zam@athena.mit.edu (Nor Aazizam Mohd Aasif) (03/06/91)
From: zam@athena.mit.edu (Nor Aazizam Mohd Aasif)
I am a bit confused with the term "infra-red" and "heat
seeking" since they are so often used interchangeably. Is there any
significant difference between infra-red and a pure heat-seeking
missile? I remembered reading that the AIM-9 Sidewinder is equipped
with an infra-red homing devise, apart from its heat-seeking ability.
Does that fact that it has the infra-red homing devise contribute to
the missile performance of being able to attack the target from any
angle, and not just from the behind? Considering that jet fighters
body(surface) temperature increases as they fly, can't a pure
heat-seeking missile zero in on the kinetic heating generated by the
aircraft?
Hope someone can help me out on this.
Thank you
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------------------------------------------henry@zoo.toronto.edu (Henry Spencer) (03/13/91)
From: henry@zoo.toronto.edu (Henry Spencer) >From: zam@athena.mit.edu (Nor Aazizam Mohd Aasif) > I am a bit confused with the term "infra-red" and "heat >seeking" since they are so often used interchangeably. Is there any >significant difference between infra-red and a pure heat-seeking >missile? ... The two terms are exactly synonymous. Radiant heat is infra-red radiation. It is just possible that someone has (erroneously) made a distinction between the two in an attempt to distinguish modern seeker systems from older ones. >Does that fact that it has the infra-red homing devise contribute to >the missile performance of being able to attack the target from any >angle, and not just from the behind? The original heat-seeking missiles homed on the infra-red emissions of the hot engine parts, e.g. the tailpipe. This did limit them to homing more or less from behind. Modern cooled seekers home on the IR emissions of the exhaust-gas plume, which is visible from almost any angle. >Considering that jet fighters >body(surface) temperature increases as they fly, can't a pure >heat-seeking missile zero in on the kinetic heating generated by the >aircraft? Only if the aircraft is at high supersonic speed. Below Mach 2 or so, kinetic heating does not get the surface hot enough to emit conspicuous amounts of infra-red. Except for specialized types like the SR-71, combat aircraft spend very little time beyond about Mach 0.9 or so. -- "But this *is* the simplified version | Henry Spencer @ U of Toronto Zoology for the general public." -S. Harris | henry@zoo.toronto.edu utzoo!henry