Abstract: A system and method of monitoring a pressure, temperature, and/or vibration of a hostile environment without requiring the use of active electronics or an oscillator circuit in that environment. The system and method interrogate a resonant pressure sensor and a resonant or passive temperature sensor connected to a transmission line and located at least 100 feet (30.48 m) away from a network analyzer. The system and method use the reflected frequencies from the sensors to determine the pressure, temperature, and/or vibration. If the sensors are networked by the transmission line or a network filter, the reflected portion can include the reflected transmission energy. The applied signal and reflected portion travel along the transmission line, which is preferably impedance matched to that of the system. If a multi-conductor cable is used, the effects of the cable's length and temperature are compensated for via a system calibration when in field use.

Abstract: Method, source and shuttle configured to generate acoustic waves under water. The shuttle includes a firing piston closing a firing chamber and contributing to holding the compressed gas, and a transitional region connected to the firing piston. The firing chamber and the transitional region define a most restrictive area through which the compressed gas is released toward the at least one exhaust port, the most restrictive area is substantially smooth while the movable shuttle moves toward the open position, and a profile of the transitional region is selected to reduce a high-frequency content of the acoustic waves.

Abstract: A coupling device is provided for a sensor unit having at least one sensor located within a housing. The coupling device includes at least one supporting portion, wherein the supporting portion is configured for maintaining the sensor unit in a stable position, with the coupling device either resting on or being buried into the ground, and at least one rod, arranged in a plane which is essentially perpendicular to a peripheral surface of the supporting portion and linked to the supporting portion. The coupling device further includes a fastener for connecting the sensor unit to the coupling device. The supporting portion maintains the sensor unit in a stable position when resting on the ground, while the rod provides an additional stiffness to the housing.

Abstract: A method and apparatus are provided for estimating the water speed of a first acoustic node D belonging to a network of acoustic nodes, at least some of the acoustic nodes being arranged along towed acoustic linear antennas (S). The method includes steps of: a) defining a N-dimensional base, the center of which is the first acoustic node and comprising a single axis, when N=1, or N non-collinear axes, when N=2 or N=3, each axis being associated with a base vector extending from the first acoustic node to another acoustic node; and b) estimating an amplitude of the water speed, as a function of: for each given other acoustic node defining the base vector: an acoustic propagation duration of an acoustic signal transmitted from the first acoustic node to the given other acoustic node, and an acoustic propagation duration of an acoustic signal transmitted from the given other acoustic nodes to the first acoustic node; and a value c of the underwater acoustic sound velocity.

Abstract: A wing releasing system is provided for releasing at least one wing of a set of wing or wings of a navigation control device. The navigation control device is adapted for controlling depth and/or lateral position of a towed acoustic linear antenna and includes a body to which is attached the set of wing or wings. The wing releasing system includes: a releasing decision circuit, for generating a release request signal when detecting that a foreign object is caught by at least one wing of the set of wing or wings; and an actuator comprised in the navigation control device, for releasing from the body the at least one wing of the set of wing or wings, when receiving the release request signal.

Abstract: A method for electrically setting a gap for a piezoelectric pressure sensor. The method includes positioning a piezoelectric flex element on a tray; attaching a voltage source to the piezoelectric flex element of a piezoelectric pressure sensor; applying a voltage from the voltage source to the piezoelectric flex element; curing an adhesive between the piezoelectric flex element and the tray while the piezoelectric flex element is deflected by the voltage; and stopping the voltage from the voltage source to the piezoelectric flex element when the adhesive has been cured.

Abstract: A method is provided for automatically detecting marine animals, carried out by a detection device. The method includes obtaining acoustic signal measurements collected by at least one acoustic sensor in a underwater environment; and at least one of a first branch for detecting frequency modulated sounds and a second branch for detecting impulsive sounds; each branch comprising a step of detecting sounds by: implementing in parallel several detection channels each having a different and fixed value for at least one degree of freedom; selecting the detection channel having a maximum signal to noise ratio; and comparing the signal to noise ratio of the selected detection channel to a determined threshold. The method further includes taking an alarm decision, indicating the presence of at least one marine animal, as a function of an output of the first branch and/or an output of the second branch.

Abstract: A method and apparatus are provided for managing the acoustic performances of a network of acoustic nodes arranged along towed acoustic linear antennas. The network of acoustic nodes is adapted to determine inter-node distances allowing to locate the acoustic linear antennas. The method includes: obtaining a determined layout of the network of acoustic nodes; obtaining at least one marine environment property relating to an area of performance of a survey with the network of acoustic nodes; and quantifying the acoustic performances of the network of acoustic nodes, using a sound propagation model, the at least one marine environment property and the determined layout.

Abstract: The present invention relates to an underwater floating device (1) characterized in that it comprises: an insert (4) comprising a thermoplastic material and a hollow tube (7), a foam (5) of a thermoplastic material, at least partly covering the insert (4), an outer skin (6) comprising a thermoplastic material formed by injection molding over the foam and configured for being in contact with water during use.

Abstract: A seismic sensor detects a characteristic of a medium during a seismic survey. The seismic sensor includes a casing; a magnet located inside the casing; a coil assembly located inside the casing, wherein the coil assembly moves relative to the magnet; and a temperature-sensitive device connected to terminals of the coil assembly and configured to improve the damping. The magnet and the coil assembly produce some intrinsic damping and the additional damping introduced by the temperature-sensitive device is selected to counterbalance the temperature-dependent intrinsic damping so that a phase of a recorded seismic signal is compensated for temperature induced magnetic field changes.

Abstract: A seismic cable including sensors, data transmission lines extending the length of the seismic cable for conveying data signals issued from the sensors. Controllers distributed along the seismic cable operate as an interface between the sensors and the data transmission lines. Power supplying lines supply power to the controllers and the sensors. X power supplying lines are alternately connected to one out of X successive controllers. Each controller is adapted for applying on a power supplying line detected as defective the electrical tension provided by another power supplying line. Y data transmission lines are alternately connected to one out of Y successive controllers. Each controller is adapted to redirect towards at least one adjacent controller the data associated with a data transmission line which is determined to be defective.

Abstract: A method and apparatus are provided for steering a first acoustic linear antenna belonging to a plurality of acoustic linear antennas towed by a vessel. A plurality of navigation control devices are arranged along the plurality of linear antennas in order to act at least laterally on the position of the linear antennas. At least one of the navigation control devices arranged along the first acoustic linear antenna performs steps of: obtaining a local measurement of a feather angle or of a parameter linked to the feather angle, the local measurement being associated with the at least one of the navigation control devices arranged along the first acoustic linear antenna; computing a lateral force, as a function of the obtained local measurement; and applying the computed lateral force.

Abstract: A streamer for seismic prospection comprising directional sensors (20), such as geophones or accelerometers, distributed along the streamer, characterized in that said streamer comprises at least two tilt sensors (30, 40) located in remote positions and in locations distant from the directional sensors (20) and means which determined the effective orientation of each directional sensor (20) by interpolating along the streamer the tilt detected by the two tilt sensors (30, 40).

Abstract: An underwater cable deployment system for deploying an ocean bottom cable on the seabed including a cage having a lower frame and an upper frame, which lower frame is adapted to receive the ocean bottom cable and the upper frame is connected to an umbilical cable mounted on a vessel, the upper frame being removably attached to the lower frame, guiding and tensioning means for deploying the ocean bottom cable on the seabed, the lower frame further including a recording unit which is connected to the ocean bottom cable and is adapted to record data detected by at least one sensor unit of the ocean bottom cable and an electrical power unit adapted to provide power to the recording unit and to the ocean bottom cable.

Abstract: Device, system and method for protecting towed marine survey equipment from line entanglement are provided. A cutter device has a mounting mechanism configured to fixedly attach at a predetermined position along a cable used for towing, and one or more cutting structures. The cutting structures are attached to and extend away from the mounting mechanism, being configured to cut lines that get caught by the cutting structures or slide along the cable to the predetermined position.

Abstract: A digital seismic sensor adapted to be connected, via a two-conductor line, to an acquisition device. The digital seismic sensor includes: a digital sensor; a local sampling clock providing a sampling frequency; a receiver for receiving command data coming from the acquisition device and synchronization information providing accurate timing information to enable seismic sensor synchronization; a compensator for compensating, as a function of the synchronization information, a drift of the local sampling clock; a transmitter for transmitting seismic data towards the acquisition device; a driver for driving the receiver and the transmitter, according to a half-duplex transmission protocol over the two-conductor line and using a transmission clock extracted from the received command data; a power receiver for receiving electrical power; and a coupler for coupling the command and synchronization information receiver, the transmitter and the power receiver to the two-conductor line.

Abstract: An acquisition device includes a pair of input terminals for connection to an analog seismic sensor generating a seismic signal. The device includes a detector for detecting a disconnection of the sensor, which includes a current source for injecting a low current in the sensor to generate an offset signal which depends on electrical resistance of the sensor and is added to the seismic signal. The offset signal encroaches on only a part of an operating range of the acquisition device. The voltage measured at the input terminals is applied to an analog-digital converter and a filter to obtain a measured value of the offset signal. A processing unit either analyzes a temporal variation of the measured value and triggers an alarm if a determined condition is satisfied, or transmits the measured value to a remote device adapted to analyze the temporal variation.

Abstract: A method and apparatus are provided for estimating an inter-node distance between a sender node and a receiver node belonging to a network comprising a plurality of nodes arranged along towed acoustic linear antennas. An acoustic signal is transmitted from the sender node to the receiver node through an underwater acoustic channel. The method includes estimating the inter-node distance as a function of an estimate of a sound speed profile of the underwater acoustic channel, the sound speed profile depending on depth.

Abstract: A module is provided for processing geophysical data coming from at least one geophysical sensor. The module includes: an electronic board configured to enable the processing of geophysical data captured by the at least one geophysical sensor; and two cable sections each including, at one extremity, a connector designed to be connected to said electronic board. Each connector forms one half-shell and is arranged so as to cooperate with one other half-shell in such a way as to form a shell in which the electronic board is placed.

Abstract: A stress-relief device is provided, which is configured for being mounted on a geophysical equipment or node connected to at least two cables. The device includes a case configured for surrounding the geophysical equipment or node and for making at least an opening for enabling a connection between each of the at least two cables and the geophysical equipment or node. The device also includes a housing for housing a portion of each of the two cables, the housing being configured for substantially preventing any movement of said portions of the two cables.