OVERVIEW: CIRCE is an active, expendable underwater decoy designed to protect ships and submarines from acoustic-homing torpedoes. It deploys jammers and mobile decoys to create false sonar targets, diverting torpedoes away from the platform.

DETAILS: CIRCE, standing for Containerized Integrated Reaction Countermeasures Effectors, is built by Leonardo/WASS as part of the CONTRALTO system and is deployed via dedicated launchers mounted on submarines (C303/S) or surface ships (C310). It uses a combination of stationary acoustic jammers and mobile target emulators to generate hundreds of false echoes, overloading the torpedo’s sonar seeker through dilution and confusion. The submarine version uses pneumatic multi-barrel launchers carrying buoyant effectors with acoustic pingers, while the ship version employs pneumatic trainable launchers and a surface control computer for coordinated deployment .

FUNCTION:
It is launched from ship or submarine using pneumatic or mortar-type multi-barrel decoy launchers.
Once deployed, it emits broadband acoustic jamming signals and/or moves via a mobile target emulator to create numerous false sonar contacts.
This saturates the torpedo’s acoustic processing and draws torpedoes toward the decoy rather than the vessel.

SOURCE:
Leonardo C310 brochure: https://electronics.leonardo.com/documents/16277707/0/C310%2BMM08738%2BNR.pdf ; Leonardo C303/S brochure: https://electronics.leonardo.com/documents/16277707/18299996/C303S_Anti-Torpedo_countermeasure%2B%28MM08736%29_LQ.pdf ; Military Periscope CIRCE overview: https://www.militaryperiscope.com/weapons/sensorselectronics/electronic-support-measureselectronic-warfare/circe/overview/