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Constrained and network multi-receiver single-epoch RTK positioning / Mieczysław Bakula in Survey review, vol 52 n° 373 (July 2020)  

Public [article]  inSurvey review > vol 52 n° 373 (July 2020) . - pp 289 - 298 Titre : Constrained and network multi-receiver single-epoch RTK positioning Type de document : Article/Communication Auteurs : Mieczysław Bakula, Auteur Année de publication : 2020 Article en page(s) : pp 289 - 298 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes descripteurs IGN] compensation par moindres carrés [Termes descripteurs IGN] EUPOS [Termes descripteurs IGN] instrumentation Trimble [Termes descripteurs IGN] modèle mathématique [Termes descripteurs IGN] positionnement cinématique en temps réel [Termes descripteurs IGN] récepteur GNSS [Termes descripteurs IGN] station de référence Résumé : (auteur) This work presents the concept of RTK positioning based on two or three rover GNSS receivers from two or three different reference stations. Additionally, detailed mathematical models of constrained least squares adjustments of RTK positioning based on two or three different RTK/GNSS receivers are presented. The models were tested on real RTK data using three rover Trimble RTK receivers and three reference stations of the ASG-EUPOS system. Practical calculations obtained from the adjustments showed improved accuracy over traditional RTK positioning when reference GNSS stations were located far away (about 30 km from the mobile RTK receivers). The maximum average absolute error for horizontal and vertical coordinates in constrained RTK positioning was over two times lower than in the single baseline RTK positioning, and reached 0.021 and 0.046 m, respectively. Since the concept of constrained and redundant, single-epoch RTK adjustment can be used for static or kinematic applications in real-time positioning, it can also be widely used in geoscience surveying and remote sensing. Numéro de notice : A2020-376 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2018.1547532 date de publication en ligne : 28/11/2018 En ligne : https://doi.org/10.1080/00396265.2018.1547532 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95352 [article]

Evaluations of the significant wave height products of HY-2B satellite radar altimeters / Yongjun Jia in Marine geodesy, Vol 43 n° 4 (July 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 4 (July 2020) . - pp 396 - 413 Titre : Evaluations of the significant wave height products of HY-2B satellite radar altimeters Type de document : Article/Communication Auteurs : Yongjun Jia, Auteur ; Mingsen Lin, Auteur ; Youguang Zhang, Auteur Année de publication : 2020 Article en page(s) : pp 396 - 413 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] données Jason [Termes descripteurs IGN] précision centimétrique [Termes descripteurs IGN] précision des données Résumé : (Auteur) In the present study, the qualities of the HY-2B along-track significant wave heights (SWH) are assessed, including precision and accuracy. A quality evaluation based on 1 Hz standard deviations is proposed to detect the precision of HY-2B SWH products. The density plots of the (SWH, std) pairs obtained by the HY-2B, Jason-2 and Jason-3 are compared. And the results indicates that the HY-2B SWH root mean square error levels are significantly lower than those observed for the other altimeters. With respect to the SWH obtained from the wave rider buoys, buoys of the National Data Buoy Center (NDBC), Jason-2 and Jason-3, the root mean square errors are 24 cm, 27 cm, 26 cm and 23 cm respectively. The comparison results confirm that the quality of the HY-2B SWH data higher. Numéro de notice : A2020-249 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1750513 date de publication en ligne : 10/04/2020 En ligne : https://doi.org/10.1080/01490419.2020.1750513 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95370 [article]

GPS + Galileo + BeiDou precise point positioning with triple-frequency ambiguity resolution / Pan Li in GPS solutions, Vol 24 n° 3 (July 2020)  

Public [article]  inGPS solutions > Vol 24 n° 3 (July 2020) . - 13 p. Titre : GPS + Galileo + BeiDou precise point positioning with triple-frequency ambiguity resolution Type de document : Article/Communication Auteurs : Pan Li, Auteur ; Xinyuan Jiang, Auteur ; Xiaohong Zhang, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 13 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] constellation Galileo [Termes descripteurs IGN] décalage d'horloge [Termes descripteurs IGN] erreur systématique interfréquence d'horloge [Termes descripteurs IGN] positionnement par BeiDou [Termes descripteurs IGN] positionnement par Galileo [Termes descripteurs IGN] positionnement par GPS [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] résolution d'ambiguïté [Termes descripteurs IGN] retard troposphérique [Termes descripteurs IGN] temps de convergence [Termes descripteurs IGN] triple différence Résumé : (auteur) Along with the rapid development of GNSS, not only BeiDou, but also Galileo, and the newly launched GPS satellites can provide signals on three frequencies at present. To fully take advantage of the multi-frequency multi-system GNSS observations on precise point positioning (PPP) technology, this study aims to implement the triple-frequency ambiguity resolution (AR) for GPS, Galileo, and BeiDou-2 combined PPP using the raw observation model. The processing of inter-frequency clock bias (IFCB) estimation and correction in the context of triple-frequency PPP AR has been addressed, with which the triple-frequency uncalibrated phase delay (UPD) estimation is realized for real GPS observations for the first time. In addition, the GPS extra-wide-line UPD quality is significantly improved with the IFCB correction. Because of not being contaminated by the IFCB, the raw UPD estimation method is directly employed for Galileo which currently has 24 satellites in operation. An interesting phenomenon is found that all Galileo satellites except E24 have a zero extra-wide-lane UPD value. With the multi-GNSS observations provided by MGEX covering 15 days, the positioning solutions of GPS + Galileo + BeiDou triple-frequency PPP AR have been conducted and analyzed. The triple-frequency kinematic GNSS PPP AR can achieve an averaged 3D positioning error of 2.2 cm, and an averaged convergence time of 10.8 min. The average convergence time can be reduced by triple-frequency GNSS PPP AR by 15.6% compared with dual-frequency GNSS PPP AR, respectively. However, the additional third frequency has only a marginal contribution to positioning accuracy after convergence. Numéro de notice : A2020-325 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-00992-1 date de publication en ligne : 27/05/2020 En ligne : https://doi.org/10.1007/s10291-020-00992-1 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95205 [article]

Learning evolving user’s behaviors on location-based social networks / Ruizhi Wu in Geoinformatica [en ligne], vol 24 n° 3 (July 20202)  

Public [article]  inGeoinformatica [en ligne] > vol 24 n° 3 (July 20202) . - pp 713 – 743 Titre : Learning evolving user’s behaviors on location-based social networks Type de document : Article/Communication Auteurs : Ruizhi Wu, Auteur ; Guangchun Luo, Auteur ; Qi jin, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 713 – 743 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes descripteurs IGN] comportement [Termes descripteurs IGN] données localisées des bénévoles [Termes descripteurs IGN] filtrage d'information [Termes descripteurs IGN] géopositionnement [Termes descripteurs IGN] interaction homme-milieu [Termes descripteurs IGN] modèle dynamique [Termes descripteurs IGN] réseau social géodépendant [Termes descripteurs IGN] utilisateur Résumé : (auteur) With the popularity of smart phones, users’ activities on location-based social networks (LBSNs) evolve faster than traditional social networks. Existing models focus on modeling users’ long-term preferences, leveraging social collaborative filtering to enhance prediction performance. However, the dynamic mobility mechanism of user’s check-in behaviors on LBSNs is seldom considered. In this paper, we propose a new dynamic model that considers both geo-aware user preferences and the social interaction excitation arising from social connections to learn the dynamic mobility mechanism of user’s behaviors on LBSNs. Geo-aware location features, such as semantic features, latent features and dynamic features, are utilized to characterize the location information and reveal the evolution of the geographical impact of location. These geo-aware location features enable us to exploit user’s personal preferences. Meanwhile, we integrate a user’s social connections and friends’ preferences for modeling social interaction excitations. Finally, we jointly incorporate geo-aware user preference learning and social interaction excitation modeling to create a conditional intensity function for temporal point processes with which to explore the dynamic mobility mechanism of evolving user’s check-in behaviors on LBSNs. Extensive experiments on several real-world check-in datasets confirm that our proposed algorithm performs better than existing state-of-the-art methods. Numéro de notice : A2020-372 Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10707-020-00400-3 date de publication en ligne : 16/03/2020 En ligne : https://doi.org/10.1007/s10707-020-00400-3 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95267 [article]

Precise point positioning with decimetre accuracy using wide-lane ambiguities and triple-frequency GNSS data / Manoj Deo in Journal of applied geodesy, vol 14 n° 3 (July 2020)  

Public [article]  inJournal of applied geodesy > vol 14 n° 3 (July 2020) . - pp 263 – 284 Titre : Precise point positioning with decimetre accuracy using wide-lane ambiguities and triple-frequency GNSS data Type de document : Article/Communication Auteurs : Manoj Deo, Auteur ; Ahmed El-Mowafy, Auteur Année de publication : 2020 Article en page(s) : pp 263 – 284 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes descripteurs IGN] ambiguïté entière [Termes descripteurs IGN] bruit atmosphérique [Termes descripteurs IGN] combinaison linéaire [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] phase [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] triple différence Résumé : (auteur) This paper proposes precise point positioning (PPP) methods that offer an accuracy of a few decimetres (dm) with triple frequency GNSS data. Firstly, an enhanced triple frequency linear combination is presented for rapid fixing of the extra wide-lane (EWL) and wide-lane (WL) ambiguities for GPS, Beidou-2 and Galileo. This has improved performance compared to the Melbourne-Wübbena (MW) linear combination, and has 6.7 % lower measurement noise for the GPS L1/L2 signals, 12.7 % for L1/L5 and 0.7 % for L2/L5. Analysis with tested data showed a 5–6 % reduction in time required to fix the N21 and N51 ambiguities. Once the EWL/WL ambiguities are fixed with the proposed linear combinations, three methods are presented that aim to provide positioning accuracy of a few dm. In the first approach, the three EWL/WL ambiguities in their respective phase equations are used to derive a low-noise ionosphere-free (IF) linear combination. The second method uses a low noise IF combination with two carrier-phase EWL/WL equations and a single pseudorange measurement. The third method uses a low noise IF combination with a single carrier phase EWL equation and two pseudorange measurements. These proposed methods can provide dm level positioning accuracy if carrier phase measurements with mm precision is tracked by the receiver. When comparing these combinations with a combination proposed in [], it is found that superior performance is achieved with the third method when carrier phase noise is >5–6 mm for GPS and Beidou-2 and >2–3 mm for Galileo. This model only requires the EWL ambiguity to be fixed which typically takes just one epoch of data. Thus, the user achieves instant decimetre level PPP accuracy. Numéro de notice : A2020-396 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0068 date de publication en ligne : 11/03/2020 En ligne : https://doi.org/10.1515/jag-2019-0068 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95432 [article]

Reestimating a minimum acceptable geocoding hit rate for conducting a spatial analysis / Alvaro Briz-Redon in International journal of geographical information science IJGIS, vol 34 n° 7 (July 2020)  

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Stochastic modeling for VRS network-based GNSS RTK with residual interpolation uncertainty / Thanate Jongrujinan in Journal of applied geodesy, vol 14 n° 3 (July 2020)  

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Accuracy assessment of real-time kinematics (RTK) measurements on unmanned aerial vehicles (UAV) for direct geo-referencing / Desta Ekaso in Geo-spatial Information Science, vol 23 n° 2 (June 2020)  

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Developing shopping and dining walking indices using POIs and remote sensing data / Yingbin Deng in ISPRS International journal of geo-information, vol 9 n° 6 (June 2020)  

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Improving GNSS-acoustic positioning by optimizing the ship’s track lines and observation combinations / Guanxu Chen in Journal of geodesy, vol 94 n° 6 (June 2020)  

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Indoor positioning using PnP problem on mobile phone images / Hana Kubickova in ISPRS International journal of geo-information, vol 9 n° 6 (June 2020)  

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Dynamic floating stations model for emergency medical services with a consideration of traffic data / Chih-Hong Sun in ISPRS International journal of geo-information, vol 9 n° 5 (May 2020)  

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Optimal lowest astronomical tide estimation using maximum likelihood estimator with multiple ocean models hybridization / Mohammed El-Diasty in ISPRS International journal of geo-information, vol 9 n° 5 (May 2020)  

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Pedestrian network generation based on crowdsourced tracking data / Xue Yang in International journal of geographical information science IJGIS, vol 34 n° 5 (May 2020)  

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Antenna phase center correction differences from robot and chamber calibrations: the case study LEIAR25 / Grzegorz Krzan in GPS solutions, vol 24 n° 2 (April 2020)  

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