Investigation of off-axis detection and classification in bottlenosed dolphins

Mine-hunting dolphins in the Navy´s Marine Mammal Systems (MMS) are likely to initially encounter targets on the edge of the maximum response axis (MRA) of the echolocation beam. Understanding how Fleet dolphins perform their search-and-report tasks will provide valuable information toward the enhancement of Navy mine countermeasure (MCM) signal processing approaches that utilize off-MRA acoustic returns. Current research to this end will contribute toward development of biomimetic sonar systems that are robust in detecting and classifying targets encountered in real-world search conditions where detection, localization, and identification of those targets prior to selecting appropriate MCM actions is required. This paper addresses ongoing investigations of the ability of an echolocating dolphin to detect and classify targets that are presented off the main axis of its transmit and receive sonar beam.