Low Frequency Acoustic Spiral Waves
Abstract
This proposal is for the development and modeling of underwater electro-acoustic transduction for creating low frequency acoustic spiral waves. Underwater acoustic spiral waves for navigation are a new development started at NRL (Dzikowitz et. al 2010) that propagate outward spiral waves (helical wavefronts) in sequence with traditional omni-directional (circular wavefront) reference signals to allow receivers to determine bearing angle (and range for synchronized systems) to an underwater beacon. Spiral waves hold greatpromise for underwater avigation in GPS denied areas and also for underwater acoustic communications. For navigation a UUV or platform may determine the bearing angle to a spiral wave beacon by determining the phase between two pulses, a spiral wave signal and a reference omni-phase signal. The emphasis on this proposal is on low frequency, longer range transduction approaches to create spiral waves and challenges of system integration.The spiral wave navigation method is derived from the VOR (Very high frequency Omni-directional Range) is a type of radio navigation system for aircraft, enabling aircraft with a receiving unit to determine navigation system used to provided navigations signals for aircraft to find airports for over four decades [Ref. 1]. Traditionally, RF aircraft navigation was accomplished with a multi-element (e.g. 36 element) phased array and that produced an outgoing spiral RF wave and an omni-directional reference wave. Such systems are located virtually every major and minor airport in the US and world-wide. The phased array approach is expensive and cumbersome for both RF and underwater variants. Researchers at NRL proposed an underwater acoustic version of this phased array to demonstrate an underwater acoustic navigation capability. In contrast, this work concentrates on the Low Frequency generation using orthogonal dipoles driven in phase quadrature, a technique pioneered by Aronov and Brown.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 05, 2021
- Source ID
- N000142112549
Entities
People
- David F. Brown
Organizations
- Office of Naval Research
- United States Navy
- University of Massachusetts