Spectrometer channel characterization for the airborne remote earth sensor (ARES)

The ARES (Airborne Remote Earth Sensing) program employs a dual mode instrument for the collection of calibrated IR data. The instrument can be used as either an imaging radiometer (Staring Radiometer (STR)), or as an imaging spectrometer (Spatially Scanning Dispersive Spectrometer (SSDS)). In the SSDS mode, the instrument is capable of resolving 75 bands in the 2 mu m to 6 mu m region. Spectral separation is achieved by spatial dispersion of incoming radiation across the FPA using a bi-prism. As with other instruments of this type, mechanical and optical imperfections produce errors in spectral registration and radiometric calibrations; non-uniform dispersion by optics and a finite size for the FPA elements produce imperfect bandpass characteristics, most notably channel crosstalk. The methods developed at Lockheed-Martin Advanced Technology Center (LMATC), the sensor contractors, and at SciTec to characterize the spectral response of each spectrometer channel using a scanned monochromator and normalization algorithms will be discussed.