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: A first, transmitting, device transmits a digitized data message using a short range radio link followed by digital data representing a digitized acoustic signal, such as a tone. Simultaneously, or with a predetermined time delay, the transmitting device emits an acoustic version of the same signal using an acoustic transducer such as a loudspeaker. A second, receiving, device receives the data message and the digitized acoustic signal via the short range radio link and receives the acoustic version of the signal via a microphone, which converts the acoustic signal to a second digitized version of the acoustic signal. Digital signal processing circuits then correlate the second digitized signal received acoustically with the digitized acoustic signal received over the short range radio link to determine a time difference of arrival.

Abstract: A simulated grenade for MILES-type simulations generates a unique RF signal and a unique audio signal. A detector utilizes the time between receipt of the RF signal and the slower-traveling audio signal to determine the distance between the detector and the simulated grenade.

Abstract: This invention is a system for locating an object. A tag unit (100) that is attached or embedded into the object to be located generates radio frequency signals when excited by an ultrasonic wave (108). The locator unit (100) generates the ultrasonic wave (108) and receives radio frequency signals from the tag unit (110). The locator unit (100) determines the signal strength of the received radio frequency signal and provides a representation of the strength. By monitoring the signal strength indication, the user will be directed to the object.

Abstract: Robot and remote controlled devices have been utilized for information gathering purposes. However these robotic vehicles lack efficiency because they are not capable of operating out of doors or where the sensors and apparatus located on the robots are subject to harsh environments. The present invention provides a new and unique manner of overcoming these problems by providing a platform system that is placed upon existing robots without requiring adjustments to these devices. The platform effectuates easy installation of a plurality of sensors and apparatus on its top surface while providing internal housing for its wires and components, thereby providing a water, dirt and dust resistant environment which leads to better equipment function and ease of maintenance and repair.

Abstract: An apparatus for providing Global Positioning System (GPS) position data to an underwater diver for use in navigation is comprised of a SCUBA Flag/Antenna Float, positioned on the surface of the water, containing a Spring-loaded Cable Reel which is connected via a Signal Umbilical Cable to a GPS Capsule carried by the underwater diver. A GPS Antenna and power supply provide a signal to a GPS Receiver/Display which is encased in the GPS Capsule. The diver views icons displayed on the GPS Receiver to determine his/her current position in relation to previously entered waypoints, or geographical coordinates, such as a wreck, dive boat, or locations of interest plotted by the diver during the dive. The position information displayed by the GPS receiver enables the diver to navigate to and from the various locations or geographical coordinates while submerged.

Abstract: An arithmetic unit detects difference &agr; (=X−Y) between a sound source arrival azimuth X° of a sound wave, which is transmitted from a sound source buoy and is directly received in a wave receiving buoy, to a reference axis of the wave receiving buoy, and a target arrival azimuth Y° of a reflective sound, which is reflected by a target, to the reference axis of the wave receiving buoy. The arithmetic unit detects an azimuth angle &bgr; of the sound source buoy on the basis of position information (latitude and longitude) of the sound source buoy and wave receiving buoy that is obtained by using GPS. Then, the arithmetic unit detects the azimuth (target azimuth) of the target to a magnetic north azimuth by the operation of (&bgr;−&agr;).

Abstract: An apparatus for providing Global Positioning System (GPS) position data to an underwater diver for use in navigation is comprised of a SCUBA Flag/Antenna Float, positioned on the surface of the water, containing a Spring-loaded Cable Reel which is connected via a Signal Umbilical Cable to a GPS Capsule carried by the underwater diver. A GPS Antenna and power supply provide a signal to a GPS Receiver/Display which is encased in the GPS Capsule. The diver views icons displayed on the GPS Receiver to determine his/her current position in relation to previously entered waypoints, or geographical coordinates, such as a wreck, dive boat, or locations of interest plotted by the diver during the dive. The position information displayed by the GPS receiver enables the diver to navigate to and from the various locations or geographical coordinates while submerged.

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 radio wave transmitter transmits a transmission command to an artificial fish in a water tank. A radio wave receiver in the artificial fish outputs the received transmission command to an ultrasonic transmitter so that the ultrasonic transmitter is caused to transmit ultrasonic transmission pulses. The ultrasonic transmission pulses are received by reception devices in the water tank, and a reception signal thereof is supplied to a propagation time clock generator. The propagation time clock generator generates propagation time clock pulses according to ultrasonic propagation times from the artificial fish to the reception devices. The propagation time clock pulses are counted by a pulse counter, and a count value thereof is inputted to an arithmetic operation control portion to obtain a propagation time, thereby calculating a three-dimensional position of the artificial fish.

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 weapon localization system for determining the location of hostile weapon fire. In one embodiment, the weapon localization system includes acoustical detection means for detecting energy of a first frequency originating from said hostile weapon fire; and for transmitting a first set of data describing the location of said hostile weapon fire; optical detection means for detecting energy of a second frequency originating from said hostile weapon fire, and for transmitting a second set of data describing the location of said hostile weapon fire; and processing means coupled to said acoustical and said optical detection means for receiving said first and said second set of data and for determining whether said location of said first set of data match said location of second set of data and for generating a signal output if said match occurs.

Abstract: A presence detection system includes a reader device attached to a first body, and a tag device attached to a second body. The reader device has an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence; an RF receiver for receiving a RF signal; and a microcontroller coupled to the ultrasonic transducer and the RF receiver for receiving signals from the ultrasonic transducer and the RF receiver and for controlling the operation of ultrasonic transducer and the RF receiver. The tag device has an ultrasonic receiver for receiving ultrasonic pulses from the ultrasonic transducer of the reader device; and an RF pulse generator for generating and transmitting an RF pulse.

Abstract: A local positioning system (LPS) using acoustic time-of-flight and a fixed array of receivers. The LPS provides an automatic means of determining the position of a roving transmitter with respect to that of a fixed reference station based on the known relative positioning of the receivers and the times-of-flight of the pulsed signal to each receiver. The location means is local in nature and independent of any remote transmissions such as those from remote radio antennae or satellites. The LPS employs pulsed acoustic emissions and does not require a clear line of sight between the rover and the receiver. To provide a more accurate calculation of the location of the rover, the position data is adjusted for the current speed of sound and the wind velocity.

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: This transducer comprises means (16 to 24, 56 to 60) for determining the respective positions of ultrasound emitting elements (6) with respect to an object to be inspected (8) during displacement of the transducer. Means (62) generate pulses exciting emitting elements, and create delay laws starting from determined positions enabling emitting elements to generate a focused ultrasonic beam (F), and apply these laws to the excitation pulses. Ultrasound receiving elements provide signals used to form images related to the object. Application to medicine and nondestructive testing.

Abstract: A method and apparatus for distance measurement is disclosed in which first and second signals having different propagation speeds are transmitted between a transmitter (2) at a first location and a receiver (3) at a second location. The distance between the first and second locations is determined from the difference in propagation time between the first and second signals.

Abstract: A presence detection system includes a reader device attached to a first body, and a tag device attached to a second body. The reader device has an ultrasonic transducer for generating and transmitting ultrasonic pulses at a first rate of occurrence; an RF receiver for receiving a RF signal; and a microcontroller coupled to the ultrasonic transducer and the RF receiver for receiving signals from the ultrasonic transducer and the RF receiver and for controlling the operation of ultrasonic transducer and the RF receiver. The tag device has an ultrasonic receiver for receiving ultrasonic pulses from the ultrasonic transducer of the reader device; and an RF pulse generator for generating and transmitting an RF pulse.

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 radio wave transmitter transmits a transmission command to an artificial fish in a water tank. A radio wave receiver in the artificial fish outputs the received transmission command to an ultrasonic transmitter so that the ultrasonic transmitter is caused to transmit ultrasonic transmission pulses. The ultrasonic transmission pulses are received by reception devices in the water tank, and a reception signal thereof is supplied to a propagation time clock generator. The propagation time clock generator generates propagation time clock pulses according to ultrasonic propagation times from the artificial fish to the reception devices. The propagation time clock pulses are counted by a pulse counter, and a count value thereof is inputted to an arithmetic operation control portion to obtain a propagation time, thereby calculating a three-dimensional position of the artificial fish.

Abstract: An article classifying system includes a conveyor 9 for conveying mail pieces 1, a weighing conveyor 18, and a sorting conveyor 26. A length measuring unit 5 measures the length of the mail pieces while they are being conveyed by the conveyor 9. Also, the width and the thickness of the mail pieces are measured by a width measuring unit 4 and a thickness measuring unit 3. The weight of the mail pieces is measured by a weighing unit 6 while the mail pieces are being conveyed on the weighing conveyor 18. Then, a control unit classifies the mail pieces into categories according to their length, width, thickness and weight.

Abstract: A method and an apparatus is disclosed for controlling electrical loads as a function of displacement detection of objects within a monitored zone by utilizing the non-Doppler shifted component of an electromagnetic, acoustic, microwave, infrared, or optical field. In the case of an ultrasonic field, a transmitter generates an ultrasonic transmission frequency into a zone to be monitored. Information is extracted from the spatial and temporal variation of the amplitude and/or phase of the total ultrasonic field at the original (i.e. non-Doppler shifted) frequency of transmission. At a detection stage, after filtering all Doppler returns, the signal received from each of a plurality of receivers/transducers, if not already digital, is digitized and passed to a gate array, microprocessor, or similar processing means where amplitude and/or phase changes are demodulated to control one or more electrical loads, for example, lighting, alarms, A/C according to an embedded algorithm within the processor.

Abstract: An automated object following system includes a tracker associated with a following device, and a guider associated with an object to be followed. The tracker includes a first processor, and at least two transducers for generating an encoded ultrasonic signal. Each transducer has a control input communicating with the first processor for emitting an encoded ultrasonic signal generally toward the guider in response to a command signal from the first processor. The encoded ultrasonic signals carry signal source identification information. A radio frequency (RF) receiver communicates with the first processor for receiving from the guider an encoded RF signal carrying distance and direction information of the guider relative to the tracker to be used for steering the following device toward the object to be followed.

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: An weapon localization system for determining the location of hostile weapon fire. In one embodiment, the weapon localization system includes acoustical detection means for detecting energy of a first frequency originating from said hostile weapon fire; and for transmitting a first set of data describing the location of said hostile weapon fire; optical detection means for detecting energy of a second frequency originating from said hostile weapon fire, and for transmitting a second set of data describing the location of said hostile weapon fire; and processing means coupled to said acoustical and said optical detection means for receiving said first and said second set of data and for determining whether said location of said first set of data match said location of second set of data and for generating a signal output if said match occurs.

Abstract: A position tracking system comprises a transmitter at a first location for producing a signal and an array of plural ultrasonic transducers at a second location arranged in a grid pattern at a plurality of respective discrete locations. The plural ultrasonic transducers are responsive to the signal to produce plural reactive signals corresponding to the signal as received at respective ones of the plural ultrasonic transducers. A computer is responsive to the reactive signals from the plural ultrasonic transducers for continuously determining the position of the array. The ultrasonic transducers are physically separated.The ultrasonic transducers and spatial light modulators share a common backplane.

Abstract: An underground object detector can locate and identify the shape of underground objects using a pulsed laser to generate acoustic waves in soil. A remotely located microphone detects an acoustic signal between the soil surface and subsurface objects. The amplitude of this acoustic signal is correlated with the position of the laser beam source and output on a visual display, resulting in an acoustic map of the ground. A raster scanning of the suspect ground in the vicinity reveals the shape of the underground object, allowing the operator to discriminate benign and natural objects.

Abstract: A method and apparatus for ensuring accuracy of weight measurement of objects on a conveyor and providing security against pilferage or miscoding of the objects. A series of sensors such as photocells linked to a process control unit sense passage of objects to respectively activate a scale and cubing system associated with the conveyor, to release an additional object for weighing and cubing, to sense overlong objects exceeding the length of the scale, and to detect when an object has been stolen or otherwise removed (as by falling off) the conveyor between various locations through the use of programmed timing "windows" between the various sensors. If an object does not trigger a sensor within the window measured from passage past a preceding sensor, an error message is generated.

Abstract: An weapon localization system for determining the location of hostile weapon fire. In one embodiment, the weapon localization system includes acoustical detection means for detecting energy of a first frequency originating from said hostile weapon fire; and for transmitting a first set of data describing the location of said hostile weapon fire; optical detection means for detecting energy of a second frequency originating from said hostile weapon fire, and for transmitting a second set of data describing the location of said hostile weapon fire; and processing means coupled to said acoustical and said optical detection means, for receiving said first and said second set of data, and for determining whether said location of said first set of data match said location of second set of data and for generating a signal output if said match occurs.

Abstract: A navigation system and method for identifying a position or navigating an autonomous robotic platform within an area is provided including a moveable device having an acoustic transmitter for transmitting an acoustic signal, an electronic processor device and an RF receiver; and three or more beacons positioned proximate the area, each beacon including a signal receiving apparatus responsive to the acoustic signal and an RF transmitter, the acoustic signal and the RF signal received from each of the beacons being processed in the electronic processor device to identify the location of the platform within the area.

Abstract: A method and apparatus for measuring the dimensions and determining the three-dimensional, spatial volume of objects, particularly small objects. Reflected laser light sensors are employed. A stationary measurement embodiment of the apparatus may be employed to measure regular cuboidal objects. A dynamic or in-motion embodiment may be employed to measure the dimensions of cuboidal objects or a three-dimensional outline of objects of irregular configuration.

Abstract: A portable ranging system for analyzing gait is disclosed comprising a transponder having an infrared receiver and an ultrasound emitter, a base unit having an infrared emitter and an ultrasound receiver, and a computer terminal. During gait analysis, the transponder is worn by a subject at approximately the level of the body center of mass. As the subject walks away from the base unit, the base unit continuously causes, at a constant sampling rate, the ultrasound emitter to emit ultrasound pulses. These ultrasound pulses are received by the ultrasound receiver of the base unit. The computer terminal, by counting during the flight of each ultrasound pulse, is able to calculate the time of flight of each ultrasound pulse, and thus calculate and display in real time the forward progression of the subject. At the end of the walking trial, the computer terminal displays the instantaneous velocity profile, or gait velocigram (GVG), for that trial.

Abstract: A fiber optic cable, coated to increase its sensitivity to acoustic press, is towed through a medium. The optical fiber contains Bragg grating sensors at regular intervals along its length. A steerable array of transducers sends a pulse of sound in the direction of the optical cable while broadband pulses of light are directed down the optical fiber. The pulses of light are selectively reflected back according to the spacing between the Bragg gratings. The sound pressure field causes a local strain in the fiber, thus changing the grating spacing. The sound velocity profile along the length of the optical cable is computed by measuring the amount of time necessary for successive Bragg gratings to respond to the acoustic pressure associated with the advancing wave front of the acoustic pulse.

Abstract: A method and system for detecting the presence, and the location of, a concealed listening device. In the method, the acoustic signal from the actual acoustic source and electromagnetic signals in the radio frequency band (containing the electromagnetically-transmitted version of the acoustic signal on an unknown frequency) are obtained and an average cross correlation of the auto correlation of each of these two signal types is derived for determining whether a concealed listening device is even present and, if so, the frequency of the electromagnetically-transmitted version. The method then utilizes timed pulse responses of a plurality of acoustic transducers, as well as a distinguishing function, to determine the location of the concealed listening device. In the system, a controller controls the operation of a radio receiver, a microphone and an arrangement of acoustic transducers in accordance with the method described above.

Abstract: A method and system are provided for detecting objects at or below a surf of a body of water. A focused beam of amplitude varying electromagnetic radiation, e.g., a pulsed laser beam, is directed through the air towards the water's surface. Acoustic energy under the water's surface is monitored for any acoustic return that may be generated in the water as a result of the beam being incident on either an object at the water's surface or the water's surface above an object.

Abstract: A method and apparatus for measuring the dimensions and determining the three-dimensional, spatial volume of objects, particularly small objects. Reflected laser light sensors are employed. A stationary measurement embodiment of the apparatus may be employed to measure regular cuboidal objects. A dynamic or in-motion embodiment may be employed to measure the dimensions of cuboidal objects or a three-dimensional outline of objects of irregular configuration.

Abstract: On Fork Lift 100, Load Cell Assemblies 40a and 40b are affixed to Fork Arms 32a and 32b and as such are capable of determining the weight of any object lifted by Fork Arm Lift Assembly 30. Continuous weight information is transmitted from Assemblies 40a and 40b to Fork Lift Computer 52 via wires and IR Transmitter 44 and Receiver 48. Changes in weight information are interpreted as load engagement and disengagement by Computer 52, which then responds by receiving the current relative vertical height of Fork Arm Lift Assembly 30 from Ultrasonic Distance Measuring Unit 56. The Computer 52 then transmits, via Telescoping Antenna 70, an uniquely encoded signal with both weight and height information to Stationary Elevated Locating Modules such as 74a and 74b, which have been strategically placed throughout the operating range of Fork Lift 100. This signal is then transmitted to Unit Tracking Computer System 80 by Locating Modules such as 74a and 74b.

Abstract: A device for assessing an impact of a projectile with a target using optical radiation from the flash of the impact. The invention includes an optical radiation detector, which detects optical radiation from the impact flash using optical, electronic and optoelectronic devices. The optical radiation detector is situated on a tank firing the projectile at a target. Further included is an optical radiation augmenter, which is a pyrotechnic material, mountable on a projectile, for augmenting the flash of the projectile impact with the target. By analyzing the signatures of pyrotechnic materials using the optical radiation detector, one can easily identify which projectile impacted the target, determine a distance traveled by the projectile, and assess the projectile impact by ascertaining whether the projectile perforated the target.

Abstract: A communication system that communicates for locating one or more tags in a time and energy efficient manner. The tags are positioned in a communication region and are located by a locator. The tags are located through organized transmission and reception of signals between the tags and the locator. The locator locates and gives directions to tags from the locator using a radio link and a multi-channel ultrasonic acoustic link. The combination of linkages provides the means to determine the unobstructed bearing and distance between the locator and the tag and resolves multipath reflections.

Abstract: A system and method for determining the position of an automatically guided vehicle within a workspace is disclosed which operates by detecting sounds generated by beacons placed within the workspace. The time for the beacon sounds to reach the vehicle is measured and a distance to each beacon is determined. From these measured distances and the known positions of the beacons, the vehicle can determine its relative position.

Abstract: An object locating system, especially for use in locating a gaming ball in the game of football, utilizes a series of three sensors positioned on one side of a football playing field and a calibration source positioned on the other side. The calibration source emits an ultrasonic signal which is received by the sensors in order to provide a calibration signal. A ball marking unit is positionable on the field at a location of the ball and emits an ultrasonic signal which is received by the sensors and an RF signal which is received by the calibration source in order to turn the calibration source off. The sensors provide signals in which a processing unit calculates time delays by a time acquisition process in order to determine the position of the ball. In an alternate embodiment, the ball marking unit emits only an RF signal which is received by the sensors. The sensors again provide signals which are analyzed by the processing unit to determine delay between receipt of the signals at the sensors.

Abstract: A torpedo relative position measuring system, including an active sonar system and a passive magnetic system, is coupled to computing apparatus which operates in response to a set of stored computer programs, all located in the torpedo for homing in on a ferrous target. At long ranges and mid ranges, the torpedo is directed to the target by the sonar system, while at near ranges the magnetic system determines the x, y, z, relative position coordinates between the target and the torpedo in accordance with a calibrated stored magnetic model of the target and numerical solution of the non-linear equations linking the target's magnetic field, as measured at the torpedo, with the target's relative position. Guidance information derived therefrom is then fed to the torpedo's guidance system. With the magnetic system providing the relative position of the target at close range, the torpedo's normal guidance system can readily steer the torpedo to a desired hit point on the target.

Abstract: A system is provided for tracking the three-dimensional position of an object within a three-dimensional region by triangulation techniques to generate signals corresponding to such three-dimensional positions. The signals may be used to operate a variably operable system to create a virtual reality system. The triangulation means may comprise at least three ultrasound emitters cooperating with ultrasound receivers located on a body moving in the three-dimensional region. The signals are produced from multiplexed frequencies and/or intermediate signals may be projected using a triaxial accelometer.

Abstract: An apparatus and method for determining the velocity of sound propagation a fluid as a function of position in the fluid along an axis. A wave of acoustic energy is transmitted along the axis to produce a disturbance that moves in the medium at the velocity of sound. A laser generator transmits a light pulse substantially along the axis through the fluid medium. As the light passes through the disturbance, light backscatters in a characteristic pattern that a detector senses for analysis to provide information concerning the distance traveled and the time of travel for the acoustic wave through the fluid medium and to provide a profile of output characteristic, such as the speed of sound in the medium, as a function of position in the medium.

Abstract: A system is provided for tracking the three-dimensional position of an object within a three-dimensional region by triangulation techniques to generate signals corresponding to such three-dimensional positions. The signals may be used to operate a variably operable system to create a virtual reality system. The triangulation means may comprise at least three ultrasound emitters cooperating with ultrasound receivers located on a body moving in the three-dimensional region.

Abstract: A trailer hitching aid includes a dual transmitter mounted on the forward end of a trailer or other vehicle to be towed and arranged to transmit pulses of infrared light and pulses of ultrasonic sound. A towing vehicle mounts on its rear end an infrared light detector and a pair of laterally spaced ultrasonic sound detectors. The detectors are incorporated in an electrical circuit which includes a computer the program of which operates to measure the time difference between the detection of a light burst and the detection of sound bursts. The time differences then are utilizes to calculate the distance from each detector to the transmitter, and the distances and angles between the detectors and transmitter are displayed on the computer screen as visual indications to direct the operator of the towing vehicle to maneuver the vehicle to back it up and bring the hitch components on the vehicles into coupling registry.

Abstract: A system for detecting the approach of a vehicle toward the line of sight an antenna comprises an alerter for receiving an acoustic noise signal from the vehicle and determining whether the signal is increasing or decreasing. The increase of a noise signal indicates the approach of a vehicle and is used to activate a power supply to supply power to a digital signal processor. The digital signal processor receives the acoustic signal and performs a comparison to determine whether the signal in fact is noise produced by a vehicle. If so, the digital signal processor activates a radar based primary sensor which more accurately detects the approach of the vehicle and determines the instant at which the vehicle passes an antanna of the sensor. When the vehicle passes the antenna, the digital processor receives data and produces an output signal that can be used to activate a counter to count the passage of vehicles, surveillance equipment or to fuse a mine if the vehicle is assumed to be hostile.

Abstract: An apparatus and method for determining the position of an object, especially the position of a movable object in an industrial vessel. The position is determined by the use of two signals having a very large difference in their velocities, such as electromagnetic and acoustic waves. The object whose position is to be determined receives the electromagnetic signal, analyzes the electromagnetic signal, and, if appropriate, transmits an acoustic signal. In addition to the object containing an electromagnetic receiver and an acoustic transmitter, there is required an electromagnetic transmitter, three or more receivers to receive the acoustic signal from the object, and supporting equipment to process signals and log data. When the object transmits an acoustic signal, the acoustic receivers, which are in known positions in the vessel, receive the signal at different times depending on the distance of the object from each receiver.

Abstract: The detection and localization of an antiship torpedo is accomplished by ustic and optical means. A ship's sonar determines the approximate location of the incoming torpedo and a laser scans this location with energy in the blue-green spectrum. Surface reflections are gated out of a linear detector array and reflected portions of the scanning beam which penetrate the water's surface are divided among the elements of the linear detector array into field of view element signals. These field of view element signals are subsequently compared in time and amplitude to determined disparities between them which point to the torpedo's position, depth and bearing. Optionally, spectral and polarizing filters are provided to enhance the signal to noise ratios and to facilitate signal processing.

Abstract: A system is disclosed for determining the location from which a sound blast having an identifiable audio signature originates. The system is particrly suited for determining the location of the muzzle blast from which a projectile, such as a bomb, is being launched by an enemy. The system comprises a plurality of elevated or airborne sensors whose position is accurately determined and which supply information to a land base station that performs the trigometric operations to ascertain the location of the enemy weapon.