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Estimation of swell height using spaceborne GNSS-R data from eight CYGNSS satellites / Yanli Zheng in Remote sensing, vol 14 n° 18 (September-2 2022)
[article]
Titre : Estimation of swell height using spaceborne GNSS-R data from eight CYGNSS satellites Type de document : Article/Communication Auteurs : Yanli Zheng, Auteur ; Fu Zheng, Auteur ; Cheng Yang, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 4640 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données GLONASS
[Termes IGN] données GPS
[Termes IGN] double différence
[Termes IGN] latitude
[Termes IGN] positionnement ponctuel précis
[Termes IGN] positionnement statique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] temps de convergenceRésumé : (auteur) The orbital inclination angle of the GLONASS constellation is about 10° larger than that of GPS, Galileo, and BDS. Theoretically, the higher orbital inclination angle could provide better observation geometry in high latitude regions. A wealth of research has investigated the positioning accuracy of GLONASS and its impact on multi-GNSS, but rarely considered the contribution of the GLONASS constellation’s large orbit inclination angle. The performance of GLONASS in different latitude regions is evaluated in both stand-alone mode and integration with GPS in this paper. The performance of GPS is also presented for comparison. Three international GNSS service (IGS) networks located in high, middle, and low latitudes are selected for the current study. Multi-GNSS data between January 2021 and June 2021 are used for the assessment. The data quality check shows that the GLONASS data integrity is significantly lower than that of GPS. The constellation visibility analysis indicates that GLONASS has a much better elevation distribution than GPS in high latitude regions. Both daily double-difference network solutions and daily static Precise Point Positioning (PPP) solutions are evaluated. The statistical analysis of coordinate estimates indicates that, in high latitude regions, GLONASS has a comparable or even better accuracy than that of GPS, and GPS+GLONASS presents the best estimate accuracy; in middle latitude regions, GPS stand-alone constellation provides the best positioning accuracy; in low latitude regions, GLONASS offers the worst accuracy, but the positioning accuracy of GPS+GLONASS is better than that of GPS. The tropospheric estimates of GLONASS do not present a resemblance regional advantage as coordinate estimates, which is worse than that of GPS in all three networks. The PPP processing with combined GPS and GLONASS observations reduces the convergence time and improves the accuracy of tropospheric estimates in all three networks. Numéro de notice : A2022-770 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.3390/rs14184640 Date de publication en ligne : 16/09/2022 En ligne : https://doi.org/10.3390/rs14184640 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101796
in Remote sensing > vol 14 n° 18 (September-2 2022) . - n° 4640[article]Accuracy of GNSS RTK/NRTK height difference measurement / Robert Krzyzek in Applied geomatics, vol 14 n° 3 (September 2022)
[article]
Titre : Accuracy of GNSS RTK/NRTK height difference measurement Type de document : Article/Communication Auteurs : Robert Krzyzek, Auteur ; Jacek Kudrys, Auteur Année de publication : 2022 Article en page(s) : pp 491 - 499 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement par GNSS
[Termes IGN] précision du positionnementRésumé : (auteur) The absolute error of ellipsoidal heights that may be achieved from Real-Time Kinematic/Network Real-Time Kinematic Global Navigation Satellite Systems (RTK/NRTK GNSS) measurements varies between 3 and 5 cm. Although the vertical root mean square (RMS) error reported by receivers generally has smaller values, it can only be treated as a measure of the precision of the obtained results. Nowadays, real-time GNSS measurements are commonly used to implement surveys with increased accuracy. In some cases, it may be of concern to determine the height difference with real-time techniques than the height itself. The use of height difference may be applicable when a point with a known height is available. This offers the possibility of transferring the known height to a distant point using GNSS technology instead of geometric leveling, which is more labor-intensive. The aim of the study was to verify if achieving accuracy better than 2 cm in ellipsoidal height difference using RTK/NRTK GNSS is possible, providing special conditions of measurement. In this paper, the results of research consisting of RTK/NRTK measurement of specific points with fixed heights in various terrain conditions are presented. A single GNSS reference station was used as a base station to determine ellipsoidal height in RTK mode and Ground-Based Augmentation System (GBAS) for measurements in NRTK mode. Comparison of the ellipsoidal height difference to the results of precise leveling allows us to determine ellipsoidal height measurement errors. The measurements were carried out in open terrain, with the covered horizon (under trees) and in urbanized areas (high buildings). The method proposed by the authors in this paper does not require knowledge of the quasi-geoid model, neither normal correction to obtain measurement results. Numéro de notice : A2022-618 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s12518-022-00450-2 En ligne : https://doi.org/10.1007/s12518-022-00450-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101378
in Applied geomatics > vol 14 n° 3 (September 2022) . - pp 491 - 499[article]Ambiguity resolution for smartphone GNSS precise positioning: effect factors and performance / Bofeng Li in Journal of geodesy, vol 96 n° 9 (September 2022)
[article]
Titre : Ambiguity resolution for smartphone GNSS precise positioning: effect factors and performance Type de document : Article/Communication Auteurs : Bofeng Li, Auteur ; Weikai Miao, Auteur ; Guang'e Chen, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 63 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] ambiguïté entière
[Termes IGN] fréquence multiple
[Termes IGN] phase GNSS
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] précision du positionnement
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GNSS
[Termes IGN] téléphone intelligentRésumé : (auteur) With the availability of Global Navigation Satellite Systems raw measurements in smartphones, high-precision positioning using smartphones has become possible in recent years. Integer ambiguity resolution (IAR) is critical for smartphone precise positioning, which would be more difficult in smartphones and affected by various factors. In this paper, we will numerically study the effect factors for integer property of phase ambiguities, data quality, IAR efficiency and positioning accuracy for the smartphone. The results show that integer property of phase ambiguities and data quality are governed not only by the smartphone brands and embedded antennas, but also by the mobile operating system and smartphone attitudes. In general, the different constant offsets exist for the different frequency ambiguities, and the ambiguities are fixable once the corresponding offsets are calibrated. With the operating system of EMUI 9.0, the ambiguities are fixable for Xiaomi Mi8 but not for Huawei Mate20. However, with the updated operating system of EMUI 9.0.1, the ambiguities of Huawei Mate20 become fixable. Besides the smartphone brands and embedded antennas, the smartphone attitudes significantly affect the data quality, such as carrier-to-noise density ratio (C/N0) values, data availability and observation precisions, thus affecting the ambiguity fixing rate and positioning accuracy. The ambiguity fixing rates differ from attitudes by 17%, and generally, the upward attitude has the best performance. Finally, the kinematic positioning results indicate that only the meter-level accuracy is obtained with an embedded antenna, while the centimeter to decimeter-level accuracy is achievable with the external antenna. Numéro de notice : A2022-667 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01652-7 Date de publication en ligne : 05/09/2022 En ligne : https://doi.org/10.1007/s00190-022-01652-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101531
in Journal of geodesy > vol 96 n° 9 (September 2022) . - n° 63[article]Deflection of vertical effect on direct georeferencing in aerial mobile mapping systems: A case study in Sweden / Mohammad Bagherbandi in Photogrammetric record, vol 37 n° 179 (September 2022)
[article]
Titre : Deflection of vertical effect on direct georeferencing in aerial mobile mapping systems: A case study in Sweden Type de document : Article/Communication Auteurs : Mohammad Bagherbandi, Auteur ; Arash Jouybari, Auteur ; Faramarz Nilfouroushan, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 285 - 305 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie
[Termes IGN] couplage GNSS-INS
[Termes IGN] déviation de la verticale
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] ellipsoïde de référence
[Termes IGN] géoréférencement direct
[Termes IGN] photogrammétrie aérienne
[Termes IGN] quasi-géoïde
[Termes IGN] Suède
[Termes IGN] système de numérisation mobileRésumé : (auteur) GNSS/INS applications are being developed, especially for direct georeferencing in airborne photogrammetry. Achieving accurately georeferenced products from the integration of GNSS and INS requires removing systematic errors in the mobile mapping systems. The INS sensor's uncertainty is decreasing; therefore, the influence of the deflection of verticals (DOV, the angle between the plumb line and normal to the ellipsoid) should be considered in the direct georeferencing. Otherwise, an error is imposed for calculating the exterior orientation parameters of the aerial images and aerial laser scanning. This study determines the DOV using the EGM2008 model and gravity data in Sweden. The impact of the DOVs on horizontal and vertical coordinates, considering different flight altitudes and camera field of view, is assessed. The results confirm that the calculated DOV components using the EGM2008 model are sufficiently accurate for aerial mapping system purposes except for mountainous areas because the topographic signal is not modelled correctly. Numéro de notice : A2022-937 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.1111/phor.12421 Date de publication en ligne : 25/07/2022 En ligne : https://doi.org/10.1111/phor.12421 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102683
in Photogrammetric record > vol 37 n° 179 (September 2022) . - pp 285 - 305[article]Orbit determination, clock estimation and performance evaluation of BDS-3 PPP-B2b service / Chengpan Tang in Journal of geodesy, vol 96 n° 9 (September 2022)
[article]
Titre : Orbit determination, clock estimation and performance evaluation of BDS-3 PPP-B2b service Type de document : Article/Communication Auteurs : Chengpan Tang, Auteur ; Xiaogong Hu, Auteur ; Jinping Chen, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 60 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] filtre de Kalman
[Termes IGN] horloge du satellite
[Termes IGN] orbitographie
[Termes IGN] positionnement par BeiDou
[Termes IGN] positionnement ponctuel précis
[Termes IGN] temps réelRésumé : (auteur) This paper focuses on PPP-B2b, one of the featured services for BDS-3, which provides users around China with centimetre-level static positioning accuracy and decimetre-level kinematic positioning accuracy by broadcasting precise corrections for GPS/BDS-3 satellites. The GEO PPP-B2b signal broadcasted information types, including the PRN mask, orbit corrections, differential code bias corrections and clock corrections, are introduced, as well as a brief description of their usage. A new orbit determination strategy using regional L-band code/phase measurements and inter-satellite link measurements in combination and a real-time clock estimation strategy based on the Kalman filter for PPP-B2b precise correction generation are introduced in this contribution. Then, the accuracy of the orbit and clock corrections is assessed. The orbit user ranging error (URE) is 0.05 m for the BDS-3 MEO and GPS satellites. The orbit URE for BDS-3 IGSO satellites is worse, i.e., 0.15 m. The clock correction accuracy is 0.2 ns for BDS-3 and GPS satellites. Finally, the PPP-B2b performance is validated by both the static PPP process and simulated kinematic PPP process. BDS-3/GPS dual-system PPP offers faster convergence and better accuracy. The positioning accuracy achievable using PPP-B2b real-time products is at the same level as that using post-processed products. The RMS for BDS-3/GPS dual-system static positioning errors is less than 1.0 cm in east and north and about 3.0 cm in the up. The simulated kinematic positioning accuracy is better than 2.5 cm in the north, 3.5 cm in the east and 8.5 cm in the up directions after convergence. Numéro de notice : A2022-669 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-022-01642-9 Date de publication en ligne : 29/08/2022 En ligne : https://doi.org/10.1007/s00190-022-01642-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101553
in Journal of geodesy > vol 96 n° 9 (September 2022) . - n° 60[article]Rapid source models of the 2021 Mw 7.4 Maduo, China, earthquake inferred from high-rate BDS3/2, GPS, Galileo and GLONASS observations / Jianfei Zang in Journal of geodesy, vol 96 n° 9 (September 2022)PermalinkGNSS integer ambiguity posterior probability calculation with controllable accuracy / Zemin Wu in Journal of geodesy, vol 96 n° 8 (August 2022)PermalinkPositioning performance of GNSS-PPP and PPP-AR methods for determining the vertical displacements / Burak Akpinar in Survey review, vol 55 n° 388 (January 2023)PermalinkAn accurate train positioning method using tightly-coupled GPS + BDS PPP/IMU strategy / Wei Jiang in GPS solutions, vol 26 n° 3 (July 2022)PermalinkEvaluation of QZSS orbit and clock products for real-time positioning applications / Brian Bramanto in Journal of applied geodesy, vol 16 n° 3 (July 2022)PermalinkGlobal forecasting of ionospheric vertical total electron contents via ConvLSTM with spectrum analysis / Jinpei Chen 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)PermalinkMulti-frequency phase-only PPP-RTK model applied to BeiDou data / Pengyu Hou in GPS solutions, vol 26 n° 3 (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)PermalinkEstimation a priori de l’incertitude altimétrique des positionnements GNSS en RTK ou en statique post-traité : existe-t-il un modèle ? / Thomas Touzé in XYZ, n° 171 (juin 2022)Permalink