Passive Acoustic Sensor System for Marine Mammal Detection

Protecting marine mammals from harm during Navy explosive operations is a high priority. A dedicated sensor system for field mitigation that has a high probability of detection, is flexible and can be tailored to fit the scope of an exercise is highly desirable. A preliminary examination of the characteristics and behavior of marine mammals suggests that a unique dedicated passive acoustic sensor system could be developed from existing sonobuoy technology. It would have near 100% probability of detection and would be a cost effective adjunct to the existing technique of visual observations. A program is proposed for the development of a passive acoustic sensor and processor/display system meeting those criteria. A comprehensive analysis of the vocalization characteristics and behavior of cetaceans and other marine mammals will be used to determine system characteristics for optimizing detection and localization. Frequency range, source level, conditions that induce vocalizations and variety of sounds will be important criteria. Omnidirectional and directional sensors will be compared for detection effectiveness, complexity, number of sensors required and cost. Various processing schemes will be evaluated to determine the most effective method of detection and localization. The goal is to develop a practical, simple, cost effective and flexible system.