Automated Association of Narrowband Signatures with Broadband Tracking in Passive Underwater Surveillance Systems

Underwater surveillance systems use passive sensor arrays for detection, classification and tracking of both surface and subsurface targets. A passive sensor array in a linear or circular configuration is used to detect and track targets with acoustic radiations into water i.e. frequency lines, machinery and propulsion noises, commonly known as narrowband signatures. Narrowband processing is responsible for analysis and classification of target's acoustic signatures. Broadband processing provides information about target's bearing, amplitude and its movement with time. Target bearing history along with detailed analysis of its narrowband signatures are valuable information for any underwater surveillance system. This paper presents an automated approach for association of narrowband signatures with broadband tracking that relates the frequency lines to the corresponding bearings common to a single target. The proposed methodology requires the system operator to select a target's frequency lines and the association algorithm automatically starts tracking the corresponding bearings on the bearing-time history display. This automated association approach provides several advantages such as resolving crossing targets scenario, facilitating target motion analysis, and improving the response time of system operators.