Missile warning receiver

A missile warning receiver detects the thermal signature of potential surface-to-air and air-to-air missile threats to tactical aircraft, and is related to theater and strategic electro-optical MASINT systems that detect ballistic and cruise missiles.

Tactical sytems
The technology is considered is a form of infrared countermeasures, The name is somewhat confusing, as the actual threat detector is in the ultraviolet, not infrared light spectrum. See infrared countermeasures for some issues and trends.

Strategic systems
While the term "missile warning receiver" is usually considered a tactical system, strategic warning of ICBM launches goes back to the Defense Support Program (DSP), which were space-based missile-launch-only detectors. These, and their upgrades, became significant theater-level assets in the Gulf War, when they provided warning to troops and MIM-104 Patriot missiles of SS-1 SCUD launches.

The new Space Tracking and Surveillance System (STSS). As opposed to DSP and its high-altitude launch sensor replacement, SBIRS, STSS actually can track the missiles after launch, and may give cruise missile warning relevant to ships.