Submarine Non-Hull Penetrating (Wireless) Hydrophone

An acoustic device capable of acoustically transmitting wide-bandwidth information through the pressure hull of a submarine requires careful design but appears feasible based on prior work performed at Sonatech. The current application addresses only out-board to in-board, or wet-side to dry-side, communication; however, the system can be easily modified for two-way communication-a vital capability in emergency situations. Sonatech's approach is to focus on the fundamental problem that limits channel bandwidth for this application: interference from bounce-path signals off the hull interfaces and discontinuities. In our initial tests we will utilize COTS NDT transducers, but we will use acoustic modeling and analysis to design and develop custom transducers that are accurately impedance-matched to the hull and that provide narrow beams-these features strongly reduce bounce path interference. Our analysis, modeling, and testing will address all of the important design parameters: operating frequency and achievable channel bandwidth, impedance matching the front and back faces of the transducers, signal encoding and protocol, and system power requirements.