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The improvement in integer ambiguity resolution with INS aiding for kinematic precise point positioning / Xiaohong Zhang in Journal of geodesy, vol 93 n°7 (July 2019)  

Public [article]  inJournal of geodesy > vol 93 n°7 (July 2019) . - pp 993 - 1010 Titre : The improvement in integer ambiguity resolution with INS aiding for kinematic precise point positioning Type de document : Article/Communication Auteurs : Xiaohong Zhang, Auteur ; Feng Zhu, Auteur ; Yuxi Zhang, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 993 - 1010 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] affaiblissement de la précision [Termes IGN] ambiguïté entière [Termes IGN] couplage GNSS-INS [Termes IGN] délai d'obtention de la première position [Termes IGN] milieu urbain [Termes IGN] positionnement ponctuel précis [Termes IGN] précision du positionnement [Termes IGN] résolution d'ambiguïté Résumé : (auteur) Despite the benefits of integer ambiguity resolution (IAR) in precise point positioning (PPP), observation outages and harsh signal environments still impact float ambiguity estimation in kinematic surveying, consequently resulting in ambiguity-fixed failure. The inertial navigation system (INS) is an autonomous and spontaneous positioning one, which could provide continuous and superior positioning accuracy over short time. Thus, the INS attains more accurate position than code solution. Moreover, the tight integration of INS and PPP is capable of continuous operation where there are less than four satellites available. These advantages can improve float ambiguity estimation and assist in re-initializing the interrupted ambiguity and PPP solution. Based on the good quality of float ambiguity, the ambiguity dilution precision (ADOP) and the size of integer ambiguity search space are reduced, and then, the IAR-PPP is improved. In this work, the INS aiding effect on IAR-PPP was revealed by the sufficient theoretical analysis and performance assessment. A ring laser gyroscope-based navigation-grade IMU and a fiber optic gyroscope-based tactical-grade IMU were utilized to conduct experiments in an open-sky environment and urban area. The assessment adopted the following aspects of ADOP, bootstrapping success rate, time to fix and position errors. It is found that IAR-PPP with INS aiding achieves an enhanced performance during GPS outage when INS could deliver a superior accurate position. For the navigation- and tactical-grade IMU, the INS-aided ambiguity re-fixing performance can be classified as three levels: significant improvement for the outage duration less than 10 s, moderate improvement for the outage duration from 10 to 60 s and a little or zero improvement for the outage duration longer than 60 s. From the viewpoint of the INS-predicted position domain, an accuracy better than 0.1 m and 1.0 m is required for the significant and moderate improvement, while one can only achieve a little or zero improvement if the position error is larger than 1.0 m. Besides, we also performed the INS-aided IAR-PPP in real urban environment. For the urban environments, the span of clean data is often shorter than 30 min due to intermittent signal interruptions; thus, ambiguity re-fixing for PPP always fails. INS-aided information could bridge the data gaps and achieve fast ambiguity re-fixing. In summary, INS aiding information is capable of improving IAR-PPP performance significantly over a short GPS outage. Numéro de notice : A2019-356 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1222-3 Date de publication en ligne : 08/12/2018 En ligne : https://doi.org/10.1007/s00190-018-1222-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93424 [article]

New optimal smoothing scheme for improving relative and absolute accuracy of tightly coupled GNSS/SINS integration / Xiaohong Zhang in GPS solutions, vol 21 n° 3 (July 2017)  

Public [article]  inGPS solutions > vol 21 n° 3 (July 2017) . - pp 861 – 872 Titre : New optimal smoothing scheme for improving relative and absolute accuracy of tightly coupled GNSS/SINS integration Type de document : Article/Communication Auteurs : Xiaohong Zhang, Auteur ; Feng Zhu, Auteur ; Xianlu Tao, Auteur ; Rui Duan, Auteur Année de publication : 2017 Article en page(s) : pp 861 – 872 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] algorithme de filtrage [Termes IGN] combinaison linéaire [Termes IGN] filtrage du signal [Termes IGN] positionnement inertiel [Termes IGN] positionnement par GNSS [Termes IGN] précision absolue [Termes IGN] précision relative [Termes IGN] système à couplage étroit [Termes IGN] test de performance Résumé : (auteur) For mobile surveying and mapping applications, tightly coupled integration of global navigation satellite system (GNSS) and Strap down Inertial Navigation System is usually recommended for direct georeferencing since it can provide position, velocity, and attitude information at higher accuracy and better reliability in a self-contained manner. A post-mission smoothing method is applied to optimally use observation information of both systems and to overcome the shortcomings of Kalman filter in GNSS degraded environments. We propose the revised Rauch–Tung–Streibel Smoother (RTSS) and Forward–Backward combination (FBC) smoothing algorithms for tightly coupled integration. From the analysis and field test, it is found that RTSS smoothing mainly improves the relative accuracy, while FBC mainly contributes to the absolute accuracy. With the complementary characteristics of both smoothing algorithms, an optimal new smoothing scheme combining RTSS with FBC is built. The performance of these three smoothing algorithms is evaluated through a real vehicular test. Compared with RTSS and FBC smoothing algorithms, the new smoothing scheme improves the mean 3D position RMS and the mean 3D attitude RMS by 65.7 and 70%, respectively. It provides better accuracy and smoothness for the position, velocity, and attitude at the same time. Numéro de notice : A2017-439 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-017-0601-1 En ligne : https://doi.org/10.1007/s10291-017-0601-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86354 [article]