Cumulative Track-Initiation Probability as a Basis for Assessing Sonar-System Performance in Anti-Submarine Warfare

Calculations of sonar-system performance for anti-submarine warfare yield detection probability as a function of range to the target; whereas sonar operators typically think in terms of a ‘detection range’. This Note considers how to connect these two concepts for active sonar. Four types of probability are explored and their relative advantages teased out in the light of realworld examples. It is concluded that cumulative probability of track initiation provides the most practical route to a definition of detection range, for two reasons. First, unlike detection probability as usually computed, it produces values that operators are likely to regard as believable. Secondly, it reflects more closely than the standard detection probability the steps that operators typically go through in deciding to declare a detection.