OVERVIEW: Defensive Electronic Countermeasures (DECM) systems are onboard self-protection suites designed to detect and counter radar-guided threats by jamming or deceiving incoming radar signals. They evolved from basic noise jammers to complex systems using DRFM and adaptive techniques.

GENERAL DESCRIPTION: DECM systems are a subset of electronic warfare (EW) dedicated to self-protection, primarily against radar-guided missiles and tracking systems. Early systems of the 1970s relied on brute-force noise or barrage jamming. By the 1990s–2020s, they integrated advanced processing, Digital Radio Frequency Memory (DRFM), and threat libraries for deceptive jamming. DECMs operate in coordination with RWRs and missile approach warners (MAWs), responding automatically or semi-autonomously to threats. Platforms include fighter aircraft, bombers, helicopters, naval ships, and some ground vehicles.

ROLE SUMMARY:
Category: Electronic Countermeasures (ECM)
Primary Use: Disruption and deception of enemy radar systems
Function: Active jamming, deception, and self-protection
Platform: Deployed on combat aircraft, naval vessels, helicopters, and high-value ground platforms
Integration: Works with RWR, MAW, and towed decoy systems as part of integrated EW suites

See Specific information under [Sensors/EW] section.

SOURCE:
Leonardo, Northrop Grumman, Saab, and Elbit Systems brochures
https://en.wikipedia.org/wiki/Electronic_countermeasure