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Proceedings Paper

Resampling algorithm for the Spatial Infrared Imaging Telescope (SPIRIT III) Fourier transform spectrometer
Author(s): Steven D. Sargent; Mark E. Greenman; Scott M. Hansen
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Paper Abstract

The Spatial Infrared Imaging Telescope (SPIRIT III) is the primary sensor aboard the Midcourse Space Experiment (MSX), which was launched 24 April 1996. SPIRIT III included a Fourier transform spectrometer that collected terrestrial and celestial background phenomenology data for the Ballistic Missile Defense Organization (BMDO). This spectrometer used a helium-neon reference laser to measure the optical path difference (OPD) in the spectrometer and to command the analog-to-digital conversion of the infrared detector signals, thereby ensuring the data were sampled at precise increments of OPD. Spectrometer data must be sampled at accurate increments of OPD to optimize the spectral resolution and spectral position of the transformed spectra. Unfortunately, a failure in the power supply preregulator at the MSX spacecraft/SPIRIT III interface early in the mission forced the spectrometer to be operated without the reference laser until a failure investigation was completed. During this time data were collected in a backup mode that used an electronic clock to sample the data. These data were sampled evenly in time, and because the scan velocity varied, at nonuniform increments of OPD. The scan velocity profile depended on scan direction and scan length, and varied over time, greatly degrading the spectral resolution and spectral and radiometric accuracy of the measurements. The Convert software used to process the SPIRIT III data was modified to resample the clock-sampled data at even increments of OPD, using scan velocity profiles determined from ground and on-orbit data, greatly improving the quality of the clock-sampled data. This paper presents the resampling algorithm, the characterization of the scan velocity profiles, and the results of applying the resampling algorithm to on-orbit data.

Paper Details

Date Published: 18 November 1998
PDF: 12 pages
Proc. SPIE 3437, Infrared Spaceborne Remote Sensing VI, (18 November 1998); doi: 10.1117/12.331303
Show Author Affiliations
Steven D. Sargent, Campbell Scientific, Inc. (United States)
Mark E. Greenman, Utah State Univ. (United States)
Scott M. Hansen, Utah State Univ. (United States)

Published in SPIE Proceedings Vol. 3437:
Infrared Spaceborne Remote Sensing VI
Marija Strojnik; Bjorn F. Andresen, Editor(s)

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