Active multistatic track initiation cued by passive acoustic detection

Fields of distributed passive and multistatic active sonar sensors provide surveillance capabilities against quiet submarine threats in Anti-Submarine Warfare scenarios. The joint cooperative use of passive and active sonar offers synergistic and complimentary acoustic performance as well as operational advantages. However, a significant challenge of heterogeneous, multi-sensor systems is the successful fusion of information from the various sensors to enable robust target detection, classification, localization, and tracking. This paper describes a fusion algorithm which is based on a passive acoustic detection cue that triggers a multistatic active sonar system. It provides the capability to reduce false track rate by selectively initiating active tracks via a passive cue. The algorithm is developed for the case of fixed passive arrays, which are unable to determine target range. However, the passive system may automatically detect Closest-Point-of-Approach (CPA) events and forward these as cues to the active system for multistatic active track initiation. The passive range and bearing ambiguities, time-of-CPA and speed-to-range ratio as provided by CPA detections are then mapped into a set of hypotheses in a 4-dimensional Cartesian space (x and y positions and velocities) via a Gaussian Mixture representation for active track initiation. The highly probable target state hypothesis is identified within a multi-bank multistatic tracker. The paper describes the algorithm and presents results on a simulated passive-active dataset. It demonstrates the effective “hand off” of the cue, target localization, tracking and false alarm reduction.