Thomson-csf

Gilles Posseme

Francois Peynaud

Gilles Kervern

Noel Clavelloux

Germain Guillemin

Christian Labiau

Guy Le Bihan

Method and system for destroying submerged objects, in particular

Apparatus for determining the location of a naval vessel includes a magnetic source connected to the vessel for emitting a predetermined magnetic field. Two magnetic detection devices fixed to the seabed detect and measure at least two components of the emitted magnetic field. Location calculation means are coupled to the two magnetic detection devices for calculating the location of the vessel from the components measured by the two magnetic detection devices.

System for calculating the path of a naval vessel

A compass, by which under-water divers can find their direction, comprise two crossed flux-gate type magnetometers, the measurements of which are processed by logic signals to light up a set of light-emitting diodes which indicate the right direction and, if necessary, the direction and approximate value of the offset of the compass. By using non-magnetic materials and low-consumption electronics, the disturbance of the local field is considerably reduced as compared with a conventional compass. This enables divers to avoid triggering magnetically fired mines.

Weakly magnetic compass

A process for automatically correcting alignment errors between the measuring magnetometers of a magnetic gradient meter, consists in adding to such a gradient meter two additional magnetometers perpendicular to each other and to the axis of the measuring magnetometers. The measurements delivered by these additional magnetometers allow, with two coefficients obtained by previous calibration, the two main errors terms to be calculated and the measured value of the gradient to be corrected accordingly, which allows the alignment error to be corrected electronically and automatically.

Method and apparatus for correcting alignment errors in a magnetometer

A goniotelemetry system comprises two acoustic goniometers directed along two perpendicular axes taking measurements of angles at the intersection O of the two axii, as well as a triaxial magnetometer and a magnetic field gradientmeter situated at this intersection O. It allows to localize marine craft simultaneously from their radiated acoustic noise and from their disturbance on the ground magnetic field in order to fire underwater mines.

Goniotelemetry system

Device for positioning a moving body in a plane indicated by the axes OX and OY by using a magnetic field. A current i, which is the sum of a current i.sub.o at frequency f.sub.o in which f.sub.o .perspectiveto.100 Hz and a current i.sub.1 at frequency f.sub.1 in which f.sub.1 .perspectiveto.10 kHz modulated by bursts of recurring pulses having a period T.sub.o with T.sub.o =1/f.sub.o flows through a conductor. The moving body carries two pairs of magnetometers supplying the components of the magnetic field h.sub.x.sup.o, h.sub.y.sup.o and h.sub.x.sup.1, h.sub.y.sup.1 with respect to axes associated with the moving body about frequencies f.sub.o and f.sub.1. A subassembly, on the basis of the values of h.sub.x.sup.o and h.sub.y.sup.o, supplies a signal U.sub.1 of frequency 2f.sub.o. A subassembly, on the basis of the signal U.sub.1, supplies two signals S.sub.1 and S.sub.2 displaced by T.sub.o /2. Another subassembly supplies signals T on the basis of the values of h.sub.x.sup.1 and h.sub.y.sup.1, which are compared with the signals S.sub.1 and S.sub.2 for supplying a signal S on the basis of signal U.sub.1. Signal S makes it possible to demodulate the components h.sub.x.sup.o and h.sub.y.sup.o, which are thus obtained with their signs, determining without ambiguity the position of the moving body.

Method and apparatus for positioning a boat by monitoring the magnetic

Apparatus for the dynamic positioning of a moving body such as a boat alongside a drilling platform at sea by means of a magnetic field in a plane OXY in which the moving body comprises one or more magnetometers (m.sub.100), and an apparatus for taking bearings on the angle .theta., which a moving reference point O'xy makes with the reference point OXY. The magnetometer (m.sub.100) measures the components of the magnetic field H.sub.x and H.sub.y in the reference point O'xy, a circuit calculates the components of the field H.sub.X an H.sub.Y in the fixed reference point and other circuits determine the position of the moving body. A circuit prepares control signals for the motor of the moving body from the values of H.sub.x an H.sub.y and values X.sub.p and Y.sub.p of the position stored in the memory.

Apparatus for positioning a body by means of a magnetic field

A system on board which provides measurement of flow rates of a liquid layers at different depths, the provided results being corrected from error due to the craft movement, said system being proper for location and establishment of an underwater drilling site. In this system arrangement, are combined to cooperate a Doppler sonar system providing the craft speed with respect to the sea bottom and a flow rate meter system providing the liquid flow rate by reference to the craft, a common electro-acoustic transducers unit being switched for sequential operation from sonar to flow rate system and an output data processing system derives from these two measures the values of flow rate with respect to the sea bottom.

Growing community of inventors

Brest, France

Gilles Posseme