Abstract: A method for identifying a seismic even makes it possible to determine the direction to a source of a seismic disturbance both on the surface and in a three-dimensional space and increases the probability of correct identification of a seismic event and the accuracy of the determination of the direction to the source. A compact seismic detector for implementing the method reduces the cost of scanning and servicing a perimeter protection system constructed on the basis of such detectors. In the method, two or three pairs of seismic sensors which are divided by a distance and are oriented at an angle with respect to one another, for example mutually perpendicularly along the axes X, Y or along the axes X, Y, Z, respectively, are combined to form one seismic detector. The resultant seismic data are processed to determine the direction to the source of the seismic disturbance.

Abstract: Provided is a sound source signal filtering method and apparatus. The sound source signal filtering method includes: generating two or more microphone output signals by combining sound source signals input through a plurality of microphones; calculating distances between the microphones and a sound source from which the sound source signals are emitted by using distance relationships according to frequencies of the sound source signals extracted from the generated microphone output signals; and filtering the sound source signals to obtain one or more sound source signals corresponding to a predetermined distance by using the calculated distances. Accordingly, it is possible to obtain only sound source signals emitted from a sound source at a particular distance from the microphone array among a plurality of sound source signals input through the microphone array.

Abstract: A sensor assembly has first sensors spaced apart along a first direction, and second sensors oriented in a second direction generally orthogonal to the first direction. Differencing of outputs of the first sensors is performed, and differencing of outputs of the second sensors is performed. A signal output is produced by combining the differenced outputs of the first sensors and the differenced outputs of the second sensors, where the signal output represents a seismic response of a subterranean structure.

Abstract: The present invention contemplates a variety of improved techniques including methods and apparatus for coordinating a plurality of devices, and more specifically, a method and apparatus for coordinating a plurality of devices to estimate or calculate various distances, relative positions, device attitudes, and other absolute and/or relative kinematic data.

Abstract: An ultrasonic sensor includes a transmitting device, a receiving device, and a circuit device. The circuit device determines that the receiving device receives an ultrasonic wave reflected from an object, when an output voltage of the receiving device is equal to or greater than a first threshold. The circuit device includes a humidity detection section configured to detect an ambient humidity of the transmitting and receiving devices and a threshold adjustment section configured to calculate, based on the detected ambient humidity, a sound pressure of the ultrasonic wave that is received by the receiving device after propagating over a round-trip distance between the ultrasonic sensor and the object. The threshold adjustment section reduces the first threshold, when the output voltage corresponding to the calculated sound pressure is less than a second threshold that is greater the first threshold.

Abstract: A method or system for detecting a seismic event includes detecting a primary wave of a seismic event using at least one sensor at a measurement location; using at least one parameter of the detected primary wave to determine an estimated peak ground intensity at the measurement location without determining the magnitude of the seismic event; determining an epicenter of the seismic event; and estimating the intensity of the seismic event at a specified location using the determined estimated peak ground intensity and the distance of the specified location from the epicenter. The epicenter can be determined using sensors at a single location. A noise detection system can filter out detected signals that correspond to local vibrations rather than seismic events.

Abstract: Some aspects relate to an apparatus for detecting an edge of a material web. In some examples, the apparatus comprises an ultrasound sensor which comprises two or more separately readable ultrasound receiver elements and an ultrasound transmitter element, wherein the ultrasound transmitter element is designed and arranged such that it applies an ultrasound measurement signal to two or more of the ultrasound receiver elements.

Abstract: A method includes enabling a power supply of a ground sensor device to provide power to one or more components of the ground sensor device based on one or more rotations of a rotor of the ground sensor device.

Abstract: Systems, methods, and apparatus for matching pair-wise differences (e.g., phase delay measurements) to an inventory of source direction candidates, and application of pair-wise source direction estimates, are described.

Abstract: Systems and methods for parallel and distributed processing of audio signals produced by a microphone array are described. In one aspect, a distributed signal processing system includes an array of microphones and an array of processors. Each processor is connected to one of the microphones and is connected to at least two other processors, enabling communication between adjacent connected processors. The system also includes a computing device connected to each of the processors. Each microphone detects a sound and generates an audio signal, and each processor is configured to receive and process the audio signal sent from a connected microphone and audio signals sent from at least one of the adjacent processors to produce a data stream that is sent to the computing device.

Abstract: A weld travel speed sensing system includes at least one sound sensor configured to sense a sound generated to allow determination of a position of a welding torch. The weld travel speed sensing system is configured to determine a position of a point on the welding torch based on the sensed sound.

Abstract: An audio source localization apparatus receives signals from a microphrine array (101), and a reference processor (105) generates at least three reference beams with different directional properties. An estimation processor (107) which generates simultaneous direction estimates for two sound sources, comprises a circuit (401) combining signals of the at least three reference beams with a beam shape parameter reflecting a shape of an audio beamform and a beam direction parameter reflecting a direction of an audio beamform for the combined signal. A cost processor (403) generates a cost measure indicative of an energy of the combined signal and a minimization processor (405) estimates values of the beam shape parameter and the beam direction parameter which correspond to a local minimum of the cost measure. A direction processor (407) then determines simultaneous direction estimates for two sound sources from the determined parameter values.

Abstract: The systems and methods described herein relate to an airborne shooter detection system having a plurality of sensors coupled to the body of an aircraft such as a helicopter. The system includes at least five sensors configured and arranged to disambiguate the location of a shooter. By measuring the arrival times of the shockwaves of projectiles at each of the sensors and determining the differences in the arrival times among sensors, the systems and methods may determine the location of one or more sources of the projectiles. A distance of at least ten meters separates two or more of the sensors. Such a separation is advantageous because it allows the system to disambiguate multiple shooters by resolving the curvature of the shockwave.

Abstract: Disclosed are various embodiments of methods, devices and systems for performing a microseismic survey. According to some embodiments, microseismic signals are detected at seismic sensor stations deployed in two sets of seismic sensor lines, the seismic sensor lines within each set being substantially parallel to one another and the two sets of seismic sensor lines being mutually orthogonal. According to other embodiments, microseismic signals are detected at seismic sensor stations deployed in a hexagonal pattern. Such sensor geometries offer advantages over linear or radial arrays, including noise reduction, data acquisition flexibility as new wells are added to the survey area, and an improved distribution of data points above points in the subsurface.

Abstract: A passive electro-optical tracker uses a two-band IR intensity ratio to discriminate high-speed projectiles and obtain a speed estimate from their temperature, as well as determining the trajectory back to the source of fire. In an omnidirectional system a hemispheric imager with an MWIR spectrum splitter forms two CCD images of the environment. Three methods are given to determine the azimuth and range of a projectile, one for clear atmospheric conditions and two for nonhomogeneous atmospheric conditions. The first approach uses the relative intensity of the image of the projectile on the pixels of a CCD camera to determine the azimuthal angle of trajectory with respect to the ground, and its range. The second calculates this angle using a different algorithm. The third uses a least squares optimization over multiple frames based on a triangle representation of the smeared image to yield a real-time trajectory estimate.

Abstract: Systems and methods are disclosed for locating a weapon fire incident such as an acoustic transient from a gunshot, explosion, weapons launch, etc. In one exemplary implementation, there is provided a method of locating the incident from a combination of propagation phenomena including a discharge time of the weapon fire incident. Moreover, the method may include obtaining a first propagation parameter of the incident from one or more first sensors, obtaining the discharge time from another sensor, and processing the data to determine a location using a common time basis among sensor measurements. According to further exemplary implementations, the discharge time may include a transient event that has a different propagation velocity than that of sound in the atmosphere.

Abstract: A survey method giving improvements in weapons fire location systems is disclosed. In an urban system with a distributed array in the midst of many buildings that block signal paths or create echoes, methods are provided to measure signal propagation. A survey or tour of the covered region uses a moving signal source to probe propagation inside the region. Survey results may indicate where more or fewer sensors are needed. Survey results plus current measured noise gives prediction of instantaneous system sensitivity. In addition, multipath propagation may be used to determine a location even when only one or two sensors detect the signal. In such exemplary cases, triangulation may be replaced or augmented by pattern recognition. Further, signals of the survey need not be acoustic impulses such as gunfire, but may be RF signals, or coded continuous signals so that gunfire-like sounds would not disturb citizens in the area.

Abstract: An inline inspection system and method for calibrating an acoustic monitoring structure installed along a pipe. The system includes a pipe inspection vehicle; a microprocessor configured to attach a time stamp to a measured distance traveled by the pipe inspection vehicle; an acoustic source attached to the pipe inspection vehicle and configured to generate sound waves inside the pipe, the sound waves having predetermined frequencies and predetermined amplitudes; plural sensors disposed along the pipe and configured to record time of arrivals and intensities of the sound waves generated by the acoustic source; and a processing unit configured to communicate with the plural sensors and receive the time of arrivals, intensities and frequencies of the sound waves from the plural sensors. The processing unit calibrates the acoustic monitoring structure by calculating a distance between the acoustic source and a first sensor of the plural sensors.

Abstract: A survey method giving improvements in weapons fire location systems is disclosed. In an urban system with a distributed array in the midst of many buildings that block signal paths or create echoes, methods are provided to measure signal propagation. A survey or tour of the covered region uses a moving signal source to probe propagation inside the region. Survey results may indicate where more or fewer sensors are needed. Survey results plus current measured noise gives prediction of instantaneous system sensitivity. In addition, multipath propagation may be used to determine a location even when only one or two sensors detect the signal. In such exemplary cases, triangulation may be replaced or augmented by pattern recognition. Further, signals of the survey need not be acoustic impulses such as gunfire, but may be RF signals, or coded continuous signals so that gunfire-like sounds would not disturb citizens in the area.

Abstract: A system for three-dimensional tracking of high speed undersea projectiles may utilize a distributed field of randomly positioned passive acoustic sensors. The system measures variables related to the pressure field generated by a supercavitating projectile in flight wherein the amplitude of the pressure generated at a point in space is related to the projectile dimensions, velocity, and trajectory. The system iteratively processes data from the sensors to measure launch velocity, flight direction (trajectory), ballistic coefficient (drag), and/or maximum range.

Abstract: The invention relates to an automated estimation of the position (co-ordinates) of a set of loudspeakers in a ioom Based on measured impulse responses the distances between each pair of loudspeakers are estimated, thereby forming a distance matrix, and the resultant distance matrix is used by a multidimensional scaling (MDS) algorithm to estimate the co-ordinates of each individual loudspeaker An improved co-ordinate estimation can, if desired, be derived by utilizing the stress values provided by the MDS algorithm.

Abstract: A multi-sensor sound source localization (SSL) technique is presented which provides a true maximum likelihood (ML) treatment for microphone arrays having more than one pair of audio sensors. Generally, this is accomplished by selecting a sound source location that results in a time of propagation from the sound source to the audio sensors of the array, which maximizes a likelihood of simultaneously producing audio sensor output signals inputted from all the sensors in the array. The likelihood includes a unique term that estimates an unknown audio sensor response to the source signal for each of the sensors in the array.

Abstract: A system and method are provided for monitoring bladder distention. Independently controllable acoustic transmitters are coupled to the surface of a user's abdomen region in a spaced-apart fashion. Each transmitter can introduce a broadband acoustic signal into a portion of the abdomen region. Acoustic receivers are also coupled to the surface of the abdomen region to detect acoustic reflections generated when the acoustic signals are introduced into the abdomen region. A controller is positioned on the user and is correlated to an orientation of the user. The controller stores a profile indicative of anatomical features of the user. The controller initiates periodic activations of selected ones of the transmitters based upon the profile and the orientation of the user. The controller uses a weighted combination of all of the acoustic reflections to determine bladder distention of the user. The weighted combination is defined by at least the profile and orientation of the user.

Abstract: There is provided a method of tracking an object in a three-dimensional (3-D) space by using particle filter-based acoustic sensors, the method comprising selecting two planes in the 3-D space; executing two-dimensional (2-D) particle filtering on the two selected planes, respectively; and associating results of the 2-D particle filtering on the respective planes.

Abstract: Disclosed is a system of transferring wireless power using an ultrasonic wave, including: an ultrasonic wave generating device converting and transferring electric energy to an ultrasonic wave; and an ultrasonic wave receiving device receiving the ultrasonic wave to convert the ultrasonic wave to electric energy, wherein the ultrasonic wave generating device includes a radiation plate with a plurality of ultrasonic elements and controls an effective area of the radiation plate by turning on/off the plurality of ultrasonic elements so that the ultrasonic wave receiving device is disposed at a position minimizing dispersion effect due to a circular radiation of the ultrasonic wave.

Abstract: A method of locating a sound source based on sound received at an array of microphones comprises the steps of determining a correlation function of signals provided by microphones of the array and establishing a direction in which the sound source is located based on at least one eigenvector of a matrix having matrix elements which are determined based on the correlation function. The correlation function has first and second frequency components associated with a first and second frequency band, respectively. The first frequency component is determined based on signals from microphones having a first distance, and the second frequency component is determined based on signals from microphones having a second distance different from the first distance.

Abstract: This invention concerns the field of passive sonar systems simultaneously processing several linear antennas. This invention includes a method to eliminate ghost sources for a passive sonar having at least two linear antennas A and B, the method including: An initial acquisition step during which the signal received is measured at different moments ti, and for each antenna, the Doppler frequency f of the signal received is determined, as well as the potential values of the azimuth ? of the source; A second step of determining the potential values of the source performed by use of the measured azimuth ? frequency f values; A third step of eliminating ambiguity and rejecting ghost sources during which it is determined, for which of the potential sources, the speed and frequency values will satisfy, for each moment ti, the measurement equations linking the frequency of the signal received to the frequency f0 emitted by the source, at the source speed and position.

Abstract: In accordance with some embodiments of the present disclosure, a process for determining a direction vector of a sound source is described. The process may be implemented to detect, by a first sound sensor, a first sound pressure of a sound wave propagated from the sound source, and detect, by a second sound sensor, a second sound pressure of the sound wave. The process may further be implemented to determine, by a processor, the direction vector of the sound source relative to the first sound sensor and second sound sensor, wherein the direction vector is based on the first sound pressure, the second sound pressure, and a first distance between a first physical location of the first sound sensor and a second physical location of the second sound sensor.

Abstract: Systems and methods for obtaining target elevation information are disclosed. The systems and methods use multiple vertical transmitters and one or more receivers to infer changes in the elevation plane and the height of objects. Changes in elevation and heights of objects are inferred from path length differences between the transmitters and a particular backscattering point. Using known geometric information regarding the configuration of the transmitters, propagation time differences can be estimated via time delay estimation methods in either the time or frequency domain. Appropriate modulation schemes are used such that the multiple signals transmitted are separable upon reception.

Abstract: Disclosed are systems and methods that can be used to detect shooters. The systems and methods described herein use arrival times of a shockwave, produced by a shot, at a plurality of sensors to assign weights to each of the plurality of sensors, and determine a shot trajectory based on the assigned weights.

Abstract: A method for identifying position of acoustic source proximate sediments below the bottom of a body of water includes deploying a plurality of arrays of acoustic sensors on the bottom of the body of water. Each array includes a plurality of lines of acoustic sensors disposed in a substantially radial pattern. The arrays have a center to center distance therebetween of about twice a diameter of each of the arrays. Signals are detected from each of the sensors for a selected time period. A direction of the acoustic source with respect to each of the arrays is determined by steering a response of the sensors in each array. A range of the acoustic source is determined using the determined directions.

Abstract: An aircraft capable of hovering, and characterized by having at least one sensor, which has a plane sweep region and is designed to acquire, when the aircraft is manoeuvring, values of respective distances between first points on an obstacle within the plane sweep region, and a second point on the aircraft; and a control unit designed to generate an alarm signal when at least one of the first points lies within a safety region containing the second point on the aircraft.

Abstract: Described is modeling a room to obtain estimates for walls and a ceiling, and using the model to improve sound source localization by incorporating reflection (reverberation) data into the location estimation computations. In a calibration step, reflections of a known sound are detected at a microphone array, with their corresponding signals processed to estimate wall (and ceiling) locations. In a sound source localization step, when an actual sound (including reverberations) is detected, the signals are processed into hypotheses that include reflection data predictions based upon possible locations, given the room model. The location corresponding to the hypothesis that matches (maximum likelihood) the actual sound data is the estimated location of the sound source.

Abstract: The invention proposes utilizing the known geometry of the measurements in order to assign them to one another and to resolve ambiguities, wherein the 3D position of an object (3) in space is determined by a spatial section at the same time.

Abstract: Disclosed is a UHF partial discharge and its location measuring device for high-voltage power devices. The measuring device includes a partial discharge sensor, an external noise sensor, an analogue-digital converter, a peak detector, a partial discharge signal processor, an arrival time detector, a discharge location processor, and a display unit.

Abstract: A method and system for locating a sound source within a defined area in which the sound data is collected with a plurality of spaced apart microphones. The sound data received by the microphones is processed to form a cross spectral density matrix containing vectors of cross correlations and auto correlations of the sound data. A replica vector matrix containing sound data from at least one test sound at a plurality of predetermined locations within the defined area is then constructed. The sound data vectors in the cross spectral density matrix are then projected on the replica vectors in the replica vector matrix to obtain a probability of the location of the sound source at each predetermined location within the defined area. These probabilities form a distribution within the defined area in which the largest probability distribution correlates with the location of the sound source.

Abstract: A system for three-dimensional tracking of high speed undersea projectiles may utilize a distributed field of randomly positioned passive acoustic sensors. The system measures variables related to the pressure field generated by a supercavitating projectile in flight wherein the amplitude of the pressure generated at a point in space is related to the projectile dimensions, velocity, and trajectory. The system iteratively processes data from the sensors to measure launch velocity, flight direction (trajectory), ballistic coefficient (drag), and/or maximum range.

Abstract: A method for tracking motion using an audio compass is disclosed. The method comprises receiving motion sensor data indicating seismic activity recorded by at least two seismic sensors, and converting the received motion sensor data into audio signals for interpretation at an audio compass. The method uses the audio compass to determine a current distance to the seismic activity based on an interpreted signal intensity of the audio signals. The method further uses the audio compass to identify a current position of the audio compass relative to the seismic activity.

Abstract: A range finding audio system automatically modifies the audio output of an audio source based on the distance of a listener from the speakers. A speaker in an audio system may include a range device coupled with a controller. The range device may utilize infrared, laser, or acoustic technology to determine the distance between the speaker and the listener. The controller may transfer distance information to an audio interface of a processor unit. The audio lo interface may include a positioning routine to modify the audio output according to the distance from the speaker to the listener. Alternatively, the controller may perform the functions ascribed to the positioning routine making the necessary modifications to the audio output based on the distance information.

Abstract: Systems and methods are disclosed for processing information associated with weapon fire. In one exemplary embodiment, there is provided a method of processing information associated with weapon fire, including identifying a weapon fire incident, determining positional information regarding a source location of the weapon fire, and processing positional information regarding a device within a particular proximity of the source location of the weapon fire. Moreover, exemplary methods may include providing information for displaying the positional information of the source location of the weapon fire and the device together on a display. Other exemplary embodiments may include performing processing that provides one or more of source location of the weapon fire, device location information and/or other information related to the device for various uses.

Abstract: A thermometer and extensometer for cables and conductors is described. The travel time of one or more acoustic signals along a conductor is used to determine the temperature along the conductor and the length of the conductor. The acoustic frequency is selected to minimize temporal dispersion of the propagating acoustic energy. The technique can be used to measure the temperature of the windings in a transformer or other electrical apparatus.

Abstract: A thermometer and extensometer for cables and conductors is described. The travel time of one or more acoustic signals along a conductor is used to determine the temperature along the conductor and the length of the conductor. The acoustic frequency is selected to minimize temporal dispersion of the propagating acoustic energy. The technique can be used to measure the temperature of the conductor in a buried, undersea or submerged electrical power cable.

Abstract: The trajectory of at least one marine animal emitting sound signals in the form of series of clicks, such as a cetacean, is passively determined. During successive processing time windows, raw analog signals are acquired from a plurality of hydrophones disposed in a marine environment and converted into digital data. Digital data filtering eliminates spurious noises and keeps the data, for each pair of hydrophones and each processing window, that corresponds to potential values (TDOAs) for the time-difference of arrival of the sound signals at two different hydrophones. For each hydrophone pair, the consistency of the TDOAs is checked and a number of filtered and mutually-consistent TDOAs are selected. Based on the filtered and mutually-consistent TDOAs, the successive instantaneous positions of the click sources are determined by means of nonlinear regression, and the trajectory of at least one marine animal in the environment is deduced in real time.

Abstract: Systems and methods of providing precision locations for sensors which make up an array of sensors in a gunshot detection system. Consistent with some exemplary implementations, sensors may employ a commercial GPS which reports a sensor position or a group of pseudoranges to GPS satellites. A server may collect differential information from a differential node and, in one exemplary implementation, may calculate a precision position for each sensor by adjusting the reported position or pseudoranges with the differential information. In other exemplary implementations, differential information may be sent from the host to individual sensors which calculate their own precision positions. Exemplary differential information may include latitude and longitude corrections, pseudorange corrections, ionospheric delay, GPS satellite clock drift, or other corrective term which will improve the accuracy of a sensor position.

Abstract: A method and apparatus for estimating the positions of sensors in an array of connected sensors. The sensors are operable to sense a propagating phenomenon, such as an acoustic disturbance in water or air. For each sensor i in the array of connected sensors, the direction vector di that corresponds to a direction of propagation between a reference point and the sensor i is measured. The position of the sensors relative to the reference point are determined dependent upon the vectors di. Additional information, such as propagation time, sensor orientation, and/or the lengths of the connections between sensors may be used. Optionally, the direction d are found using a singular value decomposition of a matrix formed from vectors of sampled signals components.

Abstract: A ballistic-acoustic transducer system includes a processor and one or more acoustic sensors. The sensors are positioned in a body of water and are in communication with the processor. The system is configured such that acoustic energy generated by a non-explosive projectile as it impacts the water, enters the water, and sinks through the water, is sensed by the one or more acoustic sensors, and the processor is configured to process the acoustic energy sensed by the one or more acoustic sensors.

Abstract: The invention relates to an automated estimation of the position (co-ordinates) of a set of loudspeakers in a room Based on measured impulse responses the distances between each pair of loudspeakers are estimated, thereby forming a distance matrix, and the resultant distance matrix is used by a multidimensional scaling (MDS) algorithm to estimate the co-ordinates of each individual loudspeaker An improved co-ordinate estimation can, if desired, be derived by utilising the stress values provided by the MDS algorithm.

Abstract: User-wearable sensor arrays for use with projectile-detection systems, and methods of detecting a projectile with user-wearable sensor arrays.

Abstract: Systems and methods are provided for locating threats to an aircraft that are located on the ground. Associated bearings are determined from an aircraft for each of a plurality of detected shots from a threat at ground level. A plurality of pairs of bearings are selected, and a weight value is calculated for each selected pair of bearings. An estimated position for the threat is determined from each selected pair of bearings. An improved estimation of the position for the threat is calculated as a weighted combination of the estimated positions.

Abstract: Apparatus configured for processing of both audible and ultrasonic sound inputs, including a sensor with a frequency response spanning both audible and ultrasonic frequencies, and processing electronics configured to separate the audible and ultrasonic input frequencies for independent use. Apparatus configured for processing of both audible and ultrasonic sound inputs, including a sensor with a frequency response spanning both audible and ultrasonic frequencies, and processing electronics configured to process each one of the audible and ultrasonic input frequencies independently. Related apparatus and methods are also described.