Cylindrical transducer for producing an acoustic spiral wave for underwater navigation (L)

A cylindrical piezoceramic transducer using two orthogonal dipoles driven in phase quadrature to create an acoustic spiral wave, having constant amplitude and phase that varies linearly with azimuthal angle, is considered as a source for an underwater acoustic navigation system. Comparison of the spiral-wave signal with an omnidirectional reference signal having a constant phase originating from the same or co-located source provides a means for an underwater vehicle to determine its bearing angle relative to the signaling beacon [B. Hefner and B. Dzikowicz, J. Acoust. Soc. Am. 129(6), 3630-3639 (2011)]. An alternative proof-of- principle transducer along with experimental results including transmit frequency response, directional factors, and computed versus measured bearing angle are presented. (C) 2012 Acoustical Society of America. [http://dx.doi.org/10.1121/1.4763994]