Abstract: Optical radiation is propagated through an attenuating medium to a target om which it is reflected and picked up by an echo receiver system to provide ranging and imaging data during one mode of operation. The optical radiation is transformed into acoustical pulse energy alternatively radiated to and reflected from the target in another mode of operation. The operational mode is selected so as to optimize the data extracted from the echo receiver system under different conditions affecting receiver reception.

Abstract: A wide-aperture array, used to sonically measure range to a source, is calibrated by providing a beam of optical energy from a first location, rigidly affixed to a first end sensor of a trio of array sensors, through a lens at a second location rigidly affixed to a middle one of the trio of sensors, to an optical sensor of the retinal type at a third location, rigidly affixed to the remaining sensor, at the opposite end of an initially straight line from the first sensor, and then measuring the deviation of the beam at the retinal sensor due to deviation of the sensors from positions on a straight line. The wavefront curvature found for any energy received by the array sensors is corrected by the measured deviation.

Abstract: An energy beam-forming array of N+2 stations which utilizes a companion network of N optical sensors which mutually image each other to determine deviations of the optical sensors, and therefore the energy-receptive sensors, from a common linear axis. Each optical sensor measures the equivalent of a second-difference, which are then combined to reconstruct the actual array deviations. Each optical sensor is equipped with at least one pinpoint light source, to provide a light beam to an imaging subsystem provided at the next sensor station. The imaging subsystem includes a lens, either simple or compound, coupled to a retinal sensor array. The location of the light source image at the retinal array provides all of the necessary information for reconstruction of the array sensor location.

Abstract: A device for detecting a covert transmitter having a time varying impedance therein including a radio frequency transmitter and an audio frequency transmitter which are directed so as to illuminate a target area. The audio tone drives the active elements into a non-linear mode of operation to modulate the transmitted radio frequency. The re-radiated energy is detected by a further radio frequency receiver.

Abstract: Propagation of modulated radiation from a platform is substantially limited o unidirectional transmission through a body of water. Acoustical energy is generated at the surface of a remote object submerged in the water in response to impingement and absorption of the modulated radiation from the platform. Radiation of the acoustical energy generated adjacent the object is detected at the platform to extract data therefrom from which the location of the object relative to the platform is indicated.

Abstract: With the measurement of spatial movement of test points by means of ultrasonic signals, the problem exists that often interferences occur which may lead to distortion of test results. It is proposed to check the space between sound transmitter and sound receiver by means of electromagnetic waves, in particular light waves, for absence of obstacles, and/or not to use for the derivation of the distances those ultrasonic signals whose transit time and/or amplitude lie outside a given expectancy range, but to discard them.

Abstract: In a geomembrane defined impoundment, a leak is located by vessel supported means. The present invention is directed to locating the vessel so as to then locate the leak. A set of N hydrophones spaced around the impoundment detect a liquid transmitted acoustic pulse from the vessel. The vessel supports an RF transmitter which broadcasts a timing pulse. With the timing pulse, elapsed acoustic travel time is measured to define range in the liquid. The range defines an arc of a circle around a single hydrophone. Using N hydrophones, N arcs are defined on the impoundment, each centered on the respective hydrophones, to intersect at the vessel location.

Abstract: A system for monitoring the safety and location of individuals includes a portable transceiver worn by each individual and a base control unit for sending interrogation signals to the individual units. The interrogation signals are transmitted through both air and water, and the individual units transmit a response through the medium through which the interrogation signal was received. The base unit measures both the elapsed time from transmission to reception and the incoming phase angles of the response signal, and converts these measurements to indications of distance and angle between the base unit and the individual transceivers.

Abstract: Disclosed is a method for measuring a distance by using a radio-wave and an ultra-sonic wave. The method includes the steps of generating a certain start pulse in the form of a radio-wave between a measuring position and a position to be measured from the measuring position, receiving the radio-wave at the position to be measured while simultaneously generating an ultra-sonic wave from the same measuring position, determining a time difference between the moment of generating the start pulse and the moment of receiving the ultra-sonic wave, and multiplying the obtained difference by the sonic velocity.The method of measuring distances by utilizing the radio-wave and the ultra-sonic waves is very accurate without false operation and is simple, brief and convenient to use.

Abstract: Three or more listening devices (A1, A2, A3) are dispersed over the water area where the location of a sound source is to be determined, and transmit radio signals over respective channels to a master station upon detecting sound. The master station correlates the signals from selected ones of the listening devices to derive the position of the sound source relative to those listening devices. If the positions of those listening devices are unknown, for example if the devices are floating free, their positions are determined by the master station by comparing the relative times at which an identifying radio signal transmitted by each listening device is received by the master station directly and relayed from each of two stationary radio stations with known positions. The listening devices may also be provided with receivers for receiving radio command signals from the master station, for example relating to activation of certain listening devices and assignment of radio channels.

Abstract: A device for indicating a certain proximity between movable units emitting to the units a synchronizing signal with a very high transmission speed. A transmitter device is situated at least on certain of the units. The transmitter device is activated by the synchronizing pulse to emit an information signal in the form of a wave propagation movement in the medium in which the units are located. The wave propagation movement has in comparison with the synchronizing signal a considerably lower transmission speed. In at least certain others of the units the information signal is received by and related to the difference in time between the synchronizing signal and the received information signal to a predetermined time value corresponding to a certain proximity between the units. Thereafter the difference in time is evaluated in relation to the predetermined time value.

Abstract: Acoustic positioning device for a vessel comprising N transponders (B.sub.1 . . . B.sub.i . . . B.sub.N).A fixed acoustic transmitting means (E) periodically transmits acoustic pulses at frequency f. The responses of the transponders (B.sub.1 . . . B.sub.i . . . B.sub.N) are received by the acoustic array (A.sub.1, A.sub.2) of the vessels. The time origins are transmitted by a radio antenna to the surface vessel. In the case of submarines, two stable clocks are used, one of which is on board the submarine. Processing circuits make it possible to know the position of submarines.Application to the positioning of vessels in an oil production field or for oceanographic research.

Abstract: A signal having the form cos (.OMEGA.t+.phi.) where .OMEGA. is the frequency of the signal and .phi. is a phase angle which may be zero is phase shifted to improve the results of the summation of such a signal with other signals having the same form but different phase angles.

Abstract: An acoustic distance measuring device using a predetermined frequency shift keyed bit pattern as the acoustic signal transmitted and received. A phase lock loop detector is provided. Variations in lag from the time required for the loop to lock are eliminated and the remainder of the FSK bit sequence is detected and accumulated in response to changes in the phase detector output. Preferably the FSK bit sequence is generated via radio frequency transmitter from a first location and reproduced and transmitted acoustically from a second station back to the first station.

Abstract: A lift truck (16) carries a leftwardly directed ultrasonic receiver (32L) and a rightwardly directed ultrasonic receiver (32R) and an RF transmitter (34). Upon depositing its load in an assigned bin in a warehouse (FIG. 1), a load sensor (22) is actuated to cause transmission of a coded signal as to lift height and vehicle identification to a central station (60). This initiates a vehicle search by energizing ultrasonic transmitters (42-52). The ultrasonic receivers (32L and 32R) on a vehicle in a path under surveillance detect the sonic signal and relay this to the central station by way of the RF transmitter (34). The time duration which elapsed from energization of the ultrasonic transmitter to detection of the sonic signal is used to measure vehicle path depth and a comparison of the magnitudes of the sonic signals received by the receivers (32L and 32R) indicates the heading direction of the vehicle.

Abstract: Pipe measuring apparatus is disclosed. In the preferred embodiment, a transmitter is arranged at one end and a receiver at the other end of the pipe. At the transmitter, there is a tone generator which transmits acoustic signal along the pipe. In addition, a power amplifier drives an output diode which transmits light of a specified frequency, and both are funneled along the pipe to be measured. At the receiving end, an amplifier picks up the sound. In like manner, the light which is transmitted through the pipe is also detected. Both detected signals are amplified. After amplification, their modulating envelopes are compared to one another. There is a time shift which is a function of transmission distance, treating the transmitted light as the reference. This time shift is converted by a scale factor into a multi-digit output. The conversion occurs through the use of a clock connected through a decimal counter which is gated on by the light signal and which is gated off by the advent of the sound signal.

Abstract: An alarm or signalling system between a transmitter station and a receiver station either or both of which may be in motion. A signal is selectively radiated from the transmitter station for detection at the receiver station. The receiver station includes processing means for responding to the received signal and producing a new signal indicative of selected physical relationships between the transmitter and receiver stations during the period of signal transmission and reception. The modified signal may indicate approaching or departing relative motion and/or magnitude of separation. One embodiment may incorporate synchronizing signals transmitted from a central control station. This embodiment may include receiver stations with and without the synchronizing equipment.