Identification of submerged object materials methods of hydroacoustic sounding

Balakin R.A., Vilkov G.I.

This paper reviews physical mechanisms of formation for informative features of acoustic target echo induced by elastic characteristics of the object’s material. It is demonstrated that a probing acoustic signal causes forced and selfinduced vibrations of various kinds in the investigated object (including on frequencies unconnected with exposure rate). The vibrations have sufficient amplitude and cause secondary stimulated emission that is added to the main reflection, and as a result of interference there appears an ultimate modulated signal carrying information on the object’s material. The main classification features that allow identifying the object’s material are: surge resistance, surface acoustic wave speed, frequency and damping ratio of natural resonant vibrations.
To improve the returned signal’s informative features, especially for identifying small-sized objects, it is required to optimize the characteristics of transducing devices in a particular direction, including the characteristics of transducing
antennas. Moreover, probing signal parameters and reflected signal processing algorithms need to be optimized.

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