Thomson-csf

Michel Lagier

Claude Gragnolati

Jena-Pierre Besombes

Philippe Dufourcq

Flexural strain gauge acoustic transducer for deep submersion

A low-frequency hydrophone for a sonar array comprises at least a lacunary ceramics element with open porosity saturated by a viscous fluid, on which metal electrodes have been deposited. This hydrophone forms a high-pass filter whose cutoff frequency is adjusted by modulating the area of the electrodes. The present invention may find particular application in towed linear arrays and passive sonars.

Low-frequency hydrophone and sonar array including such hydrophones

To manufacture an anechoic coating which prevents a wall from reflecting acoustic waves, the wall is coated with an elastic material of low compressibility, which is highly absorbent under shear stresses, and then with a highly compressible layer of material. A set of plates covers the second layer and vibrates under the effect of the acoustic waves. Rods fixed to these plates transmit these vibrations to the first layer which is thus subjected to shear stresses and dissipates the energy of the vibrations, thus making it possible to avoid the sonar detection of submarines.

Anechoic coating for acoustic waves

A self-guidance system for submarine vehicles containing a parametric sonar including preformed channel, transmission device and, in each channel, two beams at the primary frequencies formed simultaneously. Reception takes place with preformed beams at the primary and the secondary frequencies followed by a filter giving frequential channels. An echo comparator receives the signals at the primary and secondary frequencies and enables interference echoes from decoys in particular to be eliminated and the rudders to be controlled.

Acoustic self-guidance systems for submarine vehicles

An improved-performance transducer for deep submersion operation. An axially operating sandwich type transducer has its active part arranged in a housing designed and embodied to form a filter for decoupling the active face. Such a transducer is usable in systems for underwater acoustics.

Growing community of inventors

Le Cannet, France

Michel Lagier