radar warning receiver

Radar warning receiver (RWR) systems detect the radio emissions of radar systems. Their primary purpose is to issue a warning when a radar signal that might be a threat (such as a police speed detection radar) is detected. The warning can then be used, manually or automatically, to evade the detected threat. RWR systems can be installed in all kind of airborne, sea-based, and ground-based assets (such as aircraft, ships, automobiles, military bases). This article is focused mainly on airborne military RWR systems; for commercial police RWR systems, see radar detector.