What is Directional Infrared Counter Measures?

Directional Infrared Counter Measures are a class of anti-missile systems produced to protect aircraft from infrared homing missiles, primarily MANPADS and similar simple systems.

Earlier infrared countermeasures like flares or hot block systems that produce random flashes of IR light are semi- or omnidirectional. This results in the missile seeker receiving relatively little IR energy due to the inverse square law. DIRCM systems instead aim their IR output directly at the missile using some source of tracking information and a trainable emitter. This allows a relatively small device to overwhelm the missile seeker by focusing all of its output on it.