Cooling
All-aspect seekers also tend to require cooling to give them the high degree of sensitivity required to lock onto the lower level signals coming from the front and sides of an aircraft. Background heat from inside the sensor, or the aerodynamically heated sensor window, can overpower the weak signal entering the sensor from the target. (CCDs in cameras have similar problems; they have much more "noise" at higher temperatures.) Modern all-aspect missiles like the AIM-9M Sidewinder and FIM-92 Stinger use compressed gas or liquid nitrogen to cool their sensors in order to lock onto the target at longer ranges and all aspects. (Some such as the AIM-9J and early-model R-60 used a peltier thermoelectric cooler).
Read more about this topic: Infrared Homing
Famous quotes containing the word cooling:
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—Ezra Pound (1885–1972)
“her in her cooling planet
Revere; do not presume to think her wasted.”
—William Empson (1906–1984)
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—James Weldon Johnson (1871–1938)