Fiber Optic Measurement of Towed Array Shape

Systems Planning and Analysis, Inc. (SPA) proposes to develop a fiber optic towed array shape measurement system capable of greatly improving the accuracy and efficiency with which current array shape estimates are made. The instrumentation will use Bragg Grating sensor technology and wavelength division multiplexing to allow for up to 24 strain measurements along one fiber path. Using multiple fibers, shape determination of the towed array and the tow cable can be made with minimal ambiguity, thereby improving the beamforming and wavefront curvature processing of acoustic signals. During the proposed effort, a software package will be developed to resolve the array shape based on finite element analysis, breadboard experiments will be conducted to establish rms shape error, and mechanical reliability tests will be conducted on a 100 foot array hose to simulate handling operations. To facilitate Phase II development of a sea-worthy prototype array, a 30 foot array hose section will be instrumented and tested in a tow tank to demonstrate the feasibility of the proposed concept.