Abstract: A guided coherent atom source (1) includes elements for generating neutral atoms in a gaseous state (2), elements for cooling the atoms gas (3), elements for generating a magnetic field (4), including an electro-magnetic micro-chip (6) deposited on a surface (18) of a substrate (14), and capable of condensing the atoms in a magnetic trap, elements for generating an electro-magnetic RF field capable of extracting the condensed atoms, optical elements (10) for emitting and directing an optical coherent beam (12) toward the condensed atoms able to guide the condensed atoms, characterized in that the optical elements (10) and the electro-magnetic micro-chip (6) are integrated onto the same substrate (14). An atomic interferometer using such a source is also disclosed.

Abstract: A synthetic antenna sonar system, includes: a sonar provided with emission elements and reception elements, the reception elements including a composite physical antenna having N transducers, the sonar being located on a mobile carrier; an inertial unit arranged on the carrier and suitable for measuring instantaneous position and orientation informations of the carrier; a common clock supplying a temporal signal enabling the synchronization of both the inertial unit and the sonar; elements for determining the instantaneous speed of the carrier, the determined speed feeding the inertial unit to correct the drift thereof; and micronavigation elements enabling an image of the seafloor to be obtained through formation of the synthetic antenna channels from K sonar operation recurrences, considering that the physical antenna movement during the carrier displacement is fully known from the informations measured by the inertial unit.

Abstract: The invention concerns a method for acquiring and processing magnetometric data for representing on an at least two-dimensional map magnetometric characteristics of a geographical zone including a step of measuring the intensity of a magnetic field (1) on a geographical zone producing a set of magnetometric data of intensity B(s), a step of computing 2D interpolation (3), a step of computing reduction at the poles (5) and a step of computing an analytical signal (7). The invention is characterized in that it includes sectioning the map of magnetic disturbances into a matrix of pixels, a step of locally updating in real time the map of magnetic anomalies, a step of locally updating in real time the map of 2D interpolation by applying the 2D interpolation calculation in the neighborhood of the updated pixel, a step of locally updating in real time the 2D map of reduction at the poles and a step of locally updating in real time the 2D map of the analytical signal.

Abstract: An acoustic antenna requiring the fewest possible number of assembly operations, which operations can be easily automated. The acoustic antenna includes an array of elementary transducers (15), each elementary transducer including, between a counterweight (10) and a horn (9), at least one ceramic (8), all the elementary transducers being mounted on a common printed circuit (7, 16) for electrical connection between the transducers and for positioning the transducers relative to one another, and at least one connector (26, 27) fixed to this printed circuit, each of the transducers being mounted in such a way that the printed circuit is clamped between the ceramic(s) thereof and the counterweight thereof.

Abstract: A positioning system has at least one underwater apparatus, which includes an acoustic receiver and a computer. The system includes a base station placed in the sea environment, the base station transmitting an acoustic signal received by the acoustic receiver, wherein the acoustic receiver includes a hydrophone, the base station includes at least two acoustic transmitters forming an antenna, the distances between the acoustic transmitters of the antenna being known and the transmitters being synchronized therebetween. According to the invention, the computer includes an element for calculating differences in arrival time and differences in phases of acoustic signals coming from the base station transmitters, and an element for calculating the possible geometric loci of the position of the apparatus relative to the base station and to the orientation thereof, and the position of the underwater apparatus is predetermined from these possible geometric loci.

Abstract: The invention relates to a method and an optical-fiber measuring device including a light source with a light power P, a Sagnac ring interferometer in which propagate two counter-propagating waves, a detector receiving a light flux from the interferometer and converting it into an electrical signal representing the total phase difference ??t between the counter-propagating waves. It also includes an electronic element receiving the electrical signal from the detector and providing a first signal S1 function of the measured parameter. The electronic element includes a demodulator contributing to provide the first signal function of the measured parameter and provide a second signal S2 function of the power P of the light flux measured by the detector. The optical phase modulator generates a disturbance component ??cp adding to the phase difference ??m=??b+??cr.

Abstract: The present invention provides an improved architecture for integrating an inertial navigation system (INS) into a dynamic positioning (DP) system for a vessel. The architecture includes an INS unit and a DP system having a Kalman filter or other algorithm for combining data supplied by a plurality of position measuring equipment (PME) and the INS unit to derive an estimate of the position or speed of the vessel. A switch array and a switch array controller are also provided. These may optionally form a part of the DP system. The switch array is operable under the control of the switch array controller to supply data supplied by one or more of the plurality of position measuring equipment to the INS unit for the purposes of correcting drift. The selection of which of the one or more PME is/are to be combined with the INS unit is made automatically, in real time, to dynamically optimise the DP system.

Abstract: A sonar system includes at least one transmitter and one flexible antenna including a plurality of sections articulated one after the other, each section being provided with at least one acoustic receiver. The system is equipped with positioning elements making it possible to determine the instantaneous position of each of the receivers, and calculation elements making it possible to reconstruct an image of the seabed by taking account of the instantaneous micromovements of each of the receivers.

Abstract: The invention concerns a method for acquiring and processing magnetometric data for representing on an at least two-dimensional map magnetometric characteristics of a geographical zone including a step of measuring the intensity of a magnetic field (1) on a geographical zone producing a set of magnetometric data of intensity B(s), a step of computing 2D interpolation (3), a step of computing reduction at the poles (5) and a step of computing an analytical signal (7). The invention is characterized in that it includes sectioning the map of magnetic disturbances into a matrix of pixels, a step of locally updating in real time the map of magnetic anomalies, a step of locally updating in real time the map of 2D interpolation by applying the 2D interpolation calculation in the neighbourhood of the updated pixel, a step of locally updating in real time the 2D map of reduction at the poles and a step of locally updating in real time the 2D map of the analytical signal.

Abstract: A guided coherent atom source (1) includes elements for generating neutral atoms in a gaseous state (2), elements for cooling the atoms gas (3), elements for generating a magnetic field (4), including an electro-magnetic micro-chip (6) deposited on a surface (18) of a substrate (14), and capable of condensing the atoms in a magnetic trap, elements for generating an electro-magnetic RF field capable of extracting the condensed atoms, optical elements (10) for emitting and directing an optical coherent beam (12) toward the condensed atoms able to guide the condensed atoms, characterized in that the optical elements (10) and the electro-magnetic micro-chip (6) are integrated onto the same substrate (14). An atomic interferometer using such a source is also disclosed.

Abstract: Frontal sonar for observing the seafloor, characterized in that it includes: elements for insonifying a seafloor area divided into M sectors, able to perform a characteristic insonification of each sector of the area during an operation recurrence of the sonar; and receiving elements including a physical antenna consisting of an array of K transducers, the antenna being lacunar and thus ambiguous, so that it defines N image lobes, and in that each of the characteristically insonified sector is associated with a single image lobe defined by the antenna, so that the antenna ambiguity is removed.

Abstract: A synthetic antenna sonar system, includes: a sonar provided with emission elements and reception elements, the reception elements including a composite physical antenna having N transducers, the sonar being located on a mobile carrier; an inertial unit arranged on the carrier and suitable for measuring instantaneous position and orientation informations of the carrier; a common clock supplying a temporal signal enabling the synchronization of both the inertial unit and the sonar; elements for determining the instantaneous speed of the carrier, the determined speed feeding the inertial unit to correct the draft thereof; and micronavigation elements enabling an image of the seafloor to be obtained through formation of the synthetic antenna channels from K sonar operation recurrences, considering that the physical antenna movement during the carrier displacement is fully known from the informations measured by the inertial unit.

Abstract: The invention relates to a method and an optical-fibre measuring device including a light source with a light power P, a Sagnac ring interferometer in which propagate two counter-propagating waves, a detector receiving a light flux from the interferometer and converting it into an electrical signal representing the total phase difference ??t between the counter-propagating waves. It also includes an electronic element receiving the electrical signal from the detector and providing a first signal S1 function of the measured parameter. The electronic element includes a demodulator contributing to provide the first signal function of the measured parameter and provide a second signal S2 function of the power P of the light flux measured by the detector. The optical phase modulator generates a disturbance component ??cp adding to the phase difference ??m=??b+??cr.