Abstract:
An ocean bottom cable system includes: a cable adapted to be extended from a vessel at the surface of a body of water to the bottom of a body of water. The cable includes at least one electrical conductor or at least one optical fiber. A plurality of sensor units is disposed at spaced apart locations along the cable; and at least one swivel is disposed in the cable between the vessel and at least one of the sensor units. The swivel is adapted to enable relative rotation thereby relieving torsional stress between ends of the cable coupled thereto, and is adapted to transmit axial force along the cable therethrough.
Abstract:
The disclosure relates to a signal processing method for a towed linear antenna, notably to resolve right-left ambiguity, said antenna comprising a set of hydrophone multiplets each with n≧3 hydrophones spread over a straight section of the longitudinal axis of said antenna, wherein the roll angle of each multiplet relative to the vertical is measured, the signals of said hydrophones and said roll angles are used to synthesize p≧3 linear sub-antennas, then M azimuth channels are formed with each sub-antenna and 2 adaptive right-left channels are formed from said p sub-antennas for each direction corresponding to each azimuth channel. The invention resolves right-left ambiguity with optimal performance in detection and for long antennas.
Abstract:
A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of the jacket. The strength member is disposed inside the jacket. Seismic sensors are disposed at spaced apart locations along the interior of the jacket. A flexible, acoustically transparent material fills the space inside the jacket. The material is introduced into the inside of the jacket in liquid form and undergoes a state change thereafter. The strength member, prior to and during the state change, is maintained in substantially a same position with respect to the jacket as would occur during ordinary operation of the streamer. The maintaining position is performed at least at a location along the jacket where a device is to be coupled externally to the jacket.
Abstract:
A cable connection for connecting a cable 9 to an underwater installation 7 comprises a connector (2, see FIG. 2) for connection to an end of the cable 9, the connector having at a first end engagement means for engaging with the installation 7, a tether (4, see FIG. 2) which in use has a first end attached to the connector and a second end attached to the cable at a distance from said end of the cable and guide means (12, 13, 14) located proximate a section of the cable adjacent said end of the cable so that in use said section is substantially restrained by said guide means at a predetermined angle with respect to the engagement means.
Abstract:
A device that allows control of the navigation of a towed underwater device, such as a linear acoustic antenna. The device is equipped with a pair of horizontal wings and a pair of vertical wings. These wings are kept horizontal and vertical by pendular movement of the device about the antenna on which the device is fixed. The action of the horizontal wings, which influence only immersion, and of the vertical wings, which influence only the lateral offset, are thus decoupled. The power consumption of the device is reduced, thus allowing the device to be powered by internal batteries and allowing the device to be mounted on existing antennas.
Abstract:
The present invention relates to a system for sensing the curvature of a towed hydrophone array and a curvature sensor used in the system. The system has at least two curvature sensors positioned along the length of the array. Each of the curvature sensors comprises a bend member which bends as the array bends, at least one optical fiber within the bend member, and at least one detection device embedded within the at least one optical fiber to detect a change in the strain in the at least one optical fiber.
Abstract:
A distributed fiber strength member tow cable termination assembly (DTCTA) having a strength member termination area which is spaced from a signal conductor termination area, and which includes a seal area having a plurality of sealing members is disclosed. The strength member termination area preferably includes a strength member termination wedge having a curved outer face which allows for higher termination efficiency. The strength member termination area and signal conductor termination area are distributed, or separated, a predetermined distance by an interface section, for example a length of hose. The separation of the strength member termination area from the signal conductor termination area allows for several improvements in the DTCTA not possible in the prior art due to the previous need to terminate the signal conductors co-located with the strength termination member.
Abstract:
The sonar array system includes a receive array of hydrophones and a transmit array of acoustic projectors disposed on a common axis. The sonar array system can be coupled to a ship and deployed and recovered from a single winch and through a single ship hull penetrator. When towed through water by the ship, the sonar array system provides a substantially horizontal transmit/receive array.
Abstract:
An acoustic emitter for coupling in series in a marine seismic streamer is provided with an annular housing and an annular piezoelectric emitting element positioned coaxially within the housing. This form of construction permits the electrical or electro-optical transmission line which normally runs along the axis of the streamer to pass through the centre of the emitting element, while also permitting the emitter to be spooled with the streamer.
Abstract:
An inner race for a streamer cable connector. The inner race includes first and second curved sections with a screwless fastener for clamping the two sections together about the streamer cable. The two curved sections may be hinged at first ends so that the inner race can be opened like a clam shell for placement about the cable. Cooperating teeth on the second ends of the inner race provide a screwless fastener for the two halves, with the teeth cooperatively arranged to ratchet by each other as the curved sections are closed around the cable.