Estimation of Noise Field Directionality; Comparison with Fourier Series Method

Abstract

For a line array immersed in a stationary homogeneous noise field, the noise field directionality, at any temporal-frequency of interest, is estimated without any a priori assumptions about the field and without the limitations of ill-conditioning. The key to this development is the deferment of the inherent discretization associated with any array until after the integral equation for the noise field directionality has been solved in terms of the observed spatial correlation. Comparison with the Fourier series method reveals nearly identical results, except that the Fourier series method reveals nearly identical results, except that the Fourier series method has some inaccurate low-order Fourier coefficients. Also, no Bessel function evaluations are required for the new method proposed here; instead, one FFT suffices for approximate evaluation of the field directionality. However, neither procedure has the superresolution capability of some of the recent eigen-decomposition approaches. Keywords: Acoustic fields, Underwater acoustics; Acoustic arrays; Aliasing/smoothing; Fourier integral method; Equispaced line arrays.

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Document Details

Document Type
Technical Report
Publication Date
Oct 15, 1989
Accession Number
ADA220366

Entities

People

  • Albert H. Nuttall

Organizations

  • Naval Underwater Systems Center

Tags

Communities of Interest

  • Air Platforms
  • Materials and Manufacturing Processes
  • Sensors
  • Weapons Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Bessel Functions
  • Canada
  • Coefficients
  • Equations
  • Fourier Series
  • Frequency
  • Geometry
  • Integral Equations
  • Integrals
  • National Security
  • Plane Waves
  • Security
  • Standards
  • Stationary
  • Test And Evaluation
  • Two Dimensional

Readers

  • Acoustics.
  • Approximation Theory.
  • Plasma Physics / Magnetohydrodynamics