Use of the Wavenumber Technique with the Lloyds Mirror for an Acoustic Doublet.
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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This thesis examines a method to determine the depth of a point source in and isospeed ocean environment. Using the Fourier Transform on the acoustic pressure field in the range domain results in the attainment of the acoustic pressure spectrum in the wave-number domain and a characteristic nodal spacing unique to the source-receiver depths. Quantitative examination of a magnitude plot of the spectrum and use of simple mathematical formulae yield the source depth. The debilitative effects of narrowband noise and surface roughness on the pressure spectrum is recognizable in noise after the pressure field in the range domain has been lost in the noise field. The effect of surface gravity waves on the pressure spectrum is similar to that on the pressure field in the range domain the characteristic nodal spacing is suppressed as the height of the surface waves increases. Keywords include Lloyds mirror Underwater acoustics Fast fourier transform Wavenumber technique Pressure spectrum Source depth determination Acoustic propagation Isospeed environment Antisubmarine warfare. Author
- Undersea and Antisubmarine Warfare
- Acoustic Detection and Detectors