Thales

Louis Raillon

Régis Quer

Yves Doisy

Jean-Jacques Fyot

Christine Debaillon-Vesque

An acoustic detection system for detecting at least partly submerged targets in a sensitive area defined with respect to an infrastructure, wherein the system includes at least one multistatic detection group, each multistatic detection group defining a detection area, and comprising: a submerged transmitter transmitting at low frequencies; a plurality of submerged receivers comprising at least two receivers, each receiver of a given group forming, with the transmitter of the group, a bistatic pair, each bistatic pair generating an elementary detection area surrounding a blind zone, the detection area of the group being formed by all of the elementary detection areas of the receivers of the group, the blind zone of each receiver in a given detection group being at least partly covered by the elementary detection areas of the neighbouring receivers of the detection system.

Modular distributed system for the acoustic detection of underwater threats in a sensitive zone

An acoustic detection system for detecting at least partly submerged targets in a sensitive area defined with respect to an infrastructure, the detection system includes at least one multistatic detection group, each multistatic detection group defining a detection area, and comprising: a submerged transmitter emitting at low frequencies; a plurality of submerged receivers comprising at least two receivers, each receiver of a given group forming, with the transmitter of the group, a bistatic pair, each bistatic pair generating an elementary detection area surrounding a blind zone, the detection area of the group being formed by all of the elementary detection areas of the receivers of the group, the receivers being arranged in at least one layer. For at least one group of the system, the form described by the receivers of at least one layer of the group is an at least partly circular form of given radius, the inter-receiver distance between two adjacent receivers of the layer depending on the distance between the transmitter of the group and the rectilinear segment linking the adjacent receivers of the layer, called reference transmitter-receiver distance.

Optimised acoustic detection system for detecting various underwater threats in a sensitive zone

A method for achieving omnidirectional transmission using of a towed linear antenna of length L greater than the wavelength &#x3bb; of the signal transmitted. The antenna has a plurality of P projectors. The spacing between projectors is substantially less than &#x3bb;/2. The method includes applying, to each projector, a transmit signal coming from a common transmit signal. The common signal is assigned a delay based upon a calculation that includes a non-linear term as a function of the position of the projector in the antenna, thereby allowing the angular aperture of the transmission pattern to be modulated. the method permits sonar detection systems comprising transmit and receive antennas having substantially identical diameters, which thereby can be reeled onto the same winch without it being necessary to separate them.

Method for optimizing the power supply for a towed linear transmit antenna for transmitting in omnidirectional mode

The invention relates to low-frequency underwater detection systems comprising a towed linear antenna (). It consists in producing the transducers of the transmission antenna () in the form of flextensional arrays of cylindrical type () and in forming directional transmission channels covering all of space. It makes it possible to lighten the assembly and to facilitate implementation at sea, which becomes able to be automated.

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Cagnes sur Mer, France

Louis Raillon