9. Active Target Strength

  1. Richard P. Hodges SB degree principal analyst member

Published Online: 5 MAY 2010

DOI: 10.1002/9780470665244.ch9

Underwater Acoustics: Analysis, Design and Performance of Sonar

Underwater Acoustics: Analysis, Design and Performance of Sonar

How to Cite

Hodges, R. P. (2010) Active Target Strength, in Underwater Acoustics: Analysis, Design and Performance of Sonar, John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9780470665244.ch9

Author Information

  1. Sonalysts, Inc., USA

Publication History

  1. Published Online: 5 MAY 2010
  2. Published Print: 18 JUN 2010

ISBN Information

Print ISBN: 9780470688755

Online ISBN: 9780470665244



  • active sonar;
  • elastic waves;
  • reverberation;
  • scattering layer;
  • target strength model;
  • technical advisory panel (TAP) model;
  • theory of sound scattering


In active sonar, target strength refers to the ability of a target to return an echo. Depending on the interest of the observer, the target may be a submarine, mine, whale, or sunken ship. The ability of the surface, bottom, or various scattering layers to return sound is generally called reverberation because their indefinite extent produces a continuum of returns as opposed to a discrete echo. Rayleigh developed the theory of sound scattering by a small, rigid, immobile sphere. Very small in size, the circumference of this sphere is much smaller than the wavelength. The Technical Advisory Panel (TAP) model is a target strength model for the bistatic response of a submarine due to four scattering mechanisms: (1) backscatter for a cylinder, (2) forward scatter from a cylinder, (3) scattering of elastic waves in a cylinder, and (4) scattering from hemispherical end caps.

Controlled Vocabulary Terms

elastic waves; scattering; sonar arrays