As the Gulf War demonstrated, undersea mines will be a major threat to U.S. Naval forces during regional conflict in littoral waters, especially those involving countries without sufficient air or naval forces to pose a threat to U.S. warships. Acoustic systems designed to find bottom mines must not only detect objects with very small target strength against a reverberant background, they must provide extremely high resolution in order to discriminate between mines and mine-like objects on the bottom. Even with high-resolution sonars, observation of an object from multiple look angles is sometimes needed to successfully classify as non-mine or mine. Classification therefore limits the search rate of such sonars, both because high operating frequencies are needed to obtain high resolution in angle and because achieving multiple look angles slows the rate of advance. This proposal will investigate use of multistatics to improve mine detection and extend ranges at which classification is possible. Practical system configurations for a multistatic acoustic mine detection sonar will be developed and estimates of detection range, localization accuracy and classification range will be developed for these configurations. Search rate will be determined as a measure of effectiveness for comparison with conventional monostatic MCM sonars. The acoustic sensor developments anticipated under the proposed project will improve the detection of small objects on the sea floor. Further, by providing improved resolution with lower frequency sonars, these developments are anticipated to improve the range at which such objects can be classified. The primary candidate markets for this effort are anticipated to be the US Navy's mine avoidance and MCM programs. However, resolving objects multistatically can support improved classification in tactical ASW sonars as well. Other potential civilian markets include any application requiring imaging of the ocean floor such as shipwreck location, downed aircraft search and locating pipeline or cable routes.
