Abstract: A transmit-receive FM-CW radar apparatus according to one mode of the invention comprises: a mixer for downconverting an IF signal; a switch provided on the input side of the mixer; and a switch controller for controlling the switch on and off in different modes and selecting the IF signal in the different modes for supply to said mixer. A transmit-receive FM-CW radar apparatus according to another mode of the invention comprises: a mixer for downconverting an IF signal; a switch for turning on and off a local signal to be supplied to the mixer; and a switch controller for controlling the switch on and off in different modes and selecting the local signal in the different modes for supply to the mixer.

Abstract: An FM-CW radar apparatus capable of detecting a stationary object, in particular, an overbridge, located above the road ahead in a simple manner uses a traveling wave antenna as a transmitting antenna, and includes a means for varying, in upward and downward directions the projection angle of a combined beam pattern of a transmitted wave radiated from the traveling wave antenna, and an overbridge is detected by varying the projection angle of the combined beam pattern in the upward direction using the varying means. Further, a phase shifter for varying the projection angle of the beam pattern in upward/downward directions by controlling the phase of the radio wave to be transmitted or received is provided on either a transmitting antenna or a receiving antenna or on a transmitting/receiving antenna, and an overbridge is detected by controlling the phase shifter and varying the projection angle of the beam pattern in the upward direction.

Abstract: To provide a radar system for controlling a gate power supply and drain power supply of a MMIC (micro wave monolithic IC), protecting the MMIC at the time of start and shut-off, and simultaneously avoiding an occurrence of a failure in the MMIC due to a residual charge and an abnormal supply potential at the time of shut-off.

Abstract: This invention relates to a frequency modulation of continuous wave (“FMCW”) radar altimeter capable of controlled linear sweep modes. The FMCW radar altimeter is characterized by the following functions: (1) adopts sweep up frequency and sweep down frequency to solve problems of distance and doppler signal mixture; (2) injects a random generated variable time delay in between sweep intervals to overcome interferences among different altimeters; and (3) switches different sweep frequency bands in accordance with different altitudes.

Abstract: A method for radar-based gauging of the level of a substance in a tank (13) having at least one interfering structure (16a-c), comprises the steps of: (i) transmitting a microwave signal in a plurality of radiation lobes (15a-b; 15a-d), each of which being individually directed towards the substance and at least one of which being directed towards the interfering structure; (ii) for each of the radiation lobes detecting temporally resolved the microwave signal as reflected against the substance, and for at least one of the lobes detecting the microwave signal as reflected against the interfering structure; (iii) based on signal strengths of the detected microwave signals, distinguishing the detected microwave signals, which have been reflected against the substance; and (iv) based on a propagation time of at least one of the microwave signals distinguished as those, which have been reflected against the substance, calculating the level of the substance.

Abstract: A distance-measuring device for measuring the distance to an object (M) which comprises (i) a frequency-controlling means (11A) which outputs a frequency-control signal whose frequency is changing, (ii) a transmitting means (12A) which sends out an electromagnetic wave whose frequency is the same as the frequency of the frequency-control signal, (iii) a detecting means (13A) which is provided between the transmitting means (12A) and the object (M), detects the amplitude of a standing wave formed between the transmitting means (12A) and the object (M), and outputs an amplitude signal corresponding to the detected amplitude, and (iv) a signal-processing unit (14A) which forms a frequency-amplitude function representing the relation between the frequency of the frequency-control signal and the value of the amplitude signal and calculates the distance between the detecting means (13A) and the object (M) by using the period of the frequency-amplitude function.

Abstract: A system and method for adapting weather radar gain is disclosed. The system and method includes estimating a freezing altitude. The system and method also includes determining, based on the freezing-altitude estimate, the altitude of more than one atmospheric layer. The system and method further includes determining the proportion of a radar beam sample in each atmospheric layer and adjusting the radar gain, based on the proportion.

Abstract: Amplitude phase distortion adding sections are provided for the power amplifiers on the antenna arrays greater in amplitude weighting while amplitude distortion adding sections are provided for the power amplifiers on the antenna arrays smaller in amplitude weighting. Due to this, because a required amount of distortion compensation is made based on each antenna array, there is no bad effect upon the adjacent other antenna array, suppressing the deterioration in beam control accuracy. This, also, reduces the size of the apparatus and improves the power efficiency on the array antenna apparatus overall.

Abstract: A sensor front end is disclosed that is able to discriminate objects based on their range from the sensor. The sensor includes an antenna that transmits a sensor signal and, if an object is present receives a reflected signal therefrom. A pulsed oscillator provides a pulsed first signal having a first frequency and phase, and wherein the pulsed oscillator provides the pulsed first signal for a predetermined pulse duration and with a predetermined pulse repetition frequency. The pulsed oscillator provides the pulsed first signal to a first input port of a dual mode mixer that is further coupled to the antenna via a second port. The dual mode mixer transmits a portion of the pulsed first signal from the first input port to the second port and thus to the antenna to be transmitted as the sensor signal. In addition, the dual mode mixer uses a portion of the first signal to mix with the received reflected signal. The dual mode mixer then provides a mixed signal as an output at a third port.

Abstract: A radar based sensor detection system comprises a microwave source operative to provide a continuous wave signal at an output. A pulse-former is coupled to the output of the source and is operative to provide at an output a variable length pulse that increases the transmitted energy of the radar system according to the range of object detection. A modulator is coupled to the output of the pulse-former for providing a modulated pulse signal. A transmit receive switch coupled to the output of the modulator is selectively operative between a first transmit position and a second receive position. A transmit channel coupled to the transmit receive switch transmits the pulse signal when the switch is operated in the transmit position. A receiving channel coupled to the transmit receive switch receives the modulator signal when the switch is operated in the receive position.

Abstract: The invention provides a signal process apparatus for an on-vehicle radar and a method thereof that can reduce operation load and obtain a sufficient detection capability.

Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.

Abstract: A device which can accurately detect even objects in very close proximity to a vehicle and at the same time can reliably detect more distant objects has means (MM) that can execute a selection of those reception pulses (EI) whose chronological offset in comparison to the respective transmission pulses (SI) emitted is of such a magnitude that these reception signals (EI) result exclusively from reflections against objects from a selected distance range correlating to the chronological offset. Means (DG) are also provided that permit the transmission pulse power to be increased and decreased as the distance range rises and falls.

Abstract: The present invention relates to a radar device and, particularly, to a radar device mounted on a vehicle to be used for a collision alarm and the like. The invention provides a radar device that has a unit for removing the FMAM noise without lowering the signal detection sensitivity. The radar device transmits a frequency modulation signal by switching the frequency modulation signal with a first switching signal, receives a signal reflected from a target object, switches the reception signal with a second switching signal, mixes the switched reception signal with the transmission signal, and further mixes the mixed signals with a third switching signal thereby to obtain a beat signal. The radar device obtains a distance to the target object and a relative speed of the target object from the beat signal.

Abstract: An FM-CW radar system comprises a modulating signal generating means for changing a modulating signal to be applied to a FM-CW wave, a calculating means for calculating a distance or relative velocity with respect to a target object by performing processing for detection by fast-Fourier transforming a beat signal occurring between a transmitted signal and a received signal, and a control means for determining a detection range based on the calculated distance, and for performing control to change the modulating signal, wherein the modulating signal is changed by changing one parameter selected from among a modulation frequency, a triangular wave frequency, and a transmit wave center frequency. The detection range is set to a distance obtained by adding a prescribed distance to the shortest distance detected, or to a distance obtained by subtracting a prescribed distance from the distance of a fixed object.

Abstract: The present invention provides a method for efficient use of the transmit power of a Traffic Alert Collision Avoidance System (TCAS) that allows enhanced surveillance range and limits radio frequency (RF) interference in crowded airspace. The method reduces power density in crowded airspace by modifying Mode S, Mode A and Mode C interrogations. During Mode S broadcasts, tracking interrogation power is reduced as a function of range. Further transmit power reduction is achieved by broadcasting a variable power density whisper-shout interrogation technique for Mode A/C aircraft when garbling is detected. If garbling is observed during a medium whisper-shout interrogation sequence, the method of the present invention attempts to clear the garbling by using focused high-density whisper-shout steps but only in the ranges where garbling was detected. Formation members can account for other formation members that are TCAS equipped using a special E-TCAS Broadcast Interrogation.

Abstract: A device which can accurately detect even objects in very close proximity to a vehicle and at the same time can reliably detect more distant objects has means (MM) that can execute a selection of those reception pulses (EI) whose chronological offset in comparison to the respective transmission pulses (SI) emitted is of such a magnitude that these reception signals (EI) result exclusively from reflections against objects from a selected distance range correlating to the chronological offset. Means (DG) are also provided that permit the transmission pulse power to be increased and decreased as the distance range rises and falls.

Abstract: A silent radar system which detects a target and its position without the countermeasure operator located at the target being able to detect the presence of the radar. The silent radar operates by transmitting signals with specific characteristics which allow optimum processing by the radar while taking advantage of the limitations inherent in typical signal receiving equipment. The silent radar transmits low energy per cycle signals which are wideband, purely random noise, e.g. spread spectrum signals.

Abstract: A vehicular radar apparatus comprising a radar beam transmission device and a reception device, and a processing unit for detecting the position of a target object from transmission signals and reception signals. The processing unit has a preceding vehicle judgment circuit for judging if a vehicle travelling in front of a subject vehicle in the same direction is the same vehicle as previously detected or not, and a signal strength comparing device for comparing the signal strength of a current reception signal reflected from the preceding vehicle, with a signal strength of a reception signal reflected from the preceding vehicle a predetermined comparison reference time prior, to thereby calculate a change amount in signal strength.

Abstract: A radar gauge adapted to sense fluid level in a tank and including a radar gauge circuit in which radar transmission and level sampling are controlled by a transmit frequency and a sample frequency respectively. A first frequency separation between first and second frequencies is controlled by a control input. The first and second frequencies can be divided to generate the transmit and sample frequencies, separated by a second frequency separation. At least one frequency difference is evaluated and the evaluation used to generate the control input, stabilizing the first frequency difference, and to correct the gauge output.

Abstract: A system (10) for determining the range between a missile (14) and a target (18) adapted for use with a semi-active missile system. The system (10) includes a first circuit (12) for generating a periodic signal (24) that is periodically frequency modulated. A second circuit (16) determines a closing rate at which the missile 14 is approaching the target 18 via the periodic signal 24. A third circuit (16) determines a value containing information corresponding to the range and the closing rate via the periodic signal. A fourth circuit (16) determines the range from the closing rate and the value. In a specific embodiment, the first circuit (12) includes an illumination system (12). The illumination system (12) includes a periodically modulated carrier signal generator (32) that generates the periodic signal (24). The periodically modulated carrier signal generator (32) includes a frequency source, a frequency modulator, and an illumination system computer.

Abstract: An FM-CW radar apparatus is provided which may be employed in automotive anti-collision or radar cruise control systems. The radar apparatus transmits as a radar wave a high-frequency signal which is so modulated in frequency with a modulating signal as to vary with time in the form of a triangular wave and mixes a received signal with a local signal that is part of the transmitted signal to produce a beat signal consisting of a fundamental frequency component as a function of the distance to and relative speed of a target object. The radar apparatus also includes an amplitude modulator which modulates the amplitude of at least one of the transmitted signal, the received signal, and the local signal in accordance with the modulating signal so that the modulation index falls within a range of zero (0) to one (1). This allows harmonic components with an improved SN ratio to be extracted from the beat signal which may be used in calculating the fundamental frequency component of the beat signal.

Abstract: A process for determining the distance between a distance sensor and an object, wherein an analog input signal is directed to a transmitter of the distance sensor. The transmitter emits a wave which is reflected by the object. A receiver of the distance sensor receives the reflected wave and thereupon emits an analog output signal whose level is dependent upon the distance and/or the type of object. The output signal is amplified by a subsequently added amplifier. The amplifier signal is directed to an analog/digital converter and is converted into a digital signal. The digital signal is directed to an evaluation circuit for the computation of a distance value. The signal amplification of the amplifier is controlled in an adaptively dependent manner on the level of the output signal and/or in a manner dependent on the signal value of an amplification signal made available by the evaluation circuit which is characteristic of an anticipated distance range.

Abstract: A radar apparatus installed on a vehicle includes a transmission section, a reception section and a processing section. The transmission section includes at least a transmission antenna, and emits a transmission wave toward a detection area in front of the vehicle. The transmission wave is reflected by a reflector to produce a reflection wave, and the detection area includes a plurality of sub-areas. The reception section includes at least a reception antenna, and receives and detects the reflection wave. The processing section detects a reflector indication data indicative of a reflector attribute based on the detecting result by the reception section, and then determines whether there is the reflector in the detection area, based on the reflector indication data. Also, the processing section manages the reflector indication data over a management area which is wider than the detection area.

Abstract: A cost-effective ultra-wideband radar system capable of locating nearby buried objects such as reinforcing steel rods, pipes, and other objects buried in concrete, soil, behind walls, or in the air. A sequence of ultra-wideband radar pulses e.g. at a plurality of frequencies in a range of about 2 MHz to about 10 GHz are emitted without a carrier and the system detects deflected pulse energy caused by the transmitted pulse whenever encountering a change in the medium i.e. an air to metal change or concrete to metal change. This reflected energy is detected and visually displayed. The range gate delay of the receiver is continuously varied, thus changing the distance from the unit to where the reflected energy would be potentially detected from the target. By continuously sweeping the "depth" of the scan, the operator need only move the unit in two dimensions across the surface to detect objects buried or hidden at varying depths interior to or behind the surface.

Abstract: A cost-effective ultra-wideband band radar system capable of locating nearby buried objects such as reinforcing steel rods, pipes, and other objects buried in concrete, soil, behind walls, or in the air. A sequence of ultra-wideband band radar pulses are emitted without a carrier and the system detects deflected pulse energy caused by the transmitted pulse whenever encountering a change in the medium i.e. an air to metal change or concrete to metal change. This reflected energy is detected and visually displayed. The range gate delay of the transmitter is continuously varied, thus changing the distance from the unit to where the reflected energy would be potentially detected from the target. The receiver is driven by a fixed delay. By continuously sweeping the "depth" of the scan, the operator need only move the unit in two dimensions across the surface to detect objects buried or hidden at varying depths interior to or behind the surface.

Abstract: A radar device for vehicle use which can be manufactured inexpensively while enhancing its monitoring function for an adjacent object as well as a remote object. The radar device includes a radar module for monitoring an adjacent object having a plurality of adjacent object monitoring antennas, a signal transmitting/receiving section for supplying transmitting signals to the adjacent object monitoring antennas and outputting signals by mixing the transmitting signals with received signals supplied from the adjacent monitoring antennas and a delay circuit inserted between the signal transmitting/receiving section and the adjacent object monitoring antennas. The radar device also includes a module for monitoring a remote object having a remote object monitoring antenna and a signal transmitting/receiving section for supplying transmitting signals to the remote object monitoring antenna and generating signals by mixing the transmitting signals with received signals supplied from the remote monitoring antenna.

Abstract: An FM-CW multibeam radar apparatus includes a plurality of antennas designed to serve both for beam transmission and receiving are arranged in such a manner that radiated beams overlap in part with each other. For sensing a short-distance-away target, a beam is transmitted by means of one of the antennas and a reflected beam is received by a separate adjacent one of the antennas to thereby obtain a beat signal. For sensing a long-distance-away target, one and the same beam transmitter-receiver is used. Upon sensing the short-distance-away target, the per-unit-time amount of change of the frequency of a frequency modulated transmitted signal is set to be larger than that for sensing the long-distance-away target so that a beat signal becomes higher, whereby the distance resolution is improved.

Abstract: A multichannel radar system for use on a motor vehicle has a plurality of transmission and reception channels each composed of an AM or FM signal generator for generating an AM or FM signal including a carrier which is amplitude- or frequency-modulated by a modulation signal, transmission and reception antennas for radiating the generated AM signal and receiving a return signal reflected by an obstacle, an amplifier for amplifying the received return signal, and either a detector for detecting the amplified return signal or a mixer for mixing the amplified return signal with the FM signal generated by the FM signal generator thereby to generate a beat signal. A power supply circuit supplies DC voltages respectively to the AM or FM signal generators and the amplifiers of the respective transmission and reception channels in a time-division multiplex manner at successive times.

Abstract: A cost-effective ultra-wideband radar system capable of locating nearby buried objects such as reinforcing steel rods, pipes, and other objects buried in concrete, soil, behind walls, or in the air. A sequence of ultra-wideband radar pulses are emitted without a carrier and the system detects deflected pulse energy caused by the transmitted pulse whenever encountering a change in the medium i.e. an air to metal change or concrete to metal change. This reflected energy is detected and visually displayed. The range gate delay is continuously varied, thus changing the distance from the unit to where the reflected energy would be potentially detected from the target. By continuously sweeping the "depth" of the scan, the operator need only move the unit in two dimensions across the surface to detect objects buried or hidden at varying depths interior to or behind the surface.

Abstract: A cost-effective ultra-wideband band radar system capable of locating nearby buried objects such as reinforcing steel rods, pipes, and other objects buried in concrete, soil, behind walls, or in the air. A sequence of ultra-wideband band radar pulses are emitted without a carrier and the system detects deflected pulse energy caused by the transmitted pulse whenever encountering a change in the medium i.e. an air to metal change or concrete to metal change. This reflected energy is detected and visually displayed. The range gate delay is continuously varied, thus changing the distance from the unit to where the reflected energy would be potentially detected from the target. By continuously sweeping the "depth" of the scan, the operator need only move the unit in two dimensions across the surface to detect objects buried or hidden at varying depths interior to or behind the surface.

Abstract: A method and apparatus for determining an altitude for a radar fuze. The method includes the steps of receiving a return signal and transmitting a transmitted signal. The return signal and the transmitted signal are mixed and a mixed signal representing an altitude is responsively generated therefrom. The mixed signal is amplified to generate an amplified signal. The amplified signal is filtered to generate a filtered signal which is envelope detected to provide a detected signal responsive to the filtered signal. The detected signal is integrated responsively to the detected signal. The integrated signal level is compared against a track threshold reference signal and a track/no-track comparator signal is provided responsively to the integrated signal level and the track threshold reference signal. System timing is controlled by generating a plurality of control signals responsive to the track/no-track comparator signal and proportional to an altitude.

Abstract: A telemetric process for measuring short distances comprises emitting an electromagnetic signal modulated by a pseudo-random sequence having a number (n) of bits delivered at a clock frequency (fH), correlating the echo detected with the modulated signal time-delayed by known means, and varying the clock frequency, as a function of the correlation measurement, within an operational field divided into a plurality of operating ranges, the number of bits inthe pseudo-random sequence being modified accoridng to the operating range of the clock frequency. The process is particlualry useful for proximity measurement close to a reflecting surface.

Abstract: Range gate delay is effected by serially connected coarse and fine programmable delay lines. The radar transmit trigger pulse is propagated through the programmable delay lines to provide a delayed trigger pulse. The delayed trigger pulse triggers a range gate generator for generating the range gate. The delay effected by the coarse and fine programmable delay lines is controlled from the system CPU. The range gate generator comprises a D-type flip-flop with the Q output thereof connected as the input to a further programmable delay line. The delayed trigger pulse sets the flip-flop and the output of the further programmable delay line resets the flip-flop. The range gate is provided by the Q output of the flip-flop. The width of the range gate is determined by the delay set into the further programmable delay line by the system CPU.

Abstract: Subsurface target identification radar includes an antenna array, a rotary encoder, a radar controller, a polarization switching circuit, and transmitter and receiver circuits. The antenna array is constituted by dipole antennas having plane triangle elements. The antennas are disposed at angular intervals of 120.degree. with respect to a rotated symmetric point of the array. The rotary encoder generates a distance pulse every time the radar travels a presetted distance. The radar controller sequentially generates three switching pulses within one period on the basis of the distance pulse from the rotary encoder. The polarization switching circuit selects an arbitrary dipole antenna as a transmitting antenna from the antenna array, selects an arbitrary dipole antenna, other than the selected antenna, as a receiving antenna, and changes a combination of selected antennas every time the switching pulse is generated by the radar controller.

Abstract: A vehicle near obstacle detection system includes a plurality of radio frequency heads that can transmit and receive both frequency-modulated, continuous wave and two-frequency Doppler radar signals, such that the system operates in frequency-modulated, continuous wave radar mode and in two-frequency Doppler radar mode. The radio frequency heads used for transmitting the radar signals transmit their radar signals in accordance with commands from a system controller. The radio frequency heads are provided at various locations on the vehicle, directed at points around the vehicle which cannot easily be seen by the vehicle operator. The system controller switches between the two radar modes depending on which one is more appropriate to make use of one mode's strengths while avoiding the other mode's weaknesses. When there is no relative movement between objects and the vehicle, the frequency-modulated, continuous wave mode is used.

Abstract: This radar system for measuring the nearest distance "h" comprises transmitting means (9, 7, 5) for transmitting towards an object a frequency-modulated wave, receiving means (15, 17) for receiving the wave after reflection by the object, mixing means (20) for producing a beat-frequency wave between the transmitted wave and the received wave, high-speed digital processing means (30) for effecting a time-frequency transformation operation of the beat-frequency wave; it further comprises management means (50) for providing the user with the value "h" by influencing more specifically the transmitting means and the high-speed digital processing means.

Abstract: To provide stationary or mobile radar with the capability of measuring the true range profile, a radar system includes a voltage oscillator coupled to a duplexer via a pulse modulation circuit. A digital control circuit provides a sweeping 500 Mhz frequency (F) of 6N successive batches of pulses being incremented in steps of F/6N. Returns received in response to each transmitted pulse are then combined in a mixing circuit with the signal from the local oscillator to generate a signal IF; each signal is summed with signals for the same range cell derived from earlier pulses transmitted at the same frequency; thereafter the signals pass through a FFT circuit.To maintain the "dissected" spectrum centered at the 2N.sup.

Abstract: The present radar altimeter operates in accordance with the frequency modulated continuous wave principle in the C-band. The altimeter is constructed with microminiaturized integrated circuits and provides a completely digital signal evaluation and mode control which enables the transmitter to produce a wave-form providing the altimeter with the following advantages. A silent mode during the signal evaluation greatly improves the resistance of the altimeter against electronic countermeasures. The transmitter frequency is stabilized and a compensation for Doppler frequency drift is provided. Further, the altimeter is able to discriminate between intended proper targets on the one hand and false or erroneous targets on the other hand. The altimeter is equipped with a self-testing unit which provides different functions in different modes.

Abstract: A vehicle near-obstacle detector in the form of a diplex Doppler radar system provides range information between a vehicle and an object based on the phase shift between a pair of Doppler signals derived from two transmitted radar signals at slightly different frequencies. A speed dependent error introduced by the time constant of a filter circuit converting duty cycle range information based on the phase shift to an analog signal is compensated by introducing a small time shift in the signal path of one of the Doppler signals to effect a shift in the duty cycle range information.

Abstract: A frequency modulation radio altimeter has a directional antenna which is connected to a transmission-reception switch controlled by a signal generator. The generator delivers periodic signals whose recurrence period is proportional to the delay time of the ground echo. The transmitter includes a radio frequency modulator modulated in frequency by a saw tooth signal whose recurrence period is proportional to the delay time of the ground echo. A homodyne receiver includes circuits for acquiring and tracking the ground echo signal, and supplies an output signal representative of the altitude and a control signal which is supplied to the inputs controlling the recurrence period of the transmission modulator and of the generator controlling the transmission-reception switch.