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Delay-Doppler analysis of bistatically reflected signals from the ocean surface: theory and application / T. Elfouhaily in IEEE Transactions on geoscience and remote sensing, vol 40 n° 3 (March 2002)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 40 n° 3 (March 2002) . - pp 560 - 573 Titre : Delay-Doppler analysis of bistatically reflected signals from the ocean surface: theory and application Type de document : Article/Communication Auteurs : T. Elfouhaily, Auteur ; D.R. Thompson, Auteur ; L. Linstrom, Auteur Année de publication : 2002 Article en page(s) : pp 560 - 573 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] données Doppler [Termes IGN] mesurage d'effet Doppler [Termes IGN] réflexion (rayonnement) [Termes IGN] surface de la mer [Termes IGN] trajet multiple [Termes IGN] valeur efficace Résumé : (Auteur) We present a new stochastic theory for delay-Doppler mapping of the ocean surface for bistatic scattering. This stochastic theory should complement nicely the previous theories for the Global Positioning System (GPS) reflected signals from ocean surfaces, especially that of Zavorotny and Voronovich. We quantify the Doppler spread of the reflected signal before interpreting the delay. Our theoretical results compare very well to Doppler spectra computed using data collected during an airborne campaign. The bandwidth of the spectra is linked to the geometry and to the ocean roughness. The bulk of the Doppler spread is caused by the rms slope and not by the surface orbital velocity. Our stochastic theory is generalized to include the delay mapping made possible by the existence of the pseudorandom noise code on the GPS L-band carrier. These results can be seen as a generalization of Woodward's theorem for FM signals to delay-Doppler analysis of more complicated signals. Our formulation is amenable to inversion for the determination of geophysical parameters such as surface wind vector and mean sea level. Another novelty in our approach is the inclusion of the sea state. Numéro de notice : A2002-175 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2002.1000316 En ligne : https://doi.org/10.1109/TGRS.2002.1000316 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22090 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-02031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
065-02032	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Change detection for thematic mapping by means of airborne multitemporal polarimetric SAR imagery / W. Dierking in IEEE Transactions on geoscience and remote sensing, vol 40 n° 3 (March 2002)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 40 n° 3 (March 2002) . - pp 618 - 636 Titre : Change detection for thematic mapping by means of airborne multitemporal polarimetric SAR imagery Type de document : Article/Communication Auteurs : W. Dierking, Auteur ; H. Skriver, Auteur Année de publication : 2002 Article en page(s) : pp 618 - 636 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] bande C [Termes IGN] bande L [Termes IGN] carte thématique [Termes IGN] chatoiement [Termes IGN] détection de changement [Termes IGN] image radar [Termes IGN] image radar moirée [Termes IGN] polarimétrie [Termes IGN] seuillage d'image Résumé : (Auteur) The paper addresses the detection of changes in multitemporal polarimetric radar images, focusing on small objects and narrow linear features. The images were acquired at C- and L-band by the airborne EMISAR system. It is found that the radar intensities are better suited for change detection than the correlation coefficient and the phase difference between the co-polarized channels. In the case of linear features, there is no obvious difference between C- and L-band, and slight variations of the flight tracks are acceptable at look angles larger than 35 degrees. Theoretical detection thresholds are evaluated from the statistical distribution of the intensity ratio due to speckle. For the linear features and for urban environments, the observed thresholds are larger than the theoretical predictions. This is interpreted as an effect of radar intensity variations on length scales smaller than the spatial image resolution. The signature of urban areas is very sensitive to deviations between the flight tracks, and the sensitivity is larger at C-band than at L-band. On the other hand, the intensity contrast between buildings and the urban background is smaller at L-band and larger at C-band. For change detection, thresholds may have to be chosen separately for each object class because the intensity ratios of different object classes vary differently as a function of time. Numéro de notice : A2002-176 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2002.1000322 En ligne : https://ieeexplore.ieee.org/document/1000322 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22091 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-02031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
065-02032	RAB	Revue	Centre de documentation	En réserve L003	Disponible