BLACKBODY CALIBRATION SOURCES OF HIGH-ACCURACY FOR A SPACEBORNE INFRARED INSTRUMENT - THE ALONG-TRACK SCANNING RADIOMETER

We describe the two 140-mm-aperture simulated blackbody sources used f or the on-board calibration of the Along Track Scanning Radiometer, a spaceborne thermal infrared instrument for the accurate remote sensing of sea surface temperature, in operation since 1991. The design of th ese spaceborne sources, which operate at approximate to -10 degrees C and approximate to +30 degrees C, allows them to meet their unpreceden ted accuracy goal, namely a 3 sigma uncertainty in their brightness te mperature of <0.1 K for the whole mission. This performance is empiric ally demonstrated in the laboratory and in flight by long-term tempera ture readout tests, temperature uniformity measurements, and direct em issivity measurements. (C) 1996 Optical Society of America