A Methodology to Assess Capabilities Against Underwater Targets in Harbour Protection

The paper describes a stochastic model of effectiveness for a harbour-defence system to counter an underwater threat. This model is applied to a scenario in harbour X. The defence consists of an active sonar with a detection and tracking system, an intercept platform with a non lethal weapon system, and an underwater barrier with trip-wire sensors. We showed that the effectiveness of the defence system against an UUV threat depends on the reaction-time of the interceptor (the time required to launch the interceptor after a track has been initiated). Short reaction-time is required for the sonar and the interceptor to be effective against the UUV threat. However, when the interceptor reaction-time is long, the underwater barrier system becomes the only effective system against the UUV. The paper also introduces a novel and efficient algorithm to determine the probability of track-initiation and presents the concept of a safety zone as well as determine its benefits.