Abstract: Height-wise positions of objects are detected on the basis of distances to the objects from a vehicle, angles of the objects in a width-wise direction of the vehicle, and angles of the objects in a height-wise direction of the vehicle. A plurality of objects, which satisfy conditions predetermined depending on physical characteristics of delineators, are determined to be objects composing a delineator group. When the detected height-wise position of an object in the delineator group which is nearest to the vehicle corresponds to a predetermined value or less, the delineator group is determined to be a delineator group on a road surface. A determination is made as to whether each object in the on-road-surface delineator group is a non-delineator in response to conditions of the detected height-wise positions of the objects in the on-road-surface delineator group.

Abstract: An electronic counter-measure receiver can be colocated with a threat simulator radar, which transmits a radar signal. As a pulsed-Doppler signal, this transmitted radar signal is sampled as a reference signal by the receiver to determine quadrature, coherent matched filter coefficients. A return signal is received and processed with the reference signal as quadrature signal components with the quadrature, coherent matched filter coefficients within a matched filter. The return signal is processed as a first intermediate frequency via a mixer and local oscillator and a second quadrature intermediate frequency via a digital local oscillator and mixer. A fast Fourier transform is performed to determine Doppler information. In a continuous wave transmission for sampling arbitrary but unevenly spaced in time pulses are generated from a pulse generator source internal to the receiver.

Abstract: A radar apparatus is provided which includes a transmitter, a receiver, and a signal processor. The transmitter produces a transmit signal which is so modulated in frequency as to change with time cyclically and transmits the transmit signal as a radar wave. The receiver selectively establishes communication with one of receiving antennas and changes the communications with the receiving antennas in sequence in a cycle shorter than a cycle of a change in the frequency of the transmit signal to supply a series of signal components of input signals produced by the receiving antennas. The receiver mixes the series of signal components with a local signal having the same frequency as that of the transmit signal to produce a beat signal. The signal processor samples the beat signal to analyze frequency components thereof to determine the distance to, relative speed and azimuth of a target.

Abstract: A vehicle follow-up control apparatus includes a distance sensor sensing an actual vehicle-to-vehicle distance from a controlled vehicle to a preceding vehicle, a vehicle speed sensor sensing an actual vehicle speed of the controlled vehicle, and a controller for calculating a desired vehicle speed to be achieved in the controlled vehicle. The desired vehicle speed is calculated in accordance with the actual vehicle-to-vehicle distance, the relative speed and a control gain which is adjusted in accordance with the relative speed.

Abstract: A radar apparatus of the present invention is provided with a reception array antenna having a plurality of antenna elements, a first bearing detector for detecting a bearing of a target by carrying out signal processing on individual element signals received on an element-by-element basis through the respective antenna elements, and a second bearing detector for detecting a bearing of a target by carrying out signal processing different from that of the first bearing detector, on the individual element signals received through the respective antenna elements. Since the radar apparatus is provided with the two detectors of the first bearing detector and second bearing detector as means for acquiring the target bearing, both or either one of the results of detection by the two detectors can be selectively utilized as occasion demands.

Abstract: The present invention is in general related to target type estimation in target tracking systems. The invention enables a low complexity estimation of target type, using, e.g. ESM sensor data, by the introduction of an ambiguity restoring procedure in certain likelihood calculations. The invention further enables the systematic use of target type probability information in the calculation of strobe track crosses and their associated quality which is particularly useful for deghosting purposes. Methods for utilisation of target type probability information in the processes of strobe tracking, association, track quality evaluation and multiple hypothesis tracking are also disclosed.

Abstract: Provided is a radar apparatus for use on a vehicle and for detecting one target or two or more targets present in a scan range by scanning the scan range with a radar beam, which has a means for obtaining prior target data by scanning the scan range with the radar beam, a grouping means for carrying out grouping of the prior target data according to a predetermined condition to obtain group data, and a target recognition means for identifying the group data and prior target data remaining without being grouped, as detection data corresponding to respective targets and carrying out recognition of each target corresponding to each detection data. The grouping means makes provision of a plurality of predetermined conditions, selects one condition or two or more conditions according to position information of prior target data to be grouped, and carries out the grouping based on the condition(s) selected. This radar apparatus for use on the vehicle can accurately perform the grouping of point data.

Abstract: A signal-processing method for a motor-vehicle radar arrangement is specified, which method provides more extensive information on the traffic situation in observation direction by evaluating echo signals deflected at the road surface.

Abstract: A motion detector combines an FCC approved homodyne pulsed range-gated radar (“RGR”) detector (10) and a PIR detector (158). Narrow microwave pulses are transmitted at a predetermined pulse repetition frequency (“PRF”) and the pulses are reflected by a target. The RGR detector senses the presence of moving human sized objects within predetermined ranges. Moving objects beyond the ranges are not sensed. The RGR detector employs a pulsed microwave oscillator (12) that is triggered by a system clock (14) and immediately retriggered after a 3 to 100 nanosecond delay (20). The duration of each pulse is 3 to 20 nanoseconds with a half-sine envelope shape. The RGR employs a homodyne detector (36) and shares an antenna (38) with the transmitter. The receiver range is determined by the delay imposed between the transmitted pulses, the first being a transmitted pulse and the second being a local oscillator pulse. Each received 5.8 GHz pulse is mixed down to a baseband by the homodyne detector.

Abstract: Characteristics of a target are measured by a radar or sonar. Pulses (101, 102, 103) are transmitted and in between (X) the transmissions of pulses a signal is received which depends on the transmitted pulses and on the distribution of the characteristics measured at different ranges. The distribution at different ranges of the characteristics measured is determined by representing it by means of a substantially linear system of equations in which the variables are the values of the characteristics measured at desired ranges, and by solving the system of equations for the variables. The transmitted pulses form a cyclically repeated pulse code or a continuously changing pulse train.

Abstract: In an air traffic control radar system, a processor is described for correlating primary target data received from a target with a target report and a target track, wherein the processor has a search acquisition time that is adapted to the distance of the target from the radar site. The search acquisition time is shorter for more distant targets. The processor can employ a shorter cycle time (time quantum) to establish a correlation between target data and target reports than would otherwise be possible with conventional fixed search acquisition times. The average total dwell time may be reduced while complying with the mandated maximum processing time for more difficult radar reports.

Abstract: The velocity vector of a moving object is precisely determined by using radar measurements of the angle to and the radial speed of a moving object. This can be done in a radar system comprising one or more units. The technique also makes it possible to precisely determine the range to a moving object from a single moving radar unit.

Abstract: A series of police doppler single mode radars and a multimode police doppler radar, all with direction sensing capability are disclosed. A quadrature front end which mixes received RF with a local oscillator to generate two channels of doppler signals, one channel being shifted by an integer multiple of 90 degrees in phase relative to the other by shifting either the RF or the local oscillator signal being fed to one mixer but not the other. The two doppler signals are digitized and the samples are processed by a digital signal processor programmed to find one or more selected target speeds. Single modes disclosed are: stationary strongest target; stationary, fastest target; stationary, strongest and fastest targets; moving, strongest, opposite lane; moving, strongest, same lane; moving, fastest, opposite lane; moving, fastest and strongest, opposite lane; moving, fastest, same lane; moving fastest and strongest, same lane.

Abstract: The present position of a previously recognized stationary object group (SOp) is estimated based on past position data and the movement of the traveling vehicle during a past time (&Dgr;T). A clearance (Mwr, Mwl) between a traveling vehicle (Mx) and an adjacent stationary object group (Mxr, Mxl) is obtained based on the estimated position data. A clearance (Twr, Twl) between a preceding vehicle (Tx) and an adjacent stationary object group (Txr, Txl) is obtained based on the estimated position data and the position data of the preceding vehicle. A same lane judgement is performed to judge whether the traveling vehicle (VM) and the preceding vehicle (VT) are traveling on a same traffic lane based on at least one of the detected clearances (Mwr, Mwl, Twr, Twl).

Abstract: In a method for the probabilistic estimation of measurements, based on a measurement signal in which an interference signal is superimposed on the value to be measured, the measurement signal is sampled at specified chronological intervals. A defined measurement range associated with the value to be measured is divided into discrete values and a model is formed of a process on which the measurement signal is based with discrete states that correspond to the discrete values of the measurement range. In the model, a probability value of the occurrence of each state is assigned for each sampling time, and the value to be measured is determined on the basis of the probability value of at least one state in this model. In addition, for each state of the model at a sampling time, a probability for the state to remain in its current state is determined, as well as a probability for the state to change to another state by the next sampling time.

Abstract: A system is provided for generating multiple frequencies in a specified frequency band, with a specified step size between frequencies, in which the spectral purity of the frequencies is assured. The switching speed between frequencies is very fast, limited only by the speed of the switches used. In one embodiment, only five tones are generated as the base for the rest of the synthesis, in which the relationship of the five tones is f0+/−⅛f0 and +/−{fraction (1/16)}f0. The subject system may be utilized in air defense systems for generating the transmit channels to be able to permit a missile seeker to transmit a signal at the appropriate frequency. In one embodiment, spectral purity is achieved by providing a number of stages of up converting, expanding, and dividing down of an input signal.

Abstract: A method for operating a radar system using at least two antennas provides an increased angular resolution for determining the angular position, radial velocity, and/or distance to a reflection object. A plurality of successive measuring phases are carried out in at least one measuring process. In each measuring phase, operation is repeatedly switched between a transmitting operation in which a transmitted signal pulse is emitted, and a receiving operation in which reflection signals are detected as received signals in the pulse pause interval between successive transmitted pulses. In at least one measuring phase, two different neighboring antennas of the radar system are used respectively as the transmitting antenna for emitting the transmitted signal and as the receiving antenna for detecting the reflected signal. In this manner, the respective receiving antenna monitors only the angular range of overlap between the emitted beam of the transmitting antenna and the field of view of the receiving antenna.

Abstract: A radar is provided, which enables determination of whether a detected target is a false image generated by a side lobe of the beam received by the antenna. In the radar, the first phase difference is obtained by actually calculating the target angle in the angle calculating section, and by supplying the calculated angle to a theoretical formula (with respect to the phase difference) in the first phase-difference calculating section. The second phase difference is directly calculated using actual received signals in the second phase-difference calculating section. These phase differences are compared with each other by the phase-difference calculating section, thereby determining whether the target exists at a side-lobe angle position of the beam received by the receiving antenna, based on a difference between two phase-difference characteristics.

Abstract: The present invention relates to an onboard radar apparatus having a receiving and transmitting device for transmitting electromagnetic waves to objects and receiving the electromagnetic waves reflected by the objects repeatedly, and a signal processing device for repeatedly calculating relative ranges and relative velocities of the objects based on the transmitting electromagnetic waves and the receiving electromagnetic waves, wherein false images are judged by comparing their relative velocities, calculated from differences between the relative ranges of the objects in previous measurement and the relative ranges of the objects in current measurement, with said relative velocities of the objects, calculated based on the transmitting electromagnetic waves and the receiving electromagnetic waves in the current measurement; and thus judged false images are deleted from outputs of the apparatus, whereby the false images are not recognized as target objects and probability of occurrence of false images can be re

Abstract: A scatterometer orbiting around the earth globe comprises a single fanbeam radar antenna which is rotated around a vertical axis, at a slow rotation rate. The antenna foot-print sweeps a circular disc. The slow conical sweep combined with the motion of the satellite on which the scatterometer is mounted results in highly overlapping successive sweeps such that an image pixel is revisited many times during an overpass. The pixels in the radial direction are resolved by range-gating the radar echo. The radar operates in the C-band. The scatterometer is intended, in particular, to determine wind speed and direction over the ocean.

Abstract: A radar system including a means for distinguishing signals returned from (i.e., reflected by) objects that are stationary with respect to earth (i.e., "stationary objects") from signals returned from objects that are moving along with a host vehicle (i.e., the vehicle upon which the radar system is mounted). The system includes a radar antenna having a relatively narrow beam width centered at a "squint" angle .theta.. When the antenna is aimed such that the center of the beam is at a squint angle of .theta.=60.degree., the Doppler frequency of signals that are reflected from targets that are stationary along the roadside is significantly higher than the frequency of signals reflected from targets that are in the blind spot to the right-rear of the host vehicle and which are moving along with the host vehicle.

Abstract: In an FM-CW radar, a receive section has an array antenna in which a plurality of element antennas are arrayed as receive antennas, and a plurality of mixers for generating a beat signal of each channel from a receive signal for each element antenna, and a signal processing section comprises a first device for performing analog-to-digital conversion of the beat signal of each channel into a digital beat signal of each channel and storing it, a second device for performing a Fourier transform process for the digital beat signal of each channel to obtain Fourier transform data of each channel, a third device for performing a phase shift process according to beam direction angles for the Fourier transform data of each channel and thereafter synthesizing the Fourier transform data of each channel every beam direction angle to obtain Fourier transform data of each beam direction angle, and a fourth device for detecting a range to an object and a relative velocity of the object from the Fourier transform data of ea

Abstract: A meteorological radar apparatus which calculates a shift of the pulse synchronization of a transmission pulse signal output from a transmission unit and corrects the transmission timing of the transmission pulse signal based on the shift of the pulse synchronization so that the Doppler velocity of a reference target becomes zero, thereby preventing deterioration in the measurement accuracy of the Doppler velocity caused by the shift of the pulse synchronization of the transmission pulse signal.

Abstract: An FM-CW radar apparatus permits proper pairing between beat frequencies in an up interval and beat frequencies in a down interval and comprises a peak extracting section for extracting level peaks at each scanning angle of beat frequencies, each beat frequency being a frequency difference between a received wave and a transmitted wave, in each of a modulation frequency increasing interval and a modulation frequency decreasing interval; a grouping section for grouping level peaks of approximately equal beat frequencies adjacent in a scanning direction to create level peak groups having respective typical scanning angles, for either of the increasing-interval level peaks and decreasing-interval level peaks thus extracted; a pairing section for pairing a level peak group in the increasing interval with a level peak group in the decreasing interval where the level peak groups have an equal typical scanning angle; and a calculating section for calculating target information from beat frequencies of the increasing

Abstract: A method for measuring the speed (V) of a vehicle (1) relative to the ground, of the type using the deviation in frequency associated with the Doppler effect between a transmitted wave (3) sent by radar (2) solidly connected to the vehicle and a reflected wave (4) reflected by the ground, characterized in that radar of the type allowing simultaneous measurement of the relative distance (D) and the relative speed (V) between the vehicle and the ground is used, and that the distance measurement is used to validate the speed measurement.

Abstract: Level crossing number counter section 115 obtains the Doppler frequency caused by fading by counting the number of times of a received signal crossing an averaged received signal level. Corresponding to the Doppler frequency, reference signal correlation integration control section 116 controls reference signal correlation integration section 311 to suspend and restart the processing of integrating the correlation data of the received signal obtained in reference signal correlation section 306 with a reference signal.

Abstract: A phased array radar system for target tracking having a track initiation unit, a track prediction unit, a scheduling unit, a track selection unit, and a transmitter/receiver unit. The track initiation unit initiates new tracks representing detected aircraft targets. The track prediction unit predicts the expected position and the calculated position uncertainty of the target as a function of time and the minimal, maximal and optimal time difference to the next measurement. The scheduling unit performs an independent calculation of a sequence of possible time intervals to the next measurement in accordance with specified conditions, and then performs an intersection operation between the calculated sequences of time intervals in order to calculate the optimal time interval to the next measurement. A track selection unit selects that track which has the shortest remaining time interval, K.sub.i, to the next measurement and decreases the time interval to the next measurement for all other tracks with K.sub.i.

Abstract: In a vehicle mounted radar apparatus such as a pulse Doppler radar, electromagnetic waves produced by an oscillator can be prevented from returning therefrom a reception system by means of a transmission system. The vehicle mounted radar apparatus includes the oscillator for generating electromagnetic waves, a transmitter for transmitting the electromagnetic waves generated by the oscillator to a target, a receiver for receiving electromagnetic waves reflected from the target, a switch for connecting the transmitter to an antenna during transmission of the electromagnetic waves, and for connecting the antenna to the receiver during reception of the electromagnetic waves, a signal processor for calculating a distance between the vehicle and the target, and also a relative speed between the vehicle and the target based upon the electromagnetic waves transmitted to the target and reflected from the target, and a power supply interrupter for interrupting the supply of voltage to the transmitter.

Abstract: A digital signal processor (DSP) traffic radar utilizing pulses from the patrol vehicle's electronic speedometer to steer the DSP's search of Doppler return information for the patrol vehicle's radar return signal, to improve target identification and minimize inaccuracies. In moving mode, when the patrol vehicle comes to a stop, no pulses are received by the DSP and therefore the patrol speed is set to zero, eliminating false association with other moving targets.

Abstract: A radar data processing method of switching a continuous wave consisting of up phase and down phase into a transmission signal and a local signal in an interrupted manner and using a beat signal between the local signal and a reception signal. The method comprises the steps of setting a range of beat frequencies in up phase used for making a search for a combination and a range of beat frequencies in down phase used for making a search for a combination from beat frequencies corresponding to a distance range to be measured and a predetermined measurement speed range, and making a search for a combination for the same target for the beat frequencies in the up phase and the beat frequencies in the down phase only in the range.

Abstract: A Doppler-based radar system used to determine the speed of a selected moving target includes an array of selectable filters and related method for determining the speed of the selected moving target traveling in the same lane as a moving patrol vehicle supporting the radar system independent of the direction of the target relative to the platform. This allows the speed of the target vehicles traveling in the same lane and in the same direction as the patrol vehicle to be monitored without manual assistance from the operator. The radar system is further adapted in a stationary mode of operation to determine the speed of a selected moving target independent of the location of the patrol vehicle. This is accomplished by selectively filtering either all approaching or receding targets depending upon the traffic scenario.

Abstract: A method for detecting and tracking turns of a maneuvering target comprises the steps of determining first and second radar information of the maneuvering target. The first and second radar information and a set of target speeds are used to determine a set of turn radii for the maneuvering target. The first and second radar information and a set of target arc speeds are used to determine a second set of turn radii for the maneuvering target. The set of turn radii and the set of target speeds define a speed-radius curve, and the second set of turn radii and the set of target arc speeds define an arc speed-radius curve. An intersection of the speed-radius and arc speed-radius curves is located, and the intersection is used to determine whether the maneuvering target has made a turn.

Abstract: A method and apparatus are disclosed for making precise velocity measurements of a spacecraft using a two-way noncoherent Doppler tracking system. The received uplink and transmitted downlink frequencies on-board the spacecraft are compared with the resulting information being included in the downlink signal and used to cancel spacecraft oscillator drift rate effects in the two-way Doppler measurement made by the ground station. The information can also be used to characterize the drift rate of the spacecraft oscillator, thus permitting periods of accurate one-way Doppler tracking by the ground station. To improve accuracy, the times at which the measurements comprising the information would have been observed on the ground are inferred from the measurement of a signal generated by the spacecraft, e.g., the telemetry frame start times, made by the ground station.

Abstract: In an object detecting system for a vehicle to detect an object in accordance with the result of a search operation of the radar, and to allow detection of a deviation of the radar search direction irrespective of the vehicle traveling condition. The stationary object decision unit detects whether or not an object recognized by the object recognition unit as a result of the search operation of the radar is a stationary object. The moving locus of the object, which was determined to be stationary, relative to the vehicle is predicted by the locus prediction unit based on the detected value produced by the motion state detection unit. The actual moving locus of the object, determined as a stationary object, as observed from the vehicle is calculated by the actual locus calculation unit. The predicted value produced by the locus prediction unit and the calculated value produced by the actual locus calculation unit are compared by the comparison device.

Abstract: A radar system for processing a series of radar returns to determine Doppler velocity of an object. Each one of the radar returns is produced in response the object reflecting each one of a series of transmitted radar pulses. The series of radar returns is processed in a sequence of successive dwells. Each one of the dwells has a predetermined number of radar returns. The radar system includes a system clock for producing a series of clock pulses. A range gate is provided for sampling each one of a series of radar returns produced in response to a each one of a series of transmitted radar pulse. The range gate has a time duration equal to an integer number of, N, clock pulse periods. A range gate positioning system initiates the range gate a selected time, .DELTA., after each one of the transmitted pulses. The positioning system determines the selected time, .DELTA.

Abstract: An estimate of the time of the boost engine cut-off of a missile is provided by irradiating the missile after it is launched with continuous wave signals. The reflected continuous wave signals are detected and an inflection in the Doppler measurements of the reflected continuous wave signals provide an initial estimate of the boost engine cut-off time. A Kalman filter is used to provide initial estimates of the position and velocity of the missile at the boost engine cut-off time and a square root information filter responding to the Doppler measurement residuals after boost engine cut-off reduces the error in the initial estimate of the boost engine cut-off time to a minimum.

Abstract: A Doppler shift detector for determining the Doppler shift between a transmit signal and a receive signal uses clocked delay lines. The clocked delay lines count the number of edges in an applied signal thereto (e.g. the receive signal) at various positions in the delay line in accordance with a clock signal. Period detection logic ascertains the mean position of counted edges and thence the period of the applied signal. The Doppler shift is then calculated from the measured periods of the transmit signal and receive signal. The delay line for the receive signal is clocked by either the receive signal itself or the transmit signal.

Abstract: A method and system for determining a modulus of a speed of movement of a carrier of radar, including (a) illuminating a same zone on the ground laterally, with radar of the carrier, at times t.sub.1 and t.sub.2 ; (b) measuring respective distances D.sub.1 and D.sub.2 of the carrier to the same zone at the times t.sub.1 and t.sub.2, and Doppler frequency shifts F.sub.d1 and F.sub.d2 of respective echoes returned by the same zone during the times t.sub.1 and t.sub.2 ; and (c) deducing the modulus .vertline.V.sub.h .vertline. of the speed of movement of the carrier based on a relationship ##EQU1## with .lambda. being a wavelength of a radar wave transmitted by the radar. The method and system require neither the locking of the radar to the carrier nor a course drift of the carrier. In this way, precision is improved and it possible to obtain accurate imaging radar modes having images in which distances can be measured with precision.

Abstract: A method and apparatus for preventing the occurrence of range ambiguities and Doppler ambiguities in both a radar and sonar environment. A series of N pulses are produced, each of which contains a number of contagious subpulses. Each of the subpulses exhibit a different frequency than the remaining subpulses in that particular pulse. Furthermore, the order of appearance of the subpulses in each of the pulses is unique with respect to the remaining pulses in the series. A matched filter receiver and Doppler processor are used to provide auto correlations and cross correlations to prevent the range ambiguities and Doppler ambiguities.

Abstract: In an obstacle recognition system for a vehicle, transmission wave is irradiated per given angle for recognizing an obstacle ahead of the subject vehicle based on angle/distance data obtained from received reflected wave. A position of the obstacle is estimated based on a previously recognized position of the obstacle. The estimated position of the obstacle and an actually recognized position of the obstacle are compared so as to determine whether the obstacle currently recognized is identical with the obstacle previously recognized. Relative acceleration is derived for the obstacle which has been determined plural times to be identical with the previously recognized obstacle. When the derived relative acceleration is outside a given range, the corresponding obstacle is excluded from objects of further obstacle recognition.

Abstract: A pulse detector achieves high accuracy over a wide dynamic range in providing accurately spaced pulse edge markers that allow measurement of pulse to pulse time intervals. Received input pulses are transformed to a Gaussian like waveform and a single cycle AC signal having a first polarity initial half cycle is derived therefrom, accomplished by subtracting the Gaussian like waveform from a delayed, but substantially time overlapping, copy of that waveform. Upon completion of that initial half cycle, a pulse edge marker is generated. By measuring the time between the pulse edge marker obtained from one inputted pulse and that of the next, a measurement of the pulse to pulse interval is achieved that is of one nanosecond in accuracy.

Abstract: A method of determining the velocity of a radar target wherein at least two different pulse repetition frequencies are used. Each pulse repetition frequency comprises a predetermined division into equidistant Doppler numbers. For an echo signal, a Doppler number associated with the echo signal is determined for each pulse repetition frequency. Out of two Doppler numbers associated with different pulse repetition frequencies, a nonambiguous Doppler number is subsequently determined which lies within a predetermined velocity nonambiguity range, and the velocity of the radar target is determined from this Doppler number.

Abstract: Receivers 14 and 16 comprise mixers 14b and 16b for mixing reception signals of receiver antennas 14a and 16a with a transmission signal to generate beat signals B1 and B2, respectively. Signal processing section 20 performs the Fourier transformation of beat signals B1 and B2 supplied from receivers 14 and 16 to obtain the phases of beat signals B1 and B2 and then obtain the azimuth based on the difference of these phases.

Abstract: Beat signals of respective receiver channels CH1 and CH2, produced by mixing their receiving signals with a transmission signal, are subjected to Fourier transformation to detect the frequency and phase of peak frequency components in both an ascending-section where the frequency of the transmission increases and a descending-section where the frequency of the transmission decreases. Based on peak frequency components derived from the same target, phase differences .DELTA..phi.u(i) and .DELTA..phi.d(j) between receiver channels CH1 and CH2 in the ascending- and descending-sections (steps 210-230). Relative relationship between the transmission signal and the receiving signal is judged based on the signs of the phase differences. Respective peak frequencies fu(i) and fd(j), detected as absolute values of frequency differences between the transmission signal and the receiving signal, are given sings in accordance with the judgement result.

Abstract: To measure the speed of a body (1) moving relative to the ground (2) by means of a broad-band Doppler radar (3) fixed to the moving body, two incident radar waves are transmitted successively towards the ground at instants that are close together, and the corresponding reflected waves are picked up, the frequency of at least the first incident wave being time-varying, the signals representative of the first incident and reflected waves are multiplied together, a spectrum is determined for the low frequency component of the product of said two signals, the same operations are performed for second incident and reflected waves, then two peaks that correspond with a certain amount of frequency shift in the two spectra are identified, and the speed of the moving body is determined as a function of the frequencies of these two singular points and as a function of the height of the radar relative to the ground.

Abstract: A method and apparatus are disclosed for making precise velocity measurements of a spacecraft using a two-way noncoherent Doppler tracking system. By comparing the received uplink and transmitted downlink frequencies on-board the spacecraft, information is generated that is included in the downlink signal and used to cancel spacecraft oscillator drift rate effects in the two-way Doppler measurement made by the ground station. This data can also be used to characterize the drift rate of the spacecraft oscillator, thus permitting periods of accurate one-way Doppler tracking by the ground station.

Abstract: An FM-CW radar which is suitable for automotive anti-collision systems, for example, is provided. This radar outputs a radar signal in the form of a triangular wave whose frequency is increased at a given rate and decreased at a given rate. A receiver receives a wave reflected from a target to produce a beat signal and takes the Fourier transform of the beat signal to determine peak frequency components thereof showing peaks in a frequency spectrum. The receiver also determines phases of the peak frequency components and selects at least one from the peak frequency components in a frequency-rising range wherein the frequency of the radar signal is increased and at least one from the peak frequency components in a frequency-falling range wherein the frequency of the radar signal is decreased which show substantially the same phase to pair them for determining the distance to and relative speed of the target based on the frequency of the paired peak frequency components.

Abstract: A police radar utilizing digital data transmission from the antenna unit to a separately housed counting and display unit. The antenna has a double balanced mixer to suppress even order harmonics. The counting and display unit has a computer programmed to perform digital signal processing on the digital data received from the antenna to improve the quality and accuracy of calculated speeds for patrol speed, strongest target speed and fastest target speed. Fastest target speed can be displayed simultaneously with strongest target speed. Signal processing techniques are used to suppress false signals caused by double and triple bounce, harmonics, intermodulation products, video display terminal interference, etc.

Abstract: A method and device of the pulse-compression radar or sonar type which makes it possible to determine the speed of a moving object is provided with a transmitter system, a receiver system, and a signal processing system. The transmitter system is capable of transmitting two associated pulses, one of which is modulated with an increasing variation law and the other of which is modulated with a decreasing variation law. The signal processing system includes two correlators, an adder, a subtractor, and a computer.

Abstract: Range-Doppler ambiguity is eliminated from an ultra-wideband radar system by transmitting an ultra-wideband chirped pulse towards a moving target, and mixing it with the doppler-shifted chirped pulse which is received as a target echo return signal. Multioctave radar tracing systems can potentiality track stealth aircraft without ambiguity since pulses containing many frequencies can defeat narrow-band radar absorbing material coatings. The unambiguous range-doppler signal processing method mixes the chirped pulse to yield an instantaneous Doppler frequency (which indicates target velocity) and a rate of change in the instantaneous Doppler frequency (which indicates target acceleration).