High Quality Content by WIKIPEDIA articles! 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 speed detection radar from a traffic police officer or a guidance radar on a missile) is detected. The warning can then be used, manually or automatically, to evade the detected threat. RWR systems can be installed in airborne assets (such as helicopters or jet fighters) or ground-based assets (such as automobiles or military bases). This article is focused mainly on military airborne RWR systems, for commercial police RWR systems, see Radar detector.