Reliable Target Area of Uncertainty from an Underwater Acoustic Source(s)

In a multi-static drifting field of active and passive sonobuoys, reducing the area of uncertainty (AOU) around a submarine target is of paramount importance, especially when operating in Anti-Access/Area Denial (A2AD) environments. In order to take advantage of all available information, we use a joint estimation approach that simultaneously estimates all buoy states (position and velocity) and covariances, as well as multiple target states. In a three-dimensional buoy field with 20 to 40 buoys, this means that the joint state vector (and corresponding covariances) are very large. The off-block diagonal portions of the joint covariance matrix contains information that couples estimates between the individual buoy states, as well as the submarine target state. Ignoring the cross coupling simply throws away information that can be used to reduce the AOU of the target. We plan a stepped approach that integrates joint buoy and target estimation with a multiple hypothesis tracking (MHT) algorithm. Our overall objective is to reduce the AOU of the submarine, which ultimately reduces the prosecution time line.