Sea-State Observations with an Underwater Acoustic Signal

Abstract

Experiments conducted in a model tank are concerned with reflection of an acoustic signal from the surface. The statistical distributions of the amplitude and phase of this reflected signal are considered. The statistical parameters describing the height and slope of the surface have been the object of recent researches. However, the relationship between the parameters associated with the reflected signal and the parameters of the surface is not well developed. The purpose of this paper is to relate these two sets of parameters, or more specifically, the parameters of the reflected signal to the parameters experiment is conducted consisting essentially of recording simultaneously an acoustic signal reflected from the surface and the output of a waveheight detector, and of analyzing each. This experiment confirms the fact that the received signals, for several different surface states obtained with a wind generator, are well approximated by a Rayleigh probability density function. The outputs of the waveheight indicator are Gaussian distributed with increasing maximum amplitude as the wind speed decreases. Most significantly, a linear relationship between the ratio of the standard deviation Sigma sub e to the root mean square value V of the signal, and the standard deviation of the waveheights Sigma sub w is obtained. This relationship can be expressed in the simple form Sigma sub e = KV sub rms Sigma sub w. Such a result is quite satisfactory and indicates the possibility of a method for the observation of sea-state in which the only quantity observed will be an underwater acoustic signal reflected from the surface. In applications concerning the ocean, this method will have the advantage of being completely uncoupled from the surface itself.

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Document Details

Document Type
Technical Report
Publication Date
Jun 15, 1965
Accession Number
AD1135102

Entities

People

  • Leonidas O. Jacotin
  • Richard F. Hill

Organizations

  • University of Rhode Island

Tags

Communities of Interest

  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Acoustic Signals
  • Acoustics
  • Analog Computers
  • Computers
  • Data Analysis
  • Detectors
  • Electrical Engineering
  • Engineering
  • Generators
  • Measurement
  • Ocean Waves
  • Probability
  • Probability Density Functions
  • Probability Distributions
  • Random Variables
  • Rhode Island
  • Signal Generators

Fields of Study

  • Physics

Readers

  • Marine Hydrodynamics
  • Radar Systems Engineering.
  • Regression Analysis.