Abstract: A communication device includes: an ultrasonic oscillating unit which detects or generates an ultrasonic wave; a communication unit which transmits and receives information using the ultrasonic wave; a storage unit which stores a table to which a communication command to designate communication with the another communication device is allocated in time series, the table being shared by the another communication device; and a control unit which shifts the communication unit to one of a transmitting state, a receiving state, and a standby state that is neither the transmitting nor the receiving state, synchronously with the another communication device on the basis of the communication command in the table.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: A sonobuoy that includes a communications device capable of being communicatively coupled to a computer network. Also disclosed is a network of communications devices placed on sonobuoys. The communications device is capable of several forms of RF transmission. The communications devices are also provided with processors capable of performing signal processing or a portion of signal processing before communicating data to a larger computer for further processing.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: A method and system for detecting watercraft in shallow waterways. In one example, an underwater detection system includes an underwater power source, an acoustic sensor, a controller coupled to the power source and to the acoustic sensor and configured to detect a watercraft of interest based on acoustic signals generated by the watercraft of interest and received by the acoustic sensor, and a retractable communications system. The retractable communications system is configured to deploy a transmitter to the surface of the shallow water to report detection of a watercraft in the waterway and to retract the transmitter to a safe depth below the surface of the shallow waterway when not actively communicating.

Abstract: An unmanned submersible vehicle for use in a body of liquid having a top surface and in air overlying the top surface includes a hull, an integral antenna, and an antenna positioning system. The hull has first and second opposed ends. The hull includes a first hull portion adjacent the first end and a second hull portion adjacent the second end. The antenna is disposed within the first hull portion and/or is mounted on the first hull portion. The antenna positioning system is configured to reorient the hull from a transit position to a signal position.

Abstract: A method and apparatus are present for managing a transmission of photons. The number of parameters for transmitting the photons as a beam in a liquid are identified using a number of characteristics of the liquid to form a number of selected parameters. The photons are transmitted in the liquid as the beam to a target using the number of selected parameters to form the transmission of the photons.

Abstract: A device for recovery of physical objects includes a chain having two ends and a retriever attached to one of the ends. The retriever is configured to locate the object to be recovered and to grasp and retrieve that object once located. The retriever includes transducers that detect acoustic frequencies propagating in a fluid medium. Independent transponders, which can be deployed from the retriever; are provided for deployment in an area to be searched. Each transponder emits a predetermined acoustic frequency that is detectable by the transducers. The transducers signal movement of the recovery device for retrieval of the object.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A metrology device, computer program product and computer-implemented method generating survey data without having the device touch subsea objects being surveyed. The metrology device may be used with an underwater vehicle or diving personnel, and may comprise an inertial navigation system having gyroscopes to detect angular velocity and accelerometers for the detection of linear velocity and transported by an underwater robotic apparatus or diver, the inertial navigation system outputting position and orientation data of the device for storage; an aiding device for collecting image data of the subsea objects, the aiding device being positioned so that the distance and orientation between the optical scanner and the inertial navigation system is known; and a computer for using the position information and image data between a successively visited known point to determine the drift of the metrology device and to use the drift of the metrology device to correct measurements of same.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: An underwater sensing and communications node includes an underwater vehicle, target sensing capability mounted on a forward portion of the underwater vehicle, at least three passive acoustic sensors evenly distributed about a first circumferential region of the underwater vehicle, and at least three transceiving hydrophones evenly distributed about a second circumferential region of the underwater vehicle. A controller governs collection of sensed data and transmission of the sensed data into the underwater environment.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A computer implemented method for retrieving seismic data from a seismic section provided in a bitmap format. The method includes reconstructing a two dimensional matrix of seismic interpolated data in which a value at a given pixel in the matrix is proportional to local density of wiggles in the seismic section with an added value of a previously calculated pixel. The method may be implemented in either of computer hardware configured to perform said method and computer software embodied in a non-transitory, tangible, computer-readable storage medium. Also disclosed are corresponding computer program product and data processing system.

Abstract: An acoustic sensor acquires acoustic data corresponding to a rotating component of a machine during operation of the machine. The acoustic sensor can be configured to enhance acoustic signals in a range of frequencies corresponding to at least one evaluated condition of the rotating component and/or enhance the acoustic signals received from a directional area narrowly focused on the rotating component. The rotating component is evaluated using the acoustic data acquired by the acoustic sensor. In an embodiment, the machine can be a vehicle traveling past a parabolic microphone. In a more specific embodiment, the vehicle is a rail vehicle and the rotating component is a railroad wheel bearing.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A device for deflecting acoustic waves for an object in a liquid environment includes a heating grid and a cooling grid. The heating grid is positioned about the object and increases the temperature in the liquid environment. The cooling grid is positioned about the object to cool the liquid environment outside the heating grid. Jointly, these grids establish a temperature gradient in the liquid environment that is capable of bending acoustic waves in the environment. The cooling grid and heating grid can be established through mechanical, electrical or chemical methods. Alternatively, the required temperature gradient can be established by a heating grid alone in a moving vehicle wherein the heating grid is continuously in contact with undisturbed water at the ambient temperature.

Abstract: A system and method measures the time offsets of a plurality of acoustic sensor nodes relative to a reference time. The system includes an acoustic transceiver arranged to transmit a first signal to each acoustic sensor node and a processing resource arranged to record the transmission time of the first signal relative to the reference time. The acoustic sensor nodes receive the first signal and transmit a return second signal to the acoustic transceiver after a predetermined time delay, the second signal including the current acoustic sensor node internal time. The acoustic transceiver receives the second signal, and the processing resource records the time at which the second signal was received relative to the reference time and records also the combined time of flight of the first and second signal. From this data the time offset between the sensor node internal time and the reference time is calculated.

Abstract: The systems described include a light-weight, low frequency (200 Hz-1000 Hz), broadband underwater sound sources that comprise an inner resonator tube with thin walls tuned to a certain frequency surrounded by a shorter, larger-diameter, lower frequency tuned outer resonator tube that has an acoustic source suspended off-center inside the inner resonator tube.

Abstract: An underwater system (10) comprising a transmitter (12) for broadcasting an electromagnetic synchronization signal and at least one node (14) that has a receiver for receiving that signal, the node being adapted to use the received signal for synchronization.

Abstract: Methods and transducers for producing acoustical signals having a spiral wavefront with omnidirectional magnitude and a phase that varies with angle and transducers for producing broadband omnidirectional reference signals for underwater navigation and communication.

Abstract: Techniques include determining coefficients of a complex auto regression (AR) model to fit a complex average spectrum at a base frequency resolution of a set of one or more measured acoustic beams during a time block. Residuals derived by filtering actual data through an inverse of the AR model are determined at frequencies below a first threshold frequency. A quantized spectrum of the residuals is determined at the base frequency resolution. Magnitude, phase, and frequency bin at the base frequency resolution are determined for each peak of a set of one or more narrowband peaks above a second threshold frequency for the set of one or more measured acoustic beams. A message is sent, which indicates without loss the coefficients of the AR model, the quantized spectrum of the residuals, and the frequency bin, magnitude and phase for each peak of the set of one or more narrowband peaks.

Abstract: A remote power delivery system includes an electrically-conductive plate disposed adjacent to a sensor system of an underwater vehicle's hull. At least one toroidal coil is disposed between the plate and the face of the sensor system exposed to water. An AC voltage is applied to the plate so that a time-harmonic voltage is induced in each toroidal coil.

Abstract: A subsea monitoring system.

Abstract: An acoustic reflector comprises a shell surrounding a solid joint free core, said shell being capable of transmitting acoustic waves incident on the surface of the shell into the core to be focused and reflected from an area of the shell located opposite to the area of incidence so as to provide a reflected acoustic signal output from the reflector. The ratio of the speed of sound wave transmission in the shell to the average speed of the wave transmission in the core is preferably in the range of 2.74 to 3.4, inclusive or a multiple thereof with best result in the range of 2.74 to 2.86 inclusive.

Abstract: Disclosed herein is an underwater pager configured such that a hole is not formed in the outer wall of a casing. The ultrasonic underwater pager includes an ultrasonic transducer for transmitting or receiving ultrasonic signals. An electronic circuit unit generates an ultrasonic signal and analyzes a received ultrasonic signal. A switch unit is switched using a magnetic phenomenon and is configured to supply power to the electronic circuit unit and transmit external commands to the electronic circuit unit. A watertight casing is configured such that the ultrasonic transducer, the electronic circuit unit, and the switch unit are installed in the watertight casing, the ultrasonic transducer being installed in a raised position in the watertight casing using a molding process. A magnet is attached to a rubber cover connected to an outside of the watertight casing, and is configured to switch on/off the switch unit using a magnetic phenomenon.

Abstract: An omni-directional acoustic horn for applications in a liquid transmission medium deploys a plurality of transducers distributed along an interior face of the horn to radiate against an opposed surface. The arrangement mimics operation at a greater depth of submergence to depress development of acoustic cavitation bubbles.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: Disclosed is an acoustic signal detector for detecting a target with moving in water. The acoustic signal detector may include a body having a front portion, the front portion having a cross section which becomes gradually narrow and an end formed to have a plane. The plane may be perpendicular to a moving direction of the acoustic signal detector. The acoustic signal detector may further include a plurality of sensor arrays configured to generate sound and detect sound returned by being reflected by a target. The plurality of sensor arrays may be mounted on a side surface of the front portion and on the plane.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: A personal water safety device includes at least two sonar receivers, at least one water sensing device, and an alarm apparatus. The at least one water sensing device communicates with each of the at least two sonar receivers via sound waves. The alarm apparatus wirelessly communicates with each of the at least two sonar receivers. Each water sensing device is worn by a swimmer and is triggered to measure an elapsed time when the swimmer submerges in water, and transmits the measured time and a corresponding identification number to the at least two sonar receivers via the sound waves. The alarm apparatus receives the measured time and the corresponding identification number transmitted from each of the at least two sonar receivers, and generates an alarm when the measured time of one of the at least water sensing device exceeds a predetermined time limit.

Abstract: Contemplated planar magnetic microphones have a magnet and diaphragm arrangement such that substantially homogenous vertical and high horizontal magnetic flux density is realized in the inter-magnet space. Most preferably, the diaphragm is disposed in the inter-magnet space and includes a voice coil covering a significant fraction of the active portion of the membrane. In further especially preferred aspects, the membrane is sufficiently strong and tensioned to allow a large elastic excursion in the inter-magnet space. Consequently, contemplated planar magnetic microphones provide exceptionally large dynamic range without compression and/or distortion and can be easily configured to operate in an environment that is subject to moisture, rain, or to even operate in a submerged environment. Moreover, contemplated microphones can be used as speakers at even high SPL without reconfiguration.

Abstract: An environmental monitoring system including at least one underwater measurement device and a transmitter for transmitting data from the measurement device to an above water station using a magnetically coupled antenna.

Abstract: The present invention discloses a tagging and identification device and system for tracking and monitoring sea vessels as they enter sea ports, estuaries and/or other channels. The tagging device of the present invention comprises a receiver, for receiving an underwater electromagnetic signal transmitted by an underwater beacon. An acoustic transmitter is provided for transmitting an identification signal to an acoustic receiver deployed nearby. The acoustic identification signal is transmitted after an electromagnetic trigger signal is received from the underwater beacon. The tagging and device may further comprise a memory device which can store data relating to position and time of the see vessel to which it is attached. The tagging and identification device of the present invention is covert, compact and is capable of extended active deployment without replenishment of batteries etc.

Abstract: A method for monitoring the operation of underwater-located equipment is provided. The method comprises: providing a sensor, the sensor comprising at least one of an acoustic sensor and an accelerometer, locating the sensor proximate the equipment to enable detection by the sensor of acoustic and/or acceleration components produced by the operation of the equipment, and producing electrical output signals in dependence on the detected components.

Abstract: A method for localizing the range and bearing of a distant underwater object includes firing a preselected number of supercavitating projectiles sequentially from a firing location such that each projectile tracks along substantially the same trajectory. Supercavitating pellets are dispersed from a projectile at a pre-selected range. Acoustic signals are sensed to detect acoustic signals caused by supercavitating pellet impact with an object. These signals can be processed to determine the range and bearing to the object. In further steps the range and bearing can be used to aim the projectiles.

Abstract: A method of detecting a submerged vessel in or near the wake of a ship in which a plurality of optical fiber sensors are trailed from said ship and in which at least one of said sensors which is located in the ship's wake comprises a magnetically-responsive optical fiber sensor.

Abstract: The present invention relates to an underwater guidance system for guiding an underwater apparatus, for example an underwater vehicle, towards a target structure, such as a docking station. The system comprises at least one system for capturing or sensing information on the relative position of the apparatus and the target structure and/or at least one imaging system for capturing an image of the target structure and a transmitter for wireless electromagnetic transmission of data indicative of the position information and/or captured image to the underwater apparatus or an underwater apparatus controller.

Abstract: Underwater multiple input/multiple output (MIMO) communication apparatus, systems, and methods are disclosed. An underwater MIMO apparatus includes a submersible housing having a water impermeable section, a data acquisition system located within the water impermeable section of the submersible housing, and at least two transmission communication elements electrically connected to the data acquisition system. The MIMO communication apparatus may be used in a communication system including a communication array for communicating with the MIMO communication apparatus using a MIMO communication method.

Abstract: Contemplated planar magnetic microphones have a magnet and diaphragm arrangement such that substantially homogenous vertical and high horizontal magnetic flux density is realized in the inter-magnet space. Most preferably, the diaphragm is disposed in the inter-magnet space and includes a voice coil covering a significant fraction of the active portion of the membrane. In further especially preferred aspects, the membrane is sufficiently strong and tensioned to allow a large elastic excursion in the inter-magnet space. Consequently, contemplated planar magnetic microphones provide exceptionally large dynamic range without compression and/or distortion and can be easily configured to operate in an environment that is subject to moisture, rain, or to even operate in a submerged environment. Moreover, contemplated microphones can be used as speakers at even high SPL without reconfiguration.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A signal analysis method extracts transient target signals of known type from a raw data source signal that contains an unknown number of target signals. The method can enhance the analysis of data obtained from in-line oil-debris sensors. The method comprises steps of: defining signatures of the known target signal, and of at least one of the intrinsic noise and interfering signals; performing a mathematical transform that decomposes the raw data into distinct data sets; using the signal signatures to identify and nullify the data sets containing noise and interfering signal signatures; using the target signal signatures to identify the data sets containing target signal components, or may further use a thresholding rule to remove intrinsic noise from said data sets, and finally applying the inverse transform to the processed data sets in order to reconstruct an enhanced output signal.