An
electronic countermeasure (
ECM) is an electrical or electronic device designed to trick or deceive
radar,
sonar or other detection systems, like infrared (IR) or lasers. It may be used both offensively and defensively to deny targeting information to an enemy. The system may make many separate targets appear to the enemy, or make the real target appear to disappear or move about randomly. It is used effectively to protect
aircraft from
guided missiles. Most
air forces use ECM to protect their aircraft from attack. It has also been deployed by military ships and recently on some advanced tanks to fool laser/IR guided missiles. It is frequently coupled with stealth advances so that the ECM systems have an easier job. Offensive ECM often takes the form of
jamming. Defensive ECM includes using
blip enhancement and jamming of
missile terminal homers.