Full Band Acoustic Localization Processing

This Phase I project will investigate the feasibility of a submarine passive localization system which will localize and track short duration intentional and unintentional emissions from submarines and weapons. The approach combines radius of curvature ranging using time delay measurements from an array of hull mounted hydrophones with a multi hypothesis tracking algorithm for resolution of ambiguity. The algorithms will not be specific to a given sensor configuration, and can be used will multiple sensors or arrays. The system will localize both broadband transient emissions associated with weapons launch and narrowband active pulses by time delay estimation between multiple hull mounted sensors. The ambiguity in the time delay measurement on narrowband pulses will be resolved by using localization obtained on broadband transients, for example weapons launches, and/or by the use of a multi hypothesis tracking algorithm. The multi hypothesis algorithm tracks a number of ambiguous possible locations and evaluates the likelihood of each possible track as multiple pulses are received. Weapons in active mode will emit many pulses which can be averaged. A priori knowledge of weapon dynamics, e.g. constraints on weapon speed, will be used to eliminate much of the range ambiguity as the weapon is tracked, particularly at the outer ranges of active weapon sonar ranges. The goal is to provide the passive localization accuracy required for submarine defensive countermeasures.