The United Kingdom Surface Ship Torpedo Defence (SSTD) system entered into service with the Royal Navy in 2004.
The system is produced by Ultra Electronics[1] and is known as S2170 or Sonar 2170[2] by the Royal Navy and as Sea Sentor in the export market.
Through advanced AI processing it is able to generically identify torpedoes as well as classify specific weapon types and modes and undertake threat evaluation and posturing analysis.
The countermeasures - both towed and expendable variants - lure the threat away from the vessel in a soft-kill manner.
Ultra Electronics also produces a hard-kill variant known as the TRAPR DCL system currently under development for the US Navy.