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Analysis of higher-order ionospheric effects on GNSS precise point positioning in the China area / Yaozong Zhou in Survey review, vol 51 n° 368 (September 2019)  

Public [article]  inSurvey review > vol 51 n° 368 (September 2019) . - pp 442 - 449 Titre : Analysis of higher-order ionospheric effects on GNSS precise point positioning in the China area Type de document : Article/Communication Auteurs : Yaozong Zhou, Auteur ; Cuilin Kuang, Auteur ; Changsheng Cai, Auteur Année de publication : 2019 Article en page(s) : pp 442 - 449 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] Bernese [Termes descripteurs IGN] Chine [Termes descripteurs IGN] correction ionosphérique [Termes descripteurs IGN] erreur de positionnement [Termes descripteurs IGN] perturbation ionosphérique [Termes descripteurs IGN] positionnement par GNSS [Termes descripteurs IGN] positionnement ponctuel précis Résumé : (Auteur) Higher-order ionospheric error may reach several millimetres in the case of high ionospheric activity, which affects some high-accuracy applications, such as crustal movement monitoring, earthquake disaster prediction, plate motion monitoring and coordinate frame maintenance. However, accounting for higher-order ionospheric error is not yet a common strategy for regional global navigation satellite system (GNSS) network data processing. This study investigates the higher-order ionospheric effects on precise point positioning (PPP) in the China area with GNSS data selected from some IGS stations and some CMONOC stations. The Bernese GNSS software was used to calculate the effects of higher-order ionospheric error on the PPP estimated coordinates. The numerical results show that higher-order ionospheric positioning errors become larger as the station latitude decreases or the ionospheric activity increases. In addition, the positioning errors in the north direction are larger than those in the east and up directions and may reach 6 mm in south China. Numéro de notice : A2019-369 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2018.1478483 date de publication en ligne : 24/12/2018 En ligne : https://doi.org/10.1080/00396265.2018.1478483 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93475 [article]

Sensitivity of GPS tropospheric estimates to mesoscale convective systems in West Africa / Samuel Nahmani in Atmospheric chemistry and physics, vol 19 n° 14 (juillet 2019)    

Public [article]  inAtmospheric chemistry and physics > vol 19 n° 14 (juillet 2019) . - pp 9541 - 9561 Titre : Sensitivity of GPS tropospheric estimates to mesoscale convective systems in West Africa Type de document : Article/Communication Auteurs : Samuel Nahmani , Auteur ; Olivier Bock , Auteur ; Françoise Guichard, Auteur Année de publication : 2019 Article en page(s) : pp 9541 - 9561 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] Afrique occidentale [Termes descripteurs IGN] bande C [Termes descripteurs IGN] convection [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] GAMIT [Termes descripteurs IGN] GIPSY-OASIS [Termes descripteurs IGN] meso échelle [Termes descripteurs IGN] Niger [Termes descripteurs IGN] propagation troposphérique [Termes descripteurs IGN] retard troposphérique zénithal [Termes descripteurs IGN] signal GPS Résumé : (Auteur) This study analyzes the characteristics of GPS tropospheric estimates (zenith wet delays – ZWDs, gradients, and post-fit phase residuals) during the passage of mesoscale convective systems (MCSs) and evaluates their sensitivity to the research-level GPS data processing strategy implemented. Here, we focus on MCS events observed during the monsoon season of West Africa. This region is particularly well suited for the study of these events due to the high frequency of MCS occurrences in the contrasting climatic environments between the Guinean coast and the Sahel. This contrast is well sampled with data generated by six African Monsoon Multidisciplinary Analysis (AMMA) GPS stations. Tropospheric estimates for a 3-year period (2006–2008), processed with both the GAMIT and GIPSY-OASIS software packages, were analyzed and intercompared. First, the case of a MCS that passed over Niamey, Niger, on 11 August 2006 demonstrates a strong impact of the MCS on GPS estimates and post-fit residuals when the GPS signals propagate through the convective cells as detected on reflectivity maps from the MIT C-band Doppler radar. The estimates are also capable of detecting changes in the structure and dynamics of the MCS. However, the sensitivity is different depending on the tropospheric modeling approach adopted in the software. With GIPSY-OASIS, the high temporal sampling (5 min) of ZWDs and gradients is well suited for detecting the small-scale, short-lived, convective cells, while the post-fit residuals remain quite small. With GAMIT, the lower temporal sampling of the estimated parameters (hourly for ZWDs and daily for gradients) is not sufficient to capture the rapid delay variations associated with the passage of the MCS, but the post-fit phase residuals clearly reflect the presence of a strong refractivity anomaly. The results are generalized with a composite analysis of 414 MCS events observed over the 3-year period at the six GPS stations with the GIPSY-OASIS estimates. A systematic peak is found in the ZWDs coincident with the cold pool crossing time associated with the MCSs. The tropospheric gradients reflect the path of the MCS propagation (generally from east to west). This study concludes that ZWDs, gradients, and post-fit phase residuals provide relevant and complementary information on MCSs passing over or in the vicinity of a GPS station. Numéro de notice : A2019-572 Thématique : POSITIONNEMENT Nature : Numéro de périodique DOI : 10.5194/acp-19-9541-2019 date de publication en ligne : 29/07/2019 En ligne : https://doi.org/10.5194/acp-19-9541-2019 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94444 [article]

Documents numériques

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Ability of GPS PPP in 2D deformation analysis with respect to GPS network solution / C. Aydin in Survey review, vol 51 n° 366 (May 2019)  

Public [article]  inSurvey review > vol 51 n° 366 (May 2019) . - pp 199 - 212 Titre : Ability of GPS PPP in 2D deformation analysis with respect to GPS network solution Type de document : Article/Communication Auteurs : C. Aydin, Auteur ; S. O. Uygur, Auteur ; S. Çetin, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 199 - 212 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] Bernese [Termes descripteurs IGN] déformation de la croute terrestre [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] station de référence [Termes descripteurs IGN] surveillance géologique [Termes descripteurs IGN] Turquie Résumé : (Auteur) GNSS networks play an important role in monitoring the displacements, movements and deformations of the Earth’s crust and engineering buildings. In this study, we examine how GPS Precise Point Positioning (PPP) is able to determine the horizontal deformations with respect to the GPS network solution. For this purpose, 7 days data of 12 Continuously Operating Reference Stations (CORS) in Turkey (CORS-TR), located in the western part of Turkey, are considered. The Bernese (v5.2)-derived coordinates over 7 days and the ones from four free online PPP services (CSRS, GAPS, APPS, Magic-PPP) are compared using the Bursa-Wolf coordinate transformation model. The errors from these transformations are used to define the RMS values of the PPP solutions in the local coordinate system. These values are relative to the GPS network solution. This fact leads to analysing how the PPP solutions are able to determine the horizontal deformations with respect to the network solution. From many experiments, in which the displacements belonging to the PPP solutions are simulated relative to the network solution, it has been shown that several ppm extensions or contractions may be determined using the free online PPP services. Therefore, we conclude that the online PPP services studied here may be used in 2D deformation studies as an alternative to the GPS network solutions. Numéro de notice : A2019-192 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1415664 date de publication en ligne : 29/12/2017 En ligne : https://doi.org/10.1080/00396265.2017.1415664 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92638 [article]

Displacement monitoring performance of relative positioning and Precise Point Positioning (PPP) methods using simulation apparatus / Salih Alcay in Advances in space research, vol 63 n° 5 (1 March 2019)  

Public [article]  inAdvances in space research > vol 63 n° 5 (1 March 2019) . - pp 1697 - 1707 Titre : Displacement monitoring performance of relative positioning and Precise Point Positioning (PPP) methods using simulation apparatus Type de document : Article/Communication Auteurs : Salih Alcay, Auteur ; Sermet Ogutcu, Auteur ; Ibrahim Kalayci, Auteur ; Cemal Ozer Yigit, Auteur Année de publication : 2019 Article en page(s) : pp 1697 - 1707 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] déformation de la croute terrestre [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] GAMIT [Termes descripteurs IGN] GIPSY-OASIS [Termes descripteurs IGN] GLOBK [Termes descripteurs IGN] positionnement différentiel [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] simulation [Termes descripteurs IGN] surveillance géologique Résumé : (Auteur) Besides the classical geodetic methods, GPS (Global Positioning System) based positioning methods are widely used for monitoring crustal, structural, ground etc., deformations in recent years. Currently, two main GPS positioning methods are used: Relative and Precise Point Positioning (PPP) methods. It is crucial to know which amount of displacement can be detected with these two methods in order to inform their usability according to the types of deformation. Therefore, this study conducted to investigate horizontal and vertical displacement monitoring performance and capability of determining the direction of displacements of both methods using a developed displacement simulator apparatus. For this purpose, 20 simulated displacement tests were handled. Besides the 24 h data sets, 12 h, 8 h, 4 h and 2 h subsets were considered to examine the influence of short time spans. Each data sets were processed using GAMIT/GLOBK and GIPSY/OASIS scientific software for relative and PPP applications respectively and derived displacements were compared to the simulated (true) displacements. Then statistical significance test was applied. Results of the experiment show that using 24 h data sets, relative method can determine up to 6.0 mm horizontal displacement and 12.3 mm vertical displacement, while PPP method can detect 8.1 mm and 19.2 mm displacements in horizontal and vertical directions respectively. Minimum detected displacements are found to grow larger as time spans are shortened. Numéro de notice : A2019-173 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2018.11.003 date de publication en ligne : 13/11/2018 En ligne : https://doi.org/10.1016/j.asr.2018.11.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92625 [article]

Le FOSS4G-fr version 2018 / Anonyme in Géomatique expert, n° 122 (mai-juin 2018)

Public [article]  inGéomatique expert > n° 122 (mai-juin 2018) . - pp 4 - 16 Titre : Le FOSS4G-fr version 2018 Type de document : Article/Communication Auteurs : Anonyme, Auteur Année de publication : 2018 Article en page(s) : pp 4 - 16 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géomatique [Termes descripteurs IGN] données ouvertes [Termes descripteurs IGN] logiciel de traitement de données GNSS [Termes descripteurs IGN] logiciel libre [Termes descripteurs IGN] logiciel SIG [Termes descripteurs IGN] WebSIG Résumé : (éditeur) Organisée tous les deux ans par l’équipe de l’OSGeo-fr, chapitre français de l’OSGeo, la conférence FOSS4G-fr permet aux nombreux utilisateurs de logiciels géomatique libres de se rencontrer, et aux éditeurs et sociétés de service de faire le point sur produits et prestations. Numéro de notice : A2018-263 Thématique : GEOMATIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90320 [article]

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
IFN-001-P002060	PER	Revue	Nogent-sur-Vernisson	Salle périodiques	Exclu du prêt

Western Pyrenees geodetic deformation study using the Guipuzcoa GNSS network / Adriana Martin in Journal of applied geodesy, vol 12 n° 3 (July 2018)  

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Reduction of ZTD outliers through improved GNSS data processing and screening strategies [Interactive discussion] / Katarzyna Stępniak in Atmospheric measurement techniques, vol 11 n° 3 (March 2018)  

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Amélioration des calculs GNSS à façon du SGN / Mathilde Kremp (2018) 

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Introduction aux calculs en ligne GNSS / Elise-Rachel Mathis in XYZ, n° 152 (septembre - novembre 2017)

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GPS coordinate time series measurements in Ontario and Quebec, Canada / Hadis Samadi Alinia in Journal of geodesy, vol 91 n° 6 (June 2017)  

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Study of the effects on GPS coordinate time series caused by higher-order ionospheric corrections calculated using the DIPOLE model / Liansheng Deng in Geodesy and Geodynamics, vol 8 n° 2 (March 2017)  

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Verification of the polish geodetic reference frame by means of a new solution based on permanent GNSS data from the years 2011-2014 / Tomasz Liwosz in Reports on geodesy and geoinformatics, vol 102 n° 1 (December 2016)  

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CODE’s new ultra-rapid orbit and ERP products for the IGS / Simon Lutz in GPS solutions, vol 20 n° 2 (April 2016)  

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14 years of GPS tropospheric delays in the French–Italian border region : comparisons and first application in a case study / Domenico Sguerso in Applied geomatics, vol 8 n° 1 (March 2016)  

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Co-location of geodetic observation techniques in space / Benjamin Männel (2016)  

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