Abstract: A system and method for determining the range between a receiver of a radio frequency signal and a transmitter of the signal includes transmission of a ranging signal having a grossly timed trigger followed by a chirp waveform. In response to receipt of the leading edge of the grossly timed trigger, the receiver of the ranging signal generates a first reference chirp at about the same time as the expected time of receipt of the chirp waveform, and thereafter compares the two chirps to provide a time correction signal (it being known that when two identical chirp signals, one time delayed from the other, are mixed, the resulting signal will have a frequency proportional to the amount of delay between the two chirp signals.) The time correction signal is used to correct the timing of an outgoing corrected chirp that is to be used to determine range between the transmitter and receiver based on a time of arrival.

Abstract: A burst tone range processing system for determining the distance between a ranging station and a signal re-transmitting target device, generates a burst tone signal of finite duration and transmits the signal along a delay transmission path from the ranging station to the target and along a reference transmission path within the ranging station. The transmitted signals are received from the reference and delay paths and assigned time tags. The signals are then correlated and the time tags assigned to correlated signals are compared.

Abstract: A method for determination of positions of measurement objects from a number of measurements of the directions to the measurement objects made at separate points in time. During the initial measurements of the directions to the measurement objects, a number of assumed areas, within which the measurement objects are assumed to be located, are established along the direction to each measurement object. Subsequent measurements of the directions to the measurement objects are performed from at least two different measurement stations, which between the points in time are moved along different paths. In connection with the measurement of the directions to the measurement objects, the positions of the assumed areas are compared with the expected appearances of the measurement objects, and the assumed areas which exhibit the best correlation to the expected appearances of the corresponding measurement object are assumed to represent the positions of the measurement objects.

Abstract: A millimeter wave radar is placed on an aircraft and several radar targets are placed near a runway. The targets are discrete objects, each having a relatively localized radar cross section, a unique signature or a unique range bin, and a position which is accurately known. Targets should be spread over the length of the runway. Radar corner reflectors and active or passive repeaters are preferred. The locations of the radar targets with respect to the runway can be transmitted to the aircraft, or they can be stored on board. On board memory requirements can be reduced by requiring all airports to select one of only a few standard target placement patterns, or even only one. Targets are inexpensive, as are radars whose only precision requirement is in range, and not in azimuth or elevation angles. Range to at least three targets in the radar's field of view is all that is required for an on-board computer to determine the aircraft's location.

Abstract: The present invention relates to a process and a system for determining the position and orientation of a mobile, and to applications thereof.In order to ascertain both the position and orientation of a mobile, the invention proposes an interrogation/response process whose particular feature is to supply, to a given interrogation, two responses which are distinguished on the one hand, by different modulating frequencies and, on the other hand, by the fact that they are transmitted according to two patterns which differ in aim relative to one another. It is then possible, simply by measuring the angular deviation of either one of the two responses, and simply by measuring the ratio of the amplitudes of the two responses received, to deduce on the one hand the angular position .phi. and on the other hand the orientation .theta. of the mobile.The applications in the automobile sector are numerous (anticollision, control of road traffic and of compliance with the highway code, automatic toll points, etc.).

Abstract: A sensor arrangement for the sensing, through the intermediary of the intermediary of high-frequency of an actual threat against an object which is equipped with a receiver device by an attacker penetrating into a radio link. The arrangement has the receiver device designed for the receiving or pickup of radio reception links from a plurality of satellites operating at the same or different frequencies, and which includes at least one comparator stage for the evaluation of the radio reception link which has been influenced by a penetrating potential attacker in comparison with an uninfluenced radio reception link.

Abstract: A radio environment measuring system for measuring a propagation state of radio waves includes: a fixed radio apparatus provided in a base station; a mobile radio apparatus operatively connected to the fixed radio apparatus through the radio waves; the mobile radio apparatus having a repeater unit for receiving a transmission signal from the fixed radio apparatus and sending a returned signal to the fixed radio apparatus; and the fixed radio apparatus having a transmission/reception unit for sending the transmission signal to the mobile radio apparatus and receiving the returned signal from the mobile radio apparatus, and a measuring unit for measuring the propagation state of the radio waves, for example, a propagation distance, direction and reception intensity of the radio waves between the fixed radio apparatus and the mobile radio apparatus based on the transmission signal and the returned signal.

Abstract: Method and apparatus for measurement of the velocity of a moving target (20) in radio frequencies. From the measurement station (10) and from the target station (20), radio signals (S.sub.1,S.sub.2) are transmitted that are in different frequency ranges, as compared with each other, so that the receivers at the measurement station (10) and at the target station (20) are not subjected to interference. The radio signals (S.sub.1,S.sub.2) are received at stations (20,10) opposite to their transmission stations (10,20). The oscillator of the target station (20) is locked with the frequency transmitted by the measurement station (10) by means of a phase-locked loop (PLL). The frequency of said oscillator is passed to the transmitter part of the target station (20). The signal (S.sub.2) transmitted by the target station (20) is received at the measurement station (10). The Doppler shift (fd) of the frequency of the signal (S.sub.

Abstract: A passive distance measuring system for aircraft landing or other transportation related or other general usage is disclosed. The passive system operates by measuring the time interval between arrival of a precision sweep scanned signal such as a radio frequency signal at two widely dispersed different signal receptor locations on the aircraft. By knowing the angular sweep velocity of the received signals and the receptor or antenna separation distance on the aircraft, the distance of the aircraft from the scanning source of, for example, radio frequency signals may be computed with appreciable precision. The disclosure includes analog-to-digital signal conversion and modifications of the invention including optical or laser signals in lieu of the preferred microwave radio frequency signals. The disclosure also includes a table of numeric values relating pulse separation time to aircraft range distance and indicates a number of equipment and military environment advantages of the invention.

Abstract: A distance measuring system which may be used on a golf course in order for a golfer to accurately measure the distance between the present lie of his golf ball and the hole toward which he is currently advancing the golf ball. A master transceiver station is portably carried by the golfer to be disposed proximate the lie of his ball for measurement purposes, and a remote transceiver system is located in or on each hole's flag marker pole. The present system uses, as the basic measurement frequency, only the frequency of the remote carrier itself. Two separate and distinct phase measurements are made in rapid succession. The first measurement is made with the master RF carrier displaced above the remote carrier frequency by amount equal to the IF frequency, and the second measurement is made with the master carrier frequency displaced below the remote carrier frequency by the same amount.

Abstract: A bistatic radar system includes a transmitting radar site; a receiving radar site; and an optical fiber RF link system for transmitting RF signals from the receiving site to the transmitting site and for transmitting command and control signals from the transmitting site to the receiving site.

Abstract: An optical RF stereo systems includes multiple remote vehicles, a processing center, and optical RF link systems for transmitting RF signals from remote vehicles to the processing center and for transmitting command and control signals from the processing center to remote vehicles.

Abstract: In a vehicle equipped with a distance measuring unit capable of measuring a distance between the subject vehicle and an objective obstacle, the objective obstacle is detected along a widthwise direction of the vehicle by the distance measuring unit. Detection data detected by the distance measuring unit are developed on X and Y coordinates in which the widthwise direction of the subject vehicle is represented by an X axis; the longitudinal direction of the subject vehicle is represented by a Y axis, and the position of the subject vehicle is defined as an origin. Each of obstacle data is labeled in such a manner that the same labels are affixed to obstacle data which are in proximity to one another on the coordinates. The amount and direction of movement are calculated for every label on the basis of the last data and the current data, and a relative speed for every label relative to the subject vehicle is calculated by dividing the amount of movement by a sampling time.

Abstract: A radar system for passive determination of range to a non-cooperative scanning radar, to a non-emitting object illuminated by the scanning emitter and between scanning emitter and illuminated object entirely from the passive location. The radar equipment at the passive location includes a passive array with beam forming and switching matrix to provide output signals separately on the basis of angular discrimination, for each of the object and emitter. Resolver circuits respond to the angle between emitter and object vector, the incremental time between direct emitter reception and reflected echo from the object as well as to emitter scan rate and instantaneous pointing angle. Algorithms for the emitter range, object range and range between emitter and object are given.

Abstract: An emitted wave is transmitted from a central station to a passive end. A phase modulation circuit in the passive end modulates a signal resulting from the emitted wave for retransmitting it in the form of a two-phase-state modulated signal at the rhythm of a clock signal. In the central station, the modulated signal is demodulated into two quadrature signals. On the basis of the product of the two quadrature signals and the sign of the difference between the moduli of the rectified quadrature signals, the count of an up-down counter in a digital processing circuit is incremented or decremented in order for said count to be representative of the distance separating the passive end and the central station.

Abstract: A network diagnostic tool for determining the position of a workstation on a local area network (LAN) having timer and echo stations at each end of a multi-access bus. Signals from the LAN workstations propagate in both directions along the bus. When the signals are so propagated, by measuring the time delay between receipt of a data packet and its echo at the timer station, the position of the workstation along a bus can be determined in accordance with that time delay.

Abstract: A range finding system uses non-simultaneous measurements between two communicating and cooperating instruments such that a single carrier frequency is used to exchange information between the instruments with non-simultaneous transmission using the same transmission channel. The range finding system may be considered to be an interrogator/transponder arrangement in which the results of a phase measurement against a local clock is made at one transponder station during one time interval, and then the transponder transmits both a tone derived from the transponder's local clock and the measurement results back to the interrogator station during a second time interval. The interrogator then has everything it needs to accurately compute the range while eliminating local delays in clock differences, while permitting the interrogator and the transponder to share a single frequency intermittently.

Abstract: A measured displacement is determined by extracting components proportional to a sine value and cosine value of the displacement from a phase modulated wave in synchronization with a reference wave. A response delay which tends to occur in a PLL circuit due to the variations of the reference wave is not generated. The detecting resolution is determined depending upon that of the A/D convertor. Generally, the higher the resolution of the A/D converter the lower the speed at which the converter operates. However, since the upper digit is obtained by counter, it is possible to engage the low speed A/D converter even if the measured displacement varies at a high speed. For this reason, it is possible to easily detect the measured displacement at a high resolution.

Abstract: A ranging method for measuring the flight distance of a flight object is implemented by means of a simple system construction. The ranging method is also capable of continuing ranging even if an interruption occurs in data transmission. The ranging method comprises the steps of inserting ranging pulses in a telemeter signal transmitted from a transmitting apparatus provided on the flight object, separating and extracting a ranging pulse from a telemeter signal received by a receiving apparatus provided on the ground side, obtaining a time difference between the ranging pulse and a reference clock signal generated in the receiving apparatus on the basis of a time reference equal to that of the transmitting apparatus (clock signal periods t1 and t2 of both time references are equal), and calculating the flight distance.

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 process for the pseudo-synchronization of a time multiplexing communication network comprises the steps of measuring a time shift TM in reception by a mobile station of synchronization signals from first and second fixed stations, measuring the propagation times t1 and t2 of a synchronization signal between the fixed stations and the mobile station, and calculating the transmission time shift TR between the synchronization signals in accordance with the relationship TR=TM+t1 -t2. The pseudo-synchronization process can also be employed for geographically locating a mobile station.

Abstract: A system for secure distance ranging between a reader 11 and a tag 12 wherein the distance between the two is determined by the time it takes to propagate a signal from the reader to the tag and for a responsive signal to return, and in which such time is random and unpredictable, except to the reader, even though the distance between the reader and tag remains the same. A random number (19) is sent from the reader and encrypted (26) by the tag into a number having 16 segments of 4 bits each (28). A first tag signal (31) is sent after such encryption. In response, a random width start pulse (13) is generated by the reader. When received in the tag, the width of the start pulse is measured (41) in the tag and a segment of the encrypted number is selected (42) in accordance with such width. A second tag pulse is generated at a time T after the start pulse arrives at the tag, the time T being dependent on the length of a variable time delay t.sub.

Abstract: A method for assisting terrestrial vehicle traffic involves equipping at least some vehicles with a radar system and a transponder capable of re-transmitting with selected frequency transposition any radar wave received within a predetermined frequency band. The radar system semi-continuously transmits the waves capable of measuring a distance over a range of several hundreds of meter, and the radar system receives the transposed echoes in order to carry out distance measurement thereon. It is also possible to provide certain bodies, not equipped with radar, with individual transponders which are different from those provided on vehicles.

Abstract: An improvement in a coprocessor system for correcting for drifts in directions of navigation gyros, by means of satellite navigation information from global positioning satellites. Values of gyro navigation information from the gyros are interpolated to values that are valid at a cycle time. A cycle time is a time when the satellite navigation information is valid. The interpolated gyro navigation information is coprocessed with the satellite navigation information to arrive at accurate gyro drift terms. The gyro drift terms are used in correcting for the drifts in the navigation gyros.

Abstract: A propagation time detecting system wherein a transmitting station transmits to a receiving station, over a plurality of transmitting paths or lines having different propagation times, a transmission signal comprising a sequence of transmission data digitized by a clock signal of a clock frequency. The receiving station receives the transmission signal through the respective transmitting paths or lines as different received signals, and reproduces the sequence of transmission data and the clock signal as different reproduced sequences of transmission data and different reproduced clock signals, from which differences are detected among the different propagation times. In order to improve the accuracy of the detected differences, at least one subcarrier signal with a frequency higher than the clock frequency is also transmitted together with the transmission signal.

Abstract: Two miniaturized transceivers, each selectively responsive to predetermined radio frequency (r.f.) transmissions which may be coded, consisting of one control unit and one transponder unit. Transmission by the control unit of a modulated frequency which is received and decoded by the transponder will generate a like reply from the transponder whose round-trip delay is timed and because of the known velocity of radio waves can thus be displayed as the distance between the two units. An adjustable maximum range limit in the control unit will generate an audible, visual or other alerting signal in the control unit when the distance between the two units is exceeded. Such signal is also obtained when the signal from the transponder is interrupted. Low-power consumption can be effected for battery operation by arranging short periodic bursts of r.f. energy between the two transceivers, there being logical means to time-align the respective transmit and receive modes of the two units.

Abstract: A method of measuring the distance between two objects and/or the speed of one object in relation to the other, the objects incorporating respectively a transmitter-receiver unit and a transponder or reflector, in which method a phase comparison is made between a signal transmitted by the transmitter-receiver unit and a signal received in the transmitter-receiver unit and transmitted from the transponder or reflector. In accordance with the invention the transmitter-receiver unit is caused to transmit signals of microwave frequency, preferably about 2450 MHz, this transmission comprising the transmission of a first signal having a first frequency, the transmission of at least one second signal having a higher or lower frequency, and the transmission of a third signal having the same frequency as the first mentioned signal, wherewith the phase differences .phi.

Abstract: An accurate ranging system for position determination of a mobile unit using trilateralization. A pair of active reflectors return signals transmitted by the mobile unit in phase at the reflectors, after compensating for interval circuit delay. The mobile unit compares the phases and determines mutual distances and thus its position. The invention includes a two frequency technique for compensating for inaccuracies introduced at distances in excess of one wavelength and for inaccuracies observed at a large multiple of wavelengths, and also includes means for dynamically compensating for drift.

Abstract: A method for measuring the distance between a first object, which incorporates a transmitter-receiver unit, and a second object, which incorporates a transponder. In accordance with the invention there is transmitted from the transmitter-receiver unit (19) a first microwave signal (S1), which is received in the transponder (18). A second signal (S3) of much lower frequency F.sub.m is generated in the transponder and is modulated on a signal (S6) of microwave frequency in the transponder to form a modulated signal (S7). The modulated signal (S7) is transmitted from the transponder to the transmitter-receiver unit (19), where it is received and mixed down with the first signal (S1) and thereafter is (a) low-pass filtered to form a first measuring signal (S10) having the frequency F.sub.

Abstract: Monitoring apparatus including an unmodulated radio-frequency transmitter carried by or affixed to the person to be monitored and receiver/monitor apparatus at a monitoring location for providing quantized visual and audible indicia based on received signal strength. The receiver AGC level, being a function of received signal strength, provides the variable which determines the repetition rate of tone bursts and the number of LED bar visual indicia lighted within an array of such LED bars. The response levels of those indicia are then a function of the distance between transmitter and receiver. Movement of the child (for example) beyond a predetermined range is immediately detected by a person at the receiver location. Circuitry is provided for presetting the maximum allowable range before alarm is instituted.

Abstract: A signal is transmitted from a first location to a remote second location where a target carrying a transponder is positioned. The transponder re-radiates the signal to the first location where it is received. A phase comparator generates from the transmitted and received signals a measurement of their phase difference which is functionally related to the distance between the first and second locations. In one embodiment, the transponder is a passive parametric oscillator, being powered by energy received from the transmitted signal, which generates and transmits a subharmonic of the transmitted signal.

Abstract: A two-way ranging system in which deviations of transmit times of interrogation signals from a nominal transit time are determined at a transponder. These deviations are dependent upon the propagation conditions for interrogation and reply signals in the medium of propagation. A normally fixed delay is developed in the transponder. This fixed delay occurs between the reception of an interrogation signal and the transmission of a reply signal. This fixed delay is so shortened as to compensate for transit time deviations of the interrogation and reply signals.

Abstract: An electronic method is used to determine the location of a football on a playing field using a radio transmitter which is positioned at the end of the football and energized to send signals to dispersed receiving rotating antennas which automatically become positioned to point toward the transmitter and then provide via triangulating methods, signals to a computer that determines and transmits the actual location of the football to selected receivers on or off the football field.

Abstract: In a continuous wave electromagnetic positioning or distance measuring system of the Wadley type (see U.S. Pat. No. 2,907,999) a number of secondary phase measurements are obtained from a number of successively produced primary phase measurements in such a manner that any instrumental errors incorporated in the primary phase measurements are eliminated. Each secondary phase measurement represents the fractional part of the phase delay that would be experienced by a signal of accurately known measuring frequency when propagated electromagnetically along a propagation path corresponding in length to the distance to be measured. The measuring frequency is determined by the frequencies of pattern and auxiliary pattern signals used in obtaining the primary phase measurements.

Abstract: Methods for accurately measuring the range between two platforms with relative motion between them using a stable clock located on each platform. A series of pulses are sent from one platform to the other at times known to each platform by prearrangement, the arrival times measured, and statistical methods used to calculate a correction from the clocks to bring them into greater synchronization, thus allowing highly accurate determination of the range between the two platforms.