Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"Radiometers"”.
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Calibration and validation for CubeSat Microwave Radiometers
Miniaturized microwave radiometers deployed on nanosatellites in Low Earth Orbit (LEO) are now demonstrating the ability to provide science-quality weather measurements. For instance, the Micro-sized Microwave Atmospheric Satellite-2A (MicroMAS-2A) is a 3U CubeSat launched in January 2018 that …
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Three-dimensional water vapor retrieval using a network of scanning compact microwave radiometers
… number of space-borne microwave and infrared radiometers. In-situ radiosonde measurements have excellent vertical resolution but are severely limited in temporal and spatial coverage. In addition, each radiosonde takes 45-60 minutes to rise from ground level to the tropopause, and is typically …
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An On-orbit Calibration Procedure for Spaceborne Microwave Radiometers Using Special Spacecraft Attitude Maneuvers
… can be used to calibrate spaceborne microwave radiometers once in orbit. The on-orbit calibration methods discussed within this dissertation can provide accurate and early results by utilizing Calibration Attitude Maneuvers (CAM), which encompasses Deep Space Calibration (DSC) and a new use of …
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A numerical study of equivalence in scanning thermistor bolometer radiometers for earth radiation budget applications
… of the ERBE scanning thermistor bolometer radiometers. The finite-difference method is applied to the detector of the ERBE scanning radiometer to characterize its thermal and electrical dynamic behavior. The thermal analysis confirms the thermal time constant of the instrument claimed by …
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ACTS radiometers and a comparison of atmospheric attenuation derived form temperature-humidity and radiometric data
… total power radiometer for each frequency. These radiometers are used to set clear sky attenuation reference levels for satellite beacon calibration. This thesis describes the design, implementation and testing of the radiometers built at Virginia Tech. In addition, a mathematical algorithm used …
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Total power radiometers at 12, 20 and 30 GHz used in the OLYMPUS experiment at Virginia Tech
This paper discusses the total power radiometers in the propagation experiment at Virginia Tech using the OLYMPUS communications satellite. The experiment is set up to measure the received signal strength of beacons at 12.502, 19.770 and 29.656 GHz on board the OL YMPUS satellite in order to gather …
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An end-to-end model of the Earth Radiation Budget Experiment (ERBE) Earth-viewing nonscanning radiometric channels
… Radiation Budget Experiment (ERBE) active-cavity radiometers are used to measure the incoming solar, reflected solar, and emitted longwave radiation from the Earth and its atmosphere. The radiometers are carried by the National Aeronautics and Space Administration's Earth Radiation Budget …
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Optimization of radiometric channel solar calibration for the Clouds and the Earth's Radiant Energy System (CERES) using the Monte-Carlo method
… a source of energy for inflight calibration of radiometers designed to detect electromagnetic radiation in the solar spectrum. But direct viewing of the Sun would provide a flux considerably greater than the operating range of radiometers designed to observe typical Earth scenes. Therefore an …
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Review of current radiometer technology with suggestions for future South African satellites
… South Africa. For instance Passive Microwave Radiometers (PMR) in the L-Band have huge implications in Soil Moisture (SM) and Sea Salinity (SSS), which in turn affect the global climate, and are being investigated by current and soon to launch missions such as Aquarius, SMOS and SMAP. …
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A parametric study of the radiative and optical characteristics of a scanning radiometer for Earth Radiation Budget applications using the Monte-Carlo method
… the sun. Both these systems use three scanning radiometers based on a Cassegrain telescope design. Each of the three radiometers is sensitive in one of three wavelength intervals: shortwave, longwave, and total. A numerical model has been developed to investigate the radiative and optical …
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The Hemispherical Blackbody (HSBB) for improved traceability of longwave downward radiation
… of the worldwide measurement data, the detecting radiometers need to be calibrated regularly. In the past, a set of stable radiometers, the World Infrared Standard Group operated at the Physikalisch-Meteorologisches Observatorium Davos / World Radiation Center, provided the reference for global …
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A study of the thermal and optical characteristics of radiometric channels for earth radiation budget applications
… calibration of an ACR and other types of radiometers. Finally, the point spread function (PSF) of the ERBE and the Clouds and Earth's Radiant Energy System (CERES) scanning radiometers is computed. This PSF is useful in characterizing the channel optics. It also has potential use for …
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An Analysis of 12 GHz low angle radiometric data
Several types of radiometers are reviewed for their relative abilities to measure sky noise temperature. Attenuation caused by atmospheric particles (rain, ice, oxygen, etc.) can be predicted from the sky noise temperature. Three years of data (1979-1981) were available for data reduction and …
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Evaluating the Use of TROPICS Pathfinder Observations for Lunar Calibration
… in-situ calibration systems for microwave radiometers use large, on-board hot targets [12]. Small satellites such as CubeSats, however, are unable to house these hot targets due to SWaP constraints. Instead, CubeSat radiometers such as the TROPICS Pathfinder use noise diodes as smaller …
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A study of transient heat conduction and thermal noise in an Earth radiation budget radiometer
… and Earth’s Radiative Energy System (CERES) radiometers measure the radiation reflected from and emitted by the Earth from Earth orbit. The instruments are based on a two-mirror reflecting telescope which focuses incident radiation on a thermistor bolometer thermal radiation detector. The …
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Determination of the suitability of MT Gamsberg in Namibia for millimetre wave stronomy by measurements of the precipitable water vapour
… data which was taken from 2004 to 2019 by radiometers on four of the H.E.S.S. Cherenkov Telescopes (CT). The PWV at H.E.S.S. as a function of sky temperature as given by the CT radiometers was determined by relationships given by data from two other equipment present at the H.E.S.S. site, …
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Analytical and Experimental Characterization of a Linear-Array Thermopile Scanning Radiometer for Geo-Synchronous Earth Radiation Budget Applications
… development of a new technology for cavity-based radiometers. The radiometer consists of a 256-element linear-array thermopile detector mounted on the wall of a mirrored wedge-shaped cavity. The objective of this research is to provide analytical and experimental characterization of the proposed …
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High Resolution Acetic Acid Survey and Water Vapor Radiometer
… the map resolution of hot cores. Water vapor radiometers (WVRs) are designed to improve the technique by observing tropospheric water vapor along the lines of sight of interferometers. We have numerically demonstrated the importance of phase correction for interferometric observations and …
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Advanced signal processing techniques for the analysis of solar radiometer data in the presence of temporally varying aerosol optical depths
Solar radiometers, which are used for remote sensing of atmospheric aerosols and absorbing gases, have traditionally been calibrated by the Langley method. Temporally variable conditions, however, can significantly bias the zero-airmass intercepts obtained by this method. In this dissertation, a …
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Dynamic Electrothermal Model of a Sputtered Thermopile Thermal Radiation Detector for Earth Radiation Budget Applications
… the global energy balance. Current scanning radiometers used for CERES consist of thin-film thermistor bolometers viewing the Earth through a Cassegrain telescope. The Thermal Radiation Group, a laboratory in the Department of Mechanical Engineering at Virginia Polytechnic Institute and State …
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