Home page of the Russian Acoustical Society Proceedings of the X Session of the Russian Acoustical Society
 
Ocean Acoustics

A.V. Furduev
ON NEW TECHNIQUES OF UNDERWATER ACOUSTIC MONITIRING
Andreyev Acoustics Institute,
ul. Shvernika 4, Moscow, 117036 Russia.
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Data are presented on testing new methods to monitor the medium variability on a sea shelf. The difference-pulse technique is considered, in which the information on medium variations is carried by the difference between two amplitude-time sequences of pulses that passed over the propagating path. The regenerative monitoring scheme is analyzed, according to which the signal and ambient noise received by a hydrophone are retransmitted from a distant point of the fixed path. Thereby a closed scheme is formed, with the acoustic path serving as the feedback loop. The regeneration and self-excitation regimes are considered. With the latter regime, the information on the medium variability is carried by the frequency deviation of the self-sustained oscillator - a device that involves the medium to be monitored. The results of tests showed a high sensitivity of the methods to hydrophysical and technogenic inhomogeneities on the path, to variations in the mean water temperature, and to the current velocity.