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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So is the slow cooling of our chivalrous passion,
O my much praised but-not-altogether-satisfactory lady.”
—Ezra Pound (1885–1972)
“A little cooling down of animal excitability and instinct, a little loss of animal toughness, a little irritable weakness and descent of the pain-threshold, will bring the worm at the core of all our usual springs of delight into full view, and turn us into melancholy metaphysicians.”
—William James (1842–1910)
“her in her cooling planet
Revere; do not presume to think her wasted.”
—William Empson (1906–1984)