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Modeling atmospheric refraction influences by optical turbulences using an image-assisted total station / Alexander Reiterer in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement, vol 137 n° 3 (01/06/2012)
[article]
Titre : Modeling atmospheric refraction influences by optical turbulences using an image-assisted total station Type de document : Article/Communication Auteurs : Alexander Reiterer, Auteur Année de publication : 2012 Article en page(s) : pp 156 - 165 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Topographie
[Termes IGN] instrument d'optique
[Termes IGN] modèle atmosphérique
[Termes IGN] propagation du signal
[Termes IGN] réfraction atmosphérique
[Termes IGN] tachéomètre électronique
[Termes IGN] turbulenceRésumé : (Auteur) A large part of geodetic sensor systems use electromagnetic radiation to determine the measurement values (distances, directions, etc.). The geometry of the path of propagation and the velocity of the electromagnetic wave is strongly influenced by the physical state of the atmosphere. As most geodetic measurements are performed in the lower atmosphere, the study of refraction and of corresponding impact constitutes a key research field. In geodesy, the refractive index represents a common way to describe the terrestrial refraction - the literature refers to different methods for determining this value. Our study presents a method for the determination of the influence of refraction on the basis of optical measurements. The mathematical derivation is based on well-known equations - the combination of different approaches leads to a uniform processing sequence which can easily be implemented. We present the theoretical foundations, details about the implementation and some preliminary tests. Numéro de notice : A2012-268 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31714
in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement > vol 137 n° 3 (01/06/2012) . - pp 156 - 165[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 199-2012031 RSREV Revue Centre de documentation Revues en salle Disponible Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series / D. Small in Journal of geodesy, vol 86 n° 4 (April 2012)
[article]
Titre : Mitigation of atmospheric perturbations and solid Earth movements in a TerraSAR-X time-series Type de document : Article/Communication Auteurs : D. Small, Auteur ; A. Schubert, Auteur ; G. Jehle, Auteur ; E. Meier, Auteur Année de publication : 2012 Article en page(s) : pp 257 - 270 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] coin réflecteur
[Termes IGN] GPS en mode différentiel
[Termes IGN] image radar moirée
[Termes IGN] image TerraSAR-X
[Termes IGN] marée terrestre
[Termes IGN] précision géométrique (imagerie)
[Termes IGN] réfraction atmosphérique
[Termes IGN] série temporelleRésumé : (Auteur) The TerraSAR-X (TSX) synthetic aperture radar (SAR) marks the recent emergence of a new generation of spaceborne radar sensors that can for the first time lay claim to localization accuracies in the sub-meter range. The TSX platform’s extremely high orbital stability and the sensor’s hardware timing accuracy combine to enable direct measurements of atmospheric refraction and solid Earth movements. By modeling these effects for individual TSX acquisitions, absolute pixel geolocation accuracy on the order of several centimeters can be achieved without need for even a single tiepoint. A 16-month time series of images was obtained over a fixed test site, making it possible to validate both an atmospheric refraction and a solid Earth tide model, while at the same time establishing the instrument’s long-term stability. These related goals were achieved by placing trihedral corner reflectors (CRs) at the test site and estimating their phase centers with centimeter-level accuracy using differential GPS (DGPS). Oriented in pairs toward a given satellite track, the CRs could be seen as bright “points” in the images, providing a geometric reference set. SAR images from the high-resolution spotlight (HS) mode were obtained in alternating ascending and descending orbit configurations. The highest-resolution products were selected for their small sample dimensions, as positions can be more precisely determined. Based on the delivered product annotations, the CR image positions were predicted, and these predictions were compared with their measured image positions both before and after compensation for atmospheric refraction and systematic solid Earth deviations. It was possible to show that when the atmospheric distortion and Earth tides are taken into account, the TSX HS products have geolocation accuracies far exceeding the specified requirements. Furthermore, this accuracy was maintained for the duration of the 16-month test period. It could be demonstrated that with a correctly calibrated sensor, and after accounting for atmospheric and tidal effects, tiepoint-free geolocation is possible with TSX with an absolute product accuracy of about 5 cm. Numéro de notice : A2012-204 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0515-6 Date de publication en ligne : 24/09/2011 En ligne : https://doi.org/10.1007/s00190-011-0515-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31651
in Journal of geodesy > vol 86 n° 4 (April 2012) . - pp 257 - 270[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2012041 RAB Revue Centre de documentation En réserve L003 Disponible Comparison of ray-tracing packages for troposphere delays / V. Nafisi in IEEE Transactions on geoscience and remote sensing, vol 50 n° 2 (February 2012)
[article]
Titre : Comparison of ray-tracing packages for troposphere delays Type de document : Article/Communication Auteurs : V. Nafisi, Auteur ; L. Urquhart, Auteur ; M.C. Santos, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 469 - 481 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] erreur systématique
[Termes IGN] lancer de rayons
[Termes IGN] modèle atmosphérique
[Termes IGN] propagation troposphérique
[Termes IGN] réfraction atmosphériqueRésumé : (Auteur) A comparison campaign to evaluate and compare troposphere delays from different ray-tracing software was carried out under the umbrella of the International Association of Geodesy Working Group 4.3.3 in the first half of 2010 with five institutions participating: the GFZ German Research Centre for Geosciences (GFZ), the Groupe de Recherche de Geodesie Spatiale, the National Institute of Information and Communications Technology (NICT), the University of New Brunswick, and the Institute of Geodesy and Geophysics of the Vienna University of Technology. High-resolution data from the operational analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) for stations Tsukuba (Japan) and Wettzell (Germany) were provided to the participants of the comparison campaign. The data consisted of geopotential differences with respect to mean sea level, temperature, and specific humidity, all at isobaric levels. Additionally, information about the geoid undulations was provided, and the participants computed the ray-traced total delays for 5° elevation angle and every degree in azimuth. In general, we find good agreement between the ray-traced slant factors from the different solutions at 5° elevation if determined from the same pressure level data of the ECMWF. Standard deviations and biases are at the 1-cm level (or significantly better for some combinations). Some of these discrepancies are due to differences in the algorithms and the interpolation approaches. If compared with slant factors determined from ECMWF native model level data, the biases can be significantly larger. Numéro de notice : A2012-045 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2011.2160952 Date de publication en ligne : 12/08/2011 En ligne : https://doi.org/10.1109/TGRS.2011.2160952 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31493
in IEEE Transactions on geoscience and remote sensing > vol 50 n° 2 (February 2012) . - pp 469 - 481[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2012021 RAB Revue Centre de documentation En réserve L003 Disponible 4D GPS water vapor tomography: new parameterized approaches / Donat Perler in Journal of geodesy, vol 85 n° 8 (August 2011)
[article]
Titre : 4D GPS water vapor tomography: new parameterized approaches Type de document : Article/Communication Auteurs : Donat Perler, Auteur ; Alain Geiger, Auteur ; Fabian Peter Hurter, Auteur Année de publication : 2011 Article en page(s) : pp 539 - 550 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Alpes
[Termes IGN] coordonnées ellipsoïdales
[Termes IGN] distribution spatiale
[Termes IGN] données GPS
[Termes IGN] données météorologiques
[Termes IGN] filtre de Kalman
[Termes IGN] prédiction
[Termes IGN] réfraction atmosphérique
[Termes IGN] réfringence
[Termes IGN] signal GPS
[Termes IGN] Suisse
[Termes IGN] tomographie
[Termes IGN] troposphère
[Termes IGN] vapeur d'eau
[Termes IGN] voxelRésumé : (Auteur) Water vapor is a key variable in numerical weather prediction, as it plays an important role in atmospheric processes. Nonetheless, the distribution of water vapor in the atmosphere is observed with a coarse resolution in time and space compared to the resolution of numerical weather models. GPS water vapor tomography is one of the promising methods to improve the resolution of water vapor measurements. This paper presents new parameterized approaches for the determination of water vapor distribution in the troposphere by GPS. We present the methods and give first results validating the approaches. The parameterization of voxels (volumetric pixels) by trilinear and spline functions in ellipsoidal coordinates are introduced in this study. The evolution in time of the refractivity field is modeled by a Kalman filter with a temporal resolution of 30s, which corresponds to the available GPS-data rate. The algorithms are tested with simulated and with real data from more than 40 permanent GPS receiver stations in Switzerland and adjoining regions covering alpine areas. The investigations show the potential of the new parameterized approaches to yield superior results compared to the non parametric classical one. The accuracy of the tomographic result is quantified by the inter-quartile range (IQR), which is decreased by 10–20% with the new approaches. Further, parameterized voxel solutions have a substantially smaller maximal error than the non parameterized ones. Simulations show a limited ability to resolve vertical structures above the top station of the network with GPS tomography. Numéro de notice : A2011-359 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0454-2 Date de publication en ligne : 08/03/2011 En ligne : https://doi.org/10.1007/s00190-011-0454-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31138
in Journal of geodesy > vol 85 n° 8 (August 2011) . - pp 539 - 550[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2011081 RAB Revue Centre de documentation En réserve L003 Disponible Physical limitations on detecting tunnels using underground-focusing spotlight synthetic aperture radar / J. Martinez-Lorenzo in IEEE Transactions on geoscience and remote sensing, vol 49 n° 1 Tome 1 (January 2011)
[article]
Titre : Physical limitations on detecting tunnels using underground-focusing spotlight synthetic aperture radar Type de document : Article/Communication Auteurs : J. Martinez-Lorenzo, Auteur ; C. Rappaport, Auteur ; F. Quivira, Auteur Année de publication : 2011 Conférence : IGARSS 2009, International Geoscience And Remote Sensing Symposium 12/07/2009 17/07/2009 Le Cap Afrique du sud Proceedings IEEE Article en page(s) : pp 65 - 70 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] constante diélectrique
[Termes IGN] détection de partie cachée
[Termes IGN] écho radar
[Termes IGN] forme d'onde
[Termes IGN] image radar moirée
[Termes IGN] propagation du signal
[Termes IGN] réflectance du sol
[Termes IGN] réfraction atmosphérique
[Termes IGN] rugosité du sol
[Termes IGN] sable
[Termes IGN] tunnelRésumé : (Auteur) This paper examines the feasibility of underground-focusing spotlight synthetic aperture radar (UF-SL-SAR) systems for tunnel detection applications. A general formulation is reviewed for generating UF-SL-SAR imaging by using multiple frequencies across a wide band and by focusing in space to subsurface points using well-known ray refraction at the nominal ground surface. A full-wave finite-difference frequency-domain model is used to consider wave propagation in realistic soil with loss- and frequency-dependent dielectric constant and a randomly rough ground surface, both of which serve to obscure and distort the returned tunnel target signal. Imaging results are presented for two representative soil scenarios: dry sand and moist clay loam. Considering the ground surface ray refraction for focusing greatly improves the SAR image relative to conventional SAR focusing at the ground surface. Using UF-SL-SAR, a small shallow tunnel is reasonably imaged for the sand case, despite the roughness of the ground interface. However, for higher conductivity moist clay loam, the clutter from the rough surface overwhelms the significantly attenuated target signal, which must propagate through the lossy intervening soil. It is demonstrated that, despite ideal focusing, the tunnel is successfully imaged only for the sand case. Numéro de notice : A2011-048 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2010.2051952 Date de publication en ligne : 19/08/2010 En ligne : https://doi.org/10.1109/TGRS.2010.2051952 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30829
in IEEE Transactions on geoscience and remote sensing > vol 49 n° 1 Tome 1 (January 2011) . - pp 65 - 70[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2011011A RAB Revue Centre de documentation En réserve L003 Disponible A first look at the effects of ionospheric signal bending on a globally processed GPS network / E. Petrie in Journal of geodesy, vol 84 n° 8 (August 2010)PermalinkPermalinkChoix optimal du modèle troposphérique pour la détermination précise des coordonnées des stations GPS / Salem Kahlouche in Bulletin des sciences géographiques, n° 22 (octobre 2008)PermalinkEléments de physique pour l'imagerie aérienne et spatiale et la géodésie [diaporama pour le master PPMD] / Michel Kasser (2008)PermalinkProceedings of the 15th international workshop on laser ranging, Canberra, Australia, 15 - 20 October 2006 / J. Luck (2008)Permalink3D modelling of the tropospheric refractivity using a permanent GPS network / D. Marcias-Valadez in Geomatica, vol 61 n° 4 (December 2007)PermalinkHigher order ionospheric effects in precise GNSS positioning / M. Mainul Hoque in Journal of geodesy, vol 81 n° 4 (April 2007)PermalinkEstimating atmospheric transmission and surface reflectance from a glint-contaminated spectral image / W. Philpot in IEEE Transactions on geoscience and remote sensing, vol 45 n° 2 (February 2007)PermalinkLe point sur les traitements de données GNSS en réseau pour un positionnement centimétrique temps réel de meilleure qualité / Romain Legros in XYZ, n° 105 (décembre 2005 - février 2006)PermalinkA least squares adjustment of multi-temporal INSAR data: application to the ground deformation of Paris / S. Le Mouelic in Photogrammetric Engineering & Remote Sensing, PERS, vol 71 n° 2 (February 2005)Permalink