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8 February 2001 Demonstration of imaging Fourier Transform Spectrometer (FTS) performance for planetary and geostationary Earth observing
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The combination of massively parallel spatial sampling and accurate spectral radiometry offered by imaging FTS makes it extremely attractive for earth and planetary remote sensing. We constructed a breadboard instrument to help assess the potential for planetary applications of small imaging FTS instruments in the 1-5 micrometers range. The results also support definition of the NASA Geostationary Imaging FTS instrument that will make key meteorological and climate observations from geostationary earth orbit. The PIFTS pivoting voice- coil delay scan mechanism, and laser diode metrology system. The interferometer optical output is measured by a commercial IR camera procured from Santa Barbara Focal plane. It uses an InSb 128 by 128 detector array that covers the entire FOV of the instrument when coupled with a 25-mm focal length commercial camera lens. With appropriate lenses and cold filters the instrument can be used from the visible to 5 micrometers . The delay scan is continuos, but slow, covering the maximum range of +/- 0.4 cm in 37.56 sec at a rate of 500 image frames per second. Image exposures are timed to be centered around predicted zero crossings. The design allows for prediction algorithms that account for the most recent fringe rate so that timing jitter produced by scan speed variations can be minimized. Response to a fixed source is linear with exposure time nearly to the point of saturation. Linearity with respect to input variations was demonstrated to within 0.16 percent using a 3-point blackbody calibration. Imaging of external complex scenes was carried out at low and high spectral resolution. These require full complex calibration to remove background contributions that vary dramatically over the instrument FOV. Testing is continuing to demonstrate the precise radiometric accuracy and noise characteristics.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Henry E. Revercomb, Lawrence A. Sromovsky, Patrick M. Fry, Fred A. Best, and Daniel Darch LaPorte "Demonstration of imaging Fourier Transform Spectrometer (FTS) performance for planetary and geostationary Earth observing", Proc. SPIE 4151, Hyperspectral Remote Sensing of the Land and Atmosphere, (8 February 2001);

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