A terrestrial acoustic sensor array for detecting and preventing airspace collision with an unmanned aerial vehicle (UAV) includes a plurality of ground-based acoustic sensor installations, each of the acoustic sensor installations including a sub-array of microphones. The terrestrial acoustic sensor array may further include a processor for detecting an aircraft based on sensor data collected from the microphones of at least one of the plurality of acoustic sensor installations and a network link for transmitting a signal based on the detection of the aircraft to a control system of the UAV.

A harness plug and methods of use. Example devices include an arcuate portion and a lateral portion disposed at an outer periphery of the arcuate portion. The arcuate portion is configured to engage with arcuate portion of a hole within a spacer. A method of using the harness plug includes molding a harness plug about a portion of a cable bundle and inserting the cable bundle into an arcuate portion of a hole in the spacer through a lateral portion of the first hole. The harness plug is pressed into the arcuate portion of a hole in the spacer. A streamer spacer for use with the harness plug includes a hole having a portion having an arcuate shape and a second portion lateral to and abutting the arcuate portion and extending to a periphery of an elongate body of the streamer spacer.

A method for calculating a tension (T) in a towed antenna. The method includes towing the antenna in water, wherein the antenna includes plural particle motion sensors distributed along the antenna; measuring with the plural particle motion sensors vibrations that propagate along the antenna; calculating a value of a phase velocity (vp) of the vibrations that propagate along the antenna based on (1) an offset between two particle motion sensors and (2) a time delay of the vibrations that propagate from one of the two particle motion sensors to another one of the two particle motion sensors; selecting a relation that links the phase velocity (vp) to the tension (T); and using the value of the phase velocity and the relation to determine the tension (T) at various locations of the plural particle motion sensors along the antenna.

Aspects of the present disclosure describe Rayleigh fading mitigation via short pulse coherent distributed acoustic sensing with multi-location beating-term combination. In illustrative configurations, systems, methods, and structures according to the present disclosure employ a two stage modulation arrangement providing short interrogator pulses resulting in a greater number of sensing data points and reduced effective sectional length. The increased number of data points are used to mitigate Rayleigh fading via a spatial combining process, multi-location-beating combining (MLBC) which uses weighted complex-valued DAS beating results from neighboring locations and aligns phase signals of each of the locations, before combining them to produce a final DAS phase measurement. Since Rayleigh scattering is a random statistic, the MLBC process allows capture of different statics from neighboring locations with correlated vibration/acoustic signal. The combined DAS results minimize a total Rayleigh fade, in both dynamic fading and static fading scenarios.

A marine seismic acquisition system includes a frame that includes a central longitudinal axis and members that define orthogonal planes that intersect along the central longitudinal axis; a data interface operatively coupled to the frame; hydrophones operatively coupled to the frame; a buoyancy engine operatively coupled to the frame where the buoyancy engine includes at least one mechanism that controls buoyancy of at least the frame, the hydrophones and the buoyancy engine; and at least one inertial motion sensor operatively coupled to the frame that generates frame orientation data, where the hydrophones, the buoyancy engine and the at least one inertial motion sensor are operatively coupled to the data interface.

A marine seismic acquisition system includes a frame that includes a central longitudinal axis and members that define orthogonal planes that intersect along the central longitudinal axis; a data interface operatively coupled to the frame; hydrophones operatively coupled to the frame; a buoyancy engine operatively coupled to the frame where the buoyancy engine includes at least one mechanism that controls buoyancy of at least the frame, the hydrophones and the buoyancy engine; and at least one inertial motion sensor operatively coupled to the frame that generates frame orientation data, where the hydrophones, the buoyancy engine and the at least one inertial motion sensor are operatively coupled to the data interface.

A deployment module according to the present application enables both compact stowage of a sensor array and expansion of the sensor array into a three-dimensional volumetric array shape that enables improved directionality of the sensors during operation. The deployment module includes a support shell that is configured to retain a cable of the sensor array separately from sensors of the sensor array and an expandable deployment body formed of a superelastic shape memory alloy that uses superelasticity and stored energy for deployment of the sensor array. During deployment, the deployment body is removed from the support shell and the sensors are subsequently pulled out of the support shell. The deployment body then expands and holds the cable to retain the three-dimensional volumetric shape of the deployed array.

A plurality of sensors and a controller are disposed in a marine seismic streamer. Each of the sensors comprises an enclosure having two opposing interior walls, first and second piezoelectric elements disposed on the opposing interior walls, a third piezoelectric element disposed on a flexible substrate within the enclosure between the opposing interior walls, a pressure signal output node and an acceleration signal output node disposed on the exterior surface of the enclosure. A combined pressure signal derived from the pressure signal output nodes of the plural sensors is coupled to a pressure signal input of the controller. A combined acceleration signal derived from the acceleration signal output nodes of the plural sensors is coupled to an acceleration signal input of the controller. The streamer may be towed, and the combined pressure and acceleration signals may be recorded in a computer-readable medium.

A plurality of sensors and a controller are disposed in a marine seismic streamer. Each of the sensors comprises an enclosure having two opposing interior walls, first and second piezoelectric elements disposed on the opposing interior walls, a third piezoelectric element disposed on a flexible substrate within the enclosure between the opposing interior walls, a pressure signal output node and an acceleration signal output node disposed on the exterior surface of the enclosure. A combined pressure signal derived from the pressure signal output nodes of the plural sensors is coupled to a pressure signal input of the controller. A combined acceleration signal derived from the acceleration signal output nodes of the plural sensors is coupled to an acceleration signal input of the controller. The streamer may be towed, and the combined pressure and acceleration signals may be recorded in a computer-readable medium.

Systems and a method are disclosed. The method includes obtaining a plurality of raw seismic datasets for a subterranean region of interest, wherein each raw seismic dataset is generated by a high-speed train traversing a train track at a unique speed. The method further includes determining a plurality of processed seismic datasets by processing each of the plurality of raw seismic datasets and determining a final seismic dataset by combining the plurality of processed seismic datasets. The method still further includes identifying subterranean features within the subterranean region of interest using the final seismic dataset.