Infrared sensor response calibration using atmospheric limb emission measurements

摘要

A method is presented for calibrating an infrared sensing device while in an orbit above a celestial body. The infrared sensing device measures a signal profile proportional to radiance emission from the atmospheric limb region in each of a plurality of spectral bandpass regions. The radiance emission from each of the spectral bandpass regions is primarily due to a gas in the atmospheric limb region. The gas must 1) have a known mixing ratio as a function of pressure, 2) cause spectral opacity to be different for each spectral bandpass region, and 3) cause spectral opacity to be non-linearly proportional to concentration of the gas in the atmospheric limb region over at least a portion of the signal profile. A temperature/pressure profile that is indicative of the signal profiles is determined. The temperature/pressure profile is indicative of absolute radiance emission which is then used to calibrate the infrared sensing device.