Abstract: The method for estimating the drift over time of a physical operating parameter of a clock for dating seismic data samples associated with a seismic data collection node involves measuring (10) at least one quantity associated with the clock, at predetermined instants or during predetermined time periods, and applying (12), to this quantity, a predetermined non-linear law of variation of this quantity that depends on the values collected during the measurement step (10), so as to obtain an estimation of the drift over time of the physical operating parameter.

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 method for localizing a marine animal in an underwater environment implemented by a passive acoustic monitoring (PAM) system. The passive acoustic monitoring system includes network of acoustic sensors adapted to carry out measurements of acoustic signals. The method includes: obtaining, from the network of acoustic sensors, measured data of an acoustic signal emitted by a marine animal; defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells, for each cell of a predefined set, obtaining an error defined as a value of a cost function for the cell, the cost function giving a deviation between: at least some of the measured data; and corresponding theoretical data obtained by assuming the marine animal is located in the cell, the errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal.

Abstract: A method for localizing a marine animal in an underwater environment implemented by a passive acoustic monitoring (PAM) system. The passive acoustic monitoring system includes network of acoustic sensors adapted to carry out measurements of acoustic signals. The method includes: obtaining, from the network of acoustic sensors, measured data of an acoustic signal emitted by a marine animal; defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells, for each cell of a predefined set, obtaining an error defined as a value of a cost function for the cell, the cost function giving a deviation between: at least some of the measured data; and corresponding theoretical data obtained by assuming the marine animal is located in the cell, the errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal.

Abstract: A method for localizing a marine animal in an underwater environment implemented by a passive acoustic monitoring (PAM) system. The passive acoustic monitoring system includes network of acoustic sensors adapted to carry out measurements of acoustic signals. The method includes: obtaining, from the network of acoustic sensors, measured data of an acoustic signal emitted by a marine animal; defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells, for each cell of a predefined set, obtaining an error defined as a value of a cost function for the cell, the cost function giving a deviation between: at least some of the measured data; and corresponding theoretical data obtained by assuming the marine animal is located in the cell, the errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal.

Abstract: An operation managing system is provided for managing the operation of a navigation control device. The navigation control device is adapted for controlling the depth and/or the lateral position of a towed acoustic linear antenna and including a body to which is attached a set of wings. The operation managing system operates the navigation control device according to a degraded operating mode, by acting on at least one non-released and motorized wing when detecting that at least one wing of the set of wings has been released or must be released.

Abstract: A method is provided for controlling quality of operation of a passive acoustic monitoring system. The method includes, at least for one given source: (a) the given source emits at least one acoustic test signal; (b) the passive acoustic monitoring system obtains acoustic signal measurements and estimates at least one parameter, characteristic of and/or associated with the at least one test acoustic signal, as a function of the acoustic signal measurements; (c) comparing the at least one estimated parameter with at least one reference parameter, characteristic of and/or associated with the at least one test acoustic signal; (d) obtaining at least one piece of quality information, as a function of results of the comparing step. A quality control device is provided, which drives the given source to trigger the step (a), obtains the at least one estimated parameter and carries out the steps (c) and (d).

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 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: 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 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 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 method for estimating an underwater acoustic sound velocity in a network of acoustic nodes arranged along towed acoustic linear antennas and in which a plurality of acoustic signals are transmitted between the nodes. The method includes: obtaining two predetermined distances each separating a couple of nodes placed along a same first acoustic linear antenna (31); for each couple of first and second nodes, obtaining a first propagation duration of an acoustic signal transmitted between said first node and a third node placed along a second acoustic linear antenna and a second propagation duration of an acoustic signal transmitted between said second node and said third node; and estimating said underwater acoustic sound velocity, as a function of said two predetermined distances and said first and second propagation durations obtained for each couple of nodes.

Abstract: A method is provided for controlling quality of operation of a passive acoustic monitoring system. The method includes, at least for one given source: (a) the given source emits at least one acoustic test signal; (b) the passive acoustic monitoring system obtains acoustic signal measurements and estimates at least one parameter, characteristic of and/or associated with the at least one test acoustic signal, as a function of the acoustic signal measurements; (c) comparing the at least one estimated parameter with at least one reference parameter, characteristic of and/or associated with the at least one test acoustic signal; (d) obtaining at least one piece of quality information, as a function of results of the comparing step. A quality control device is provided, which drives the given source to trigger the step (a), obtains the at least one estimated parameter and carries out the steps (c) and (d).

Abstract: A method for localizing a marine animal in an underwater environment implemented by a passive acoustic monitoring (PAM) system. The passive acoustic monitoring system includes network of acoustic sensors adapted to carry out measurements of acoustic signals. The method includes: obtaining, from the network of acoustic sensors, measured data of an acoustic signal emitted by a marine animal; defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells, for each cell of a predefined set, obtaining an error defined as a value of a cost function for the cell, the cost function giving a deviation between: at least some of the measured data; and corresponding theoretical data obtained by assuming the marine animal is located in the cell, the errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal.

Abstract: An operation managing system is provided for managing the operation of a navigation control device. The navigation control device is adapted for controlling the depth and/or the lateral position of a towed acoustic linear antenna and including a body to which is attached a set of wings. The operation managing system operates the navigation control device according to a degraded operating mode, by acting on at least one non-released and motorized wing when detecting that at least one wing of the set of wings has been released or must be released.

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 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 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.