Abstract: A method and apparatus for determining range of a radar target is provided. Signal samples based on returns of a target during tracking are processed to produce a wideband envelope range estimate for components of target motion. The components of target motion include precession and spin motion. Ambiguous phase values are measured. An unambiguous phase value indicative of range is produced from the wideband envelope range estimate and measured ambiguous phase values.

Abstract: In a radar apparatus, when the width of a target cannot be determined, the width is estimated in such a manner as not to erroneously identify the lane in which the target is traveling. Denoting the actual width of the target by D, the distance to the target by R, and the scanning step width of projection angle by A, the estimated value W for the width of the target is computed in accordance with the equation W=D?2R tan A.

Abstract: A system and method for rapidly determining the source of an incoming projectile applies controlled, active RF energy source(s) to illuminate a target area/projectile, and exploits Doppler induced frequency shifts from multiple receivers to develop a vector solution. The preferred solution applies continuous wave (CW) RF illuminators to flood a local region with a controlled source of radio frequency energy and one or more displaced receiver elements. The system operates multi-statically and as an incoming projectile enters the illuminated region, reflected energy from one or more illuminators is detected by one or more displaced RF receivers. Doppler shifts imparted on the reflected signals are detected by the receivers as the projectile moves through the region. Appropriate processing of the receiver outputs generates Doppler time-frequency profiles that are used to derive an estimate of the projectile flight vector in 3-space (x,y,z).

Abstract: A radar device having means for generating a carrier-frequency signal, means for shaping pulses, means for generating modulated radar pulses from the carrier-frequency signal, means for emitting modulated signals as radar pulses, means for receiving radar pulses and means for processing the received radar pulses. The means for receiving the radar pulses have an array including a plurality of antennas, the means for processing the radar pulses have means for dividing the signal power over at least two different reception branches. Means are provided for generating different directional characteristics in the various reception branches.

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 a position detecting system used to monitor a suspicious person and to give an alarm by using a radar which transmits/receives a microwave or a millimeterwave, the shape of a detectable area of the radar and that of the area to be monitored are not always equal to each other, and thus, an alarm may be erroneously given in response to the object outside the area to be monitored. For its solution, the area to be monitored is surrounded by a plurality of reflectors, and the coordinate values of the reflectors and the detecting object are calculated based on the signals reflected from the reflectors and the detecting object and then compared. When the coordinate value of the detecting object is inside the area to be monitored, it is determined that the detecting object is an intruding person or the like and an alarm is given.

Abstract: The present invention relates to a radar device for forming multi-beams in multiple channels from reflected waves of a transmitted wave by using a minimum number of antennas. The device has: antennas used for both transmission and reception A1-A4; transmission/reception switching means 5 of each antenna; a transmitter 2; and a receiver 4 for receiving the reflected waves of the transmitted wave. The ratio of the distance between adjacent antennas A1 and A2 to the distance between adjacent antennas A2 and A3 or A3 and A4 is 1:2. The transmitted signal is transmitted from each of the antennas selected sequentially and the received signal is processed by DBF in a signal processing controller 1, wherein eleven channels can be implemented by using four antennas and a space for six antennas.

Abstract: An improved method of estimating target elevation angle for dual squinted beam radar systems is disclosed. The target's elevation angle is estimated by receiving complex I/Q data from two receive radar beams and calculating the complex ratio of the complex I/Q data. The calculated complex ratio is compared to a set of previously determined reference complex ratios in complex lookup tables that have been corelated to known target elevation angles.

Abstract: Emitter target range and heading are estimated from bearing measurements enhancing bearings-only estimator convergence to a target track, and permitting optimization of an observer position relative to the target at the end of the total bearing measurement period. One or more estimates of the target range, speed and heading made from bearing measurements before an observer maneuver are used to determine the most appropriate observer maneuver giving complete bearings-only target-motion-analysis observability. A set of parameters characterizing a set of potential emitter signal sources is generated based on measured emitter characteristics. A most probable set of emitter platforms is identified and the emitter operating mode and corresponding platform set are associated with a kinematic regime set. A specific speed or discrete set of speeds best adapted to a set of all possible platform missions, emitter speed as a continuous function of emitter range, and emitter range are all determined.

Abstract: A radar system mounted in a reference vehicle can detect a distance and orientation of a preceding vehicle to thereby compute a relative position of a width center of the preceding vehicle. A curving radius of the reference vehicle is then detected for computing a relative rotation angle between a direction from the reference vehicle and a longitudinal direction of the preceding vehicle. Relationship between a relative rotation angle and a lateral bias of the relative position of the width center is previously prepared in a map. The computed relative rotation angle is applied on the map, so that the corresponding lateral bias is obtained to correct the computed relative position of the width center of the preceding vehicle. Thus, the width center of the preceding vehicle moving in an adjacent lane can be accurately estimated.

Abstract: A combined defense and navigational system on a naval vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.

Abstract: In the on-vehicle radar apparatus of the present invention, the vertical scanning width of the radar beam is narrowed, before the horizontal scanning, thereby avoiding unnecessary data processing and improving the data processing efficiently. Further, the SIN ratio of the target detection signal is increased, thereby stabilizing the distance detection and its accuracy. The vertical scanning antenna is a single travelling wave excitation antenna (TWEA) constructed by a plurality of antenna elements. At the same time, the horizontal scanning antenna is a multi-channel antenna wherein a plurality of TWEAs is assigned to a plurality of horizontal directions. The horizontal scanning angle is arbitrarily widened by increasing the number of TWEAs.

Abstract: A method for determining the position of at least one second transmitting and receiving device (3) in respect of a first transmitting and receiving device in a passive access control system operating in the GHz range, comprising the steps of using a radar method, wherein signals (f1, f2) are received in the first transmitting and receiving device on the left-hand side and right-hand side of a modulation frequency (fmod), determining the distance of two signals (f1, f2) closest to the left-hand side and right-hand side modulation frequency (fmod) wherein the distance is proportional to the distance between the first transmitting and receiving device and at least one second transmitting and receiving device (3), so that multipath propagations are not taken into consideration.

Abstract: A method for tracking a target vehicle through a curve in a roadway is disclosed. The method includes measuring an azimuth angle between the target vehicle and a host vehicle, calculating a relative velocity between the target vehicle and the host vehicle, developing a theoretical relationship, wherein the relationship is a function of the measured azimuth angle and the measured relative velocity, and comparing the developed theoretical relationship with measured relationship between the azimuth angle and the relative velocity. Further, the target vehicle is determined to be in the same lane or path of the host vehicle by evaluating how well the developed theoretical relationship fits the with the measured azimuth angle and calculated relative velocity. Therefore, the present invention determines the path of a target vehicle without relying on inaccurate conventional methods based on the yaw rate of the host vehicle.

Abstract: A system for measuring distance between a first locus and a second locus includes: (a) at least one beacon device; a respective beacon device of the at least one beacon device being situated at the first locus and transmitting a respective electromagnetic signal; and (b) at least one locator device; a respective locator device of the at least one locator device being situated at the second locus and receiving the respective electromagnetic signal. The respective locator device is situated at a distance from the respective beacon device within near-field range of the respective electromagnetic signal. The respective locator device distinguishes at least two characteristics of the respective electromagnetic signal. The respective locator device employs the at least two characteristics to effect the measuring.

Abstract: A system and method for automatically directing a communication antenna to point to a desired wireless communication transceiver, is presented herein. The system includes a position location receiver, which receives signals indicating the position location information of the antenna and a position location transmitter and a processing mechanism, which determines calibration information of the antenna. The calibration information is achieved by first establishing a reference vector between the location of the antenna and position location transmitter and establishing a vector reference space and then calculate the necessary elevation and azimuthal components, within the vector reference space, to identify the proper calibration of the antenna. Once the calibration information has been determined, an alignment mechanism automatically orients the antenna.

Abstract: In a method and system to determine the position of a target by means of an IFF type antenna, the antenna having a given direction of aim, the method comprises a step for combining the distance D from the target to the carrier, the altitude A of the target, the altitude Apf of the carrier equipped with the IFF antenna and the angular error value of the target and the direction of aim of the antenna beam to localize the target with precision.

Abstract: In a method and apparatus for controlling the distance of a vehicle to a vehicle traveling ahead, in which the distance and the relative velocity of the vehicle traveling ahead are measured and the distance, in a distance control mode, is controlled by accelerating or decelerating the vehicle to a preestablished setpoint distance, wherein the deceleration permitted by the distance control process is limited and, in situations in which the setpoint distance cannot be maintained at this limited deceleration, the transition is made from the distance control process to a process limiting the distance to a minimum distance which is smaller than the setpoint distance, and the vehicle, after reaching the minimum distance, is further decelerated, so that the distance once again increases to the setpoint distance.

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

Abstract: An inventive frequency modulated continuous wave (FMCW) radar system realizes both of a quick detection of higher relative speed provisional target and a sure detection of smaller relative speed provisional target. The number of detection cycles used for a paring validity check (a test 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.

Abstract: A ROSAR wire detection method is based upon ROSAR focusing of entire segments of wire. By generating a wire reference signal comprised of a sum of coherent reference signals, the basis for reliable wire detectability is provided.

Abstract: By changing the direction of a detection radio-wave beam within a detection-angle range and by detecting reflected-signal intensities, wherein each of the reflected-signal intensities is detected for each predetermined unit angle, moving averages of the reflected-signal intensities are calculated by using an angular width predetermined for a given distance as an average width. Thus, data of a reflected-signal-intensity distribution is obtained. Accordingly, the direction of a target is detected by finding the direction of the highest reflected-signal intensity.

Abstract: A method for calculating the range to a moving object by way of a sensor that determines the angle of the object. The sensor and the object move relative to one another, and after one measurement the procedure is as follows: on the assumption that the target maintains a constant velocity, a number of possible target ranges are calculated, as well as areas of uncertainty associated with these ranges, so-called “straight trajectory models” (410, 411, 412), on the assumption that the target accelerates, a number of possible target ranges are calculated, as well as areas of uncertainty associated with these ranges, so-called “maneuvering models” (420, 421, 422), a number of the straight trajectory models (410, 411, 412) having a maneuvering model assigned to them.

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

Abstract: This invention relates to an object recognition apparatus. This apparatus comprises an antenna which emits transmission beams toward a plurality of directions; a receiving circuit which receives reflected signals of the transmission beams from predetermined directions; a distance and direction calculation circuit which calculates distance and direction to objects reflecting the transmission beams based on the transmission beams and the reflected signals; an object pattern storage unit which stores range direction patterns of reflected signals obtained in advance with respect to predetermined objects; an object recognition circuit which compares range direction patterns of the reflected signals received by the receiving circuit with respect to the predetermined directions, with the range direction patterns stored in the object pattern storage unit, and which recognize that a pair of reflected signals from two neighboring directions are signals reflected by the same object.

Abstract: A scanning radar system accurately determines the lateral position of a target regardless of the heading of the target.

Abstract: A system and method for detecting and tracking a target object, including the calculation of the target object's altitude, is disclosed. During the processing of signals received by a receiver, the system selectively calculates the altitude of the target object from signals modified by an interference effect pattern formed by the signals broadcast by a transmitter, or from the calculation of geometric shapes associated with three or more transmitters and determining the intersection point of those shapes.

Abstract: By changing the direction of a detection radio-wave beam within a detection-angle range and by detecting reflected-signal intensities, wherein each of the reflected-signal intensities is detected for each predetermined unit angle, moving averages of the reflected-signal intensities are calculated by using an angular width predetermined for a given distance as an average width. Thus, data of a reflected-signal-intensity distribution is obtained. Accordingly, the direction of a target is detected by finding the direction of the highest reflected-signal intensity.

Abstract: A method is described for detecting moving and/or stationary objects in the path of a vehicle, where the distance and velocity of the reflecting object are determined by using a radar sensor, where the frequency of the signal transmitted is modulated in the shape of a ramp according to a multi-ramp method, and some ramps have a lower slope in the frequency curve. The higher spectral components of the mixed signals from the ramps having the lower slope, which are to be assigned to a distance range of the reflecting object which is greater than the distance range belonging to the ramps having the greater slope, are used to determine the distance, speed and angle of objects.

Abstract: In a method for operating a rotating synthetic aperture radar system that works with pulse frequency or in FM-CW operation in order to detect, penetrate and evaluate objects that are located vertically below the helicopter carrying the ROSAR device, pixels are determined using their own specific doppler histories.

Abstract: The method and apparatus for detecting a moving object through a barrier uses radar imaging and a multiplicity of spatially separated antennas to acquire full-waveform radar data that accurately represents the measurement of the propagating wavefield. The data is enhanced by subtracting an estimate of previously recorded background data, and beamforming of the enhanced data is performed to compute an image from the data provided on multiple channels.

Abstract: The invention relates to a method for calculating the range to a moving object by means of a sensor that determines the angle of the object.

Abstract: The Ground Penetrating Radar (GPR) system introduced in this application provides data from an underground medium of the same caliber as that provided by conventional radars in air or space applications. This includes direction as well as distance to all targets, and some indication of target shape and orientation, within a conical volume of the underground having a solid angle of about 90 degrees and a depth of about 100 feet under ideal conditions. The key to this capability is depicted in FIG. 3, and is a hemispheric dome (6) which is placed against the smoothed surface (1) of the underground medium (2), and which has a relative dielectric constant (ER) substantially equal to that of the underground medium (2). A microwave horn antenna (3) is placed against the surface (7) of this dome (6) and moved from side to side (8) causing the radar beam (9) of the horn antenna (3) to systematically scan the entire conical volume. FIG.

Abstract: Interrogators, wireless communication systems, methods of operating an interrogator, methods of monitoring movement of a radio frequency identification device, methods of monitoring movement of a remote communication device and movement monitoring methods are provided. According to one aspect, an interrogator includes communication circuitry configured to output a forward wireless signal to a radio frequency identification device and to receive a return wireless signal from the radio frequency identification device; and a processor coupled with the communication circuitry and configured to process the return wireless signal to monitor movement of the radio frequency identification device.

Abstract: A bistatic passive radar system having a display; a first directional antenna for determining the angle between the reference azimuth of the bistatic passive radar system and the line of sight to a host transmitter; an omnidirectional antenna for receiving reflected radar pulses from targets at any bearing; and a second directional antenna for determining the angle B between the line of sight to the host transmitter and a second line which extends from the bistatic passive radar system to a selected target. The angle of the second directional antenna is indicated by a B cursor on the display. The system includes a bistatic range correction circuit that utilizes an empirical determination of the distance D between the bistatic passive radar system and the host transmitter for determining the correct range for display of a selected target.

Abstract: A collision warning system (10) discriminates between objects which pose a threat of collision from those which do not by measuring the relative sightline rate of the object, this being a measure of the rate of change of angular position of the object if the sightline rate is above a threshold value, there is little risk of collision. To measure the sightline rate, a radar source (20) emits microwave frequency radiation which is received by two detectors (22 and 24) after reflection from a target. Signals from the detectors are processed by processing means (26). The processing means determines if the sightline rate of an object is below a certain threshold. If it is, and the relative velocities of the object and the system are such that a collision is likely, a warning buzzer (28) sounds.

Abstract: A radar apparatus is provided with signal converting means for FFT-transforming an output signal of reception means for detecting a reception electromagnetic wave; amplitude peak value detecting means for detecting a peak value of an amplitude level from a spectrum made by data converted by this signal converting means; beam scanning means for changing a beam direction of a transmission electromagnetic wave and also a beam direction of the reception electromagnetic wave; and measured-angle processing means operated in such a manner that when the same target object can be detected along a plurality of beam directions which are changed by the beam scanning means, an angle of the target object is calculated by employing the peak value of the amplitude levels along the respective directions, acquired by the amplitude detecting means, whereas when the target object is detectable only along a single beam direction, the angle of the target object is judged as preset angles D1, E1, F1.

Abstract: A signal processing unit detects the azimuthal direction of a target in accordance with the phase difference between signals received by two receiving antennas. Then, by sequentially switching plural transmitting antennas having mutually different beam directions with a switching device, received signals are obtained using each of the transmitting antennas.

Abstract: A search radar including the improvement of apparatus for enhancing the estimation of the target angle within a search scan of the radar is disclosed. More specifically, the improvement apparatus utilizes the generated scan angles and target amplitude measurements correspondingly associated therewith to generate intermediate signals which are representative of the natural logarithm of the target amplitude measurements plus the square of the corresponding scan angle multiplied by a predetermined constant. For each search scan, the apparatus computes separately signals representative of the moments of: the scan angles, the squares of the scan angles, the products of the scan angles and corresponding intermediate signals, and the intermediate signals. In turn, the apparatus operates on the computed moment representative signals in some prespecified mathematical relationship to effect an optimum estimation for the target angle in each search scan of the radar.

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

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

Abstract: An automotive radar incorporates a repetitive randomized equivalent LFM sequence of frequencies for improved immunity to jamming from other automotive radars. Each frequency in the sequence is of sufficient duration to travel round trip over the detection range of the radar. The Doppler shift in the received signal is estimated by performing a spectral analysis on similar frequency components of the received signal, and is then removed from the entire received signal. The received signal is then reordered so as to form an equivalent LFM received signal, and is compared with a similarly reordered image of the transmitted signal so as to estimate the range to the target. The randomization sequence, initial start frequency, or initial start time of the repetitive sequence are varied to minimize the effects of jamming by other radars, and this variation can be directionally dependent.

Abstract: An FM signal generator generates a frequency-swept FM signal, which is radiated as a beam from a transmission and reception antenna. The transmission and reception antenna is angularly moved by an antenna actuator to scan the beam. An echo signal reflected from a target and a signal related to the frequency-swept FM signal are mixed into a beat signal, whose frequency spectrum is analyzed by a frequency analyzer. A target detector determines the distance up to the target based on the frequency spectrum of the beat signal. A BPF processor comprises a bandpass filter which extracts a frequency component corresponding to the distance up to the target from the beat signal. A bearing calculator compares the level of a signal that has passed through the BPF processor with a threshold level to determine a bearing and a width of the target.

Abstract: In a radar system, which is used particularly in motor vehicles, the angle at which a detected radar target is located are determined by providing that echo signals of the radar target are picked up via at least two reception channels, and their amplitudes are standardized and compared with standardized values, stored in memory, of a duplex antenna graph of the radar system.

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

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

Abstract: In a distance measuring apparatus, a large number of distance data within a certain calculation angle region are acquired so as to obtain distance data with high reliability.

Abstract: In a radar target position detecting apparatus, beams (, for example, light beams) irradiated from a transmitter(, for example, LED) have a predetermined divergence angle, a plurality of light (beam) receiving elements such as photodiode arrays each having a different receiving angle (directivity) are arranged in an array form, and a direction of a reflected wave (beam) is identified according to a position of the arrayed beam (wave) receiving elements in the array at which the reflected wave (beam) is captured.

Abstract: A time-sharing FM radar system. A plurality of beam radiating and receiving means, an FM signal generating means, a transmitting unit, a receiving unit, and a direction detecting means are configured to minimize power consumption and interference between channels. The beam radiating and receiving means are arranged to radiate partially overlapping beams in space and to receive return beams. The FM signal generating means generates an FM signal. The transmitting unit includes a plurality of transmitting switching circuits each comprised of a plurality of amplifiers. Each amplifier corresponds to one of the beam radiating and receiving means, and is configured to intermittently amplify and distribute a portion of the FM signal generated by the FM signal generating means to its corresponding beam radiating and receiving means. The receiving unit includes a plurality of receiving switching circuits and a single mixer.