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Real-Time Precise Point Positioning (RTPPP) with raw observations and its application in real-time regional ionospheric VTEC modeling / Teng Liu in Journal of geodesy, vol 92 n° 11 (November 2018)
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Titre : Real-Time Precise Point Positioning (RTPPP) with raw observations and its application in real-time regional ionospheric VTEC modeling Type de document : Article/Communication Auteurs : Teng Liu, Auteur ; Baocheng Zhang, Auteur ; Yunbin Yuan, Auteur ; Min Li, Auteur Année de publication : 2018 Article en page(s) : pp 1267 - 1283 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] modèle ionosphérique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] retard ionosphèrique
[Termes IGN] temps réel
[Termes IGN] teneur verticale totale en électronsRésumé : (Auteur) Precise Point Positioning (PPP) is an absolute positioning technology mainly used in post data processing. With the continuously increasing demand for real-time high-precision applications in positioning, timing, retrieval of atmospheric parameters, etc., Real-Time PPP (RTPPP) and its applications have drawn more and more research attention in recent years. This study focuses on the models, algorithms and ionospheric applications of RTPPP on the basis of raw observations, in which high-precision slant ionospheric delays are estimated among others in real time. For this purpose, a robust processing strategy for multi-station RTPPP with raw observations has been proposed and realized, in which real-time data streams and State-Space-Representative (SSR) satellite orbit and clock corrections are used. With the RTPPP-derived slant ionospheric delays from a regional network, a real-time regional ionospheric Vertical Total Electron Content (VTEC) modeling method is proposed based on Adjusted Spherical Harmonic Functions and a Moving-Window Filter. SSR satellite orbit and clock corrections from different IGS analysis centers are evaluated. Ten globally distributed real-time stations are used to evaluate the positioning performances of the proposed RTPPP algorithms in both static and kinematic modes. RMS values of positioning errors in static/kinematic mode are 5.2/15.5, 4.7/17.4 and 12.8/46.6 mm, for north, east and up components, respectively. Real-time slant ionospheric delays from RTPPP are compared with those from the traditional Carrier-to-Code Leveling (CCL) method, in terms of function model, formal precision and between-receiver differences of short baseline. Results show that slant ionospheric delays from RTPPP are more precise and have a much better convergence performance than those from the CCL method in real-time processing. 30 real-time stations from the Asia-Pacific Reference Frame network are used to model the ionospheric VTECs over Australia in real time, with slant ionospheric delays from both RTPPP and CCL methods for comparison. RMS of the VTEC differences between RTPPP/CCL method and CODE final products is 0.91/1.09 TECU, and RMS of the VTEC differences between RTPPP and CCL methods is 0.67 TECU. Slant Total Electron Contents retrieved from different VTEC models are also validated with epoch-differenced Geometry-Free combinations of dual-frequency phase observations, and mean RMS values are 2.14, 2.33 and 2.07 TECU for RTPPP method, CCL method and CODE final products, respectively. This shows the superiority of RTPPP-derived slant ionospheric delays in real-time ionospheric VTEC modeling. Numéro de notice : A2018-463 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1118-2 Date de publication en ligne : 29/01/2018 En ligne : https://doi.org/10.1007/s00190-018-1118-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91062
in Journal of geodesy > vol 92 n° 11 (November 2018) . - pp 1267 - 1283[article]Evaluation of three ionospheric delay computation methods for ground-based GNSS receivers / Liang Chen in GPS solutions, vol 22 n° 4 (October 2018)
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Titre : Evaluation of three ionospheric delay computation methods for ground-based GNSS receivers Type de document : Article/Communication Auteurs : Liang Chen, Auteur ; Wenting Yi, Auteur ; Weiwei Song, Auteur ; Chuang Shi, Auteur ; Yidong Lou, Auteur ; Cheng Cao, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse comparative
[Termes IGN] erreur systématique inter-systèmes
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur GNSS
[Termes IGN] retard ionosphèrique
[Vedettes matières IGN] Traitement de données GNSSMots-clés libres : carrier-to-code leveling (CCL) method ionospheric-free Hatch–Melbourne–Wubbena (HMW) function Résumé : (Auteur) GNSS observables for ionospheric estimation are commonly based on carrier-to-code leveling (CCL) and precise point positioning (PPP) methods. The CCL method is a geometry-free method which uses carrier phase to level pseudorange observation for decreasing multipath error and observation noise. However, the ionospheric observable based on the CCL has been proven to be affected by leveling errors. The leveling errors are caused by pseudorange multipath and intraday variation of receiver DCB. To obtain more accurate ionospheric observable, the PPP method takes advantage of precise satellite-to-ground range for retrieving slant total electron content and is less affected by the leveling errors. Previous studies have only proven that the ionospheric observables extracted by the two methods are affected by the leveling errors. The influence on ionospheric observable by the pseudorange inter-receiver satellite bias (IRSB) of the receiver has not been taken into consideration. Also, the magnitude of the differences between the ionospheric observables extracted by the two methods has also not been given. In this work, three methods, namely, the CCL, the conventional ionospheric-free PPP method which uses the ionospheric-free Hatch–Melbourne–Wubbena (HMW) function, and the University of Calgary (UOFC) PPP method, are selected to analyze and compare the differences of ionospheric observables and the global ionospheric maps, using a large number of measured data from international GNSS service global stations. Experimental results show that the accuracy of ionospheric observables obtained by the three methods is not only related to the leveling error, but also pseudorange IRSB. The IRSB of the receiver exerts a major effect on the ionospheric observables obtained by the CCL method and a minor effect on the ionospheric observables obtained by the HMW and UOFC methods. The accuracies in the latter case are similar and superior to those obtained by the CCL. The differences of the ionospheric observables obtained by the CCL and UOFC methods, or the CCL and HMW methods, are at decimeter level, whereas the difference of the ionospheric observables obtained by the UOFC and HMW methods is at centimeter level. The UOFC method presented the highest single-frequency pseudorange positioning accuracy using estimated global ionospheric products, followed by the HMW and the CCL methods which presented the lowest positioning accuracy. Numéro de notice : A2018-376 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0788-9 Date de publication en ligne : 01/10/2018 En ligne : https://doi.org/10.1007/s10291-018-0788-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90780
in GPS solutions > vol 22 n° 4 (October 2018)[article]Methods for quantification of systematic distance deviations under incidence angle with scanning total stations / Miriam Zámečníková in ISPRS Journal of photogrammetry and remote sensing, vol 144 (October 2018)
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Titre : Methods for quantification of systematic distance deviations under incidence angle with scanning total stations Type de document : Article/Communication Auteurs : Miriam Zámečníková, Auteur ; Hans Neuner, Auteur Année de publication : 2018 Article en page(s) : pp 268 - 284 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Topographie
[Termes IGN] angle d'incidence
[Termes IGN] erreur systématique
[Termes IGN] Multistation
[Termes IGN] tachéomètre électronique
[Termes IGN] télémètre laser terrestreRésumé : (Auteur) If scanning total stations (TLS+TS) are used in scanning mode for high accurate engineering applications, the systematic influence of the incidence angle (IA) on the reflectorless distance measurement has to be eliminated. At present, methods for quantifying the systematic distance deviations under IA are missing because the measured points are not reproducible. In this paper, three such methods are presented. They are conditional on the used instruments and the required accuracy. These methods are validated with respect to specified framework conditions. The distance deviations are derived in all three methods as difference between the distance measured with TLS+TS in the scanning mode (DTLS) and the corresponding reference distance (Dref). The Dref is determined in three steps: measurement of a high accuracy network, measurement for determining the starting point of the Dref; object measurement to determine the endpoints of Dref. The corresponding DTLS and Dref are identified by means of the horizontal direction Hz (HzTLS and Hzref) and the vertical angle V (VTLS and Vref), both pairs of angles referring to the same origin marked by the axis of the common coordinate system. Depending on the used method, the Dref is determined with a standard uncertainty of 0.1–0.3 mm (at a distance of 30 m). The quantified influence of IA on the distance measurement of the Leica MS50 at a distance of 30 m to a granite plate varies in the interval of 0.8 mm. The strong variation due to the IA occurs from 0 to 20 gon, its effect is stable from 20 to 60 gon. Numéro de notice : A2018-391 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2018.07.008 Date de publication en ligne : 03/08/2018 En ligne : https://doi.org/10.1016/j.isprsjprs.2018.07.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90825
in ISPRS Journal of photogrammetry and remote sensing > vol 144 (October 2018) . - pp 268 - 284[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2018101 RAB Revue Centre de documentation En réserve L003 Disponible 081-2018103 DEP-EXM Revue LASTIG Dépôt en unité Exclu du prêt 081-2018102 DEP-EAF Revue Nancy Dépôt en unité Exclu du prêt Object-based crop classification using multi-temporal SPOT-5 imagery and textural features with a Random Forest classifier / Huanxue Zhang in Geocarto international, vol 33 n° 10 (October 2018)
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Titre : Object-based crop classification using multi-temporal SPOT-5 imagery and textural features with a Random Forest classifier Type de document : Article/Communication Auteurs : Huanxue Zhang, Auteur ; Qiangzi Li, Auteur ; Jiangui Liu, Auteur ; Taifeng Dong, Auteur ; Heather McNairn, Auteur Année de publication : 2018 Article en page(s) : pp 1017 - 1035 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse d'image orientée objet
[Termes IGN] bande spectrale
[Termes IGN] classification par forêts d'arbres décisionnels
[Termes IGN] corrélation par régions de niveaux de gris
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] image SPOT 5
[Termes IGN] indice de végétation
[Termes IGN] limite de terrain
[Termes IGN] Ontario (Canada)
[Termes IGN] réflectance spectrale
[Termes IGN] segmentation d'image
[Termes IGN] surface cultivée
[Termes IGN] surveillance agricole
[Termes IGN] texture d'image
[Termes IGN] variogrammeRésumé : (auteur) In this study, an object-based image analysis (OBIA) approach was developed to classify field crops using multi-temporal SPOT-5 images with a random forest (RF) classifier. A wide range of features, including the spectral reflectance, vegetation indices (VIs), textural features based on the grey-level co-occurrence matrix (GLCM) and textural features based on geostatistical semivariogram (GST) were extracted for classification, and their performance was evaluated with the RF variable importance measures. Results showed that the best segmentation quality was achieved using the SPOT image acquired in September, with a scale parameter of 40. The spectral reflectance and the GST had a stronger contribution to crop classification than the VIs and GLCM textures. A subset of 60 features was selected using the RF-based feature selection (FS) method, and in this subset, the near-infrared reflectance and the image acquired in August (jointing and heading stages) were found to be the best for crop classification. Numéro de notice : A2019-049 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2017.1333533 Date de publication en ligne : 23/06/2017 En ligne : https://doi.org/10.1080/10106049.2017.1333533 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92063
in Geocarto international > vol 33 n° 10 (October 2018) . - pp 1017 - 1035[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-2018041 RAB Revue Centre de documentation En réserve L003 Disponible PPPH : a MATLAB-based software for multi-GNSS precise point positioning analysis / Berkay Bahadur in GPS solutions, vol 22 n° 4 (October 2018)
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Titre : PPPH : a MATLAB-based software for multi-GNSS precise point positioning analysis Type de document : Article/Communication Auteurs : Berkay Bahadur, Auteur ; Metin Nohutcu, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] affaiblissement géométrique de la précision
[Termes IGN] données GNSS
[Termes IGN] erreur en position
[Termes IGN] horloge du récepteur
[Termes IGN] Matlab
[Termes IGN] positionnement ponctuel précis
[Termes IGN] retard troposphérique zénithal
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) The integration of different GNSS constellations offers considerable opportunities to improve Precise Point Positioning (PPP) performance. Being aware of the limited number of the alternatives that utilize the potential advantages of the multi-constellation and multi-frequency GNSS, we developed a MATLAB-based GNSS analysis software, named PPPH. PPPH is capable of processing GPS, GLONASS, Galileo and BeiDou data, and forming their different combinations depending on user’s preference. Thanks to its user-friendly graphical interface, PPPH allows users to determine a variety of processing options and parameters. In addition to an output file including the estimated parameters for every single epoch, PPPH also presents several analyzing and plotting tools for evaluating the results, such as positioning error, tropospheric zenith total delay, receiver clock estimation, satellite number, dilution of precisions. On the other hand, we conducted experimental tests to both validate the performance of PPPH and assess the potential benefits of multi-GNSS on PPP. The results indicate that PPPH provides comparable PPP solution with the general standards and also contributes to the improvement of PPP performance with the integration of multi-GNSS. Consequently, we introduce a GNSS analysis software that is easy to use, has a robust performance and is open to progress with its modular structure. Numéro de notice : A2018-377 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0777-z Date de publication en ligne : 18/08/2018 En ligne : https://doi.org/10.1007/s10291-018-0777-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90781
in GPS solutions > vol 22 n° 4 (October 2018)[article]Assessment of local GNSS baselines at co-location sites / Iván Herrera Pinzón in Journal of geodesy, vol 92 n° 9 (September 2018)
PermalinkEstimation of winter wheat crop growth parameters using time series Sentinel-1A SAR data / P. Kumar in Geocarto international, vol 33 n° 9 (September 2018)
PermalinkResearch on the estimation model of vegetation water content in halophyte leaves based on the newly developed vegetation indices / Zhe Li in Photogrammetric Engineering & Remote Sensing, PERS, vol 84 n° 9 (September 2018)
PermalinkVisible + Near Infrared spectroscopy as taxonomic tool for identifying birch species / Mulualem Tigabu in Silva fennica, vol 52 n° 4 (September 2018)
PermalinkICARE-VEG: A 3D physics-based atmospheric correction method for tree shadows in urban areas / Karine R.M. Adeline in ISPRS Journal of photogrammetry and remote sensing, vol 142 (August 2018)
PermalinkMulti-scale assessment of invasive plant species diversity using Pléiades 1A, RapidEye and Landsat-8 data / Siddhartha Khare in Geocarto international, vol 33 n° 7 (July 2018)
PermalinkPrecise orbit determination of the Sentinel-3A altimetry satellite using ambiguity-fixed GPS carrier phase observations / Oliver Montenbruck in Journal of geodesy, vol 92 n° 7 (July 2018)
PermalinkThe impact of solid Earth-tide model error on tropospheric zenith delay estimates and GPS coordinate time series / Fei Li in Survey review, vol 50 n° 361 (July 2018)
PermalinkA two-stage tropospheric correction model combining data from GNSS and numerical weather model / Jan Douša in GPS solutions, vol 22 n° 3 (July 2018)
PermalinkConnecting infrared spectra with plant traits to identify species / Maria F. Buitrago in ISPRS Journal of photogrammetry and remote sensing, vol 139 (May 2018)
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