Resistor array performance errors associated with extended targets

In recent hardware-in-the-loop tests conducted in a cryogenic chamber, a dual band sensor observed radiometric anomalies for extended targets. In order to understand the radiometric errors associated with the infrared projection arrays, systematic measurements were performed at both cryogenic and ambient temperatures. Air Force Research Laboratory (AFRL) engineers have previously investigated an artifact observed in these arrays called "busbar robbing," but these observations were of square blocks of emitters and did not characterize radiometric accuracy of extended targets in a dynamic engagement scenario. It was discovered that when numerous emitters in a contiguous pattern are turned on, rather than scattered over the array, the "busbar robbing" effect causes the actual emitter outputs to be different from what you measure if you drive them to the same level with fewer pixels. When the emitters that are driven have some "aspect ratio" or elongated shape, then the effect is dependent on how this pattern is aligned with the emitter axes. The results of these experiments address the radiometric error that can be expected from the resistor array projectors for end game scenarios when a target becomes extended at both ambient and cryogenic temperatures.