DocumentCode :
3789839
Title :
An airborne radiometer for stratospheric water vapor measurements at 183 GHz
Author :
V. Vasic;D.G. Feist;S. Muller;N. Kampfer
Author_Institution :
Inst. of Appl. Phys., Univ. of Bern, Switzerland
Volume :
43
Issue :
7
fYear :
2005
Firstpage :
1563
Lastpage :
1570
Abstract :
The Airborne Millimeter- and Submillimeter Observing System (AMSOS) is a total-power radiometer for observations of the 183.3-GHz water vapor rotational line, operated onboard a Learjet aircraft of the Swiss Air Force. The radiometer is also used to observe the 175.45-GHz ozone line in the other sideband. The neatly designed quasi optics provide a regular and narrow output beam with a half-power beam-width angle of 1.2/spl deg/ and efficient sideband switching. A /spl lambda//4-quasi-optical isolator is used for baseline reduction securing attenuation of internal reflections by more than 30 dB. A low noise temperature of the ambient-temperature-operating system (1900 K) and excellent target pointing (better than 0.1/spl deg/) provide a good duty cycle and reliable calibration. A reliable control over the radiometer´s operational parameters, like system stability and system temperatures, and higher automatization were required to come up with high demands of an onboard operation. The measured spectra look typical for the region and time where they were observed.
Keywords :
"Radiometry","Optical attenuators","Optical noise","Military aircraft","Optical design","Isolators","Optical reflection","Acoustic reflection","Temperature","Calibration"
Journal_Title :
IEEE Transactions on Geoscience and Remote Sensing
Publisher :
ieee
ISSN :
0196-2892
Type :
jour
DOI :
10.1109/TGRS.2005.846860
Filename :
1459022
Link To Document :
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