Abstract: A sensing system is provided that includes a first sub-sensing system having a first azimuth plane. The first sub-sensing system includes a Gradient-index lens, and a first plurality of antenna elements arranged adjacent to the Gradient-index lens and configured to receive a first signal emanating from a first field of view. The sensing system also includes a second sub-sensing system having a second azimuth plane oriented at an angle with respect to the first azimuth plane and a second plurality of antenna elements configured to receive a second signal emanating from a second field of view.

Abstract: A device and method used to image conduits, such as pipes, wellbores and tubulars, with imaging sensors, such as cameras and ultrasound arrays. The speed and location of the device are determined using one or more speed sensor modules. Images are then registered to more precise axial locations along the conduit than are normally possible using wireline encoders or other methods. The conduit may be visualized to proper scale for improved analysis of defects.

Abstract: A radio-frequency transceiver device includes a transmission circuit generating a transmission signal at a transmission pad connected to a transmission antenna by modulating a radio frequency signal as a function of a control signal. First and second reception circuits receive first and second signals at first and second reception pads connected to first and second reception antennas. The received first and second signals are demodulated via the radio frequency signal to generate first and second demodulated reception signals. A control circuit operates during a reception test phase to generate only the control signal in order to test, as a function of the first and second demodulated reception signals, whether the received first signal corresponds to the received second signal. A reception error signal indicating a reception error is generated when the test indicates that the received first and second reception signals do not correspond.

Abstract: A radar apparatus includes: a radar transmission signal generator, which in operation, outputs a plurality of radar signals; a switching controller, which in operation, switches among plurality of transmitting antennas in sequence in a determined order to every one radar signal transmission period; and a radio transmitter, which in operation, transmits one radar signal every one radar signal transmission period through a allocated transmitting antenna to which switching has been made. A plurality of transmission timings at which the allocated transmitting antennas to which switching have been made transmit each of the plurality of radar signals within a determined period have identical time differences from a reference timing within the determined period.

Abstract: A method includes forming an output amplitude vector of an array antenna of addition values of a signal incoming wave reception output and a reception system noise output; generating a virtual array antenna output amplitude vector of addition values of a signal incoming wave reception output amplitude and a virtual noise wave reception output amplitude such that array output average power of the virtual noise wave is equivalent to average power of the reception system noise output, and deriving a singular linear equation indicating cause-effect relationship of the concerned generation; deriving a non-singular linear equation from the singular linear equation; and obtaining a signal incoming wave amplitude vector using the non-singular linear equation.

Abstract: A method or system for controlling a vehicle having auto stop and auto start functions includes selectively inhibiting or disabling the auto stop or auto start functions in response to a detected vehicle position relative to an automatically learned vehicle route. The vehicle route is learned in response to previous drive cycles.

Abstract: An alarm system for a vehicle comprises a sensor disposed on an installation plane of the vehicle, configured to emit a plurality of frequency-modulated continuous waveform (FMCW) signals toward a reverse plane of the installation plane and receiving reflected signals of the plurality of FMCW signals, to detect information of a plurality of targets within a specified range corresponding to the vehicle; an alarm being controlled to generate an alarm signal; and a control module coupled to the sensor and the alarm, capable of receiving the information of the plurality of targets detected by the sensor; determining a vehicle information of the vehicle in relation to an external environment according to the information of the plurality of targets; and determining movement statuses of the plurality of targets in relation to the vehicle according to the vehicle information and the information of the plurality of targets, and accordingly controlling the alarm.

Abstract: A speed sensor which aligns a normal direction of one patch antenna which is disposed on a mounted board, and an optical axis of a dielectric lens uses a frame for inclining a sensor module, in order to obtain a component cos ? in a traveling direction when the speed sensor is installed on a horizontally vertical surface of an automobile or a railway car. When beams are condensed by using the one patch antenna and the cannonball-shaped dielectric lens, the dielectric lens is inclined and a bottom surface portion of the lens is cut with a plane parallel with a surface of the antenna-mounted board. The one patch antenna is configured by one patch and a GND electrode and the gain center of radiation characteristics is a normal direction of the antenna board. However, the radiation characteristics have a substantially hemisphere surface wave shape.

Abstract: A method of determining the ground speed or drift angle of an aircraft is described. It is determined whether or not a weather threshold has been met based on returns of a radar beam which is pulse compressed in a first scan. If the weather threshold is determined to have not been met, a ground speed or drift angle of the aircraft is determined based on Doppler processing of radar beam returns of a radar beam in a second scan. If the weather threshold has been met, a bottom radar beam is directed lower to the ground, and a ground speed or drift angle of the aircraft is determined based on Doppler processing returns of the bottom radar beam directed lower to the ground. A corresponding radar system is also described.

Abstract: A traffic collision avoidance system (TCAS) based navigation system including a TCAS equipped with a directional antenna, the TCAS configured to generate a RF transmission pattern at a selected frequency, the transmission pattern including a plurality of directional beams, receive a plurality of RF signals reflected from the ground across a selected frequency band, the selected frequency band including the selected frequency, and measure frequency differences between one or more beams of the plurality of RF beams and one or more beams of the plurality of RF signals reflected from the ground, and a computing systems in communication with the TCAS, the computing system configured to calculate a ground speed of the aircraft utilizing the measured frequency differences, calculate a drift angle of the aircraft utilizing the measured plurality of frequency differences, receive a heading reference of the aircraft, and determine an aircraft navigation parameter of the aircraft.

Abstract: The present invention is directed to a radar system that includes an antenna array having a plurality of antenna elements and a plurality of transmit antenna phase centers. A transmitter portion is configured to transmit a plurality of transmit beams characterized by a transmit beam pattern. The transmit beam pattern has a predetermined transmit beamwidth that is a function of the number of orthogonal transmit waveforms. The number of orthogonal transmit waveforms is less than the plurality of antenna elements. A receiver portion is also coupled to the antenna array and is configured to extract a plurality of orthogonal receive signal components from a received signal provided by the antenna array. A plurality of extracted orthogonal receive signal components are digitally beam formed to implement a virtual antenna array and generate a receive signal having a receive beamwidth.

Abstract: A communication system for supporting communications with a target market area. The system includes one or more solar-powered aircraft maintained in, or successively passing through, flight stations or flight patterns around the market area. Each of the aircraft targets limited beamwidth communication antennas on a substantial portion of the target market area. The control system is configured to fly selective flight patterns depending on the aircraft characteristics and the flight conditions. The flight patterns may emphasize high-power-generation patterns such as flying away from the sun for aircraft with wing-mounted solar cells.

Abstract: A radar apparatus is provided which includes a plurality of antennas arranged at unequally spaced intervals in a single row, the plurality of antennas configured to transmit a radio wave as transmitting antennas during continued multiple periods, and receive a reflected radio wave as receiving antennas during the continued multiple periods. A plurality of transceivers are included for transmitting a radio wave from the transmitting antennas and receiving received signals from the receiving antennas, said received signals representing the reflected wave received at the receiving antennas. A signal processing unit is included for selecting a transceiver which transmits a radio wave during each of the continue multiple periods, selecting transceivers which receive the received signals from the receiving antennas during each of the continued multiple periods, and perform digital beam forming with a first receiving signal channel group and a second receiving signal channel group.

Abstract: A radar device capable of detecting a target object by itself only in a range required by a vehicle control system by changing the detection angle depending on the distance without changing the hardware structure is provided. The radar device includes transmitting means for transmitting an electromagnetic wave as a transmission signal, receiving means for receiving the electromagnetic wave reflected from the target object as a reception signal, and signal processing means for detecting a target object existing around the vehicle from the transmission signal and the reception signal, and calculating the relative position and the relative speed between the object and the vehicle. The detection angle is changed depending on the distance for measurement, so that the target object is detected only in a region necessary in operating the vehicle control system.

Abstract: A power gated variable hop cycle beam laydown (700) manifests itself as first cells (C, D) supported by a first hop cycle, second cells (G, H) supported by a second hop cycle, and transition cells (E, F) supported by a transition hop cycle. The transition hop cycle uses power gating to transition the laydown (700) from cells (C, D) operating at the first hop cycle to cells (G, H) operating at the second hop cycle. To this end, the transition hop cycle power gates its downlink beam for a portion of time needed to reduce interference between nearby (e.g., adjacent) cells.

Abstract: This invention provides a ground-speed measuring apparatus for a vehicle that can detect a velocity along the movement of the vehicle (in the fore direction), a velocity across the movement of the vehicle (in the athwartships direction), a side-skid angle of the vehicle, and an angular velocity of the vehicle. A ground-speed measuring apparatus comprising three or more transceivers each of which contains a transmitter for transmitting a wave and a receiver for receiving a reflection of the wave transmitted from the transmitter, wherein at least three of said transceivers are placed outside a cylindrical area whose axis of symmetry passes through a point on the floor of the vehicle, three straight lines which respectively pass through said transceivers perpendicularly thereto intersect with each other or skewed in said cylindrical area, and the transmitter of each transceiver is at a preset angle with the floor of the vehicle.

Abstract: An FM-CW radar includes a transmitting section, a mixing section, an A/D conversion section, a storage unit, and a signal processing section. The transmitting section transmits a continuous wave frequency-modulated with a triangular wave. The mixing section mixes the continuous wave transmitted and a reflected wave from a target, to generate a beat wave. The A/D conversion section A/D converts the beat wave into digital data. The storage unit includes a first storage section and a second storage section. The signal processing section reads data from the first storage section to process the read data. The A/D conversion section writes the digital data into the second storage section. The control section switches the first storage section and the second storage section alternately in synchronous with switching between up and down of the triangular wave.

Abstract: A sensor system on motor vehicles for locating objects in front of the vehicle, wherein at least two sensors, each having a locating depth of at least 50 m, are arranged in such a way on both sides of longitudinal center axis of the vehicle that their locating angular ranges together cover the entire vehicle width as of a first distance d1, and overlap each other as of a second distance d2.

Abstract: The present invention relates to a radar apparatus that forms multiple digital beams based on reflected waves of a transmitted radio wave. A transmit signal is transmitted in a predetermined cycle from one of transmitting/receiving antennas A1 to A4 arrayed in a row. The antennas A1 to A4, each switched between transmission and reception, are arranged such that the ratio of the spacing between one pair of adjacent antennas to the spacing between the other pair of adjacent antennas is 1:2. The reflected waves are received by the respective antennas, and DBF is performed based on the resulting received signals. Eleven-channel DBF is achieved using the four antennas with a space equivalent to six antennas. By achieving multiple channels with a minimum number of antennas, the size and cost of the apparatus can be reduced while also reducing the processing time and thus enhancing the performance.

Abstract: The present invention relates to a method and apparatus for pointing the beams (63–67) of a wind profiler comprising a stationary antenna matrix (61) with several individual antenna elements (62). According to the method an input signal is fed to the antenna matrix (61), and the phase of the input signal is adjusted for the individual antenna elements (62) in order to point the beam (63–67) of the profiler. In accordance with the invention separate feeder lines for each beam are used for feeding the signals to the antenna elements (62), and the phase differences between the individual antenna elements (62) are controlled with hybrid coupler elements (3, 4).

Abstract: Radar sensor for motor vehicles, having a transmitter and receiver unit whose directional characteristic has multiple lobes, at least one of which is directed parallel to the roadway surface, at least one other lobe being directed obliquely to the roadway surface.

Abstract: To measure the absolute speed of a body 100 moving relative to the ground 33 using an onboard speed sensor 1, a radar wave is transmitted towards the ground by an antenna with a wide aperture angle. The wave reflected by a reflecting obstacle on the ground and the transmitted wave are mixed and the frequency content of the low frequency signal obtained is determined. The speed of the moving object and the height of the transmitter and receiver antennas above the ground can then be measured by adjusting a theoretical curve to the time-varying evolution of the Doppler frequency corresponding to the reflecting obstacle.

Abstract: A device for non-contractual measurement of the speed of an object moving over a surface comprises a means for radiating a signal of fixed frequency at an angle onto the surface in or against the direction of motion, said angle being variable by the movement of the object, and for receiving a Doppler-shifted signal reflected at the surface. A means is provided for combining a plurality of reflected Doppler-shifted signals, which are received in temporal succession, so as to produce a combined spectrum. The device for non-contractual speed measurement additionally comprises a means for detecting from the combined spectrum the spectral portion having the highest or lowest frequency and exceeding a predetermined signal power, and a means for deducing the speed from the frequency of the detected spectral portion.

Abstract: A system and method for identifying the position of an airborne platform on a flight path includes at least three radar transceivers that are directed along respective beam paths to generate return signals. Each of the return signals respectively indicate a speed and a direction of the platform relative to points on the surface of the earth. A computer uses the return signal to establish a ground speed, an altitude and a direction of flight for the platform. This information is then used to identify the position of the platform on its flight path. Additionally, the system can include a last known position, or a site-specific radar clutter model, to establish a start point for the platform. The computer can then calculate the position of the platform relative to the start point.

Abstract: A method and a radar sensor for determining an elevation angle error of a multibeam radar sensor are described. In order to detect an elevation angle of the multibeam radar system with respect to a predefined target, a plurality of laterally arranged cutting planes at a predefined distance are formed. The values of the corresponding antenna diagrams in each plane are stored in a suitable form, for example, normalized and in a parametric form taking into account the elevation angle &agr;. In order to reduce the size of the memory, it is sufficient to store one symmetry half for reasons of symmetry if additional information, for example, road clutter values are added, so that the upward or downward direction of the angle can be recognized. By comparing the measured echo values obtained by normalization and application of a quality factor, a corresponding elevation angle &agr; is obtained for each cutting plane.

Abstract: A microstrip antenna radiates and receives six beams in sequence out of a common aperture and processes return signals with common electronics in order to measure the velocity components relating to a backscattering surface. Sequentially, the first four beams are processed by measuring Doppler shift in a return signal while the last two beams are processed for time correlation. The result of the present invention is a combined time correlation and Doppler measurement velocity sensor available for operation over virtually all terrains and the vehicle speed range.

Abstract: A radar apparatus for preventing a problem due to an abnormal state such as degradation of a transmitting or receiving unit. The apparatus includes a transmitting section including beam transmitting units for radiating a plurality of beams, where adjacent beams have an overlapped portion; and a receiving section including beam receiving units for receiving reflection waves reflected from a target object. Transmitting and receiving combinations between the beam transmitting units and the beam receiving units are determined so as to detect the position of the target object. The apparatus further includes a sensitivity comparing section for comparing sensitivities with respect to the transmitting and receiving combinations; and an abnormal state determination section for determining an abnormal state of any one of the above units based on a result of the comparison of the sensitivity comparing section.

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 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 terrain bias compensator for a Doppler navigation system utilizes an auxiliary beam with each beam of the Doppler system to form Doppler beam pairs. The axis of the auxiliary beam is slightly offset from the axis of the main beam and is positioned so that the two axes are in the same vertical plane. After slant range compensation, the amplitudes of the Doppler spectrum of each beam is averaged over a predetermined time interval. The difference between the mean amplitudes of the two beams is divided by the offset angle to establish an amplitude per degree correction factor which is applied to the main beam signal returns to establish a main beam amplitude corrected Doppler spectrum.

Abstract: A terrain bias compensator for a Doppler navigation system utilizes an auxiliary beam with each beam of the Doppler system to form Doppler beam pairs. The axis of the auxiliary beam is slightly offset from the axis of the main beam and is positioned so that the two axes are in the same vertical plane. After slant range compensation, the amplitudes of the Doppler spectrum of each beam is averaged over a predetermined time interval. The difference between the mean amplitudes of the two beams is divided by the offset angle to establish an amplitude per degree correction factor which is applied to the main beam signal returns to establish a main beam amplitude corrected Doppler spectrum.

Abstract: An angular velocity calculating apparatus which is low-priced and capable of obtaining an angular velocity with high accuracy is realized. Two velocity detectors which are substantially small in offset error, noise, or the like, unlike the conventionally employed gyroscope, is disposed at portions on the moving matter or in the vicinity thereof, and the angular velocity is obtained on the basis of the velocity information obtained from these detectors. Accordingly, the angular velocity calculating apparatus and a navigation apparatus can be realized which is higher in accuracy and cheaper as compared with the conventional ones.

Abstract: A measurement device (103) and method determines various metrics between a vehicle (101) and a ground surface (105) using a transmitter-antenna (109) for emitting energy including a portion directed down toward the ground surface. A receiving antenna (115), has a portion oriented facing toward the transmitter-antenna for receiving a portion of the emitting energy along a direct path (117), and a portion oriented facing downwardly toward the ground surface for receiving a portion of the emitting energy reflected from the ground surface along a reflected path (113). A decoder provides separate indications of forward (121) and sideward (123) velocity relative to motion of the vehicle along the ground surface.

Abstract: A multibeam radar system. A matrix or inverse matrix indicating the characteristics of beams of ultrasonic waves or radio waves are previously created for each individual scanning direction (channel) and stored in a memory. Physical quantities corresponding to the intensities of echo signals and to the distance to an object are detected, and temporarily stored in another memory together with the corresponding scanning directions. Those of the temporarily stored data items which represent physical quantities corresponding to the same distance are arranged in rows or columns corresponding to the scanning directions. Inverse calculation processing, or deconvolution processing, is performed according to the matrix or inverse matrix indicating the beam characteristics. In this way, the reception level is corrected.

Abstract: A speed detecting apparatus mounted on an object moving on the ground detects a Doppler frequency for computing a moving speed thereof by receiving reflection waves of a microwave signal or a millimeter wave transmitted to the ground. The apparatus comprises a plurality of transmitting/receiving systems each having an antenna and a transmitter/receiver, and a signal processing section for computing moving speed according to Doppler frequency detected by the transmitting/receiving systems. Directivity of an antenna provided in each of the plurality of transmitting/receiving systems is set at a different angle respectively.

Abstract: A continuous wave Doppler radar system having a transmitter module and a receiver module is provided for automotive vehicles. Each module includes an antenna system, including a horn, a lens, and a waveguide system, which is attached to a monolithic microwave integrated circuit (MMIC) chip that provides all necessary electronic functions. Each MMIC chip may be attached to a metal base heat sink, which may be conveniently connected to a base plate heat sink that holds the entire radar assembly. The transmitter module includes a voltage controlled oscillator (VCO) that generates a VCO frequency signal which is amplified and switched sequentially to three multiplier chains for transmission in three different directions. Each transmit signal is taken off the MMIC chip by a dielectric waveguide and directed to the antenna system. The receiver module includes three receivers that are selected sequentially to provide a beam azimuth scanning function.

Abstract: Satellite radar apparatus measures the backscatter coefficient of the sea to determine the speeds and directions of winds at sea. The apparatus implements three aiming directions per swath with the track thereof on the Earth being parallel. The radar technique used operates by pulse compression, and on reception noise is measured in parallel with the measurement of signal plus noise. The apparatus includes an assembly for calibrating the product of transmission power multiplied by reception gain, which assembly includes a servo-control loop connected to the transmission line via a directional coupler.

Abstract: A Doppler radar speed sensor for a land vehicle comprises a radar transmitter/receiver circuit (1) coupled to an aerial system (2). R.F. energy from a source (3) is transmitted by the aerial system in forward (9) and backward (10) directions and energy reflected from these directions is mixed with a sample of the transmitted energy in a mixer arrangement (8) to yield a pair of Doppler frequency components representative of the vehicle speed. In order to ensure that these components always have mutually different frequencies, and thereby avoid the necessity of constructing the mixer arrangement as a pair of quadrature-related mixers, the forward and backward directions make different angles (.theta.+.DELTA..theta. and .theta.-.DELTA..theta. respectively) with the direction of travel (15).

Abstract: A method for preventing errors in the Doppler radar measurement of velocity in aircraft that result from the radar receiver being locked to backscatter from side lobes of a plurality of main lobes radiated in a fixed radiation geometry. The inertial vertical velocity component (V.sub.IZ) obtained by a baro-inertial control loop is compared with the vertical velocity component (V.sub.DZ) determined from the Doppler frequencies to derive an error detection signal. When the error signal occurs, the inertial vertical velocity component replaces the corresponding velocity component supplied from the Doppler system while the horizontal velocity components are determined, for example, from the last calculated wind and the corresponding airspeed components, for the duration of the error signal.

Abstract: A method for measuring a vehicle's own speed by the Doppler radar principle, in accordance with which microwaves of a transmission frequency are sent out by the vehicle, a part thereof being reflected back and mixed with the microwave signal at transmission frequency. In this way Doppler signals are produced which, after pulse formation, are evaluated as Doppler pulse signals by a frequency measurement in the time range plus direction-of-travel evaluation, so as to form digital Doppler signal values. For the determination of a mean Doppler period in each case, a median M(n-3) is continuously determined from a predetermined number of the last generated digital Doppler signal values of the sequence M(n-1), M(n-2), M(n-3), M(n-4), M(n-5).

Abstract: An arrangement for measuring speeds between a first and a second object with the aid of microwave signals and including a microwave generator which is connected to a transmitter antenna, and two receiver antennae which are preferably placed on respective sides of the transmitter antenna for receiving microwave signals reflected against an object and each of which receiver antennae is connected to a respective receiver channel, the channels being connected to a correlator for correlating the signals received by the receiver antennae, the mutual time difference of said signals corresponding to the relative speed between the objects. According to the invention the microwave generator (11) is also connected to a respective mixer (13, 14, 15, 16) in each of the receiver channels, to which respective mixers (13-16) respective receiver antennae (6, 7) are connected.

Abstract: Contactless measurement of the distance traveled by a vehicle during selected time intervals is provided by a device operating on the Doppler principle. The device has a "phase-locked loop" circuit which generates pulse signals having a frequency proportional to the vehicle velocity. Using the pulses as path length increases, the pulses are added in a counter and the counter output is supplied to an indicating unit to indicate the distance traveled by the vehicle.

Abstract: A side-looking array antenna system is disclosed in which the inclination angle of the antenna main beam is determined depending on the intervals of a plurality of antenna elements forming an array. A switch is provided to selectively connect one of the ports of an antenna feeder to a signal source or the like. The switch is used to select one of the ports of the antenna feeder as an excitation port, thereby reversing the direction of inclination of the antenna main beam. The antenna main beam can thus be directed in either of the two directions by the operation of the switch. Also, by using this antenna system, a Doppler radar vehicle speedometer with small calculation error, automotive radar and the like may be simply configured.

Abstract: The invention concerns a Doppler radar kinemometer intended to measure the speed of a railway vehicle. According to the invention, it includes two antennas (1,2) mechanically connected to one another such that their axes form a determined angle between them. This angle is preferably between 60.degree. and 120.degree.. For safety operation, the antennas are each supplied with ultrahigh frequency waves (F1,F2) by their own wave generators (4,5), and each furnishes corresponding Doppler frequencies (Fd1,Fd2) to a distinct processing unit (11,12), with the signals coming from these two processing units then processed within a computing assembly (15) which supplies the value of the measured velocity.

Abstract: A gamma feed microstrip antenna for a Doppler navigation system includes a forward firing feed parallel spaced to a backward firing feed. A plurality of parallel spaced radiating arrays are transversely connected between the feeds. Each array includes radiating elements of preselected sizes having radiating coefficients and coupling coefficients to the feeds whereby an amplitude function of the antenna along the axis of travel is a truncation of a long slanted array amplitude function. Sequential excitation of four input ports at the ends of the feeds causes sequential generation of four beams. Return signals to the antenna, at the four input ports, may be sampled and held for averaging. This antenna structure is adapted for use to as to provide frequency, temperature and over-water corrections.

Abstract: A vehicle speedometer is disclosed which accurately measures vehicle velocity despite significant vehicle vibration, which causes variation of the angle of incidence of the measuring wave. Two transceivers are mounted on the vehicle, along with means to determine a frequency difference and an angle variation, both being used in an accurate velocity determination.

Abstract: A radar system includes a clock for generating timing signals of a predetermined period, an exciter for generating high frequency signals of predetermined frequencies in sequence and in time series in response to the timing signals, a transfer switch and an antenna. The transfer switch has an input terminal and a plurality of output terminals. The input terminal receives the high frequency signals and provides one of these high frequency signals at each of its outputs in accordance with the received timing signals. The antenna is connected to receive the high frequency signals from the output terminals of the transfer switch to form radar beams corresponding to the high frequency signals.

Abstract: A Doppler radar system for mounting on a vehicle to sense the speed of movement of the vehicle and to provide an output proportional to the speed of the vehicle. The output is substantially free from errors due to the vibration and of the vehicle. A Janus configuration is also provided which also eliminates errors due to the angle of tilt of the vehicle.