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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]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-07071A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Stabilization of the Brightness temperature of a calibration warm load for spaceborne microwave radiometers / G. De Amici 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 1921 - 1927 Titre : Stabilization of the Brightness temperature of a calibration warm load for spaceborne microwave radiometers Type de document : Article/Communication Auteurs : G. De Amici, Auteur ; R.A. Layton, Auteur ; S.T. Brown, Auteur ; D. Kunkee, Auteur Année de publication : 2007 Article en page(s) : pp 1921 - 1927 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] capteur spatial [Termes IGN] radiomètre à hyperfréquence [Termes IGN] température de luminance Résumé : (Auteur) We present the results of a study that shows that a simple design modification is sufficient to avoid a major shortcoming in the layout of external warm loads commonly used in the calibration of spaceborne microwave radiometers. The modification consists of placing a layer of Plastazote, a polyethylene foam, over the opening of the warm load enclosure. The foam is transparent at micrometer and millimeter wavelengths, is opaque in the infrared and visible, and isolates the warm load from the environment, keeping the temperature of the radiometric warm load constant. The proposed solution can be easily implemented and is suitable even for retrofitting on instruments that have already been built but not yet launched, and the material presents no obvious shortcomings that could prevent its intended application in space. Copyright IEEE Numéro de notice : A2007-171 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2006.888283 En ligne : https://doi.org/10.1109/TGRS.2006.888283 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28534 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-07071A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Postlaunch calibration of the NOAA-18 Advanced Microwave Sounding Unit-A / T. Mo 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 1928 - 1937 Titre : Postlaunch calibration of the NOAA-18 Advanced Microwave Sounding Unit-A Type de document : Article/Communication Auteurs : T. Mo, Auteur Année de publication : 2007 Article en page(s) : pp 1928 - 1937 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] Advanced Microwave Sounding Unit [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] étalonnage en vol [Termes IGN] radiomètre à hyperfréquence [Termes IGN] température de luminance Résumé : (Auteur) The National Oceanic and Atmospheric Administration (NOAA)-18 Polar-orbiting Operational Environmental Satellite (POES) was successfully launched with the fourth Advanced Microwave Sounding Unit-A onboard in May 2005. After launch, a systematic postlaunch calibration and validation of the instrument performance was conducted with on-orbit data. A brief report of the initial assessment of the instrument performance is presented in this paper. Scan-by-scan examination of the radiometric calibration counts is employed to confirm normal functioning of the instrument and to detect any anomalous events, such as lunar contamination in the space radiometric counts, which are accurately detected, flagged, and corrected using a physical model of lunar surface temperature and antenna patterns derived from on-orbit data. The long-term trends of the space and warm calibration counts, channel gains, and housekeeping temperature sensors are monitored. Temperature sensitivity (or the noise-equivalent $Delta hbox{T}$) values for individual channels are also monitored since launch. The long-term temporal trends of the monthly averages and angular distributions of brightness temperature measurements from the NOAA-16 and -18 over the Amazon rain forest region are obtained and compared to demonstrate that the Amazon rain forest can be used as a hot reference calibration target. The establishment of a land calibration target is an important addition to the few tools available to date for calibration and validation of spaceborne microwave radiometers. Copyright IEEE Numéro de notice : A2007-172 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2007.897451 En ligne : https://doi.org/10.1109/TGRS.2007.897451 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28535 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-07071A	RAB	Revue	Centre de documentation	En réserve L003	Disponible