Abstract: A measuring apparatus for measuring a distance from an object to be measured has, a transmitting means for alternately modulating amplitudes of a first continuous wave having a first frequency and a second continuous wave having a second frequency for transmitting a transmission signal as a carrier wave using an AM signal. The AM signal is produced by an AM producing circuit for modulating the amplitudes. The transmission signal is reflected as a reflection signal by the object to be measured and received by a receiving circuit. A first distance calculating circuit calculates the distance using a phase difference between the first and second continuous waves. A second distance calculating circuit is used for demodulating the receipt signal, detecting a phase difference, and calculating a distance from the object to be measured using the detected phase difference. A determining circuit determines a final distance measurement based on the above calculations.

Abstract: For an angle-resolving antenna system, only two radar sensors are provided including separate transmitting and receiving antennas. The receiving antennas of the two radar sensors are switchable with reference to their main beam direction as well as to their beam width.

Abstract: A method of detecting radar returns and measuring their parameters with or without clutter present and no clutter cancellation employed which includes transmitting at least one pulse; processing the returns surpassing a threshold detected in one range azimuth bin and by processing and separating out the returns based on their different range and azimuth. Another method includes transmission of many pulses and has minimum of one channel return surpassing detected threshold, which is detected in one range Doppler bin. The method also includes processing and thereby separating out the returns based on their different radial velocity and or azimuth and comparing the returns to a database of expected returns and adaptively processing returns that do not correspond to the expected returns. The method identifies the non-corresponding returns as indicative of at least one of clutter, land sea interface, clutter discretes and antenna sidelobe returns each without utilizing clutter cancellation.

Abstract: A method for maintaining a position of a hovering vehicle that incorporates a radar altimeter is described. The method includes receiving signals at the radar altimeter based on a change of horizontal direction, operating the radar altimeter to generate a Doppler frequency spectrum based on the received signals, and determining a change in vehicle direction and velocity which will reduce a width of the Doppler frequency spectrum of the received signals. A radar altimeter which generates the Doppler frequency spectrum is also described.

Abstract: Unknown alignment biases of sensors of a tracking system are estimated by an iterative Kalman filter method. Current measurements are corrected for known alignment errors and previously estimated alignment biases. The filter time reference is updated to produce estimated target state derivative vectors. A Jacobian of the state dynamics equation is determined, which provides for observability into the sensor alignment bias through gravitational and coriolis forces. The target state transition matrix and the target error covariance matrix are propagated. When a new measurement becomes available, the Kalman gain matrix is determined, the state vector and covariance measurements are updated, and sensor alignment biases are estimated. The state vector, covariance measurements, and estimated sensor alignment biases are transformed to an estimated stable space frame for use in tracking the target and updating the next iteration.

Abstract: Systems and methods for detecting targets using pulse-compressed radar signals are disclosed. In one application, relatively small targets that are masked by the time-sidelobes of a larger target's return signal can be detected. The methods include a signal expansion type algorithm that is used to process the pulse-compressed return signal. Specifically, a generalized Fourier expansion expression having a summation of PSF terms is used to expand the pulse-compressed signal. Each term represents a respective target and includes a point spread function and a complex coefficient. The signal expansion procedure can be used to determine a set of optimum complex coefficients, with one coefficient for each range bin. Doppler frequency can be used together with range to optimize the complex coefficients. Next, targets are detected by analyzing each range bin to determine whether the corresponding complex coefficient has an absolute magnitude greater than a pre-determined threshold.

Abstract: A radar apparatus calculates distances or relative speeds of a target according to a plurality of formulae. An predicted distance calculation formula is obtained at the following observation from the distances or the relative speeds thus calculated. A determination is made as to whether the distance calculation formula at the current observation is equal to the predicted distance calculation formula, and only when they are equal to each other, the result of the calculation is output. A distance, a relative speed and a distance calculation formula at the following observation are calculated, and a determination is made as to whether there is a correlation between the result at the current observation and the result of the prediction section. Only the result of the calculation at the current time point is output in the presence of a correlation.

Abstract: In an FM-CW radar system, a frequency modulating said modulating wave output from said modulating signal generator has a frequency variation skew with respect to a time axis (modulation skew), and the radar system includes a means for varying the modulation skew by controlling the modulation frequency amplitude or modulation period of the modulating signal. The radar system further includes a means for discriminating a signal component varying in response to the variation of the modulation skew, thereby discriminating a signal related to a target object from other signals. In the case of an FM-CW radar system that performs transmission and/or reception by time division ON-OFF control the radar system includes a means for discriminating a signal which, when the frequency used to perform the ON OFF control is varied, varies in response to the variation of the frequency, thereby discriminating a signal related to a target object from other signals.

Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.

Abstract: A synthetic aperture radar (SAR) system having a single phase center antenna is provided, the SAR system including a measurement unit and a tracker unit. The measurement unit is capable of receiving a phase history of a target point scatterer. From the phase history, then, the measurement unit is capable of estimating a ground position, velocity and acceleration of the target to thereby detect the target. The tracker unit, in turn, is capable of updating the ground position, velocity and acceleration of the target to thereby track the target based upon the ground position, velocity and acceleration. In this regard, the tracker unit is capable of updating the ground position, velocity and acceleration using a Kalman filter.

Abstract: A radar equipment of the present invention amplifies a reception signal with feedback based on the delay amount obtained from the correlation detection result. Accordingly, it becomes possible to maintain the reception signal (demodulated signal) level to a proper level depending on the distance to the target, and accurate measurement can be achieved with high precision. Namely, the reception signal is amplified depending on the distance to the target, and the reception signal level is made within a tolerable input level range of a logic circuit for performing correlation calculation. In particular, during tracking the target, even when a reflected signal is received with abrupt level variation caused by noise or a reflected signal from an object other than the target, incorrect detection of the target can be avoided by disabling the correlation calculation.

Abstract: A vehicle positioning and tracking radar system includes a rotating antenna with a pair of spatially separated transmit feeds for simultaneously transmitting a pair of frequency-modulated continuous-wave (FMCW) electromagnetic signals having a first polarisation and a pair of spatially separated receive feeds for receiving an electromagnetic signal having a second polarisation, wherein the first and second polarisations are different from one another, such that the transmit feed and receive feed at the rotating antenna are isolated from each other; and a coded modulated transponder receives transmit signals from the rotating antenna with the first polarization and transmits a receive signal to the rotating antenna with the second polarization.

Abstract: The invention relates to a method for detecting the passage by a vehicle of a determined point for monitoring on a road, wherein from a remotely situated location a radar beam is transmitted continuously to the point for monitoring, reflections from the transmitted radar beam are received at the remotely situated location, and it is determined from the received reflections that the vehicle is passing the point for monitoring. The radar beam can herein be transmitted at an acute angle to the travel direction of the passing vehicle. The detection can be used to activate a red-light camera, to measure the speed of the vehicle or measure the traffic intensity, without sensors, for instance induction loops, having to be arranged in the road for this purpose.

Abstract: A target tracking arrangement predicts the state of a target. The predictor may be a Kalman filter. In the presence of a target which is maneuvering, the prediction may be in error. A maneuver detector is coupled to receive residuals representing the difference between the predictions and the target state. The maneuver detector is matched to the predictor or Kalman filter to thereby tend to reduce the undesirable effects of system noise. The matching may be of the frequency response.

Abstract: In an FM-CW radar system, a frequency modulating said modulating wave output from said modulating signal generator has a frequency variation skew with respect to a time axis (modulation skew), and the radar system includes a means for varying the modulation skew by controlling the modulation frequency amplitude or modulation period of the modulating signal. The radar system further includes a means for discriminating a signal component varying in response to the variation of the modulation skew, thereby discriminating a signal related to a target object from other signals. In the case of an FM-CW radar system that performs transmission and/or reception by time division ON-OFF control the radar system includes a means for discriminating a signal which, when the frequency used to perform the ON OFF control is varied, varies in response to the variation of the frequency, thereby discriminating a signal related to a target object from other signals.

Abstract: In a radio wave radar system using a two-frequency CW modulation method, it is possible to detect a distance between a host vehicle and a forward vehicle and to realize a stable ACC following travel, even in a condition in which the relative speed is 0. By combining the two-frequency CW modulation method with the frequency pulse CW modulation method, that is, by using combination with the two-frequency CW method when the relative speed occurs and the frequency pulse CW method when the relative speed is close to 0, even if the relative speed is 0, the IF signal obtained from the reflected wave from the forward vehicle can be generated to detect the existence of the ACC target vehicle, so that it is possible to realize a stable ACC following travel.

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: A target determination apparatus for determining type of a target, includes a transmission unit, a reception unit, and a determination unit. The transmission unit emits an electromagnetic wave. The reception unit receives the electromagnetic wave reflected at the target to obtain reception information. The determination unit determines the type of the target on the basis of radar cross section obtained from the reception information.

Abstract: The present invention relates to a radar measuring device which, with a simple design, ensures reliable distance determination even when a mixed signal is zero, and a method for operating a radar measuring device. The radar measuring device includes: A high-frequency oscillator (11) which emits two different carrier frequency signals (F1, F2), A first switching device (14) for switching the carrier frequency signals (F1, F2) as a function of first pulse signals (P1) and emitting radar pulse signals (T1, 2), A transmission antenna (16) and a receiving antenna (18), A second switching device (24) for switching the carrier frequency signals as a function of a delayed second pulse signal (P2) and emitting delayed radar pulse signals (S1, 2), A mixing device (21) for mixing received radar signals (R1, 2) with the delayed radar pulse signals (S1, 2) and emitting mixed signals (M1, 2).

Abstract: The present invention provides a method for generating HF signals for determining a distance and/or a speed of an object, having the following steps: generating a pulsed demodulated signal (6?) from a first signal (3) and a second signal (4) in a signal generator (31; 1, 2, M1, 7, 8); with a transmitting device (20), sending the pulsed modulated signal (6?) in the direction of an object (40); with a receiving device (21), receiving a pulsed signal (6?) reflected by the object (40); generating a pulsed demodulated signal (4?) from the received signal (6?) and the first signal (3) in a first signal processor (32; M2, 15); and generating a coherent signal (23) from the pulsed demodulated signal (4?) and the second signal (4) and a noncoherent signal (22) from the pulsed demodulated signal (4?) in a second signal processor (33; M3, 16, 17, 18). The present invention also provides an apparatus for generating HF signals for determining a distance and/or a speed of an object.

Abstract: A system and method for calibrating a vehicular traffic surveillance Doppler radar are disclosed. In one embodiment, a modulation circuit portion generates double-modulated FM signals. An antenna circuit portion transmits the double-modulated FM signals to a target and receives reflected double-modulated FM signals therefrom. A calibration circuit portion responds to the reflected double-modulated FM signals by sending a calibration signal to the modulation circuit. The calibration signal is indicative of a relationship between a first range measurement derived from phase angle measurements associated with the reflected double-modulated FM signals and a second range measurement derived from speed and time measurements associated with the reflected double-modulated FM signals.

Abstract: A target determination apparatus includes a reception unit, a judgment unit, and a determination unit. The reception unit receives a reflection wave from a target. The judgment unit judges as to whether or not a fluctuation state of reception intensity of the reflection wave with time corresponds to a distinction state occurring when the target is a predetermined type, on the basis of information concerning the reception intensity of the reflection wave. The determination unit determines type of the target on the basis of judgment result of the judgment unit.

Abstract: A method for measuring distance and relative speed between two points, one of which is stationary. The method employs a radio signal modulating a periodic pulse train sent from stationary point to a movable point and simultaneously being retransmitted back to the stationary point with both the transmission and the retransmission occurring during exactly the same period of time. The number of pulses sent from the stationary point during that period of time is known. The number of pulses received by the stationary point during the transmission period, being less than all of the pulses sent to the movable point is used to determine the distance. The process is repeated after a precise time period of no transmissions and a new distance is between the points is determined. Knowing the change in distance and the precise time period over which the change occurred, permits a determination of relative speed of the two points.

Abstract: An FM-CW radar detects at least one of the relative distance and the relative speed of a predetermined object based on the frequencies of projection portions observed in the frequency spectrums of beat signals in an ascending-modulation section and a descending-modulation section, where the projection portions are generated by one and the same object. The radar determines the moving speed of a predetermined moving object such as a vehicle or the like having the radar mounted thereon, and the frequency difference between the projection portions observed in the frequency spectrums of the beat signals in the ascending-modulation section and the descending-modulation section is inversely calculated, where the frequency difference corresponds to the stationary object, and a predetermined pair corresponding to the frequency difference is extracted on a priority basis.

Abstract: Disclosed is a radar apparatus equipped with a function for detecting an FM-AM conversion noise peak. When the direction of radiation is swept, any peak whose level remains substantially unchanged is judged to be a peak due to FM-AM conversion noise. Further, when FM modulation is stopped, any peak appearing in a region not lower than 50 kHz is judged to be a noise peak.

Abstract: The invention relates to remote distance measurement by means of a transmitted noise modulated probing signal (E), whereby at least one of a distance (Y(t)) and a velocity (V(t)) in relation to a signal transceiver (200) is determined. The probing of signal (E) is generated on basis of at least one first noise signal (x1(t), x2(t)). The transmitted signal (E) is presumed to be reflected to the signal transceiver (200) via at least one signal reflecting object in the form of an information carrying signal (e). This signal thus constitutes a delayed and possibly doppler shifted version of the transmitted signal (E). Moreover, according to the invention, a second noise signal (x2(t)) is added either to the probing signal (E) before it is transmitted or to the information carrying signal (e) before information pertaining to the reflecting object is derived there from.

Abstract: In an FM-CW radar system, a frequency modulating wave output from said modulating signal generator has a frequency variation skew with respect to a time axis (modulation skew), and the radar system includes a means for varying the modulation skew by controlling the modulation frequency amplitude or modulation period of the modulating signal. The radar system further includes a means for discriminating a signal component varying in response to the variation of the modulation skew, thereby discriminating a signal related to a target object from other signals. In the case of an FM-CW radar system that performs transmission and/or reception by time division ON-OFF control, the radar system includes a means for discriminating a signal which, when the frequency used to perform the ON-OFF control is varied, varies in response to the variation of the frequency, thereby discriminating a signal related to a target object from other signals.

Abstract: Provided is a radar apparatus capable of continuously and stably making a detection of a target even if a reflected wave from a target already detected falls into obscurity due to the presence of low-frequency noises or reflected waves from other targets. An estimated value of information on a target to be obtained when the target is detected in the present cycle are acquired from the target detected in a previous cycle. When a peak compatible with the estimated value is detected in only one of a frequency-rising section and a frequency falling section of a radar wave, if the frequency of the non-detected peak pertains a low-frequency noise domain or if a side-by-side travel flag is set with respect to the target detected in the previous cycle, the non-detected peak is considered as buried by low-frequency noises or peaks of other targets, and a peak pair corresponding to the detected target is extrapolated.

Abstract: A radar device includes a mixer that mixes an output of a transmit antenna 4 and an input of a receive antenna 6, an LPF 8, an A/D converter 9 that samples an output signal of the LPF 8 and subjects the sampled signal to A/D conversion, an FFT processing device 10 that subjects the converted signal to high-speed Fourier transformation, an aliasing discriminating/correcting device that discriminates a signal having a frequency component where aliasing occurs from a result by the FFT processing device 10 and corrects the signal to a signal of a normal frequency component where no aliasing occurs to obtain a distance and relative velocity data of the object, and a target object selecting device that selects necessary data from the distance and relative velocity data of the object which are obtained from the aliasing discriminating/correcting means.

Abstract: A method for determining position and velocity of targets from signals scattered by the targets using a first and a second station each including a transmitter/receiver of electromagnetic or acoustic signals. First, mono-static measurements are carried out from each station, and also a bi-static measurement between the stations. The two mono-static measurements are used to calculate a number of target candidates with 2-dimensional position and 2-dimensional velocity. These target candidates are tested against the result of the bi-static measurement and the target candidates which are found in all measurements with suitable error margins are retained.

Abstract: A sensor front end for an electronic radar sensor is disclosed that provides for a lower parts count while providing technical functionality by using multifunction parts, i.e., parts that are used both in transmitting and receiving. The sensor front end includes a continuous wave signal source that functions as a signal source when the front end is transmitting a signal and as a local oscillator when the front end is receiving a signal. The sensor front end also includes a tri-mode mixer that functions as a phase-modulator and transmit switch when the front end is transmitting a signal and as a mixer/down-converter when the front end is receiving a signal. The sensor front end further includes a common aperture antenna that acts as both a transmitting antenna for transmitting a sensor signal and for receiving a reflected signal from a object.

Abstract: A radar is provided which transmits a radar wave whose frequency is so modulated as to rise, fall, and be kept constant cyclically. The radar uses beat signals produced by the radar wave and radar echoes received by two antennas to produce radar data on a target. When it is impossible to pair frequency peaks of the beat signals in a modulated frequency-rising and -falling ranges, the radar determines that the frequency peaks have arisen from different objects so that they overlap each other and uses frequency peaks of the beat signals in a constant modulated frequency range to acquire the radar data.

Abstract: A sensor front end that is able to discriminate objects based on their range from the sensor and to derive bearing information therefrom. The sensor system may include a signal source for generating source signal; an antenna system for transmitting the source signal to and receiving a reflected signal from the object; wherein the antenna system is configured for introducing a phase shift into either the source signal or the reflected signal to create a plurality of signal patterns; and an information processor programmed to receive the reflected signal and to determine bearing information for the object based on position and phase information in the plurality of signal patterns.

Abstract: In an object-detecting system using an FM-CW wave, points f1 to f4 corresponding to detection peaks of a reflected wave from a road-side object such as guardrail and points m1 and m2 corresponding to detection peaks of a reflected wave from a moving object such as a reflector of a preceding vehicle are indicated on two-dimensional coordinates along with the shape of a road ahead of a subject vehicle. Among the points f1 to f4, m1 and m2, the points f1 to f4 are determined as being provided by the reflected wave from the road-side object, and a distance from the subject vehicle to the object and a speed of the subject vehicle relative the object are calculated using the remaining points m1 and m2 excluding the points f1 to f4. Thus, only the moving object except the road-side object can be detected.

Abstract: To provide a radar system mounted on a vehicle that reliably detects the reception of the interference wave with high-performance and inexpensively. There is provided a radar system mounted on a vehicle for detecting a target object, including a transmitter for transmitting an electromagnetic wave, a receiver for receiving the electromagnetic wave reflected by the target object, a signal processor for measuring a distance between a vehicle of his/her own and the target object and a relative velocity on the basis of the transmitting electromagnetic wave and the receiving electromagnetic wave, and an interference detector for suspending a transmit operation of the transmitter under a control of the signal processor to detect an interference signal from another external device.

Abstract: An inventive frequency modulated continuous wave (FMCW) radar system realizes both a quick detection of a higher relative speed provisional target and a sure detection of a smaller relative speed provisional target. The number of detection cycles used for a paring validity check, used to see if a detected target or a pair of frequencies is an actual target or a pair for an actual target, is set in response to the relative velocity enabling the target information for a target of higher relative velocity to be output more quickly.

Abstract: The system comprises: detector devices (1) operable to provide electrical signals indicative of the relative distance and relative speed of the motor vehicle (V) with respect to a fixed or moving obstacle (O) ahead, and a processing and control unit (ECU) connected to such detector devices (1) as well as to brake actuators (2-4) and arranged to cause activation of the brake actuators (2-4) to effect automatic emergency braking of the motor vehicle (V) when the relative distance between the motor vehicle (V) and an obstacle (O) ahead lies between a first predetermined limit value (dF) equal to the minimum value at which it is still possible to avoid collision by braking and a preselected intermediate value (dE) comprised between said first limit value (dF) and a second limit value (dEcrit) which is less than the said first limit value (df) and is equal to the minimum relative distance value at which it is still possible to follow a path which avoids the obstacle (O), or when the relative distance (dR) becomes

Abstract: The distance and relative speed of an object remote from an observation point determined using a signal form which includes two signals having a predetermined spacing relative to each other. The two signals are transmitted for a certain time interval during which the frequency of the signals is modulated in a stepwise fashion. Additionally, the signal sections of the two signals are transmitted alternately for each step so that there is a predetermined frequency spacing between the signal sections being emitted consecutively.

Abstract: Disclosed is a method of storing data for temporarily storing a plurality of detected data in a data buffer or the like included in a radar used for a vehicle. The radar detects signals reflected from a plurality of target objects so as to obtain a plurality of detected data, and detects the presence of the plurality of target objects on the basis of the plurality of detected data.

Abstract: Disclosed is a radar apparatus which receives a transmitted signal reflected from an object by switching between a plurality of antennas, wherein the plurality of antennas are divided into a plurality of groups, and at least one of the plurality of antennas contained in each of the groups is a common antenna.

Abstract: A radar system is operated by controlling and thereby limiting the mean power of the transmitted signal in response to the mean power of the received signal thereby limiting the power to a predetermined power range. Preferably the power control or regulation is performed by varying the pulse repetition frequency and/or the pulse duration of the transmitter pulses. This method is well suited for operating a motor vehicle range warning system.

Abstract: A method for adaptive target processing in a vehicle the radar involves first detecting targets in the monitored environment with respect to their speed and location in a standard mode of the radar sensor, and then switching to a precision mode, in which the distance measuring range of the radar sensor is adapted to the target surroundings detected in the standard mode. More particularly, the measuring accuracy and/or resolution regarding speed is increased by increasing the time of observation within the distance measuring range adapted to the target surroundings.

Abstract: Disclosed is a radar apparatus equipped with a function for detecting an abnormality of modulation width. Distance rt2 at time t2 is calculated from the values of the distance Rt1 and the relative velocity Vt1 measured at time t1 and the elapsed time t2−t1, and the difference relative to the actual measured value Rt2 is compared with a threshold value C1. If the difference relative to the actual measured value exceeds the threshold value C1, the modulation width is judged to be abnormal.

Abstract: A target determination apparatus for determining type of a target, includes a transmission unit, a reception unit, and a determination unit. The transmission unit emits an electromagnetic wave. The reception unit receives the electromagnetic wave reflected at the target to obtain reception information. The determination unit determines the type of the target on the basis of radar cross section obtained from the reception information.

Abstract: A method for processing pulsed-Doppler radar signals to detect a target includes transmitting radar signals from a radar system according to a predetermined frequency technique including signals having frequency diversity, receiving signals within a frequency band, including a target return signal having a frequency indicative of the velocity of the target, and transforming the target return signal using a Fourier Transform having a variable frequency scale.

Abstract: The present invention provides a method for generating HF signals for determining a distance and/or a speed of an object, having the following steps: generating a pulsed demodulated signal (6′) from a first signal (3) and a second signal (4) in a signal generator (31; 1, 2, M1, 7, 8); with a transmitting device (20), sending the pulsed modulated signal (6′) in the direction of an object (40); with a receiving device (21), receiving a pulsed signal (6″) reflected by the object (40); generating a pulsed demodulated signal (4″) from the received signal (6″) and the first signal (3) in a first signal processor (32; M2, 15); and generating a coherent signal (23) from the pulsed demodulated signal (4″) and the second signal (4) and a noncoherent signal (22) from the pulsed demodulated signal (4″) in a second signal processor (33; M3, 16, 17, 18).

Abstract: In an object-detecting system using an FM-CW wave, points f1 to f4 corresponding to detection peaks of a reflected wave from a road-side object such as guardrail and points m1 and m2 corresponding to detection peaks of a reflected wave from a moving object such as a reflector of a preceding vehicle are indicated on two-dimensional coordinates along with the shape of a road ahead of a subject vehicle. Among the points f1 to f4, m1 and m2, the points f1 to f4 are determined as being provided by the reflected wave from the road-side object, and a distance from the subject vehicle to the object and a speed of the subject vehicle relative the object are calculated using the remaining points m1 and m2 excluding the points f1 to f4. Thus, only the moving object except the road-side object can be detected.

Abstract: A ranging Doppler radar system for identifying, and measuring range, velocity, direction of movement of a vehicle with minimal interference from surrounding environs and with low probability of intercept by the vehicle. The transmitted radar signal is modulated with pseudorandom code which acts as a frequency spreading agent and which allows a radar system to resolve range to targets into discrete “range cells”. Range cells can be grouped to yield a “range segment” which defines a region of roadway, such as a school zone. Traffic can be monitored in all range cells, or only in a predetermined range segment. Maps of traffic flow and vehicle parameters are generated and displayed using radar output parameters. Images representing vehicles violating posted speed limits are identified and highlighted on the traffic flow maps.

Abstract: Disclosed is a radar apparatus equipped with a function for detecting an FM-AM conversion noise peak. When the direction of radiation is swept, any peak whose level remains substantially unchanged is judged to be a peak due to FM-AM conversion noise. Further, when FM modulation is stopped, any peak appearing in a region not lower than 50 kHz is judged to be a noise peak.

Abstract: An uncorrelated clutter noise cancellation method and apparatus employing a measured ambiguity function sample for each randomly-modulated transmission pulse in a randomly-modulated pulsed Doppler radar system. The ambiguity function samples are calculated from a stored copy of the randomly-modulated transmission signal. Estimates of the uncorrelated clutter backscatter are first developed by calculating the amplitude and phase of the radar returns detected in target range and velocity cells corresponding to stationary scatterers. The stationary scatterer contribution to each target cell, computed according to the sample ambiguity function, is then subtracted to eliminate the uncorrelated noise component in the return signal for the target cell. This clutter cancellation technique does not rely on correlations between the randomly-modulated transmission signal and the clutter return signal.