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Identifying spurious cycle slips based on iterative filtering under disturbed ionospheric conditions for undifferenced GNSS observations / Yan Xiang in Advances in space research, vol 70 n° 11 (December 2022)  

Public [article]  inAdvances in space research > vol 70 n° 11 (December 2022) . - pp 3582 - 3593 Titre : Identifying spurious cycle slips based on iterative filtering under disturbed ionospheric conditions for undifferenced GNSS observations Type de document : Article/Communication Auteurs : Yan Xiang, Auteur ; Sijie Lyu, Auteur ; Wenxian Yu, Auteur Année de publication : 2022 Article en page(s) : pp 3582 - 3593 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] erreur de positionnement [Termes IGN] filtre [Termes IGN] glissement de cycle [Termes IGN] itération [Termes IGN] perturbation ionosphérique [Termes IGN] phase GNSS [Termes IGN] positionnement ponctuel précis [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) The TurboEdit method is widely used to detect cycle slips on the global navigation satellite system (GNSS) carrier-phase measurements. However, it leads to an increasing number of false alarms in detecting cycle slips under disturbed ionospheric conditions. Besides, once the method detects a cycle slip at one satellite, it treats dual frequencies with cycle slips rather than at one frequency. Considering these two challenges, we developed a solution-based iterative filter detection method to reduce the number of spurious cycle slip detection under disturbed ionospheric conditions. The method initially assumes that there is no cycle slip at each frequency. We then estimate the solutions without cycle slips. A decision of exiting cycle slips is made by examining and comparing the two results solutions with or without cycle slips in terms of usable satellites, ambiguities, and residuals. The uncombined precise point positioning (PPP) during disturbed ionospheric conditions on 17 March 2015 at high latitude was studied to validate the proposed method. Results showed that the detected number of spurious cycle slips was reduced significantly. With fewer marked cycle slips, more stable and smoother positioning performance was achieved when fewer ambiguity parameters were reinitialized. Numéro de notice : A2022-861 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.asr.2022.08.008 Date de publication en ligne : 08/08/2022 En ligne : https://doi.org/10.1016/j.asr.2022.08.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102144 [article]

Robust modeling of GNSS orbit and clock error dynamics / Elisa Gallon in Navigation : journal of the Institute of navigation, vol 69 n° 4 (Fall 2022)  

Public [article]  inNavigation : journal of the Institute of navigation > vol 69 n° 4 (Fall 2022) . - n° 539 Titre : Robust modeling of GNSS orbit and clock error dynamics Type de document : Article/Communication Auteurs : Elisa Gallon, Auteur ; Mathieu Joerger, Auteur ; Boris Pervan, Auteur Année de publication : 2022 Article en page(s) : n° 539 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] centrale inertielle [Termes IGN] décalage d'horloge [Termes IGN] erreur [Termes IGN] erreur de positionnement [Termes IGN] filtre de Kalman [Termes IGN] modèle stochastique [Termes IGN] orbitographie par GNSS [Termes IGN] Receiver Autonomous Integrity Monitoring Résumé : (auteur) In this paper, we develop new stochastic orbit and clock error models for positioning, fault detection, and integrity monitoring over time. GPS and Galileo orbit and clock data are evaluated and ranging errors are analyzed and modeled over time. This work is intended for time-sequential safety-critical navigation systems including global navigation satellite systems (GNSSs) integrated with inertial navigation systems (INSs) and Kalman filter implementations of Advanced Receiver Autonomous Integrity Monitoring (ARAIM). Numéro de notice : A2022-867 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.33012/navi.539 Date de publication en ligne : 22/05/2022 En ligne : https://doi.org/10.33012/navi.539 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102160 [article]

A new partial ambiguity resolution method based on modified solution separation and GNSS epoch-differencing / Yang Jiang in Journal of geodesy, vol 96 n° 11 (November 2022)  

Public [article]  inJournal of geodesy > vol 96 n° 11 (November 2022) . - n° 88 Titre : A new partial ambiguity resolution method based on modified solution separation and GNSS epoch-differencing Type de document : Article/Communication Auteurs : Yang Jiang, Auteur ; Wei Ding, Auteur ; Yuting Gao, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 88 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] compensation Lambda [Termes IGN] erreur de positionnement [Termes IGN] phase [Termes IGN] positionnement cinématique en temps réel [Termes IGN] récepteur GNSS [Termes IGN] résolution d'ambiguïté Résumé : (auteur) Partial ambiguity resolution has been widely used in real-time kinematic (RTK) positioning to provide accurate and continuous centimeter-level positioning solutions. Current PAR methods are concerned with the exclusion of ambiguities that otherwise would result in low rate of full ambiguity resolution (FAR). With an assumption of unbiased ambiguities, the traditional PAR methods use the ambiguity-domain test statistics and probability-domain quantitative evaluation to select and validate the ambiguity subset. Consequentially, they would degrade the performance using low-cost devices in challenging environments where ambiguity biases exist, causing high probabilities of false alarm and missed detection of PAR and subsequently poor availability and accuracy of PAR. To deal with this issue, in this study, we propose a new PAR method for application in challenging environments. The proposed method consists of two major steps. First, a global navigation satellite system epoch-differencing (GED) algorithm is applied to derive a prior ambiguity solution. Second, we use a modified solution separation (SS) method with the prior ambiguity solution as an external input to obtain more accurate ambiguity test statistics. Based on a dynamic road test under environments with significant signal blockages, the performance of the proposed method is analyzed by using a low-cost GNSS receiver. The proposed method provides ambiguity test statistics with higher accuracy and can achieve 73.19% and 50.55% improvement in the accuracy and availability of the fixed solution, compared with the traditional PAR methods. Besides, the RMS of positioning errors with fixed solution are 1.03 cm, 0.70 cm, and 1.50 cm for the proposed PAR method in the east, north, and upward directions, respectively, which are 1.06 cm, 0.72 cm, and 1.35 cm for SS-based PAR, and 5.29 cm, 0.86 cm, and 5.56 cm for ILS-based PAR. The proposed PAR method achieves 90.36% fixed epochs, versus 79.06%, and 88.28%, for ILS-based PAR and SS-based PAR, respectively. Numéro de notice : A2022-810 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01674-1 Date de publication en ligne : 02/11/2022 En ligne : https://doi.org/10.1007/s00190-022-01674-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101967 [article]

An efficient method to compensate receiver clock jumps in real-time precise point positioning / Shaoguang Xu in Remote sensing, vol 14 n° 20 (October-2 2022)  

Public [article]  inRemote sensing > vol 14 n° 20 (October-2 2022) . - n° 5222 Titre : An efficient method to compensate receiver clock jumps in real-time precise point positioning Type de document : Article/Communication Auteurs : Shaoguang Xu, Auteur ; Jialu Long, Auteur ; Jinling Wang, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 5222 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] ambiguïté entière [Termes IGN] décalage d'horloge [Termes IGN] erreur de positionnement [Termes IGN] glissement de cycle [Termes IGN] horloge du récepteur [Termes IGN] phase [Termes IGN] positionnement cinématique en temps réel [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] retard troposphérique zénithal [Termes IGN] temps réel Résumé : (auteur) In global navigation satellite systems (GNSSs)-based positioning, user receiver clock jump is a common phenomenon on the low-cost receiver clocks and can break the continuity of observation time tag, carrier phase and pseudo range. The discontinuity may affect precise point positioning-related parameter estimation, including receiver clock error, position, troposphere and ionosphere parameters. It is important to note that these parameters can be used for timing, positioning, atmospheric inversion and so on. In response to this problem, the receiver clock jumps are divided into two types. The first one can be expressed by the carrier phase and pseudo range having the same scale jump, and the second one is that they are having different scale jumps. For the first type, if a small priori variance of receiver clock error is provided, it can affect the accuracy of ionospheric delay estimation both in static and kinematic mode, while in the latter mode, it also affects position estimation. However, if large process noise is provided, numerical problems may arise since other parameters’ process noises are usually small, it is proposed to use the single point positioning with pseudo ranges to provide a priori value of receiver clock error, and an empiric value is assigned to its prior variance, this handle can avoid the above problems. For the second type, instead of compensating so many raw observations in the traditional methods, it is proposed to compensate the ambiguities at the clock jump epochs only in a new method. The new method corrects the Melbourne–Wubbena (MW) combination firstly in order to avoid the misjudging of cycle slips for current epoch, and the second step is to compensate the corresponding ambiguities, then, after Kalman filtering, the MW and its mean should be corrected back in order to avoid the misjudging of cycle slips at the next epoch. This approach has the advantage of handling the clock jump epoch-wise and can avoid correcting the rest of the observations as the traditional methods used to. With the numerical validation examples both in static and kinematic modes, it shows the new method is simple but efficient for real time precise point positioning (PPP). Numéro de notice : A2022-792 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.3390/rs14205222 Date de publication en ligne : 19/10/2022 En ligne : https://doi.org/10.3390/rs14205222 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101909 [article]

3D LiDAR aided GNSS/INS integration fault detection, localization and integrity assessment in urban canyons / Zhipeng Wang in Remote sensing, vol 14 n° 18 (September-2 2022)  

Public [article]  inRemote sensing > vol 14 n° 18 (September-2 2022) . - n° 4641 Titre : 3D LiDAR aided GNSS/INS integration fault detection, localization and integrity assessment in urban canyons Type de document : Article/Communication Auteurs : Zhipeng Wang, Auteur ; Bo Li, Auteur ; Zhiqiang Dan, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 4641 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] canyon urbain [Termes IGN] couplage GNSS-INS [Termes IGN] détection de cible [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] erreur de positionnement [Termes IGN] filtre adaptatif [Termes IGN] intégration de données [Termes IGN] intégrité des données [Termes IGN] khi carré [Termes IGN] semis de points Résumé : (auteur) The performance of Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) integrated navigation can be severely degraded in urban canyons due to the non-line-of-sight (NLOS) signals and multipath effects. Therefore, to achieve a high-precision and robust integrated system, real-time fault detection and localization algorithms are needed to ensure integrity. Currently, the residual chi-square test is used for fault detection in the positioning domain, but it has poor sensitivity when faults disappear. Three-dimensional (3D) light detection and ranging (LiDAR) has good positioning performance in complex environments. First, a LiDAR aided real-time fault detection algorithm is proposed. A test statistic is constructed by the mean deviation of the matched targets, and a dynamic threshold is constructed by a sliding window. Second, to solve the problem that measurement noise is estimated by prior modeling with a certain error, a LiDAR aided real-time measurement noise estimation based on adaptive filter localization algorithm is proposed according to the position deviations of matched targets. Finally, the integrity of the integrated system is assessed. The error bound of integrated positioning is innovatively verified with real test data. We conduct two experiments with a vehicle going through a viaduct and a floor hole, which, represent mid and deep urban canyons, respectively. The experimental results show that in terms of fault detection, the fault could be detected in mid urban canyons and the response time of fault disappearance is reduced by 70.24% in deep urban canyons. Thus, the poor sensitivity of the residual chi-square test for fault disappearance is improved. In terms of localization, the proposed algorithm is compared with the optimal fading factor adaptive filter (OFFAF) and the extended Kalman filter (EKF). The proposed algorithm is the most effective, and the Root Mean Square Error (RMSE) in the east and north is reduced by 12.98% and 35.1% in deep urban canyons. Regarding integrity assessment, the error bound can overbound the positioning errors in deep urban canyons relative to the EKF and the mean value of the error bounds is reduced. Numéro de notice : A2022-769 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.3390/rs14184641 Date de publication en ligne : 16/09/2022 En ligne : https://doi.org/10.3390/rs14184641 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101795 [article]

An algorithm to assist the robust filter for tightly coupled RTK/INS navigation system / Zun Niu in Remote sensing, vol 14 n° 10 (May-2 2022)  

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A new method for evaluation of the positional error of low-cost devices based on GNSS integrity for transportation applications / Luciano Aparecido Barbosa in Boletim de Ciências Geodésicas, vol 28 n° 1 ([01/03/2022])  

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Point-of-interest (POI) data validation methods: An urban case study / Lih Wei Yeow in ISPRS International journal of geo-information, vol 10 n° 11 (November 2021)  

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Real-time GNSS precise point positioning using improved robust adaptive Kalman filter / Abdelsatar Elmezayen in Survey review, Vol 53 n° 381 (November 2021)  

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Effect of using different satellite ephemerides on GPS PPP and post processing techniques / Khaled Mahmoud Abdel Aziz in Geodesy and cartography, vol 47 n° 3 (October 2021)  

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Mitigating high latitude ionospheric scintillation effects on GNSS Precise Point Positioning exploiting 1-s scintillation indices / Kai Guo in Journal of geodesy, vol 95 n° 3 (March 2021)  

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Adaptive filtering / Wenping Cao (2021)  

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An advanced residual error model for tropospheric delay estimation / Szabolcs Rózsa in GPS solutions, Vol 24 n° 4 (October 2020)  

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Assessing the quality of ionospheric models through GNSS positioning error: methodology and results / Adria Rovira-Garcia in GPS solutions, vol 24 n° 1 (January 2020)  

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Partial GNSS ambiguity resolution in coordinate domain / Shengyue Ji in Survey review, vol 51 n° 369 (November 2019)  

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