Abstract: An underwater station including: a transmitter means located on a flotation means connected to the station, and a tracking means to determine the relative location of the flotation means.

Abstract: A system to position at least one vessel or object in an aquatic environment including: each vessel or object having a receiver connected thereto; and at least two transmitters; wherein each transmitter transmits a unique signal and the receiver on each vessel or object receives each unique signal and a calculation means determines the position of the vessel or object based on the received signals.

Abstract: System and method for determining a location of a first target. The sensor network comprises a first sensor cluster comprising a first plurality of bearing measuring sensors. A first gateway is operatively coupled to the first plurality of bearing measuring sensors. A second sensor cluster comprises a second plurality of bearing measuring sensors. A second gateway is operatively coupled to the second plurality of bearing measuring sensors. A central command node is operatively coupled to the first and the second gateways. A first limited set of pre-computed numbers representative of information for generating a global target location estimation is transmitted from the first gateway to the central command node. A second limited set of pre-computed numbers representative of information for generating the global target location estimation is transmitted from the second gateway to the central command node.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. The system uses at least five, preferably seven, spaced acoustic sensors. Sensor signals are detected for shockwaves and muzzle blast, wherein muzzle blast detection can be either incomplete coming from less than 4 sensor channels, or inconclusive due to lack of signal strength. Shooter range can be determined by an iterative computation and/or a genetic algorithm by minimizing a cost function that includes timing information from both shockwave and muzzle signal channels. Disambiguation is significantly improved over shockwave-only measurements.

Abstract: A method for obtaining an increased update rate in an indoor acoustic positioning system for determining the position of one or more identification tags, comprising transmitting from an identification tag an acoustic spread spectrum sequence that is unique to the identification tag, receiving the spread spectrum sequence in a detector unit and recording the arrival time of the spectrum sequence, and comparing the spectrum sequence with stored values of the spectrum sequences used by all the identification tags in the positioning system.

Abstract: A method and apparatus is provided for suppressing noise which includes receiving a plurality of signals from an array of sensors and transforming each of these signals to the frequency domain. The transformed signals are beamformed so that noise sources can be identified by bearing and frequency range. A planewave-fit noise-suppression routine is then used to remove identified noise sources from the transformed signals and to provide a noise-suppressed transformed signal having signals from said identified noise sources suppressed.

Abstract: A method for determining the likely range and depth of an acoustically radiating source in which characteristics are used from hypothetical ranges and depths. A received sonar signal is compared with modeled ranges and depths. The correlation between the received signal characteristics and the modeled characteristics gives the likely range and depth. In a preferred embodiment this is presented as a contour plot.

Abstract: The invention relates to an identification chip for insertion in an object located in a liquid. The identification chip comprises an acoustic resonator (100), which exhibits a number of distinct resonant frequencies, where the combination of resonant frequencies is unique to the identification chip. This enables the identification chip to be identified by exposing it to an acoustic polling signal, measuring an acoustic response signal and analysing the frequency of the response signal. The resonator (100) comprises a cavity-forming part (110, 120) and a membrane (130). The acoustic resonant frequencies are determined by at least one cavity (140), which is enclosed by the cavity-forming part (110, 120) and the membrane (140). The identification chip can be implanted in a fish, with the object of identifying the fish when it is located in water.

Abstract: A to method and system provide a range and depth localization of a passive sound generator, e.g., a submarine target. The method and system use an autocorrelation and/or a cross correlation to arrive at a plurality of range versus depth estimates, which are resolved and evaluated using likelihood factors in order to provide a range and depth localization.

Abstract: A scale adaptive filtering scheme is developed for underspread channels based on a model of the linear time varying channel operator as a process in scale. Recursions serve the purpose of adding detail to the filter estimate until a suitable measure of fidelity and complexity is achieved.

Abstract: Systems and methods for locating the shooter of supersonic projectiles are described. Muzzle blast signals are neither sought nor required. The system uses at least two sensors, with each sensor having a 3-axis accelerometer. The sensors are spaced apart at least 1 meter and have each a diameter of about one centimeter. The three accelerometer signals of each sensor represent pressure gradients and are processed to find the shockwave arrival angle unit vector, the shockwave arrival time instant and peak pressure. Noise signals seldom cause false detections with this sensing method because the sensors have maximum sensitivity at the high frequency characteristics of shockwaves, while their sensitivity to the low frequency characteristics of ambient noise is relatively low.

Abstract: A system and a method are provided to accurately track the trajectory of high-speed underwater objects. A number of hoops with means for controlling the buoyancy thereof are aligned on a range in the anticipated path of the high speed projectile. The hoops are sufficiently large relative to the size of the projectile and anticipated path. Each hoop contains a number of independent hydrophones. The signals from the hydrophones may be analyzed to accurately determine position and track of an underwater projectile along the plane of each hoop. The system may be used as a fixed range or as a mobile range in a remote location.

Abstract: A global localization apparatus, medium, and method, with the global localization method including selecting one from a plurality of samples and shifting the selected sample according to a movement of a robot, generating a new sample within a predetermined range of the shifted sample, determining either the shifted sample or the new sample as a next sample at a next time step according to a predetermined condition for the shifted sample and the next sample, repeating for all the samples, and estimating a next position of the robot according to positions of the next samples when the number of next samples is equal to or larger than the maximum number of samples.

Abstract: A multi-stage maximum likelihood target estimator for use with radar and sonar systems is provided. The estimator is a software implemented algorithm having four computational stages. The first stage provides angle smoothing for data endpoints thereby reducing angle errors associated with tie-down times. The second stage performs a coarse grid search to obtain the initial approximate target state to be used as a starting point for stages 3 and 4. The third stage is an endpoint Gauss-Newton type maximum likelihood target estimate which determines target range along two time lines. The final refinement of the target state is obtained by the fourth stage which is a Cartesian coordinate maximum likelihood target estimate. The four-stage processing allows the use of target historic data while reducing processing time and computation power requirement.

Abstract: A proximity detector for use in a mobile telephone having at least a microphone and a loudspeaker operatively connected to a signal processor is presented. The proximity detector includes data processing and control modules having a module for controlling the signal processor for activating the loudspeaker to reproduce an acoustic control signal. A correlator correlates a control signal received directly by the microphone and a control signal being reflected from a user of the telephone and then received by the microphone to determine the distance between the telephone and the user. A signal level controller controls the signal processor to vary the signal level of an audible signal reproduced by the loudspeaker depending on the determined distance between the telephone and the user.

Abstract: A fishing lure tracking system includes a sending unit which sends a coded acoustic signal to a hydrophone attached to a fishing vessel to provide a signal correlating to the depth of the sending unit in a body of water. The sending unit is arranged on a fishing line adjacent to the bait or lure at the end thereof. The acoustic signal is processed by a signal processor connected with the hydrophone to produce an output signal for a display to indicate the depth of the unit. With the tracking system, a fisherman can position the lure or bait at the same depth as a school of fish.

Abstract: A method of detecting and localizing a source of partial discharge in an electrical apparatus placed in an enclosure containing an acoustically-conductive fluid.

Abstract: A method and a system of triangulating an object by means of at least two sensors. Each sensor is placed in a respective local reference system. Each of the at least two sensors at least provide a bearing to the object in their respective local reference system. According to the invention a triangulation reference system is created. The triangulation reference system is different to any one of the local reference systems and suitably such that at least two local reference systems are rotated more in relation to each other than each one is in relation to the triangulation reference system. Sensor positions and bearings are transformed into the triangulation reference system where the triangulation is performed. Suitably the triangulated position is then transformed into a desired reference system.

Abstract: The present application discloses a method for resolving harmonic ambiguity and inter-array harmonic tracking. The method allows derivation of a complete set of possible harmonic families given the selection (by an operator) or automatic detection (by an automated algorithm) of a single tone (fselected) from a frequency spectrum using a novel “ambiguity matrix” approach in which a matrix of all N possible harmonic members and M hypothetical fundamentals is constructed. The ambiguity matrix provides an image of all possible harmonic families associated with a selected tone. The selection of the correct fundamental is then made based on simple comparisons between this image and the set of all possible fundamentals. The ambiguity matrix effectively provides a reduced finite solution space (discrete set of possibilities) in which to unambiguously estimate the correct fundamental.

Abstract: This invention exploits the synchronization properties of coupled, nonlinear oscillators arrays to perform power combining, beam steering, and beam shaping. This architecture utilizes interactions between nonlinear active elements to generate beam patterns. A nonlinear array integrates the signal processing concurrently with the transduction of the signal. This architecture differs fundamentally from passive transducer arrays in three ways: 1) the unit cells are nonlinear, 2) the array purposely couples the unit cells together, and 3) the signal processing (beam steering and shaping) is done via dynamic interactions between unit cells. The architecture extends to both 1- and 2-dimensional arrays.

Abstract: A driving circuit of a transmitting apparatus drives a piezoelectric element in a frequency band different from a resonance frequency at which a vibration system including the piezoelectric element resonates the most strongly. A driving circuit of a sound sensor drives the piezoelectric element for transmitting or receiving an acoustic wave in a frequency band different from a resonance frequency at which a vibration system including the piezoelectric element resonates the most strongly. Such a transmitting apparatus is mounted as a transmitting apparatus of a sound sensor to thereby realize the sound sensor with a small measurement error. The sound sensor is adopted for traveling control and steering control of an autonomous traveling vehicle to thereby enable an autonomous traveling vehicle capable of stopping in the vicinity of an obstacle to be realized.

Abstract: This system is intended for use during a regatta to indicate the distance between a sailboat and a race course marker buoy being rounded as part of the race. The system involves a transmitter on the buoy and a receiver on the boat. The buoy transmitter sends both a radio signal and an acoustic signal. The boat receiver detects both the radio signal and acoustic signal. The boat receiver measures the time delay between the radio and acoustic signals. This time duration is converted to a distance and the boat receiver displays the distance information.

Abstract: An underwater target tracking capability is disclosed for a grid-search technique utilizing parameter evaluation plot techniques comprising processing acoustic sonar measurements in conjunction with additional kinematics and environmental information. In the implementation described here, the measurements considered are passive broadband sphere bearings together with limiting knowledge of target speed and range at initial detection. These information sources are processed in a manner especially suited to enable rapid response to the emerging tactical situation.

Abstract: An apparatus for a bearing tracker is disclosed that provides improved estimates of target's bearing, bearing rate and signal-to-noise (SNR). The estimates are computed using normalized beam spectral data from short time interval preceding the initialization process.

Abstract: Disclosed is a method for recording one or more images of a source area where an impulse sound has initiated. The recording is performed by at least one of a plurality of units that include a camera, a computing device, and a connection to a network. The method comprises the steps of detecting and calculating a range and direction of the impulse sound source; slewing the camera to align its optical axis with a direction of the impulse sound; determining whether the impulse sound was a gunshot; recording images of the source area; and alerting a plurality of neighboring units to perform the recording step.

Abstract: In a method for adapting a hearing aid, and a hearing aid arrangement for improving the directivity of a hearing aid with a number of microphones that are connected to one another for generating a directional characteristic, the hearing aid is exposed to acoustic waves in a room for precision measuring while the user is wearing it, and the directional characteristic is registered. The filter parameters that arise therefrom are supplied to parameterizable filters in the hearing aid that are connected downstream from the microphones, and the desired ideal directional characteristic can be approximated taking the individual conditions into account when the hearing aid is worn.

Abstract: A proximity detector for use in a mobile telephone having at least a microphone and a loudspeaker operatively connected to a signal processor is presented. The proximity detector includes data processing and control modules having a module for controlling the signal processor for activating the loudspeaker to reproduce an acoustic control signal. A correlator correlates a control signal received directly by the microphone and a control signal being reflected from a user of the telephone and then received by the microphone to determine the distance between the telephone and the user. A signal level controller controls the signal processor to vary the signal level of an audible signal reproduced by the loudspeaker proportionally to the determined distance between the telephone and the user.

Abstract: A method of acquiring seismic data adapted for a land or transition zone environment including placing a location identifier in a particular location, placing a seismic sensor near the location identifier, reading the location identifer using a seismic data cable, recording seismic data acquired by the seismic sensor using the seismic data cable, and assigning sensor position coordinates to the seismic data based on measured position coordinates of the location identifier.

Abstract: Shells fired from the gun of a ship create an underwater explosion that is used to drive a sonar system. Sonobuoys [201] and/or a ship-towed array measure acoustic signals caused by the underwater explosion. A ship processing component [306] analyzes the signals and locates reflections of objects [102] in the signals. In addition to controlling the location at which to fire a shell, an adjustable fuze on the shell may be set to thereby control the depth at which the shell explodes. The low-frequency impulsive nature of the explosion makes it particularly suited for detecting objects in a littoral environment.

Abstract: A measuring system and method of detecting an object distance by transmission media with different wave velocities are described. The measuring system has a computer, a primary detector and a secondary detector. The primary detector is connected to the computer through bus communication and the secondary detector connected to the primary one through two different transmission media. The primary detector is able to receive separately a first signal and a second signal emitted simultaneously from the secondary detector through the transmission media. Moreover, the first signal has light-speed and the second signal has sound-speed. To calculate the distance between the objects which the primary and the secondary detector are attached respectively. The delay time of second signal and the wave velocity of the supersonic media are multiplied.

Abstract: A method and apparatus for detecting and locating leaks in buried pipes is disclosed in which ground penetrating radar, induction, acoustic, and vacuum excavation systems are selected based on soil conditions and then employed in selected combinations. The conductivity and wave speed of the soil are used in the selection process and in the process of detecting and locating a leak based on the measurements obtained from the selected combination of detection systems.

Abstract: An acoustic tracking system that uses an array of microphones to determine the location of an acoustical source. Several points in space are determined to be potential locations of an acoustical source. Beamforming parameters for the array of microphones are determined at each potential location. The beamforming parameters are applied to the sound received by the microphone array for all of the potential locations and data is gathered for each beam. The most likely location is then determined by comparing the data from each beam. Once the location is determined, a camera is directed toward this source.

Abstract: A beamformer is calibrated for use as an acoustic echo canceler in a hands-free communications environment having a loudspeaker and a plurality of microphones. To perform the calibration, a number of adaptive filters are provided in correspondence with each of the microphones, and each of the adaptive filters is trained to model echo properties of the environment as experienced by the corresponding one of the microphones. A target source is activated, thereby generating an acoustic signal that is received by the microphones. The trained adaptive filters are then used to generate jammer signals by, for example, having each one filter a pseudo noise signal. Respective ones of the jammer signals are then combined with corresponding signals supplied by the microphones, thereby generating combination signals. The combination signals are then used to adapt the beamformer to cancel the jammer signals.

Abstract: A method and apparatus for detecting, processing and tracking sonar signals to provide bearing, range and depth information that locates an object in three-dimensions underwater space. A Twenty Six Nearest Neighbor Peak Picker (TSNNPP) is disclosed that improves the detection of signals in noisy background by differentiating bandwidth (BW) characteristics of signals from BW characteristics of noise.

Abstract: An underwater object positioning system comprises a workboat, an acoustic transmitter-receiver mounted on the workboat, first and second surface tow units towed by the workboat, an acoustic transducer that is mounted on the first surface tow unit, that is connected by a communication cable to the acoustic transmitter-receiver on the workboat and that is positioned by a radio positioning means; two acoustic receivers that are mounted on the second surface tow unit, that are connected by a communication cable to the acoustic transmitter-receiver on the workboat and that are positioned by a radio positioning means. An acoustic pulse transmitter is mounted on a submerged positioning target. A processor unit on the workboat calculates the location of the submerged target based on data showing the positions of the transducer and receivers, and the distances from the transducer and receivers to the acoustic pulse transmitter.

Abstract: A plurality of sound-detecting devices are configured to detect sound from an event of interest. Information about the sound is recorded that is dependent on a distance between the source position and the location of the sound-detection devices. The source position is approximated using the recorded information and the relative position of individual sound-detection devices to one another. The approximated source position is used as input for operating a electronic device.

Abstract: A method of determining the bearing of a source of a sonar signal comprising determining the phase of a cyclic variation of the output signal of a sonar detector having a directional characteristic which occurs as the orientation of the detector, and hence its characteristic, is rotated. In a preferred method the sonar detector output is spectrum analysed at each of a plurality of different orientations of the detector to provide for each orientation a signal representative of the amplitude of a component of the signal produced by the source of a chosen frequency. The signals so obtained are then arranged to form a time series of samples of said component as the orientation of the detector is rotated at a predetermined frequency and the time series used to analyse the spectrum of the signal defined by the time series and thereby determine the phase of the sinusoidal component of the signal defined by the time series at the predetermined frequency. Apparatus for carrying out the method is also disclosed.

Abstract: High Definition Induction Logging (HDIL) tools can provide reliable information about the vertical and radial variations of resistivity structure in isotropic media. The focusing technique provides quantitative information about the resistivity variation and qualitative information about invasion at the well site. This type of logging tool utilizes transmitter-receiver arrays coaxial with the borehole and thus cannot provide information about anisotropy in vertical wells. This greatly limits the application of array induction tools in the characterization of reservoirs with finely laminated sand/shale sequences. A multi-component induction tool, 3DEX™, has been developed by Baker Atlas and Royal Dutch Shell. It provides the much needed ability to detect anisotropy for sand-shale laminated reservoirs. Data from such a logging tool are inverted to give an estimate of vertical and horizontal resistivity in a vertical borehole.

Abstract: A bottom moored and tethered directional frequency analysis and ranging (DIFAR) sensor system deployable in a wide range of water depths. The system includes a mooring platform for anchoring the system to the bottom surface of a body of water. A buoyant chamber containing a DIFAR sensor is tethered to the mooring platform at a pre-determined depth in the body of water. The DIFAR sensor includes two pairs of orthogonally oriented hydrophones and a compass for providing a directional magnetic reference signal. The tethered buoyant chamber is securely positioned such that hydrophones residing within the buoyant chamber are oriented in a plane substantially co-planer to the top surface of the body of water. By determining the angle between the directional magnetic reference signal and the hydrophones, the sensor system is able to compute heading information for a detected object. A transmitter is coupled to the DIFAR sensor for transmitting heading information detected by the DIFAR sensor to a receiver.

Abstract: An apparatus for determining the relative height between two targets is disclosed. The present invention also discloses a method for determining the relative height between two targets; the method is substantially similar to the operational aspects of the device of the present invention. The method requires no angular measurements in order to determine the different height between the two targets, but rather only distance measurements that can be performed simply and accurately. The apparatus for determining the relative height between two targets a disclosed.

Abstract: An acoustic switch, having a predetermined frequency response, is disclosed that allows for a single channel device to be interconnected to multiple transducers. The acoustic switch ensures that the signals from the transducer closest to transmitter, which has a highest possible input level, is supplied to the single channel device for processing.

Abstract: The invention involves a computationally simple and fast method for aligning the phases of complex signals (real (in phase) and imaginary (quadrature) components) before performing a coherent (in phase components) or vector sum, thus achieving the high gains of in phase summations without pre-processing overhead to determine an optimum progression of phase shifts to enable in phase summations. The method of the invention for aligning the phases, without preprocessing to get an optimum set of phase shifts, uses the temporal relationship that exists in the phase angles of successive vectors that occur evenly spaced in time.

Abstract: An ultrasonic signal is used to link a beacon unit to a tracker unit to provide a tracking and navigation system for firefighters to use in a smoke filled environment at the scene of a fire. The beacon unit transmits an omnidirectional ultrasonic signal. The tracker unit, using a directional ultrasonic receiver provides a display or other indication of the signal strength of the received ultrasonic signal to allow the direction to the beacon unit to be determined. The ultrasonic signal provided by the beacon unit may be pulse modulated to include digitally encoded data that may be used to identify particular individuals, objects, materials, dangers, or exits. In addition, the tracker unit may be provided with a transmitter and the beacon unit provided with a receiver such that audio communication may be established therebetween.

Abstract: An ultrasonic transducer is formed by a plurality of cMUT cells, each comprising a charged diaphragm plate capacitively opposing an oppositely charged base plate. A feedback controlled bias charge regulator controls the bias charge of the capacitive plates. The cMUT cells can be fabricated by conventional semiconductor processes and hence integrated with ancillary transducer circuitry such as the bias charge regulator.

Abstract: An ultrasonic transducer is formed by a plurality of cMUT cells, each has a charged diaphragm plate capacitively opposing an oppositely charged base plate. The diaphragm plate is distended toward the base plate by a bias charge. The base plate includes a central portion elevated toward the center of the diaphragm plate to cause the charge of the cell to be of maximum density at the moving center of the diaphragm plate.

Abstract: An acoustic sensor system for the detection, location and classification of sound-generating targets, such as helicopters, from a ship includes a base station aboard the ship, having a radio transmitter/receiver (B-Tx/Rx) and a digital signal processor unit (DSP). A plurality of floating remote stations, which in use are positioned remotely from the ship, are each arranged to carry apparatus including an electrical power source, a radio transmitter/receiver (STx/Rx) suitable for two way communication with the B-Tx/Rx, a control unit, sound detectors, and a data processor (DP). The control unit is responsive to signals transmitted from the B-Tx/Rx and received by the S-Tx/Rx for controlling provision of electrical power for the apparatus. The DP is operative to classify electrical signals generated by the sound detectors in response to the reception thereby of sound signals, and to initiate, dependent upon classification, transmission of data from the S-Tx/Rx to the B-Tx/Rx appertaining to the sound signals.

Abstract: A method of locating a submarine cable includes the steps of transmitting a toning signal along the submarine cable, the toning signal being a superposition of a first signal waveform to be detected and at least a second signal waveform such that the second signal waveform interferes with the first signal waveform to limit the peak to peak amplitude of the toning signal for transmission. Preferably, the toning signal is a square wave. The method provides a way of offsetting the loss of transmission distance due to the use of state of the art optical repeaters. Pre-emphasis of high frequency harmonics in the toning signal enables a detectable toning signal to propagate still further.

Abstract: An underwater communication method, device, and system that enables bi-directional communication between and among under-water divers. In accordance with the present invention, messages may be transmitted and received between and among the divers in a network and/or between divers and a diving boat, buoy, or other reference point. The present invention also permits one or more divers to receive a homing signal and to move toward the source of that signal using an acquisition and tracking feature and functionality that utilizes a Doppler frequency shift and preferably a compass to determine the distance and direction of the source of the signal. The present invention also enables a diver in distress to broadcast a distress signal (i.e., SOS) that is received by every other diver within a predetermined distance from the distressed diver. The divers receiving the distress signal are then able to locate and rescue the distressed diver using the acquisition and tracking feature and functionality.

Abstract: A laser security fence apparatus is disclosed for providing a warning signal in response to an intrusion by an intruder of a restricted area. The apparatus includes a laser generator for generating a laser beam and a first mirror aligned with the laser beam for reflecting the beam. A second mirror is aligned with the first mirror for reflecting the beam reflected by the first mirror and a collector is aligned with the second mirror for collecting the beam reflected by the second mirror. A microprocessor is associated with the collector and the generator for sensing when the beam is broken by the intruder so that the beam is not received by the collector. An alarm is connected to the microprocessor for actuation by the microprocessor when the microprocessor senses that the beam is broken so that the alarm provides the warning signal.

Abstract: An acoustic sensing countermeasure device is used to sense the direction of a threat projectile or vehicle in addition to countering the threat with noise or interference signals. Countermeasure device includes an acoustic receive array comprised of segmented vertical staves preferably mounted within a reduced diameter section around the outside housing of the countermeasure device. The staves are grouped to form directional acoustic beams across the entire horizontal plane. To determine the direction of the acoustic signals from the threat projectile or vehicle, the countermeasure device uses a method wherein the direction is indicated by the output of the directional acoustic beams. The countermeasure device locates a known reference direction used to determine the bearing of the threat. The bearing information can be transmitted, for example, to the vessel that deployed the countermeasure.