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Performance tests of geodetic receivers with tilt sensors in obstructed environments using the NRTK GNSS technique / Puttipol Dumrongchai in Journal of applied geodesy, vol 17 n° 1 (January 2023)
[article]
Titre : Performance tests of geodetic receivers with tilt sensors in obstructed environments using the NRTK GNSS technique Type de document : Article/Communication Auteurs : Puttipol Dumrongchai, Auteur ; Jittranud Patsadutarn, Auteur ; Chalermchon Satirapod, Auteur Année de publication : 2023 Article en page(s) : pp 39 - 51 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] centrale inertielle
[Termes IGN] Continuously Operating Reference Station network
[Termes IGN] délimitation
[Termes IGN] lever cadastral
[Termes IGN] microsystème électromécanique
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] récepteur GNSS
[Termes IGN] signal GNSS
[Termes IGN] station virtuelle de référence
[Termes IGN] ThaïlandeRésumé : (auteur) The Department of Lands (DOL), Thailand, has adopted the Network-based Real-Time Kinematic (NRTK) Global Navigation Satellite System (GNSS) surveying technique using a Virtual Reference Station (VRS) to support cadastral surveys since 2011. Determining accurate coordinates of parcel boundary markers at building corners or near fences and walls is difficult because a GNSS range pole cannot be leveled with a circular bubble. This study aims to evaluate the performance of the receivers equipped with tilt sensors for horizontal and vertical positioning. Two types of tilt sensors used for evaluation were a magnetometer and micro-electro-mechanical system (MEMS) and an inertial measurement unit (IMU). Conducting the NRTK GNSS surveying tests was based on the pole tilt angles of 0°, 15°, 25°, 35°, and 45° from a plumb line in controlled and obstructed environments. The IMU-based tilt sensor had more advantage of accurately positioning over the MEMS sensor. The results showed that using the IMU, better than 4 cm horizontal positioning accuracy was achievable when the pole was tilted by 15° or less under non-multipath and open-sky conditions. The vertical accuracy was of a few centimeter levels and least sensitive to tilt angles using either type of sensor. However, none of the sensors precisely compensated for pole tilt in strong-multipath and complex environments, causing increased horizontal errors in decimeter levels. Numéro de notice : A2023-111 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2022-0047 Date de publication en ligne : 07/11/2022 En ligne : https://doi.org/10.1515/jag-2022-0047 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102470
in Journal of applied geodesy > vol 17 n° 1 (January 2023) . - pp 39 - 51[article]Precise orbit determination for BDS-3 GEO satellites enhanced by intersatellite links / Xiaojie Li in GPS solutions, vol 27 n° 1 (January 2023)
[article]
Titre : Precise orbit determination for BDS-3 GEO satellites enhanced by intersatellite links Type de document : Article/Communication Auteurs : Xiaojie Li, Auteur ; Xiaogong Hu, Auteur ; Rui Guo, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 8 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes IGN] constellation BeiDou
[Termes IGN] décalage d'horloge
[Termes IGN] orbite géostationnaire
[Termes IGN] orbite précise
[Termes IGN] orbitographie
[Termes IGN] qualité des donnéesRésumé : (auteur) Geostationary orbit (GEO) satellites are an integral part of the BeiDou Navigation Satellite System (BDS). Precise orbit determination (POD) for GEO satellites is difficult due to their geostationary characteristics. The orbit determination accuracy that can be achieved based on regional tracking stations in China cannot satisfy high-precision service requirements. The third generation of BDS (BDS-3) is the first global navigation satellite system that synergistically uses regional monitoring stations and global intersatellite links (ISLs) to realize global service. In this study, the quality of ISL data is analyzed based on the residuals of the intersatellite clock offset and the observed-minus-computed residuals of the ISL data. The orbit determination accuracy is assessed based on the observation residuals, the multiday consistency of the ISL time delays, overlapping orbit comparison, the user equivalent range error (UERE), and the accuracy of the clock offset. The results show that the ISL measurement noise for the GEO satellites is 3 cm, and the multiday consistency accuracy of the ISL time delay is better than 0.07 ns. Compared to the satellite-to-ground link (SGL)-based orbit determination method, the root mean square (RMS) three-dimensional (3D) position error of the overlapping orbit differences (OODs) is improved from 1.11 to 0.22 m with the combined SGL- and ISL-based method. Simultaneously, the UERE improves from 0.57 to 0.19 m, and the accuracy of the satellite clock offset improves from 1.09 to 0.61 ns. Numéro de notice : A2023-001 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-022-01330-3 Date de publication en ligne : 14/10/2022 En ligne : https://doi.org/10.1007/s10291-022-01330-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101870
in GPS solutions > vol 27 n° 1 (January 2023) . - n° 8[article]Spatiotemporal accuracy evaluation and errors analysis of global VTEC maps using a simulation technique / Jian Lin in GPS solutions, vol 27 n° 1 (January 2023)
[article]
Titre : Spatiotemporal accuracy evaluation and errors analysis of global VTEC maps using a simulation technique Type de document : Article/Communication Auteurs : Jian Lin, Auteur ; Xinxing Li, Auteur ; Shenfeng Gu, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 6 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données GPS
[Termes IGN] harmonique sphérique
[Termes IGN] modèle cartographique
[Termes IGN] modèle ionosphérique
[Termes IGN] phase
[Termes IGN] rayonnement solaire
[Termes IGN] simulation
[Termes IGN] station GPS
[Termes IGN] teneur verticale totale en électronsRésumé : (auteur) The computation of vertical total electron content (VTEC) maps has become an important issue gradually for the international GNSS service. Given the current literature reports, little research is involved in the quantitative analysis of each error of the VTEC map and the spatiotemporal characteristic of global VTEC accuracy. Based on the single layer model and sphere harmonic function, we propose an approach using simulated GPS data to comprehensively verify the accuracy of the VTEC map. The spatiotemporal characteristic of global VTEC accuracy and the errors induced by different processing steps, i.e., carrier phase to code leveling, mapping function (MF), DCB estimation and coefficient fitting, are analyzed and discussed in detail. In addition, the effect of solar activity on the accuracy of the global VTEC map, MF and DCB estimation has been discussed. The results suggest: First, it is found that the MF error at sunrise is more significant than that at sunset, and this important characteristic can be proven based on the analysis of theory and ionospheric radio occultation and VTEC measurements; second, the MF is the most significant error source in the VTEC processing for regions with dense and homogeneous distributed GPS stations, e.g., North America and Europe. The VTEC accuracy in these regions can be improved by 100% with the satellite elevation cutoff angle increasing from 12° to 30°; finally, compared with the global VTEC accuracy using 350 GPS stations observations, the accuracy is improved by 306% based on the double GPS stations with even distribution. Numéro de notice : A2023-002 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-022-01343-y Date de publication en ligne : 13/10/2022 En ligne : https://doi.org/10.1007/s10291-022-01343-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101871
in GPS solutions > vol 27 n° 1 (January 2023) . - n° 6[article]Wavelet-like denoising of GNSS data through machine learning. Application to the time series of the Campi Flegrei volcanic area (Southern Italy) / Rolando Carbonari in Geomatics, Natural Hazards and Risk, vol 14 n° 1 (2023)
[article]
Titre : Wavelet-like denoising of GNSS data through machine learning. Application to the time series of the Campi Flegrei volcanic area (Southern Italy) Type de document : Article/Communication Auteurs : Rolando Carbonari, Auteur ; Umberto Riccardi, Auteur ; Prospero De Martino, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 2187271 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] caldeira
[Termes IGN] classification par réseau neuronal convolutif
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GNSS
[Termes IGN] filtrage du bruit
[Termes IGN] Naples
[Termes IGN] relief volcanique
[Termes IGN] risque naturel
[Termes IGN] série temporelle
[Termes IGN] surveillance géologique
[Termes IGN] transformation en ondelettesRésumé : (auteur) The great potential of the Global Navigation Satellite System (GNSS) in monitoring ground deformation is widely recognized. As with other geophysical data, GNSS time series can be significantly noisy, hiding elusive ground deformation signals. Several denoising techniques have been proposed to improve the signal-to-noise ratio over the years. One of the most effective denoising techniques has been proved to be multi-resolution decomposition through the discrete wavelet transform. However, wavelet analysis requires long data sets to be effective, as well as long computation times, that hinder its use as a real or near real-time monitoring tool. We propose training by a Convolutional Neural Network (CNN) to perform the equivalent of wavelet analysis to overcome these limitations. Once trained, the CNN model provides answers within seconds, making it feasible as a real-time data analysis tool. Our Machine Learning algorithm is tested on daily GNSS time series collected in the Campi Flegrei caldera (Southern Italy), which is a highly volcanic risk area. Without significant gaps, the retrieved RMSE and R2 values vary in the ranges 0.65–0.98 and 0.06–0.52 cm, respectively. These results are encouraging, as they hint at the possibility of applying this methodology in more effective real-time monitoring solutions for active volcanoes. Numéro de notice : A2023-180 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/19475705.2023.2187271 Date de publication en ligne : 10/03/2023 En ligne : https://doi.org/10.1080/19475705.2023.2187271 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102949
in Geomatics, Natural Hazards and Risk > vol 14 n° 1 (2023) . - n° 2187271[article]Détermination de la déviation de la verticale sur le barrage de Plan d’Aval, sans aucune instrumentation spéciale, avec une précision de 0,4 mgon / Thomas Touzé in XYZ, n° 173 (décembre 2022)
[article]
Titre : Détermination de la déviation de la verticale sur le barrage de Plan d’Aval, sans aucune instrumentation spéciale, avec une précision de 0,4 mgon Type de document : Article/Communication Auteurs : Thomas Touzé, Auteur Année de publication : 2022 Article en page(s) : pp 30 - 34 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] barrage
[Termes IGN] déviation de la verticale
[Termes IGN] données GNSS
[Termes IGN] incertitude de position
[Termes IGN] lever tachéométrique
[Termes IGN] surveillance d'ouvrageRésumé : (Editeur) Dans cet article, nous proposons une nouvelle méthode de détermination de la déviation de la verticale à partir de mesures tachéométriques corrigées de la réfraction et de lignes de base GNSS. Si l’état de l’art est bien respecté, une précision de l’ordre de 0,3 mgon (1’’) sur une visée de 1 km semble tout à fait atteignable. Nous présentons ainsi les résultats obtenus lors de la surveillance de deux barrages EDF dans les Alpes ayant permis de déterminer la déviation de la verticale avec une incertitude à 68 % de 0,4 mgon (1.3’’) et en cohérence avec la valeur déduite du géoïde. Numéro de notice : A2022-914 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102277
in XYZ > n° 173 (décembre 2022) . - pp 30 - 34[article]Réservation
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