for eliminating the influence of inter-frequency frequency bias are clarified, as are the cross-frequency assist signal selection criteria. Monte Carlo simulations and preliminary field tests validate the theoretical results using the B1C pilot signal-aided tracking B2b signal of the MEO satellite in the BeiDou satellite navigation system (BDS). Experimental results show that the carrier phase tracking threshold of the B2b signal can be reduced by about 4 dB. Numéro de notice : A2023-214 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-023-01434-4 En ligne : https://doi.org/10.1007/s10291-023-01434-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103143 [article]