OPTIMALLY DIRECTIVE HYDROPHONE

The ability to survey ocean acoustic fields with directive hydrophones is advantageous for rejection of multipath arrivals, for resolving left-right ambiguity in towed arrays, and for improving the received signal-to-noise ratio. Under this Phase I study, a concept will be evaluated for achieving a compact directive hydrophone for towed array or sonobuoy application. The proposed cylindrical hydrophone has two innovative features, the use of a shaped piezoelectric material to sense specific multipole components of the pressure field and the conditional combination of multipole signals to achieve optimal directivity. Circumferentially directive hydrophones would be beamformed in the conventional manner to achieve axial directivity. The study will evaluate optimal use of piezoelectric material in the sensor, requirements for multipole sensor backing, sensor noise, fabrication tolerances, and system integration requirements.