Infrared homing

Infrared homing is a guidance method in which a weapon’s seeker detects infrared radiation emitted or reflected by a target and steers toward it.

Infrared seeker: A sensor assembly that detects infrared radiation and supplies target-direction information to a guidance system. It turns radiation from the target into the directional signal that guides an infrared-homing weapon.
Infrared: Electromagnetic radiation with wavelengths longer than visible light and shorter than microwaves. Infrared homing depends on detecting this part of the electromagnetic spectrum.
Semi-active radar homing: A guidance method in which a weapon homes on radar energy reflected from a target illuminated by an external radar. Unlike infrared homing, it relies on reflected radio waves and an external illuminator.
Air-to-air missile: A missile launched from an aircraft to attack another aircraft. Infrared homing is widely used in short-range air-to-air missile designs.
Flares (countermeasure): Aerial decoys that produce intense infrared radiation to divert heat-seeking weapons. Their use prompted seeker designs that discriminate between decoys and aircraft.
Infrared detector: A device that converts incident infrared radiation into an electrical or other measurable signal. Its response to incoming infrared energy provides the seeker’s raw measurement.
Blackbody radiation: Electromagnetic radiation emitted by an idealized object whose spectrum depends on its temperature. Hot targets emit thermal radiation that can contribute to a seeker’s signal.
Active radar homing: A guidance method in which a weapon carries a radar transmitter and receiver to track its target. Its seeker emits radio waves rather than relying on the target’s infrared signal.
Surface-to-air missile: A missile launched from the ground or a ship to attack an airborne target. Some systems use infrared seekers to engage aircraft without radar illumination.
Infrared counter-countermeasure: A seeker feature or tactic designed to preserve infrared tracking despite defensive countermeasures. It describes how homing systems respond to flares and other attempts to break tracking.

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