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Proceedings Paper

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) on-board blackbody calibration system
Author(s): Fred A. Best; Henry E. Revercomb; Robert O. Knuteson; David C. Tobin; Scott D. Ellington; Mark W. Werner; Douglas P. Adler; Raymond K. Garcia; Joseph K. Taylor; Nick N. Ciganovich; William L. Smith Sr.; Gail E. Bingham; John D. Elwell; Deron K. Scott
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Paper Abstract

The NASA New Millennium Program's Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) instrument provides enormous advances in water vapor, wind, temperature, and trace gas profiling from geostationary orbit. The top-level instrument calibration requirement is to measure brightness temperature to better than 1 K (3 sigma) over a broad range of atmospheric brightness temperatures, with a reproducibility of ±0.2 K. For in-flight radiometric calibration, GIFTS uses views of two on-board blackbody sources (290 K and 255 K) along with cold space, sequenced at regular programmable intervals. The blackbody references are cavities that follow the UW Atmospheric Emitted Radiance Interferometer (AERI) design, scaled to the GIFTS beam size. The cavity spectral emissivity is better than 0.998 with an absolute uncertainty of less than 0.001. Absolute blackbody temperature uncertainties are estimated at 0.07 K. This paper describes the detailed design of the GIFTS on-board calibration system that recently underwent its Critical Design Review. The blackbody cavities use ultra-stable thermistors to measure temperature, and are coated with high emissivity black paint. Monte Carlo modeling has been performed to calculate the cavity emissivity. Both absolute temperature and emissivity measurements are traceable to NIST, and detailed uncertainty budgets have been developed and used to show the overall system meets accuracy requirements. The blackbody controller is housed on a single electronics board and provides precise selectable set point temperature control, thermistor resistance measurement, and the digital interface to the GIFTS instrument. Plans for the NIST traceable ground calibration of the on-board blackbody system have also been developed and are presented in this paper.

Paper Details

Date Published: 20 January 2005
PDF: 11 pages
Proc. SPIE 5655, Multispectral and Hyperspectral Remote Sensing Instruments and Applications II, (20 January 2005); doi: 10.1117/12.579017
Show Author Affiliations
Fred A. Best, Univ. of Wisconsin/Madison (United States)
Henry E. Revercomb, Univ. of Wisconsin/Madison (United States)
Robert O. Knuteson, Univ. of Wisconsin/Madison (United States)
David C. Tobin, Univ. of Wisconsin/Madison (United States)
Scott D. Ellington, Univ. of Wisconsin/Madison (United States)
Mark W. Werner, Univ. of Wisconsin/Madison (United States)
Douglas P. Adler, Univ. of Wisconsin/Madison (United States)
Raymond K. Garcia, Univ. of Wisconsin/Madison (United States)
Joseph K. Taylor, Univ. of Wisconsin/Madison (United States)
Nick N. Ciganovich, Univ. of Wisconsin/Madison (United States)
William L. Smith Sr., Hampton Univ. (United States)
Gail E. Bingham, Utah State Univ. (United States)
John D. Elwell, Utah State Univ. (United States)
Deron K. Scott, Utah State Univ. (United States)

Published in SPIE Proceedings Vol. 5655:
Multispectral and Hyperspectral Remote Sensing Instruments and Applications II
Allen M. Larar; Makoto Suzuki; Qingxi Tong, Editor(s)

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