Forward Looking Collision Avoidance and Sub-Bottom Sensor for Conceptual High Speed Submersibles

Historically, submarines have encountered difficulty in avoiding collisions with commercial, surface and submarine crafts, particularly when surfacing. Usually the consequences are drastic, as when the USS Greenville collided with the Japanese fishing boatM/V EHIME MARU, with the tragic loss of nine lives and significant political repercussions. These collisions have emphasized the weakness of acoustic methods in avoiding collisions. We have investigated in Phase I the use of electric field sensors to fillin the gaps left by acoustic sensors at medium ranges for detecting surface and submerged vessels at distances useful for avoiding collisions. The Phase I research verified useful detection ranges (up to 1000 m), investigated noise sources on E-Fieldsensors implanted on a moving submersible, and proposed mitigation strategies. Work in Phase II will test these noise mitigation concepts with a laboratory test and two at-sea experiments, as well as improve upon the theoretical E-Field noise estimationsfor turbulence, and improve our algorithms derived for target bearing and range estimation. We will also mount E-Field sensors onto a submarine and test it in a real-world situation against a variety of vessels and towed targets, to demonstrate theeffectiveness of E-Field sensing for collision avoidance.