A hydrophone may include a first piezoelectric cable including alternating sections of positive polarity and negative polarity, and a second piezoelectric cable including alternating sections of negative polarity and positive polarity. At least a portion of each section of positive polarity of the first piezoelectric cable may be bonded or adhered to at least a portion of a section of negative polarity of the second piezoelectric cable. A method of manufacturing a hydrophone may include winding or coiling a first piezoelectric cable and a second piezoelectric cable at the same time to create a series of wound sections including cables, the wound sections alternating with a series of not wound sections including the cables.

An acoustic array has a frame and multimode transducers positioned along the frame. The multimode transducers are cylindrical and divided into circumferential transducer segments. The transducer segments each have a common ground electrode and an electrode associated with the segment. An elastomeric bushing is between each multimode transducer and the frame. Electrical leads are joined to the electrodes. A proximate plug is provided at one end of the frame, and a distal plug is provided at the other. A connector is positioned in the proximate plug and joined to the electrical leads. An elastomeric hose surrounds the frame and is sealed to the proximate plug and the distal plug. The interior volume is filled with a dielectric fluid.

A method for providing a broadband constant beam width acoustic array includes providing a transducer array in an axisymmetric configuration. A beam width is specified, and an integer order Legendre polynomial is determined for that beam width. A control parameter is determined that will increase the integer order Legendre polynomial to that beam width. The Legendre polynomial is used to provide a shading function for the array of transducers that will give the specified beam width.

Systems and methods are provided for sensing acoustic signals using a floating base vector sensor. A vector sensor according to an embodiment of the present disclosure can be used to detect and characterize low frequency sound wave(s) in a viscous medium (e.g., air, water, etc.) by detecting a periodic motion of the media particles associated with the sound wave(s). The orientation of the particle velocity deduced from such measurements can provide information regarding the wave vector of the sound wave(s), can define the direction of arrival (DOA) for the acoustic signal, and can assist locating the source of the sound of interest.

Techniques are disclosed relating to calibrating sensors configured to measure both pressure and acceleration. In various embodiments, a system detects a first voltage produce by a first piezoelectric material in a hydrophone when the hydrophone is exposed to an acceleration and detects a second voltage produced by a second piezoelectric material in the hydrophone when the hydrophone is exposed to the acceleration. The system, in some embodiments, compares the first voltage and the second voltage. Based on the comparing of the first and second voltages, in some embodiments, the system determines a resistance for a variable resistor coupled to one of the first and second piezoelectric materials.

A device for receiving acoustic waves, includes an acoustic antenna able to function as a condenser microphone distributed along a line of the acoustic antenna comprising a conductor and a dielectric, the line being a transmission line or being configured to function as a transmission line when the dielectric makes direct physical contact with another conductor, an exciter configured to apply, in a receiving step, an input voltage to a first longitudinal end of the line so as to generate an input electromagnetic wave that moves toward a second longitudinal end of the line and so as to generate an output electromagnetic wave that moves in the opposite direction to the input electromagnetic wave, the input voltage simultaneously comprising a set of sinusoidal voltages comprising a fundamental sinusoidal voltage and a set of harmonics of the fundamental sinusoidal voltage, the frequency of the fundamental sinusoidal voltage being defined so that stationary waves are established in the line such that the output electromagnetic wave comprises directional acoustic-antenna channels.

Techniques are disclosed relating to sensors configured to measure acceleration and pressure. In various embodiments, an apparatus includes a first hydrophone sensor having a first piezoelectric material and a first housing structure and a second hydrophone sensor having a second piezoelectric material and a second housing structure. In some embodiments, the apparatus includes a first pair of wires configured to provide a first differential voltage and a second pair of wires configured to provide a second differential voltage. The first pair of wires may be coupled to the first hydrophone sensor and the second pair of wires may be coupled to the second hydrophone sensor. In various embodiments, the apparatus is configured to determine, based on the first and second differential voltages, a pressure and an acceleration experienced by the first and second hydrophone sensors.

A hydrophone may include a first piezoelectric cable including alternating sections of positive polarity and negative polarity, and a second piezoelectric cable including alternating sections of negative polarity and positive polarity. At least a portion of each section of positive polarity of the first piezoelectric cable may be bonded or adhered to at least a portion of a section of negative polarity of the second piezoelectric cable. A method of manufacturing a hydrophone may include winding or coiling a first piezoelectric cable and a second piezoelectric cable at the same time to create a series of wound sections including cables, the wound sections alternating with a series of not wound sections including the cables.

Systems and methods are provided for sensing acoustic signals using a floating base vector sensor. A vector sensor according to an embodiment of the present disclosure can be used to detect and characterize low frequency sound wave(s) in a viscous medium (e.g., air, water, etc.) by detecting a periodic motion of the media particles associated with the sound wave(s). The orientation of the particle velocity deduced from such measurements can provide information regarding the wave vector of the sound wave(s), can define the direction of arrival (DOA) for the acoustic signal, and can assist locating the source of the sound of interest.

Various implementations described herein are directed to methods for processing seismic data, including estimating a spectral noise power of multi-measurement seismic data received from a multi-dimensional seismic sensor array having multiple seismic sensors. The methods may include receiving a shot record of multi-measurement seismic data in time-domain, partitioning the shot record into overlapping time-space windows, and computing a frequency-domain spectrum for each time-space window. The methods may include computing a signal presence probability for each time-space window using the frequency-domain spectrum and prior probabilities of signal presence and absence for each time-space window. The methods may include iteratively updating a collective spectral noise power by recursively estimating the spectral noise power of a current time-space window based on the frequency spectrum for the current time-space window, the signal presence probability computed for the current time-space window, and a previously estimated spectral noise power of a previous time-space window.