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On the long-term stability of microwave radiometers using noise diodes for calibration / S.T. Brown in IEEE Transactions on geoscience and remote sensing, vol 45 n° 7 Tome 1 (July 2007)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 45 n° 7 Tome 1 (July 2007) . - pp 1908 - 1920 Titre : On the long-term stability of microwave radiometers using noise diodes for calibration Type de document : Article/Communication Auteurs : S.T. Brown, Auteur ; Shailen Desai, Auteur ; W. Lu, Auteur ; A.B. Tanner, Auteur Année de publication : 2007 Article en page(s) : pp 1908 - 1920 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] Advanced Microwave Radiometer [Termes IGN] bruit (théorie du signal) [Termes IGN] capteur spatial [Termes IGN] diode [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] radiomètre à hyperfréquence [Termes IGN] température de luminance [Termes IGN] water vapour radiometer Résumé : (Auteur) Results are presented from the long-term monitoring and calibration of the National Aeronautics and Space Administration Jason Microwave Radiometer (JMR) on the Jason-1 ocean altimetry satellite and the ground-based Advanced Water Vapor Radiometers (AWVRs) developed for the Cassini Gravity Wave Experiment. Both radiometers retrieve the wet tropospheric path delay (PD) of the atmosphere and use internal noise diodes (NDs) for gain calibration. The JMR is the first radiometer to be flown in space that uses NDs for calibration. External calibration techniques are used to derive a time series of ND brightness for both instruments that is greater than four years. For the JMR, an optimal estimator is used to find the set of calibration coefficients that minimize the root-mean-square difference between the JMR brightness temperatures and the on-Earth hot and cold references. For the AWVR, continuous tip curves are used to derive the ND brightness. For the JMR and AWVR, both of which contain three redundant NDs per channel, it was observed that some NDs were very stable, whereas others experienced jumps and drifts in their effective brightness. Over the four-year time period, the ND stability ranged from 0.2% to 3% among the diodes for both instruments. The presented recalibration methodology demonstrates that long-term calibration stability can be achieved with frequent recalibration of the diodes using external calibration techniques. The JMR PD drift compared to ground truth over the four years since the launch was reduced from 3.9 to $-$0.01 mm/year with the recalibrated ND time series. The JMR brightness temperature calibration stability is estimated to be 0.25 K over ten days. Copyright IEEE Numéro de notice : A2007-170 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2006.888098 En ligne : https://doi.org/10.1109/TGRS.2006.888098 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28533 [article]

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Digital terrain models / W. Lu in GIM international, vol 15 n° 12 (December 2001)

Public [article]  inGIM international > vol 15 n° 12 (December 2001) . - pp 28 - 31 Titre : Digital terrain models Type de document : Article/Communication Auteurs : W. Lu, Auteur Année de publication : 2001 Article en page(s) : pp 28 - 31 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] interpolation [Termes IGN] modèle numérique de terrain [Termes IGN] visualisation 3D Résumé : (Auteur) For geographical applications such as run-off models, 3D visualisation, simulations and visibility analysis, information on terrain relief is necessary. Basically, a Digital Terrain Model (DTM) consists of a limited point sampling of the real world. In order to reconstruct the continuous surface from the sample points, interpolation remains a crucial task. The author considers current issues in DTM generation and interpolation technology in relation to ongoing developments in information technology and increasing user demand for DTMS. Numéro de notice : A2001-146 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21841 [article]

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