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Auteur W. Chen |
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Ground-based phase wind-up and its application in yaw angle determination / M. Cai in Journal of geodesy, vol 90 n° 8 (August 2016)
[article]
Titre : Ground-based phase wind-up and its application in yaw angle determination Type de document : Article/Communication Auteurs : M. Cai, Auteur ; W. Chen, Auteur ; D. Dong, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 757 – 772 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne GNSS
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précision du positionnement
[Termes IGN] récepteurRésumé : (auteur) Ground-based phase wind-up effect (GPWU) is caused by the rotation of receiving antenna. It had been studied and applied in rapidly rotation platforms, such as sounding rocket, guided missile and deep space exploration. In Global Navigation Satellite System high accuracy positioning applications, however, most studies treated it as an error source and focused on eliminating this effect in Precision Point Positioning and Real Time Kinematic (RTK) positioning. The GPWU effect is also sensitive to the rotational status of the antenna, in particular the yaw angle variations. In this paper we explore the feasibility of yaw angle determination of relatively slow rotation platforms based on the GPWU effect. We use the geometry-free carrier phase observations from a RTK base and a moving station receivers to estimate the cumulative yaw angle of the moving platform. Several experiments, including rotating platform tests, vehicle and shipborne tests were carried out. The cumulative errors of rotating platform tests are under 0.38∘, indicating good long-term accuracy of the GPWU determined yaw angle. But the RMS are in a range of 11.98∘and 17.39∘, indicating the errors, such as multipath effect, are not negligible and should be further investigated. The RMS of vehicle and shipborne tests using a base station of 9–11 km are 24.77∘ and 23.66∘. In order to evaluate the influence of the differential ionospheric delay, another vehicle test was carried out using a base station located less than 1 km to the vehicle. The RMS reduces to 15.11∘, which gains 39.00 % improvement than before, and demonstrates that the differential ionospheric delay even from a few kilometers long baseline still cannot be neglected. These tests validate the feasibility of GPWU for real-time yaw angle determination. Since this method is able to determine the yaw angle with a minimum one satellite, such a unique feature provides potential applications for attitude determination in the environment with poor sky visibility. Numéro de notice : A2016-506 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0908-7 Date de publication en ligne : 10/05/2016 En ligne : https://doi.org/10.1007/s00190-016-0908-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81530
in Journal of geodesy > vol 90 n° 8 (August 2016) . - pp 757 – 772[article]Empirical model of the gravitational field generated by the oceanic lithosphere / Robert Tenzer in Advances in space research, vol 55 n° 1 ([01/01/2015])
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Titre : Empirical model of the gravitational field generated by the oceanic lithosphere Type de document : Article/Communication Auteurs : Robert Tenzer, Auteur ; W. Chen, Auteur ; Zhourun Ye, Auteur Année de publication : 2015 Article en page(s) : pp 72 - 82 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de gravitation
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] harmonique sphérique
[Termes IGN] isostasie
[Termes IGN] lithosphère
[Termes IGN] modèle empirique
[Termes IGN] océanRésumé : (auteur) We present an empirical model of the gravitational field generated by the oceanic lithosphere computed over the world’s oceans with a spectral resolution complete to a spherical harmonic degree of 180. This gravity model is compiled based on applying methods for a spherical harmonic analysis and synthesis of the global gravity and crustal structure models. The in situ seawater densities and the density samples from ocean-floor drilling sites are utilized in the gravimetric forward modeling of bathymetry and marine sediments. The gravitational signal attributed to the oceanic lithosphere density structure is described empirically in terms of the ocean-floor age and depth. The former is explained by the increasing density with age due to conductive cooling of the oceanic lithosphere. The latter describes the gravitational signature of thermal lithospheric contraction, which is isostatically compensated by ocean deepening. The long-wavelength gravity spectrum reflects mainly the compositional and thermal structures within the sub-lithospheric mantle. We demonstrate that this empirical gravity model reproduces realistically most of the long-to-medium wavelength features of the actual gravity field, except for some systematic discrepancies, especially along continental slopes and large sedimentary accumulations, which cannot be described accurately by applied empirical models. Numéro de notice : A2015-296 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2014.09.023 En ligne : https://doi.org/10.1016/j.asr.2014.09.023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76456
in Advances in space research > vol 55 n° 1 [01/01/2015] . - pp 72 - 82[article]Combination of overlap-driven adjustment and Phong model for LiDAR intensity correction / Q. Ding in ISPRS Journal of photogrammetry and remote sensing, vol 75 (January 2013)
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Titre : Combination of overlap-driven adjustment and Phong model for LiDAR intensity correction Type de document : Article/Communication Auteurs : Q. Ding, Auteur ; W. Chen, Auteur ; B. King, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 40 - 47 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] capteur multibande
[Termes IGN] Chine
[Termes IGN] correction du signal
[Termes IGN] données lidar
[Termes IGN] Fleuve jaune (Chine)
[Termes IGN] intensité lumineuse
[Termes IGN] réflexion spéculaire
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] zone humideRésumé : (Auteur) Airborne laser scanning LiDAR systems deliver not only geometric (X, Y, Z) information of the scanned surfaces but also the returned intensity of the laser pulse. Recent studies have shown the potential of using intensity data for many applications. However, there are limitations in using the raw intensity data because of radiometric system bias, reflectance noise and variations between adjacent strips. To overcome these limitations, a three-step LiDAR intensity correction algorithm is proposed. Following corrections for environmental and surface effects, an overlap-driven least-squares adjustment model that does not rely on the selection of homologous points minimizes intensity differences in the overlap area of strips. Finally, the Phong reflection model, which describes both diffuse and specular reflectance, is used to attenuate the effects of strong reflections that typically occur over wet or water dominated areas. The algorithm was applied to a multi-strip LiDAR dataset that covers wetlands in the estuary of the Yellow River, People’s Republic of China. Results demonstrated a significant reduction in radiometric differences in the overlap areas, and strong specular reflections in the nadir regions were reduced. Objects which were obscured by the specular reflection in the original intensity data were clearly identifiable after the adjustment. Numéro de notice : A2013-031 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2012.09.015 En ligne : https://doi.org/10.1016/j.isprsjprs.2012.09.015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32169
in ISPRS Journal of photogrammetry and remote sensing > vol 75 (January 2013) . - pp 40 - 47[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2013011 RAB Revue Centre de documentation En réserve L003 Disponible Striping noise detection and correction of remote sensing images / F. Tsai in IEEE Transactions on geoscience and remote sensing, vol 46 n° 12 (December 2008)
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Titre : Striping noise detection and correction of remote sensing images Type de document : Article/Communication Auteurs : F. Tsai, Auteur ; W. Chen, Auteur Année de publication : 2008 Article en page(s) : pp 4122 - 4131 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] délignage
[Termes IGN] filtrage du bruit
[Termes IGN] filtre de Canny
[Termes IGN] fonction spline d'interpolation
[Termes IGN] image numérique
[Termes IGN] niveau de gris (image)Résumé : (Auteur) This paper presents an image destriping system for correcting striping noise of remote-sensing images. The developed system identifies stripe positions based on edge-detection and line-tracing algorithms. Pixels not affected by striping are used as control points to construct cubic spline functions describing spatial gray level distributions of an image. Detected stripes are corrected by replacing the pixels with more reasonable gray values computed from constructed spline functions. Gray values of clean pixels not affected by stripes are not altered to preserve data genuineness. Several experimental results demonstrate that the developed system can correctly detect stripes in remote-sensing images and effectively repair them. Evaluations of the results based on an quantitative image quality index indicate that the image quality has been improved significantly after destriping. The destriped images are not only visually more plausible but also can provide better interpretability and are more suitable for computerized analysis. Copyright IEEE Numéro de notice : A2008-486 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2008.2000646 En ligne : https://doi.org/10.1109/TGRS.2008.2000646 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29555
in IEEE Transactions on geoscience and remote sensing > vol 46 n° 12 (December 2008) . - pp 4122 - 4131[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-08121 RAB Revue Centre de documentation En réserve L003 Disponible Canada-wide maps of dominant tree species from remotely sensed and ground data / G. Pavlic in Geocarto international, vol 22 n° 3 (September - November 2007)
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Titre : Canada-wide maps of dominant tree species from remotely sensed and ground data Type de document : Article/Communication Auteurs : G. Pavlic, Auteur ; W. Chen, Auteur ; R. Fernandes, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 185 - 204 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Canada
[Termes IGN] carte de la végétation
[Termes IGN] données de terrain
[Termes IGN] feuillu
[Termes IGN] image SPOT-Végétation
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] PinophytaRésumé : (Auteur) Information on the spatial distribution of dominant tree species is important as input or validation data in large scale ecological studies, such as carbon budget estimation, biodiversity assessment, and vegetation dynamic modelling. We used a 1-km resolution land cover map of Canada produced from 1998 SPOT VGT satellite data as the base map. Fractions of coniferous needleleaf or deciduous broadleaf forests within each 1-km pixel were then estimated by developing relationships with climate using land-cover maps from Landsat images selected as a representative sample. The fraction of coniferous/deciduous forest within each 1-km pixel was further divided into dominant species fractions using species composition information at the sub-ecoregion level, derived from statistics in the Canadian Forest Inventory (CanFI 1991/94 version), from narrative descriptions of ecoregions, and from topographical data. A total of 17 Canada-wide maps of dominant tree species groups at 1 km-resolution were produced. The estimates of this study agree well with CanFI data at the ecoregion level where available, and show good correspondence with published range maps of Canadian tree species. Numéro de notice : A2007-461 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106040701201798 Date de publication en ligne : 16/08/2007 En ligne : https://doi.org/10.1080/10106040701201798 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28824
in Geocarto international > vol 22 n° 3 (September - November 2007) . - pp 185 - 204[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-07031 RAB Revue Centre de documentation En réserve L003 Disponible