Abstract: A side-looking sonar system utilizing an extremely long arc transducer for ultra high resolution work. The transducer is made up of a plurality of segments each connected to signal processing apparatus which electronically varies the focus of the transducer as a function of time as well as a function of transducer altitude above a target area. Additional beams, parallel to a center beam, may be formed to give the system multi-beam capability for increased search rates.

Abstract: A computerized ultrasonic system is disclosed for classification of vehicular traffic, as at a toll collection booth. An ultrasonic ranging unit is mounted above the traffic lane, facing downward. The unit is activated by the presence of a vehicle and proceeds to measure repetitively the momentary vertical distance of the vehicle from the ranging unit. Processing circuitry is provided to ascertain average and maximum height, rejecting aberrational readings, such as from an antenna. The computerized system may include a "look-up" of standard vehicular categories, enabling classification of vehicles by comparison of the data received with pre-programmed standard categories.

Abstract: A device for processing echoes back scattered from the surface of the sea bed in response to sound pulses transmitted by a fish towed while immersed, comprising at least one assembly for determining the components X.sub.C and X.sub.S of the complex envelope of the signals received by a reception chain or from a part thereof, obtained by selective filtering of a narrow band in the frequency spectrum, and computing, storage and display means for obtaining a representation of the variations in time of the complex amplitude of the signals received.

Abstract: An ultra-sonic sensor includes a driver circuit outputting a high-frequency driver signal which orders a transmitter to transmit ultra-sonic waves toward a target object. The driver circuit also sends the driver signal to a receiver. The driver signal is superimposed on a receiver signal. The receiver differentiates the receiver signal and compares the differentiated receiver signal level to a threshold level to detect reception of the reflected ultra-sonic wave. The receiver also detects when the transmitter is actively transmitting the ultra-sonic waves toward the object and disables the aforementioned comparison at such times. Accordingly, by comparing the differentiated receiver signal level with the threshold, the influence directly transmitted ultra-sonic waves on detection of the reflected ultra-sonic wave is successfully avoided.

Abstract: An ultrasonic wave signal having its frequency varied continuously is transmitted from an ultrasonic wave transmitter toward a moving body. The wave reflected from the moving body is received by an ultrasonic wave receiver, and the resulting signal is frequency-demodulated to obtain a signal representing a frequency variation. A signal representing the feature of the moving body is produced with use of a signal representing the frequency variation of the transmitted ultrasonic wave and the signal representing the frequency variation of the received ultrasonic wave.

Abstract: An adaptable filtering device and method for filtering sonar signals to remove reverberation signals caused by the vehicle speed and trim and the sea surface and sea bottom. The vehicle itself has an antenna for transmitting and receiving sonar signals, a speed detector, a trim detector, a depth detector, and a distance-to-sea bottom detector and a sonar output device. The present invention forms paths corresponding to each distinct direction from which sonar signals are received by the antenna, each path having a path signal B.sub.i. For each path, a calculation is made to determine a central Doppler-shift frequency .DELTA.f.sub.i and a cut-off frequency f.sub.c.sbsb.i which are to be used to filter the path signal. This calculation is based upon the detected vehicle speed, the detected vehicle trim, the detected vehicle depth, and the detected distance between the vehicle and the sea bottom. The calculated frequencies .DELTA.f.sub.i and f.sub.c.sbsb.

Abstract: Sonar apparatus provided with a beamforming network (1) containing several receiving channels (4A-M) for supplying, for each direction of beam incidence, digital composite signal products obtained by superposition of the receiving channel output signals and for transforming the signal products to a low-frequency band. The signal products are fed to a signal analysing circuit (3) comprising blocking circuits (62 and 63), and to a noise detector (61) for deriving, for each direction of beam incidence, a blocking circuit control voltage from the interference signal components in the signal products. The noise detector selects signals outside the low-frequency band part representing the transmitting/receiving band, and determines the modulus of the filtered signals and the average value thereof. The modulus and, after thresholding, the average value are fed to a comparator (77) to generate the control voltage.

Abstract: An apparatus measures the distance of a target by measuring the time of travel of a light pulse from the measuring apparatus to the target and back wherein it is important to achieve high accuracy in timing to correlate, for a distant target, the time of transmission with the start of measuring the time of travel and the time of receiving a reflected light pulse and the end of the time measurement. For a near target, the start of distance measurement is correlated with receipt of a reflected measuring light pulse and a stop signal is correlated with a delayed reference light pulse. For this purpose a reference light pulse is branched off from a measuring light pulse and passed by light guides to a single receiver unit. The reference light pulse is passed to the receiver unit either through a short or a long light path depending on whether the target is distant or near, respectively.

Abstract: A distance sensing apparatus is provided in the form of a case housing electronic equipment including a piezoelectric transducer for radiating pulsed sonic or ultrasonic signals along a measurement path through a sound horn (3) which creates a narrow beam. Reflected signals received back through the horn are received by the transducer and converted into electric measurement signals. A time measurement device is providing for determining the time lapse between radiation of a pulse and receipt of a reflected signal so as to provide a distance signal which will be representative of the path distance between the apparatus and the surface which will trigger a display (7) to give a distance reading.

Abstract: A fish sonar is capable of detecting ultrasonic waves from a desired direction by shaping the waveforms of the outputs of a pair of vibrators spaced apart by a certain distance, and detecting a delay of the output from one of the vibrators with respect to that of the other of the vibrators so as to detect the direction of the ultrasonic waves coming to the pair of vibrators and to delay the output of the other of the vibrators with respect to the output of one of the vibrators.

Abstract: A ranging system employing a limiting constant false alarm rate (CFAR) receiver having reduced recognition time uncertainty, or recognition jitter. The jitter is made proportional to signal-to-noise ratio by providing the receiver with a two-part signal. A conditioning signal is provided to the receiver prior to the time the receiver is expected to sense and respond to a recognition signal for ranging. The conditioning signal has selected strength and duration sufficient to suppress noise to a desired extent in the receiver at the time the recognition signal is received. The combination of strength and frequency of the conditioning signal is selected so as to limit the probability of a false alarm, or undesired recognition of the conditioning signal in the receiver. Receiver modification is not required.

Abstract: An echo-type range finding system is rendered unresponsive to spurious signals and electronic noise, and has its object distance determining accuracy improved by rejecting signals that do not persist for a predetermined period of time.

Abstract: A device for the transit time measurement of electric, electromagnetic or oustic signals, particularly supersonic signals, of at least one predetermined frequency range, having a signal transmitter for the sending of measurement signals to an object and a signal receiver for the receiving of the measurement signals reflected by the object which have a substantially predetermined frequency corresponding to the frequency of the other signals sent and having a time measuring device for determining the transit time of the measurement signals between the signal transmitter and/or receiver and an object, from which the distance of the object from the signal transmitter and/or the signal receiver can be derived. A signal generator is provided both at least to trigger the signal transmitter and to control the signal receiver, and a filter stage for the tuning of the signal receiver in accordance with the reception frequency and for filtering out external frequencies is connected with the signal generator.

Abstract: Both signal amplitude presentation and noise suppression presentation of sonar signals have been known for some time, but have been incompatible in the same display system. In this disclosure, means are provided for separately processing the received signal in two parallel paths, one through a noise-pulse suppression processor, and the other through a signal amplitude differentiation processor which adds an additional adjustable time delay so that the signals processed through both paths are initiated at the same time and thus can be presented together.

Abstract: A digital sonar system including a redundant receiver channel is arranged to operate substantially simultaneously in both F.M. and C.W. modes. Upon failure of one receiver channel the system reverts to a single mode or alternate modes on alternate cycles.

Abstract: This invention relates to a method and system for distinguishing between displacing targets and a surface of water by transmitting pulses from a transmitter that is submerged in the water, the pulses being reflected and received by a receiver, also submerged in the water. The variations in the distance to the reflecting surface for consecutive pulses are measured and compared with a first value, determined inter alia from the state of the sea, and with another value, determined from the size of the target.

Abstract: The method and apparatus for computing the range to and depth of a submerged object that either emits or reflects pulses of acoustic energy, wherein a detecting array and related data handling apparatus measure as a function of time the apparent angles of arrival of the acoustic energy associated with each such pulse. This data is then translated into actual multipath arrival angles and multipath travel time differences which are utilized to solve mathematical equations, the solutions of which result in the calculation of the range to and depth of the submerged source of acoustic energy.

Abstract: An object confirming apparatus receives ultrasonic wave pulses periodically transmitted from a transmitter and confirms them a plural number of times according to the periodicity of the transmitted pulses so that a confirming signal may be generated which is free from the influence of noise.

Abstract: An output distance signal related to the distance between an ultrasonic transmitting transducer and an ultrasonic receiving transducer is provided by an apparatus including a reference oscillator and a burst generator responsive to the reference oscillator which periodically generates ultrasonic burst signals. The ultrasonic transmitting transducer is responsive to the generator for providing an ultrasonic acoustic energy burst in response to each of the ultrasonic burst signals. An ultrasonic receiving transducer receives the ultrasonic acoustic energy bursts and generates detection signals in response thereto. A range window circuit is responsive to detection of an acoustic energy burst by the receiving transducer, for providing a range window signal at a time period lagging the detection signal such that a range gate will be opened for passage of the next following detection signal.

Abstract: A system for the automatic measurement of the level, of material in a container and especially of liquid flowing through a channel is described. An echolocation system operates to detect returns of reflected sonic signals from the surface of the liquid in the channel during successive transmission cycles. A source of pulses is provided having a frequency which provides a certain number of pulses corresponding to the travel time of the sonic signals over a distance equal to a maximum predetermined level or head of the liquid in the channel. The time interval between signal transmission and reception is excess of twice the time for travel of the signals between the transmitter and the maximum level of liquid is a measurement of the liquid level in the channel.

Abstract: The input data format in a single-sector or multi-sector scanner imaging system is chosen such that angulated scan lines intersect a lateral line at equal increments, and along the scan lines the echo signal is sampled at different rates whereby sampling points are along parallel raster lines. Successive scan lines are stored in adjacent columns of a row-column oriented digital memory. Echo data is read out of memory row by row at a variable rate to convert the read-out data back to sector geometry. The image is displayed in real time in a cathode ray tube.

Abstract: A digital electronic system for improving the resolution of dynamic range-handling capacity for received ultrasound in reflection or transmission imaging systems. This system provides a means for preventing loss of structural detail in the display by minimizing the overlapping of signals resulting from the transducer bandwidth and pulse length. It also makes use of a (positive or negative) peak detector to recognize and print as a single point the presence of point targets. With the present technology, a point target may be represented in a B-mode display on several successive scan lines resulting in an abnormally large representation on the display. The actual target is represented by the peak point of the envelope of a series of scan lines in which the point target is displayed. The objective is to print only one point which corresponds with the actual position of the point target with an intensity that corresponds to the intensity of the received signal.

Abstract: In an apparatus for guiding or controlling a vessel over the center of an unmarked channel, a pair of ultrasonic transducers are mounted athwartship on the hull of the vessel and directed downwardly to transmit ultrasonic pulses and to receive corresponding pulses reflected from the floor of the body of water. Time durations between transmitted and corresponding received pulses are measured to determine floor or channel depth below the port and starboard sides of the vessel. The depths are digitally encoded and supplied to a comparator which generates a signal indicating whether deeper water is port or starboard of the vessel. The comparator signal is supplied to a display to instruct the navigator whether to steer port, starboard or to maintain course to guide the vessel over the center of the channel. The comparator signal may be also supplied to a rudder servo to automatically steer over the channel center. A digital filter is provided to eliminate any spurious readings obtained by the transducers.

Abstract: A distance measuring apparatus installed in an automobile to measure with a high degree of accuracy a distance between a road surface and the axle of vehicle body of the automobile in motion. With this distance measuring apparatus, the distance between the point of its installation on the automobile and the road surface is measured by transmitting wave signals from the point of installation toward the road surface, selecting only the reflected wave signals of a predetermined intensity from the received reflected wave signals from the road surface and then integrating and averaging the data of the distance to the road surface derived from the selected reflected wave signals.

Abstract: A surface acoustic signal defader for optimizing the signal received from derwater sound scattered from the ocean surface. The bandwidth of the underwater sound source is monitored and the frequency of maximum signal strength is identified. When the maximum signal strength frequency fades a predetermined amount, reception is switched to the signal of maximum anti-correlation. This process is continuous such that when the new frequency fades the anti-correlation process will determine the optimum frequency for the new fading condition, thus resulting in optimum reception of surface scattered underwater sound.

Abstract: A navigation aid for determining berthing data comprises distance detecting units embodying sonar transducers which are spaced apart along the length of a jetty a short distance behind the berthing line. The units are operative to provide signals indicative of the distance from the berthing line of correspondingly spaced sections of the ship, and a microcomputer selects two out of three of these signals and processes them to determine the distance from the berthing line of nominal bow and stern sections of the ship, the nominal measuring points being different from the actual measuring points at which the transducers are positioned. The microcomputer also processes the selected signals to determine the velocity of the bow and stern sections relative to the berthing line, and controls a jetty display of the determined distance and velocity data in addition to local and remote indications/recordal thereof.

Abstract: An underwater mapping system in which a swath of terrain, much wider than a sonar beam width, is observed by means of a sonar beam scanned in the cross track plane of a ship. Filtering and correlation techniques are employed to compensate for distortions in echoes emanating from the ocean bottom by a selection of filter coefficients in accordance with the orientation of the sonar beams and by providing a simulated echo envelope for correlation.

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