Abstract: An apparatus predicts a turn of a vehicle based on a picked-up image of a forward view of the vehicle. The forward view is imaged by an on-vehicle sensor to repeatedly acquire images. The acquired images include position coordinate information of a light source and information indicating whether the light source is a light source of a preceding vehicle or a light source of an oncoming vehicle. Based on such information, it is determined whether or not the light source is a light source of an oncoming vehicle newly appeared in the images and the light source is in a predetermined area near the left end or in a predetermined area near the right end in the images. When the determination result is affirmative, it is determined that there is a curve in the traveling direction of the vehicle.

Abstract: A radar device including an up-chirp tracking filter that performs a tracking process using a beat frequency at the time of an up-chirp to acquire a beat frequency, a down-chirp tracking filter that performs a tracking process using a beat frequency at the time of a down-chirp to acquire a beat frequency, target detectors that calculate distance and speed estimated values of the target for the chirps from beat frequency time series data about the chirps; an identical target determinator that determines whether or not the target detected for each of the chirps is an identical target using the distance and speed estimated values, and a distance and speed calculator that calculates a distance and a speed of the target using the beat frequency of the target which is determined to be an identical target.

Abstract: The cruise control apparatus includes a headway control means for making a first determination as to whether or not at least one recognized front vehicle running ahead of an own vehicle is a preceding vehicle present in an own-vehicle lane in which the own vehicle is running, performing a headway control to cause the own vehicle to run following the preceding vehicle when the first determination is affirmative, and a vehicle type recognizing means for recognizing a type of the recognized front vehicle. The headway control means is configured to change a way to perform the headway control depending on the type (vehicle size, for example) of the recognized front vehicle.

Abstract: A signal generating method for a radar system includes generating a first chirp signal and a second chirp signal having a first time delay relative to the first chirp signal; and combining the first chirp signal and the second chirp signal to determine a frequency modulated signal, wherein the first chirp signal and the second chirp signal are N-step linear stepped frequency modulated continuous waves having the same frequency modulation bandwidth, such that the frequency modulated signal includes i steps of the first chirp signal in a first duration, an interleaved combination of N?i steps of the first chirp signal and N?i steps of the second chirp signal in a second duration, and i steps of the second chirp signal in a third duration.

Abstract: A method and a device for controlling a seat belt device, which is connected to a seat belt, of a vehicle with a collision detection unit having sensor units for detecting an imminent collision with a collision object external to the vehicle includes classifying the collision object in terms of an object class and a weight class with an object identification unit, determining a value for an accident severity of the imminent collision at least from the object class, the weight class and the speed of the collision object, and from the speed and the mass of the vehicle.

Abstract: There is provided a radar apparatus. An extracting unit extracts a peak signal obtained from a difference frequency between a transmitting signal and a receiving signal during a first period in which the frequency of the transmitting signal ascends and a second period in which the frequency descends. A pairing unit pairs the peak signals of the first and second periods based on a predetermined condition. A deriving unit derives target information including a position of a target based on paired data obtained by pairing the peak signals. The pairing unit selects normal-paired data which is paired in a correct combination, from among the plurality of paired data, based on a plurality of parameter values of the peak signals of the first and second periods which are to be paired, and a discrimination function for discriminating true or false of the pairing.

Abstract: An apparatus for compensating for a beam angle of a multi-layer LiDAR includes: a beam angle calculation unit configured to calculate a distance d calculated by using ground data detected by a ground data detection unit and a beam angle of the multi-layer LiDAR by using a mounting height of the multi-layer LiDAR stored in a storage unit. When the beam angle calculated by a beam angle calculation unit is in a threshold range, a beam angle selection unit selects the calculated beam angle as the beam angle, when a beam angle compensation unit compensates for the initial beam angle by using the beam angle selected by the beam angle selection unit.

Abstract: In an in-vehicle target detecting device, a captured image which is an image capturing an area ahead of the own vehicle is acquired at a predetermined measurement cycle. Radio waves are transmitted and received. Positional information indicating at least an orientation and a distance of at least one target candidate in relation to the own vehicle is acquired. The target candidate reflects radio waves. Image recognition is performed to detect a detection object by searching a predetermined image search area in the captured image. At least an image detection position of the detection object in the captured image is stored. The image search area is set, based on an image-plane measurement position corresponding to a measurement position in the captured image. The measurement position is a position in three-dimensional space of the target candidate indicated by the positional information acquired at a timing at which the captured image is acquired.

Abstract: A negative obstacle detection system for a vehicle comprises a stereo camera mountable to the vehicle to provide a forward facing image and a long range radar mountable to the vehicle to emit a signal in a forward direction from the vehicle. An electronic control unit receives data from the stereo camera and the long range radar to determine if a negative obstacle may be located in a forward proximity to the vehicle.

Abstract: Method in which vehicles are measured repeatedly while traveling through a radar cone, and specific position values are formed so as to be associated with the measurement times. This can be a specific radial distance or a specific object angle. The change over time is analyzed with respect to a section of discontinuity. The length of this section depends upon the length of the vehicle and makes classification possible.

Abstract: A method of a terminal that forms beams and a device for performing beam tracking in a communication system that supports beamforming are provided. The method includes detecting, by the terminal, an object located at a periphery of the terminal and performing beam tracking through beams formed by the terminal, except for a beam that is formed in a direction in which the detected object is located.

Abstract: A direct conversion receiver includes: a high linearity mixer device including a sampler unit charge-sampling an input current according to a sampling frequency, and a buffer unit receiving an output signal from the sampler unit while having a low input impedance, amplifying the received signal, and outputting a current signal; and a filter device decimating an output signal from the mixer device and FIR-filtering the decimated signal.

Abstract: An ultrasonic measurement apparatus is described having a receiving device which determines a measurement sequence relating to a time variation of the period lengths of an ultrasonic signal received from an in-vehicle and/or external ultrasonic transmitter, a comparison device which determines a comparison information item relating to a deviation of the determined measurement sequence from at least one reference sequence, and an evaluation device which determines, taking into consideration the determined comparison information item, an information item relating to a signal form transmitted by the ultrasonic transmitter, a relative speed between the receiving device and the ultrasonic transmitter, a relative speed of at least one reflecting object situated in a transmission path between the receiving device and the ultrasonic transmitter, and/or a shape feature of the at least one reflecting object. A method for evaluating an ultrasonic signal is also described.

Abstract: An autonomous vehicle detects a tailgating vehicle and uses various response mechanisms. A vehicle is identified as a tailgater based on whether its characteristics meet a variable threshold. When the autonomous vehicle is traveling at slower speeds, the threshold is defined in distance. When the autonomous vehicle is traveling at faster speeds, the threshold is defined in time. The autonomous vehicle responds to the tailgater by modifying its driving behavior. In one example, the autonomous vehicle adjusts a headway buffer (defined in time) from another vehicle in front of the autonomous vehicle. In this regard, if the tailgater is T seconds too close to the autonomous vehicle, the autonomous vehicle increases the headway buffer to the vehicle in front of it by some amount relative to T.

Abstract: A driving support system detects a target area ahead of the vehicle, a position or a moving direction, etc. of an object such as a pedestrian or another vehicle by using a camera or radar, as well as determines a probability of collision between the own vehicle and the object based on the position, etc. of the object, and performs a driving support for avoiding the collision when the probability of the collision is high. Further, a sensitivity of determination is set high when the object remains in the target area, or when the object is moving towards the target area, while the sensitivity is set low when the object is not present in the target area, or the object is moving away from the target area.

Abstract: A dump truck includes a body and a plurality of cameras. The body includes an upper deck and a main frame disposed in a longitudinal direction. The cameras are configured and arranged to obtain images to be combined to generate a bird's-eye image to monitor a periphery of the dump truck. The cameras include a front camera, a rear camera and side cameras. The front camera is disposed at the front of the upper deck to obtain an image of an area in front of the body. The rear camera is disposed at a rear end of the main frame to obtain an image of an area in rear of the body. The side cameras are respectively provided on left and right sides of the upper deck to obtain images of an area between diagonally to the front and diagonally to the rear of the body.

Abstract: In an antenna apparatus, a transmitting antenna includes transmitting-side unit antennas arranged in an arranging-direction at transmitting-side arrangement intervals. Receiving antennas are arranged in the arranging-direction at arrangement intervals. Each of the receiving antennas includes receiving-side unit antennas arranged in the arranging-direction at receiving-side arrangement intervals. The receiving-side arrangement interval is larger than the transmitting-side arrangement interval. A transmission- and reception composition characteristic, which is a composition of directivities of the transmitting antenna and receiving antenna, has a main lobe including a detection angle range.

Abstract: There is provided a radar apparatus. A setting unit is configured to set a first range including at least a reference target. A deriving unit is configured to derive a representative position of targets included in the first range on the basis of position information of the targets included in the first range. An acquiring unit is configured to acquire vehicle information indicating that the vehicle is running in a curve-shaped lane or a road shape in front of the vehicle is a curve shape. When the acquiring unit acquires the vehicle information, the setting unit sets a second range wider than the first range and the deriving unit derives a representative position of targets included in the second range on the basis of position information of the targets included in the second range.

Abstract: A sensor calibration system for a mobile machine is disclosed. The sensor calibration system may have a positioning device configured to determine a desired sensing location on the mobile machine, a calibration object, and a sensor configured to sense a characteristic of the calibration object from an actual sensing location on the mobile machine and to generate a corresponding signal. The sensor calibration system may also have a controller in communication with the sensor and the positioning device. The controller may be configured to compare the characteristic sensed from the actual sensing location to a known characteristic associated with the desired sensing location, and to determine a difference between the actual sensing location and the desired sensing location based on the comparison. The controller may further be configured to correct subsequent signals generated by the sensor based on the difference.

Abstract: The invention provides an antenna arrangement for a radar system arranged for coverage of a surveillance area and comprising antenna elements. The antenna elements are arranged to receive a signal transmitted from a transmit antenna of a transmit antenna arrangement and reflected by a target towards the antenna arrangement wherein: • the antenna arrangement comprises at least two non-parallel line arrays, • each antenna element being connected to a receiver where each line array is arranged to create, by using digital beam forming, beams for instantaneous coverage of at least said surveillance area and • within the surveillance area said line arrays are arranged to allow the target position to be limited to one or two crossing areas between at least two beams from different line arrays from which target reflections have been received. The invention also provides a corresponding method and a radar system comprising the antenna arrangement.

Abstract: An adaptive sensing system is configured to acquire sensor data pertaining to objects in the vicinity of a land vehicle. The adaptive sensing system may be configured to identify objects that are at least partially obscured by other objects and, in response, the adaptive sensing system may be configured to modify the configuration of one or more sensors to obtain additional information pertaining to the obscured objects. The adaptive sensing system may comprise and/or be communicatively coupled to a collision detection module, which may use the sensor data acquired by the adaptive sensing system to detect potential collisions.

Abstract: A vehicle control apparatus for implementing inter-vehicle distance control of a subject vehicle carrying the apparatus behind a preceding vehicle based on reflected waves from a target of the preceding vehicle. A target-pair distance is a distance between the target and a non-target reflection point that is closer to the subject vehicle than the target. A corrected distance calculator is configured to, in the presence of the target-pair distance being recognized, calculate a first corrected distance by subtracting the target-pair distance from a detected distance between the target and the subject vehicle, and in the absence of the target-pair distance being recognized, calculate a second corrected distance by subtracting an offset that is the previously set target-pair distance from the detected distance. A controller is configured to implement the inter-vehicle distance control based on the first or second corrected distance depending on the presence or absence of the target-pair distance being recognized.

Abstract: A vehicle control apparatus for implementing inter-vehicle distance control of a subject vehicle carrying the apparatus behind a preceding vehicle based on reflected waves from a target that is a reflecting portion of the preceding vehicle. In the apparatus, a distance estimator is configured to calculate an estimated distance as an inter-vehicle distance between a rear end of the preceding vehicle and the subject vehicle based on an inter-vehicle distance variation calculated based on a relative speed of the target. A target determiner is configured to determine whether or not the target is displaced forward of the rear end of the preceding vehicle. A controller is configured to, when the target of the preceding vehicle is displaced forward of the rear end of the preceding vehicle, implement the inter-vehicle distance control based on the estimated distance calculated by the distance estimator.

Abstract: A blind spot detection system for a vehicle includes a vehicle information detecting module for obtaining at least one vehicle information of the vehicle corresponding to an external environment, an alarm for generating an alarm signal, a plurality of sensors each for emitting a radio signal and receiving a reflecting signal of the transmitted radio signal to detect whether an object exists within a specific range and generate a detection result accordingly, and a control module for controlling the alarm to generate the alarm signal according to the at least one vehicle information and a plurality of detection results generated by the plurality of sensors.

Abstract: There is provided a signal processing device. Data indicative of a past sensing point, and a counter value indicative of existence possibility of the past sensing point are stored in a storage. Whether the past sensing point has continuity to a recent sensing point is determined. The counter value associated with the past sensing point determined as having no continuity to the recent sensing point is decreased. The data is deleted from the storage means when the counter value becomes less than a first threshold value. The sensing point possibly detected by pairing peak signals obtained in first and second periods in a wrong manner is identified as a specific sensing point. A first value is decreased from the counter value associated with the past sensing point, and a second value different from the first value is decreased from the counter value associated with the specific sensing point.

Abstract: A vehicle control apparatus for implementing inter-vehicle distance control of a vehicle carrying the apparatus behind a preceding vehicle. In the apparatus, an offset storage is configured to calculate an offset that is a difference between detected distances to first and second targets, and store the offset associated with the first target forward of the second target. The inter-vehicle distance control may be implemented based on a distance calculated by subtracting the offset from the detected distance to the first target. An offset eraser is configured to, based on the presence or absence of relative displacement between the first and second targets, determine whether or not the first and second targets belong to different vehicles, and when the first and second targets belong to different vehicles, erase the offset stored by the offset storage.

Abstract: A radar apparatus includes a printed circuit board having a top side, on which a radar antenna unit and an RF circuit unit are mounted, and a bottom side, on which a base band circuit unit and a signal processing circuit unit are mounted. A base plate is coupled to the printed circuit board. A protective member is coupled to the top side of the printed circuit board to cover the RF circuit unit in order to protect the RF circuit unit. The protective member has a groove formed on one side thereof, which serves as a passage of a wire for connecting the radar antenna unit and the RF circuit unit mounted on the top side of the printed circuit board.

Abstract: A vehicle system includes a first sensor and a second sensor, each having, respectively, different first and second modalities. A controller includes a processor configured to: receive a first sensor input from the first sensor and a second sensor input from the second sensor; detect, synchronously, first and second observations from, respectively, the first and second sensor inputs; project the detected first and second observations onto a graph network; associate the first and second observations with a target on the graph network, the target having a trajectory on the graph network; select either the first or the second observation as a best observation based on characteristics of the first and second sensors; and estimate a current position of the target by performing a prediction based on the best observation and a current timestamp.

Abstract: A system for preventing vehicle collision according to the present invention includes a steering detection part configured to detect collision with an object, a calculation part configured to calculate a yaw rate of a vehicle and to calculate a target steering angle, a brake control part configured to control a steering operation of the vehicle according to the target steering angle, and a wheel control part interlocked with the brake control part and configured to control the steering operation of the vehicle according to the target steering angle.

Abstract: An on-board radar apparatus includes a transmission wave generating unit configured to generate a first modulated wave, a second modulated wave, and a third modulated wave which are different from each other, a transmitting antenna configured to transmit a transmission wave based on the first modulated wave, the second modulated wave, and the third modulated wave, a receiving antenna unit configured to receive a reception wave arriving by allowing the transmission wave to be reflected by an object, and an azimuth detecting unit configured to detect a signal based on the first modulated wave, the second modulated wave, and the third modulated wave from the reception, wave and to detect an azimuth of the object based on the detected signal.

Abstract: A system and method for providing target selection and threat assessment for vehicle collision avoidance purposes that employ probability analysis of radar scan returns. The system determines a travel path of a host vehicle and provides a radar signal transmitted from a sensor on the host vehicle. The system receives multiple scan return points from detected objects, processes the scan return points to generate a distribution signal defining a contour of each detected object, and processes the scan return points to provide a position, a translation velocity and an angular velocity of each detected object. The system selects the objects that may enter the travel path of the host vehicle, and makes a threat assessment of those objects by comparing a number of scan return points that indicate that the object may enter the travel path to the number of the scan points that are received for that object.

Abstract: A method and apparatus for processing a terahertz frequency electromagnetic beam are disclosed. For example, the method receives the terahertz frequency electromagnetic beam via a metamaterial having a plurality of addressable magnetic elements, where a resonant frequency of each of the plurality of addressable magnetic elements is capable of being programmably changed via an adjustment, and activates selectively a subset of the plurality of addressable magnetic elements to manipulate the terahertz frequency electromagnetic beam.

Abstract: A method for processing signals received by a plurality of receiving antennas in a radar system, for example for road safety, which emits sequences of chirp-modulated signals, wherein the received signals are mixed with local replicas of the transmitted signals so as to generate, for each receiving antenna, a sequence of detection signals. The detection signals are subjected to Fourier-transform processing and beam-forming processing for generating values of range, azimuth, and speed for at least one obstacle or “target” detected by the radar system. The method includes an acquisition process for yielding approximate values of range and azimuth of the obstacle, and a tracking process for yielding accurate range, azimuth and speed values of the obstacle itself.

Abstract: A map generation apparatus includes a memory, and a processor configured to execute a procedure, the procedure including obtaining position data indicating positions of the terminal device during moving of the terminal device, and read-position data indicating a position at which the terminal device has read data from a recording medium during the moving of the terminal device, storing the position data and the read-position data in the memory, generating a map including the positions indicated by the position data, and displaying that an area on a side of the read-position data among areas set based on a path of the positions indicated by the position data is an area of disposition target of the recording medium, on the generated map.

Abstract: An antenna for a radar sensor includes an emitter element, a receiver element, and an anti-reflection element. The emitter element is configured to direct the emitted signal along a boresight that intersects a fascia. The receiver element is configured to detect a reflected signal reflected by an object located beyond the fascia. The anti-reflection element is configured to reduce reflection by the antenna of an early-reflection portion reflected by the fascia.

Abstract: Aspects of the invention relate generally to autonomous vehicles. The features described improve the safety, use, driver experience, and performance of these vehicles by using ground markers to determine the position of the surrounding objects. In particular, the autonomous vehicle is capable of detecting nearby objects, such as vehicles and pedestrians, and is able to determine the position of these objects based on whether they have passed over ground markers.

Abstract: Embodiments of systems and methods for managing multiple overlapping electronic displays are disclosed, including the electronic displays of electronic paper, electronic books, computer monitors, and other electronic display devices. In one embodiment, a method includes sensing an overlap area of a first display and a second display relative to a specified view location, determining a nearest unobstructed display to the specified view location, and displaying within the overlap area of the nearest unobstructed display a highest priority information from among first and second information.

Abstract: A vehicle system for detecting a jamming signal may include a receiver configured to receive a signal, the signal having signal properties. A controller may be in communication with the receiver configured to determine a jamming event probability based at least in part on the signal properties.

Abstract: A signal processor is configured to: derive, using a first process, at least one of a distance and a relative speed included in the object data set; and derive, using a second process different from the first process, at least one of the distance and the relative speed included in the object data set when the distance included in the object data set is below a predetermined distance.

Abstract: In order to provide a front structure, of a vehicle, which prevents reduction in efficiency in cooling an auxiliary component, by using intake air, and suppresses damage to the auxiliary component, which are caused by a millimeter-wave radar in the event of collision, a front structure of the vehicle includes a front right side radar for transmitting and receiving a radio wave to detect obstacles to a front right side of the vehicle, a front left side radar for transmitting and receiving a radio wave to detect obstacles to a front left side of the vehicle, a bumper reinforcement, crash boxes at the left and the right, and a condenser which is cooled by intake air. The front right side radar is arranged to a side farther out than a right end of the condenser, and the front left side radar is arranged to a side farther out than a right end of the condenser.

Abstract: A vehicle-mounted radar apparatus for transmitting radar waves in a forward traveling direction of a vehicle mounting the apparatus thereon (radar-mounting vehicle) and receiving the radar waves reflected from an object to acquire information about the object. In the apparatus, a target detection unit transmits and receives the radar waves to detect positions of targets. A representative target selection unit selects a representative target from the targets detected by the target detection unit. A same-object target selection unit selects targets belonging to the same object as the representative target. An object position determination unit calculates a value of a predefined function of lateral positions of two or more targets of all the targets selected by the same-object target selection unit as a lateral position, along a vehicle-width direction of the radar-mounting vehicle, of the specific reflecting object.

Abstract: A method for monitoring the operability of a fill level sensor acting as a FMCW radar device in which the frequency of a radar signal to be sent from the fill sensor during measurement of a fill level of a medium is modulated with a set of pre-settable measuring parameters and a measured value of the fill level determined from at least one received signal received during measurement of the fill level. The method enables simple automatic monitoring of the operability of a fill level sensor acting as a FMCW radar device in that, during a test phase, the frequency of the radar signal to be sent is modulated with at least one set of pre-settable test parameters and a test measured value is determined from at least one test received signal received during the test phase, which is evaluated to establish the operability of the fill level sensor.

Abstract: A detection and ranging system includes: a signal generator configured to generate M probe signals having different carrier frequencies; M transmitting elements configured to transmit the M probe signals; N receiving elements configured to receive an echo signal from a target; N demodulators provided for the N receiving elements, each of the demodulators being configured to generate a demodulated echo signal by demodulating an echo signal received by a corresponding one of the receiving elements by using at least one of the M probe signals, and to generate M sets of data signals corresponding to the M probe signals by filtering the demodulated echo signal in a frequency domain; and a signal processor configured to detect the target according to M×N sets of data signals generated by the N demodulators.

Abstract: A dedicated short range radar system is provided for use with a GPS system. The radar system includes a transmitter which transmits a microwave radio signal. A receiver is coupled to a horizontally scanning receiver antenna array which receives an echo, if present, from the radio signal transmitted by the transmitter. The radio receiver then generates an output signal representative of the echo. A control circuit then receives the output signal from the antenna array as well as the output signal from the GPS system. The control circuit then varies the mode of operation of the receiver and/or the transmitter as a function of the type of roadway for optimal radar performance.

Abstract: A peak detecting threshold determining method is provided which determines a peak detecting threshold which is used by an FMCW radar in detecting a peak frequency component which appears as representing a target object in a frequency spectrum. A CW radar wave is transmitted to produce a CW noise spectrum. An offset is added to frequency components in a high-frequency region of the CW noise spectrum to define a first distribution as a value of the peak detecting threshold. This enables the value of the peak detecting threshold in the high-frequency region to be determined with high precision by reflecting a receiver noise containing a leakage noise.

Abstract: A tracking control apparatus is configured to include a detection unit that detects an object in front of a host vehicle, and a control unit that, when parallel traveling vehicles which travel in parallel with each other in front of the host vehicle are detected by the detection unit and in a case where a distance between the host vehicle and the parallel traveling vehicles is longer than a separate recognition distance by which a plurality of vehicles in the vehicle-width direction can be separately recognized, presumes that there exists a preceding vehicle between the parallel traveling vehicles and controls traveling of the host vehicle.

Abstract: A radar apparatus includes a transmitter, a receiver, and a signal processor. The transmitter outputs a radar wave. The receiver includes a plurality of receiving antennas and a plurality of receiving devices. Each of the receiving devices mixes a reception signal from the corresponding receiving antenna with a local signal and outputs a beat signal. The signal processor samples the beat signal while selecting one of the receiving devices in order with a selecting period that is less than a half of a sampling period. The signal processor samples the beat signal with the sampling period and derives position information of a target by pair matching of peaks of a rising-modulation signal and a falling-modulation signal of the beat signal.

Abstract: Methods and systems for object and ground segmentation from a sparse one-dimensional range data are described. A computing device may be configured to receive scan data representing points in an environment of a vehicle. The computing device may be configured to determine if a test point in the scan data is likely to be an obstacle or ground by comparing the point to other points in the scan data to determine if specific constraints are violated. Points that do not pass these tests are likely to be above the ground, and therefore likely belong to obstacles.

Abstract: A vehicle surroundings monitoring device for clarifying the accuracy of detection results and providing notification so that a driver can intuitively ascertain the position in which an object exists, the vehicle surroundings monitoring device comprising: an object detection unit for detecting objects in the periphery of a vehicle; a vehicle image generation unit for generating an image of the vehicle with the point of view set above the vehicle; a periphery image generation unit for generating an image of the periphery of the vehicle including the image of the vehicle; a position-calculating unit for calculating a corresponding position in the image of the periphery on the basis of detection results of the object detection unit; and an indicator unit for indicating the corresponding position in the image of the periphery when the degree of confirmation of the detection results of the object detection unit meets or exceeds an assessment threshold, and for indicating the corresponding region in the image of the

Abstract: An example radar apparatus has a transmission frequency modulated by a chirp waveform having three chirp segments, including increasing, decreasing, and a constant frequency segments. The chirp waveform may extend over the full revisit time of the radar beam. The frequency difference between the transmitted and echo signals are determined at least once per chirp segment. Example apparatus include a Doppler radar for vehicle use.