Electronic countermeasure 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 missile s . Most air force s 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 . History . First example of electronic countermeasures being applied in a combat situation took place during the Russo - Japanese war . On April 15 , 1904 , Russian wireless telegraphy stations installed in the Port Arthur fortress and on board Russian light cruisers successfully interrupted wireless communication between a group of Japanese battleships . The spark - gap transmitters in the Russian stations generated senseless noise while the Japanese were making attempts to coordinate their efforts in the bombing of a Russian naval base . Germany and Great Britain interfered with enemy communications along the western front during World War I while the Royal Navy tried to intercept German naval radio transmissions . There were also efforts at sending false radio signals , having shore stations send transmissions using ships ' call signs , and jamming enemy radio signals . World War II ECM expanded to include dropping chaff ( originally called Window ) , jamming and spoofing radar and navigation signals . German bomber aircraft navigated using radio signals transmitted from ground stations , which the British disrupted with spoofed signals in the Battle of the Beams . During the RAF ' s night attacks on Germany the extent of electronic countermeasures was much expanded , and a specialised organisation , No . 100 Group RAF , was formed to counter the increasing German night fighter force and radar defences . Cold War developments included anti - radiation missile s designed to home in on enemy radar transmitters . Radar ECM . Basic radar ECM strategies are ( 1 ) radar interference , ( 2 ) target modifications , and ( 3 ) changing the electrical properties of air . Interference techniques include jamming and deception . Jamming is accomplished by a friendly platform transmitting signals on the radar frequency to produce a noise level sufficient to hide echos . The jammer ' s continuous transmissions will provide a clear direction to the enemy radar , but no range information . Deception may use a transponder to mimic the radar echo with a delay to indicate incorrect range . Transponders may alternatively increase return echo strength to make a small decoy appear to be a larger target . Target modifications include radar absorbing coatings and modifications of the surface shape to either " stealth " a high - value target or enhance reflections from a decoy . Dispersal of small aluminum strips called chaff is a common method of changing the electromagnetic properties of air to provide confusing radar echos . Aircraft ECM . ECM is practiced by nearly all modern military units — land , sea or air . Aircraft , however , are the primary weapons in the ECM battle because they can " see " a larger patch of earth than a sea or land - based unit . When employed effectively , ECM can keep aircraft from being tracked by search radars , or targeted by surface - to - air missile s or air - to - air missile s . On aircraft ECM can take the form of an attachable underwing pod or could be embedded in the airframe . Fighter planes using a conventional electronically scanned antenna mount dedicated jamming pods instead or , in the case of the US , German , and Italian air forces , may rely on electronic warfare aircraft to carry them . Future Airborne Jammers . The Next Generation Jammer is being developed to replace the current AN / ALQ - 99 carried on the E / A - 18G and EA - 6B electronic warfare planes . Planned for adoption around 2020 , it will use a small AESA antenna divided into quadrants for all around coverage and retain the capability of highly directional jamming . DARPA ' s Precision Electronic Warfare ( PREW ) project aims to develop a low - cost system capable of synchronizing several simple airborne jamming pods with enough precision to replicate the directionality of an electronically scanned antenna , avoiding collateral jamming of non - targeted receivers . Shipboard ECM . The ULQ - 6 deception transmitter was one of the earlier shipboard ECM installations . The Raytheon SLQ - 32 shipboard ECM package came in three versions providing warning , identification and bearing information about radar - guided cruise missiles . The SLQ - 32 V3 included quick reaction electronic countermeasures for cruisers and large amphibious ships and auxiliaries in addition to the RBOC ( Rapid Blooming Off - board Chaff ) launchers found on most surface ships . The BLR - 14 Submarine Acoustic Warfare System ( or SAWS ) provides an integrated receiver , processor , display , and countermeasures launch system for submarines . Infrared and acoustic analogies . Infrared homing systems can be decoyed with flares and other infrared countermeasure s . Acoustic homing and detection systems used for ships are also susceptible to countermeasures . United States warships use Masker and PRAIRIE ( PRopellor AIR Ingestion and Emission ) systems to create small air bubbles around a ship ' s hull and wake to reduce sound transmission . Surface ships tow noisemakers like the AN / SLQ - 25 Nixie to decoy homing torpedoes . Submarines can deploy similar acoustic device countermeasures ( or ADCs ) from a 3 - inch ( 75 - mm ) signal launching tube . United States ballistic missile submarines could deploy the Mark 70 MOSS ( MObile Submarine Simulator ) decoy from torpedo tubes to simulate a full size submarine . Most navies additionally equip surface ships with decoy launchers .