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GNSS integer ambiguity posterior probability calculation with controllable accuracy / Zemin Wu in Journal of geodesy, vol 96 n° 8 (August 2022)
[article]
Titre : GNSS integer ambiguity posterior probability calculation with controllable accuracy Type de document : Article/Communication Auteurs : Zemin Wu, Auteur Année de publication : 2022 Article en page(s) : n° 53 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] erreur moyenne quadratique
[Termes IGN] estimation de précision
[Termes IGN] incertitude de position
[Termes IGN] positionnement par GNSS
[Termes IGN] résolution d'ambiguïtéRésumé : (auteur) Integer ambiguity resolution (IAR) is one of the key techniques in GNSS high precise positioning. However, an overlooked incorrect integer ambiguity solution may cause severe biases in the positioning results. The optimal integer aperture estimator (IAE) has the largest possible success rate given a certain fail rate. An alternative approach that take advantage of ambiguity integer nature to minimize the solution’s mean squared error (MSE) is known as the best integer equivariant (BIE) estimator. Both of which are associated with the posterior probability of the GNSS integer ambiguity. It is therefore of great significance to calculate posterior probability precisely and efficiently. Due to the occurrence of infinite sums, practical calculation approaches approximate the exact value by neglecting sufficiently small terms in the sum. As a result, they can only produce posterior probability calculation result, information about the result’s accuracy cannot be produced. In this contribution, the value of the posterior probability is bounded from below and from above by dividing the infinite sum into two parts: the major finite part and the minor infinite part. They are calculated partly by enumeration and partly by algebraical bounding. The obtained upper and lower bounds are rigorous and in closed form, so that can be conveniently used. Based on both of the bounds, a method of posterior probability calculation with controllable accuracy is proposed. It not only produces posterior probability calculation result, but also calculation error, which is always smaller than the user-defined acceptable error. Numerical experiments have verified that the proposed approach has advantages on both controllable calculation accuracy and adjustable computational workload. Numéro de notice : A2022-607 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01633-w Date de publication en ligne : 10/08/2022 En ligne : https://doi.org/10.1007/s00190-022-01633-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101386
in Journal of geodesy > vol 96 n° 8 (August 2022) . - n° 53[article]Ground surface elevation changes over permafrost areas revealed by multiple GNSS interferometric reflectometry / Yufeng Hu in Journal of geodesy, vol 96 n° 8 (August 2022)
[article]
Titre : Ground surface elevation changes over permafrost areas revealed by multiple GNSS interferometric reflectometry Type de document : Article/Communication Auteurs : Yufeng Hu, Auteur ; Ji Wang, Auteur ; Zhenhong Li, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 56 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Alaska (Etats-Unis)
[Termes IGN] analyse diachronique
[Termes IGN] dégel
[Termes IGN] données Galileo
[Termes IGN] données GLONASS
[Termes IGN] pergélisol
[Termes IGN] rapport signal sur bruit
[Termes IGN] réflecteur
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GNSS
[Termes IGN] surface du sol
[Termes IGN] variation saisonnièreRésumé : (auteur) Ground subsidence and uplift caused by the annual thawing and freezing of the active layer are important variables in permafrost studies. Global positioning system interferometric reflectometry (GPS-IR) has been successfully applied to retrieve the continuous ground surface movements in permafrost areas. However, only GPS signals were used in previous studies. In this study, using multiple global navigation satellite system (GNSS) signal-to-noise ratio (SNR) observations recorded by a GNSS station SG27 in Utqiaġvik, Alaska during the period from 2018 to 2021, we applied multiple GNSS-IR (multi-GNSS-IR) technique to the SNR data and obtained the complete and continuous ground surface elevation changes over the permafrost area at a daily interval in snow-free seasons in 2018 and 2019. The GLONASS-IR and Galileo-IR measurements agreed with the GPS-IR measurements at L1 frequency, which are the most consistent measurements among all multi-GNSS measurements, in terms of the overall subsidence trend but clearly showed periodic noises. We proposed a method to reconstruct the GLONASS- and Galileo-IR elevation changes by specifically grouping and fitting them with a composite model. Compared with GPS L1 results, the unbiased root mean square error (RMSE) of the reconstructed Galileo measurements reduced by 50.0% and 42.2% in 2018 and 2019, respectively, while the unbiased RMSE of the reconstructed GLONASS measurements decreased by 41.8% and 25.8% in 2018 and 2019, respectively. Fitting the composite model to the combined multi-GNSS-IR, we obtained seasonal displacements of − 3.27 ± 0.13 cm (R2 = 0.763) and − 10.56 ± 0.10 cm (R2 = 0.912) in 2018 and 2019, respectively. Moreover, we found that the abnormal summer heave was strongly correlated with rain events, implying hydrological effects on the ground surface elevation changes. Our study shows the feasibility of multi-GNSS-IR in permafrost areas for the first time. Multi-GNSS-IR opens up a great opportunity for us to investigate ground surface movements over permafrost areas with multi-source observations, which are important for our robust analysis and quantitative understanding of frozen ground dynamics under climate change. Numéro de notice : A2022-606 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01646-5 Date de publication en ligne : 13/08/2022 En ligne : https://doi.org/10.1007/s00190-022-01646-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101385
in Journal of geodesy > vol 96 n° 8 (August 2022) . - n° 56[article]Positioning performance of GNSS-PPP and PPP-AR methods for determining the vertical displacements / Burak Akpinar in Survey review, vol 55 n° 388 (January 2023)
[article]
Titre : Positioning performance of GNSS-PPP and PPP-AR methods for determining the vertical displacements Type de document : Article/Communication Auteurs : Burak Akpinar, Auteur Année de publication : 2022 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse comparative
[Termes IGN] ouvrage d'art
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précision millimétrique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] surveillance d'ouvrageRésumé : (auteur) This study investigates the accuracy of vertical displacements monitored by Global Navigation Satellite Systems (GNSS) precise point positioning (PPP) with float-ambiguity solution and with ambiguity resolution (PPP-AR). For this purpose, a simulation was designed. The static GNSS observations were collected at a test point during different observation times over seven periods involving vertical displacements produced with a precision of less than one mm. Each set of GNSS observations was processed with both GNSS-PPP and PPP-AR methods. The results revealed that RMS values of PPP-AR solutions are about twice better than RMS values of PPP solution for all observation times and all vertical displacement values. Numéro de notice : A2022-033 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2021.2010018 Date de publication en ligne : 13/12/2021 En ligne : https://doi.org/10.1080/00396265.2021.2010018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99295
in Survey review > vol 55 n° 388 (January 2023)[article]An accurate train positioning method using tightly-coupled GPS + BDS PPP/IMU strategy / Wei Jiang in GPS solutions, vol 26 n° 3 (July 2022)
[article]
Titre : An accurate train positioning method using tightly-coupled GPS + BDS PPP/IMU strategy Type de document : Article/Communication Auteurs : Wei Jiang, Auteur ; Mengyang Liu, Auteur ; Baigen Cai, Auteur Année de publication : 2022 Article en page(s) : n° 67 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] Chine
[Termes IGN] filtre de Kalman
[Termes IGN] phase
[Termes IGN] positionnement inertiel
[Termes IGN] positionnement par BeiDou
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] signal GPS
[Termes IGN] simple différence
[Termes IGN] trainRésumé : (auteur) A new GNSS/IMU tightly coupled positioning system is introduced to train positioning. To fulfil a train control system’s aim of reducing the need to install trackside equipment, the GNSS precise point positioning (PPP) method is applied in place of the conventional differential GNSS method. As the railway environment has the character of long operational mileage and complex GNSS measurement conditions, the GPS and BDS constellations are combined with measurement processing to improve the system’s continuity and stability. Ultra-rapid GNSS orbit and clock product is used for real-time PPP. The GNSS-PPP and IMU are tightly coupled using an Extended Kalman filter with single-differenced ionospheric-free GPS + BDS carrier phase and pseudorange observations. The carrier phase ambiguities are estimated as “float” values every epoch to reduce the impact of GNSS signal loss-of-lock and cycle slips. A train experiment was conducted on the Qinghai-Tibet Railway to evaluate system performance. The results show that the proposed system has a better performance than the conventional methods, including GPS + BDS PPP, LC GPS + BDS PPP/IMU and TC GPS PPP/IMU, with 52.1%, 49.4% and 52.1%, respectively. The tightly-coupled GPS + BDS PPP/IMU system under conditions of partly blocked GNSS coverage was evaluated to evaluate the system's continuity. It was confirmed that the proposed system had more stable positioning results and higher positioning accuracy. Numéro de notice : A2022-361 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-022-01250-2 Date de publication en ligne : 08/04/2022 En ligne : https://doi.org/10.1007/s10291-022-01250-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100580
in GPS solutions > vol 26 n° 3 (July 2022) . - n° 67[article]Detection of GNSS no-line of sight signals using LiDAR sensors for intelligent transportation systems / Tarek Hassan in Survey review, vol 54 n° 385 (July 2022)
[article]
Titre : Detection of GNSS no-line of sight signals using LiDAR sensors for intelligent transportation systems Type de document : Article/Communication Auteurs : Tarek Hassan, Auteur ; Tamer Fath-Allah, Auteur ; Mohamed Elhabiby, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 301 - 309 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] détection du signal
[Termes IGN] données lidar
[Termes IGN] positionnement ponctuel précis
[Termes IGN] semis de points
[Termes IGN] signal GNSS
[Termes IGN] système de transport intelligent
[Termes IGN] traitement de données GNSSRésumé : (auteur) The reliability and robustness of positioning systems in urban and suburban environments are intrinsic. This is obvious following the continuous increase of Intelligent Transportation Systems (ITS) applications in such challenging environments. Global Navigation Satellite Systems (GNSS) represent the primary positioning technique used for navigation purposes in these applications, which can be satisfying in open-sky areas. However, GNSS cannot provide the same level of navigation performance in urban environments. One of the main reasons for this is the No-Line of Sight (NLOS) signals. In this study, the integration of GNSS and Light Detection and Ranging (LiDAR) sensors is exploited, and a new algorithm is proposed for the detection of NLOS signals. Real field data are used to test and validate the proposed strategy and algorithm. Phase-smoothed code observations are employed to evaluate the accuracy improvement after excluding the NLOS observations. The results show that the horizontal direction's positional accuracy can be improved significantly after applying the proposed algorithm. This improvement reaches 10.403 m with a mean value of 2.162 m (62.2% improvement) over all epochs with detected NLOS signals. After analysing this improvement in the Cross-Track (CT) and Along-Track (AT) directions, it is found that the accuracy improvement reaches 8.641 m with a mean value of 1.699 m in the CT direction and 6.879 m with a mean value of 1.303 m in the AT direction. Numéro de notice : A2022-535 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2021.1937458 Date de publication en ligne : 10/06/2021 En ligne : https://doi.org/10.1080/00396265.2021.1937458 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101091
in Survey review > vol 54 n° 385 (July 2022) . - pp 301 - 309[article]Evaluation of QZSS orbit and clock products for real-time positioning applications / Brian Bramanto in Journal of applied geodesy, vol 16 n° 3 (July 2022)PermalinkEvaluation of the GSRM2.1 and the NUVEL1-A values in Europe using SLR and VLBI based geodetic velocity fields / Mina Rahmani in Survey review, vol 54 n° 385 (July 2022)PermalinkFusion of GNSS and InSAR time series using the improved STRE model: applications to the San Francisco bay area and Southern California / Huineng Yan in Journal of geodesy, vol 96 n° 7 (July 2022)PermalinkGNSS carrier phase time-variant observable-specific signal bias (OSB) handling: an absolute bias perspective in multi-frequency PPP / Ke Su in GPS solutions, vol 26 n° 3 (July 2022)PermalinkIntegration of GNSS observations with volunteered geographic information for improved navigation performance / Tarek Hassan in Journal of applied geodesy, vol 16 n° 3 (July 2022)PermalinkLidar point-to-point correspondences for rigorous registration of kinematic scanning in dynamic networks / Aurélien Brun in ISPRS Journal of photogrammetry and remote sensing, vol 189 (July 2022)PermalinkMulti-frequency phase-only PPP-RTK model applied to BeiDou data / Pengyu Hou in GPS solutions, vol 26 n° 3 (July 2022)PermalinkA new ambiguity resolution method for LEO precise orbit determination / Xingyu Zhou in Journal of geodesy, vol 96 n° 7 (July 2022)PermalinkOutliers and uncertainties in GNSS ZTD estimates from double-difference processing and precise point positioning / Katarzyna Stępniak in GPS solutions, vol 26 n° 3 (July 2022)PermalinkValidation of regional and global ionosphere maps from GNSS measurements versus IRI2016 during different magnetic activity / Ahmed Sedeek in Journal of applied geodesy, vol 16 n° 3 (July 2022)PermalinkAjustement en bloc des données de stations totales et de récepteurs GNSS dans les études de déformation / Joël Van Cranenbroeck in XYZ, n° 171 (juin 2022)PermalinkLa puissance spatiale chinoise s’affirme / Laurent Polidori in Géomètre, n° 2203 (juin 2022)PermalinkAssessing the positioning performance of GNSS receivers under different geomagnetic storm conditions / Chao Yan in Survey review, vol 54 n° 384 (May 2022)PermalinkGalileo tient enfin ses promesses / Laurent Polidori in Géomètre, n° 2202 (mai 2022)PermalinkA novel ionospheric mapping function modeling at regional scale using empirical orthogonal functions and GNSS data / Peng Chen in Journal of geodesy, vol 96 n° 5 (May 2022)PermalinkAn improved vertical correction method for the inter-comparison and inter-validation of Integrated Water Vapour measurements [under review] / Olivier Bock in Atmospheric measurement techniques, vol 15 n° 19 ([01/04/2022])PermalinkAssessment of RTK quadcopter and structure-from-motion photogrammetry for fine-scale monitoring of coastal topographic complexity / Stéphane Bertin in Remote sensing, vol 14 n° 7 (April-1 2022)PermalinkCharacteristics of the BDS-3 multipath effect and mitigation methods using precise point positioning / Ran Lu in GPS solutions, vol 26 n° 2 (April 2022)PermalinkCoastal observation of sea surface tide and wave height using opportunity signal from Beidou GEO satellites: analysis and evaluation / Feng Wang in Journal of geodesy, vol 96 n° 4 (April 2022)PermalinkDetection and mitigation of GNSS spoofing via the pseudorange difference between epochs in a multicorrelator receiver / Xiangyong Shang in GPS solutions, vol 26 n° 2 (April 2022)Permalink