Abstract: Roll data can be acquired from a magnetometer and an accelerometer of a towed object telemetry unit coupled to a towed object during rolls of the towed object in two or more different headings. The magnetometer can be calibrated based on the roll data. Turn data can be acquired from the magnetometer and the accelerometer during a turn of the towed object from a first heading to a second heading. The magnetometer can be further calibrated based on the turn data.

Abstract: Included are methods and apparatus for marine geophysical surveying. One embodiment of the presently-disclosed solution relates to a method for instantaneous roll compensation of vectorised motion data originating from a fixed-mount geophysical sensor during a marine seismic survey. A streamer is towed behind a survey vessel in a body of water. The streamer includes a plurality of geophysical sensors and a plurality of orientation sensor packages. Vectorised geophysical data is acquired using the plurality of geophysical sensors, while orientation data is acquired by the plurality of orientation sensor packages. The orientation data is used to determine an instantaneous roll angle of the streamer at different positions on the streamer. The vectorised geophysical data is adjusted to compensate for the instantaneous roll angle of the streamer at different positions on the streamer. Other embodiments and features are also disclosed.

Abstract: Roll data can be acquired from a magnetometer and an accelerometer of a towed object telemetry unit coupled to a towed object during rolls of the towed object in two or more different headings. The magnetometer can be calibrated based on the roll data. Turn data can be acquired from the magnetometer and the accelerometer during a turn of the towed object from a first heading to a second heading. The magnetometer can be further calibrated based on the turn data.

Abstract: Roll data can be acquired from a magnetometer and an accelerometer of a towed object telemetry unit coupled to a towed object during rolls of the towed object in two or more different headings. The magnetometer can be calibrated based on the roll data. Turn data can be acquired from the magnetometer and the accelerometer during a turn of the towed object from a first heading to a second heading. The magnetometer can be further calibrated based on the turn data.

Abstract: An apparatus can include a base assembly and a pivot assembly coupled to the base assembly. The apparatus can include a carriage coupled to the pivot assembly. The carriage can be shaped to receive a compass streamer telemetry unit (CSTU). The carriage can be configured to secure the CSTU. The pivot assembly can be rotatably coupled to the base assembly to adjust a pitch of the carriage. The carriage can be rotatably coupled to the pivot assembly to adjust roll of the carriage.

Abstract: Included are methods and apparatus for marine geophysical surveying. One embodiment of the presently-disclosed solution relates to a method for instantaneous roll compensation of vectorised motion data originating from a fixed-mount geophysical sensor during a marine seismic survey. A streamer is towed behind a survey vessel in a body of water. The streamer includes a plurality of geophysical sensors and a plurality of orientation sensor packages. Vectorised geophysical data is acquired using the plurality of geophysical sensors, while orientation data is acquired by the plurality of orientation sensor packages. The orientation data is used to determine an instantaneous roll angle of the streamer at different positions on the streamer. The vectorised geophysical data is adjusted to compensate for the instantaneous roll angle of the streamer at different positions on the streamer. Other embodiments and features are also disclosed.

Abstract: Included are methods and apparatus for marine geophysical surveying. One embodiment of the presently-disclosed solution relates to a method for instantaneous roll compensation of vectorised motion data originating from a fixed-mount geophysical sensor during a marine seismic survey. A streamer is towed behind a survey vessel in a body of water. The streamer includes a plurality of geophysical sensors and a plurality of orientation sensor packages, and each orientation sensor package comprises a magnetometer. Vectorised geophysical data is acquired using the plurality of geophysical sensors, while orientation data is acquired by the plurality of orientation sensor packages. The orientation data is used to determine an instantaneous roll angle of the streamer at different positions on the streamer. The vectorised geophysical data is adjusted to compensate for the instantaneous roll angle of the streamer at different positions on the streamer. Other embodiments and features are also disclosed.

Abstract: Alternating current (AC) coupled accelerometer calibration can include acquiring calibrated data from a direct current (DC) coupled accelerometer of a towed object and interpolating the acquired calibrated data to a location of an AC coupled accelerometer of the towed object. AC coupled accelerometer calibration can also include estimating a calibration parameter associated with the AC coupled accelerometer based on the interpolating and correcting for a sensitivity associated with the AC coupled accelerometer using the calibration parameter.

Abstract: A system can include a head connector, a stress member connector, and a tail connector. The system can include a first plurality of stress members coupled to the head connector and to the stress member connector. The first plurality of stress members can enter through a first side of the stress member connector. The system can include a second plurality of stress members coupled to the tail connector and to the stress member connector. The second plurality of stress members can exit through a second side of the stress member connector. The second plurality of stress members can be axially nonaligned with the first plurality of stress member connectors.

Abstract: Disclosed are methods and systems for enabling anti-twist functionality in marine geophysical streamers. An embodiment discloses a method comprising: towing a streamer behind a survey vessel in a body of water, wherein the streamer comprises rotation sensors and streamer rotation devices; receiving data from at least one rotation sensor indicative of streamer twist; and rotating a portion of the streamer with at least one streamer rotation device to reduce the streamer twist based, at least in part on the data.

Abstract: An apparatus can include a base assembly and a pivot assembly coupled to the base assembly. The apparatus can include a carriage coupled to the pivot assembly. The carriage can be shaped to receive a compass streamer telemetry unit (CSTU). The carriage can be configured to secure the CSTU. The pivot assembly can be rotatably coupled to the base assembly to adjust a pitch of the carriage. The carriage can be rotatably coupled to the pivot assembly to adjust roll of the carriage.

Abstract: Included are methods and apparatus for marine geophysical surveying. One embodiment of the presently-disclosed solution relates to a method for instantaneous roll compensation of vectorised motion data originating from a fixed-mount geophysical sensor during a marine seismic survey. A streamer is towed behind a survey vessel in a body of water. The streamer includes a plurality of geophysical sensors and a plurality of orientation sensor packages, and each orientation sensor package comprises a magnetometer. Vectorised geophysical data is acquired using the plurality of geophysical sensors, while orientation data is acquired by the plurality of orientation sensor packages. The orientation data is used to determine an instantaneous roll angle of the streamer at different positions on the streamer. The vectorised geophysical data is adjusted to compensate for the instantaneous roll angle of the streamer at different positions on the streamer. Other embodiments and features are also disclosed.

Abstract: Roll data can be acquired from a magnetometer and an accelerometer of a towed object telemetry unit coupled to a towed object during rolls of the towed object in two or more different headings. The magnetometer can be calibrated based on the roll data. Turn data can be acquired from the magnetometer and the accelerometer during a turn of the towed object from a first heading to a second heading. The magnetometer can be further calibrated based on the turn data.

Abstract: This disclosure is related to the field of streamers. In one embodiment, a streamer may include a group of particle motion sensors. In some embodiments, at least two of the particle motion sensors in the group are movable relative to one another within the streamer, and the two particle motion sensors are configured to measure motion along a particular axis. In some embodiments, the streamer may additionally include a plurality of pressure sensors.

Abstract: Disclosed are methods and systems for controlling spread and/or depth in a geophysical survey. An embodiment discloses a submersible deflector, comprising: an upper portion comprising an upper fin section and upper foils disposed below the upper fin section, wherein at least one slot is defined between the upper foils; and a lower portion coupled to the upper portion and disposed below the upper portion, wherein the lower portion comprises a lower fin section and lower foils disposed above the lower fin section, wherein at least one slot is defined between the lower foils. Also disclosed are marine geophysical survey systems and methods of performing geophysical surveys.

Abstract: Included are methods and systems for marine geophysical surveying. A system includes a streamer; a sensor package coupled to the streamer, wherein the sensor package comprises a primary orientation sensor and a complimentary orientation sensor, wherein the complimentary orientation sensor comprises a magnetometer, wherein the primary orientation sensor and the complimentary orientation sensor are capable of collecting data indicative of the orientation of the streamer; and geophysical sensors distributed on the streamer.

Abstract: This disclosure is related to the field of streamers. In one embodiment, a streamer may include a group of particle motion sensors. In some embodiments, at least two of the particle motion sensors in the group are movable relative to one another within the streamer, and the two particle motion sensors are configured to measure motion along a particular axis. In some embodiments, the streamer may additionally include a plurality of pressure sensors.

Abstract: Disclosed are methods and apparatus for adaptive source electromagnetic (EM) surveying. In accordance with one embodiment, a source waveform signal is generated, and an outgoing EM signal which is based on the source waveform signal is transmitted using an antenna. A responsive electromagnetic signal is detected using at least one electromagnetic sensor, and a receiver waveform signal based on the responsive electromagnetic signal is obtained. A feedback control signal which depends on at least one input signal is determined. Based on the feedback control signal, the source waveform signal is adapted. Other embodiments, aspects, and features are also disclosed.

Abstract: A sensor streamer stretch section. At least some of the example embodiments are methods including measuring at least one parameter related to noise while towing the sensor streamer through a body of water with a towing vessel, and adjusting at least one of a spring constant and a damping coefficient of a stretch section disposed proximate the sensor streamer such that the measured parameter is minimized.

Abstract: Electromagnetic streamer cables and methods of use. Example systems include: a first electrode, the first electrode at a first location along the streamer cable; a second electrode at a second location along the streamer cable; a first sensor module electrically coupled to the first electrode and second electrode, the first sensor module configured to measure a voltage across the first and second electrodes; a third electrode at a third location between the first and second electrodes; a fourth electrode at a fourth location along the streamer cable, the fourth location distal to the second location; and a second sensor module electrically coupled to the third electrode and fourth electrode, the second sensor module configured to measure a voltage across the third and fourth electrodes.