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 plurality of roadside wireless devices are provided on a roadside of an entry of a toll area. A first roadside wireless device, which communicates with a vehicle-mounted device over wireless communication, sends unique information obtained from the vehicle-mounted device to a second roadside wireless device located, downstream to the first roadside wireless device, along a moving direction of the vehicle. The second roadside wireless device checks if unique information on the vehicle-mounted device obtained from the vehicle-mounted device matches the unique information on vehicle-mounted device notified from the first roadside wireless device to judge if the moving direction is a direction of entry into a toll area and charges the vehicle-mounted device for toll only when it is judged that the moving direction is the direction of entry into the toll area.

Abstract: A bistatic radar system (100), method and computer program (178) are provided for mapping of oceanic surface conditions. Generally, the system (100) includes at least one transmitter (102) and at least one receiver (106) located separate from one another, and each having a local oscillator locked to a Global Positioning System (GPS) signal received by a GPS synchronization circuit (134) to provide the necessary coherency between the transmitted and received signals. Preferably, the present invention enables an existing backscatter radar systems to be quickly and inexpensively upgraded to a bistatic radar system (100) through the addition of a transmitter (102) and/or receiver (106) separate from the backscatter radar system, the GPS circuit (134), and use of the computer program (178) and method of the present invention.

Abstract: One of the objects of the present invention is to reduce the size of a radar device mounted on a vehicle body. To achieve the object, one aspect of the invention provides a radar device, which is mounted on a vehicle body and detects a target present in a moving direction of the vehicle body, with (1) a transmitting antenna for transmitting a mm-Wave that forms an electric field having a width equivalent to the width of the vehicle body at a position away in a moving direction of the vehicle body by a distance corresponding to the most-approached distance defined between the vehicle body and the target and (2) two receiving antennas for receiving the reflected mm-Waves at mutually different positions.

Abstract: The present invention relates to a method for determining position and velocity of targets from signals scattered by the targets. One uses a first and a second station comprising transmitter/receiver (s1,s2) of electromagnetic or acoustic signals and carries out mono-static measurements (M1,M2) from each station, and also a bi-static measurement between the stations (B12), and calculates first through the two mono-static measurements a number of target candidates with 2-dimensional position and 2-dimensional velocity, whereupon these are tested against the result of the bi-static measurement and the target candidates which are found In all measurements with suitable error margins are retained.

Abstract: The present invention relates to a system for using signals scattered by targets to determine position and velocity for each of the targets and comprises a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points. Each pair of transmitter and receiver, mono-static or bi-static, is named a measuring facility. The ranges of the transmitters are chosen so that a target at an arbitrary point within the position space can be measured via scattering in the target by at least four, but preferably many more, measuring facilities.

Abstract: A bistatic radar system (100), method and computer program (178) are provided for mapping of oceanic surface conditions. Generally, the system (100) includes at least one transmitter (102) and at least one receiver (106) located separate from one another, and each having a local oscillator locked to a Global Positioning System (GPS) signal received by a GPS synchronization circuit (134) to provide the necessary coherency between the transmitted and received signals. Preferably, the present invention enables an existing backscatter radar systems to be quickly and inexpensively upgraded to a bistatic radar system (100) through the addition of a transmitter (102) and/or receiver (106) separate from the backscatter radar system, the GPS circuit (134), and use of the computer program (178) and method of the present invention.

Abstract: A method for measuring range and bearing of an object. At least a portion of a first signal is transmitted from a sensor. The transmitted signal is reflected from an object and received by the sensor. At least a portion of the first signal is applied a first mixer and a second mixer. The received signal is applied to the first mixer and the second mixer. A second signal is generated from the first mixer, and a third signal is generated from the second mixer when the portion of the first signal that was transmitted overlaps the reflected signal at least partially. Bearing angle, degree on or off boresight and object range may be determined from the second and third signals, or a combination thereof. Also disclosed is a sensor for object range and bearing measurement.

Abstract: A method of estimating emitter range and heading from bearing measurements without requiring observer heading change or observer acceleration during the bearing measurement collection period. Emitter signal characteristics are measured and a set of parameters characterizing a specific emitter as a signal source are generated based on the measured characteristics. Based on the emitter characterization and an emitter-platform association data base, a most probable platform including the emitter is identified and the emitter operating mode and corresponding specific platform are associated with a particular kinematic regime.

Abstract: Correlating observations of objects in the sky to determine an orbit includes identifying an initially identified object, determining if the initially identified object will be identifiable again, and identifying a subsequently identified object. A determination is then made by comparing characteristics of the initially identified object with the subsequently identified object. If the object correlate to one another a path or orbit of the object can be determined using the characteristics of the initially identified object and the subsequently identified object.

Abstract: An outdoor microwave transceiver intrusion detector that alternately transmits pulses of RF energy at two different frequencies and uses range and direction of travel information derived from the phase of the two Doppler responses to optimize the signal processing and apply range dependent thresholds. The time delay between the onset of the transmitted pulse and the sample of the Doppler response is controlled to provide an accurate range cutoff. The two frequencies are selected so that the difference in phase of the Doppler response at the two frequencies increases from zero to ninety degrees as the target goes from the Transceiver to the maximum range. Digital signal processing is used to measure the difference in phase of the two Doppler responses and translate this information into location of the target. The location information is used to create a number of range bins.

Abstract: A method for processing radar return data to determine a physical angle, in aircraft body coordinates to a target, is disclosed. The radar return data includes a phase difference between radar return data received at an ambiguous radar channel and a left radar channel, a phase difference between radar return data received at a right radar channel and an ambiguous radar channel, and a phase difference between radar return data received at a right radar channel and a left radar channel. The method includes adjusting a phase bias for the three phase differences, resolving phase ambiguities between the three phase differences to provide a signal, and filtering the signal to provide a physical angle to the target in aircraft body coordinates.

Abstract: An FMCW radar is provided which may be employed in automotive anti-collision or radar cruise control systems. In a distance measuring mode, only one of channels is used to sample a beat signal continuously, thereby allowing a sampling frequency to be increased up to Nc times that in an azimuth measuring mode and a sweep time in which a transmit signal sweeps in frequency upward and downward cyclically to be minimized. This causes half the sampling frequency to be higher than a frequency component arising sufficiently from a distant target present outside a preset radar range, thereby eliminating an error in detecting the distant target as being located inside the preset radar range.

Abstract: Determining the angle of arrival of a signal by providing a plurality of antennae, sampling, in turn, the output from each of the antennae to obtain a set of samples, each of the samples relating to different points in time, performing a Fourier transform on the set of samples, thereby producing a sequence of spectral lines, identifying a signal impinging on the antennae from the configuration of the spectral lines, and calculating, from phase and amplitude data gathered from at least a subset of the spectral lines, the direction of arrival of the signal at the antennae.

Abstract: A system for processing radar data from two or more areas of interest is provided, such as for simultaneously processing vehicle speeds in the opposite lane in front of the patrol vehicle and in the opposite lane behind the patrol vehicle. The system includes an antenna signal processor that receives radar data from one or more radar antennae and generates speed data for a first vehicle travelling in a first direction relative to a radar observation point and a second vehicle travelling in a second direction relative to the radar observation point. A display generator system receives the speed data and user-entered display control data, and generates user-readable display data based on the speed data and the user-entered display control data.

Abstract: The invention provides an object recognition apparatus that removes virtual images without detecting a roadside object. When a predetermined vehicle is currently running on a lane, a detection area, outside of the currently running lane, is designated to include a first area and an assumed ghost area therein. The first area is enclosed by a boundary of the detection area, a boundary of the assumed ghost area adjacent thereto, and a boundary on the currently running lane whose distance is traveled by the vehicle during one control cycle. The invention detects an object for the first time in the assumed ghost area, not in the first area. When the object travels with a distance and a speed of a target vehicle, it is determined to be a ghost to be deleted.

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: A traveling support information processing unit which can prevent willful assessment of information by a device installed on a road or loaded in a vehicle and makes it possible for the device to always issue a demand for acquisition of required information or a demand for consultation for cooperated determination, and which does not require any specific and additional device for acquisition of positional information for each vehicle and also can improve safety and efficiency in road utilization. In a computer system, vehicles 114A to 114C, 115C, and 115D with the behaviors on a road such as acceleration, deceleration, and lane change projected are made to run on a road 113 simulating the road structure. Communication is performed between a function 101 for tracking or projecting behaviors of the vehicle and the vehicles 115A, 115B having a communicating function.

Abstract: A system 100 is disclosed for monitoring the position of one or more RFID tags 201. The system has a detector 301 incorporating circuitry 304 for detecting changes in the range of an RFID tag 201 from the detector and for triggering an alarm 401 if a detected change in range of an RFID tag 201 exceeds a predetermined threshold or if the RFID radio tag cannot be detected by the detector 301. Range may be detected, for example, by measuring the time of a returned radio signal from a tag 201, by measuring the strength of a returned radio signal from a tag, or by detecting changes in a periodic interval at which energy is transmitted by a tag.

Abstract: An unwanted peak occurring due to an antenna sidelobe and an unwanted peak occurring due to a harmonic are eliminated in a radar apparatus. A peak from a target that can cause an unwanted peak is found based on the intensity of the peak, and a search is made for a peak having a predetermined positional relationship with the thus found peak. If such a peak is located, then it is determined whether the peak is a candidate for an unwanted peak, based on the difference between the intensity of the peak and the intensity of the main peak. If both of the paired peaks are determined as being candidates for unwanted peaks, it is determined that the peaks are unwanted peaks.

Abstract: A bistatic radar system (100), method and computer program (178) are provided for mapping of oceanic surface conditions. Generally, the system (100) includes at least one transmitter (102) and at least one receiver (106) located separate from one another, and each having a local oscillator locked to a Global Positioning System (GPS) signal received by a GPS synchronization circuit (134) to provide the necessary coherency between the transmitted and received signals. Preferably, the present invention enables an existing backscatter radar systems to be quickly and inexpensively upgraded to a bistatic radar system (100) through the addition of a transmitter (102) and/or receiver (106) separate from the backscatter radar system, the GPS circuit (134), and use of the computer program (178) and method of the present invention.

Abstract: An FMCW radar is provided which may be employed in automotive anti-collision or radar cruise control systems. In a distance measuring mode, only one of channels is used to sample a beat signal continuously, thereby allowing a sampling frequency to be increased up to Nc times that in an azimuth measuring mode and a sweep time in which a transmit signal sweeps in frequency upward and downward cyclically to be minimized. This causes half the sampling frequency to be higher than a frequency component arising sufficiently from a distant target present outside a preset radar range, thereby eliminating an error in detecting the distant target as being located inside the preset radar range.

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: A method and apparatus for permitting a host automotive vehicle to avoid or mitigate the consequences of a collision between the host vehicle and a target automotive vehicle by using a combination of radar derived target information and transponder information. The host vehicle is equipped with a radar system operative detect the target vehicle and generate target data, and a computer which determines a likelihood of collision with target vehicle. If the likelihood of collision is above a certain level, the computer directs the radar system to transmit a directional interrogation system toward the target vehicle. The target vehicle is equipped with one or more transponders that receive the interrogation signal and respond by transmitting a response signal containing information indicating various dynamic and/or static characteristics of the target vehicle. The response signal is received by the host vehicle and is decoded to extract the target vehicle information.

Abstract: A motion detector based on the Doppler principle contains a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving the radiation reflected from the latter. An evaluation stage is connected to the microwave module and generates first and second Doppler signals from the received radiation. The first and second Doppler signals have a phase difference which is proportional to the distance of an object reflecting the microwave signal. The phase difference is determined by an integral transformation. In addition, the relative size of an object and the direction of travel of an object reflecting the microwave signal can be determined by the evaluation stage.

Abstract: The invention relates to a radar station placed on the surface of the earth, and to a radar system comprising at least two such radar stations. The signal-processing equipment of the radar stations is adapted, at each point of time, to calculate probabilities of target positions and radial target velocity in relation to each individual radar station, based on the signals emitted and received by this station. These calculated values are associated over time, giving cumulative probability measures for target positions and radial velocities in relation to each individual radar station. By providing a system of at least two radar stations, it is possible to calculate the position of a target by associating target positions, such as they are perceived by the different radar stations, with each other by an association of characteristic movements of the target. This is done without having to synchronize the stations.

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

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

Abstract: A 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: A planar array antenna comprises a plurality of antenna elements disposed in a predetermined matrix pattern. Feeders extend from a feed to the antenna elements. High-frequency switches cooperatively open or close the feeders connected to antenna elements of at least one row of the matrix pattern located at both a right-end and a left-end regions of an antenna surface. Switching signals are supplied to the high-frequency switches from switching terminals for alternately activating the associated antenna elements, thereby providing two time-divisional array antennas offset in position by a distance corresponding to the width of at least one row of the antenna elements controlled.

Abstract: An electrical surveillance measures system for measuring direction of arrival (DOA), i.e., both azimuth and elevation, of a pulsed or continuous wave radar signal from a moving emitter. Either carrier frequency or pulse repetition interval (PARI) Doppler shift are used whereby the ratio of the Doppler shift is measured by a moving observer. The DOA is measured as a unit vector having basis vectors formed from a linearly independent set of observer's velocity vectors. The DOA unit vector has a linear part where the coefficients of the basis vectors are derived directly from the ratios of frequency or PARI measurements taken in three contiguous dwells. The DOA unit vector has a nonlinear part formed from the requirement that the DOA vector have unit magnitude. The unit vector is resolved in the system coordinates in which emitter azimuth and elevation are defined to allow computation of the latter two values.

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: A method and apparatus for locating a pulse echo radar emitter in both angle and range using a single antenna and minimal use of the observer platform's navigation instruments are described. The emitter's rest frequency and pulse repetition frequencies are extracted. Using the emitter signal DOA and measurements of pulse TOA and emitter frequency, the observer's acceleration and velocity along the emitter DOA path are found. Combining observer velocity with the above kinematic quantities allows emitter range and bearing to be determined. No observer platform heading or angular attitude information is required.

Abstract: A method for detecting fixed or moving objects within an angular zone, as may be used in vehicle anti-collision systems, employs separate and distinct transmission and reception patterns. The transmission pattern successively illuminates consecutive segments of the angular zone. The reception pattern receives echo signals in parallel from illuminated objects in each zone segment. The echo signals are then digitally beam formed into a total field signal. The angular positions of the detected objects are then derived from the total field signal.

Abstract: An improved radar system and technique are disclosed for use in detecting and tracking moving or stationary targets within the antenna field of view. Precise correction of doppler induced location errors is provided by the use of raw sensor data. Return signals are doppler processed, phase shifted and compared in a manner which preserves the angle of arrival of a moving target irrespective of the boresight direction. Stationary target return signals are constructively combined so as to augment the target signal gain independent of the antenna boresight direction.

Abstract: Doppler signals from a two-port radar system are spectrally processed and searched for a pattern of points wherein clutter at a first instant of time is subsequently replaced by low-level returns indicating the movement of a target. The rate of change of the low-level signals, along the same range bin but different Doppler bins, is indicative of target azimuth position relative to the boresight of the radar antenna. The difference between the total Doppler detected from the target and the Doppler for the azimuth position of the black hole detection is the Doppler for the relative radial velocity of the target. Not only is the black hole and shadow (lack of detection) detectable but more measurable and detectable is the clutter signal difference with the target motion.

Abstract: A measuring apparatus is provided in one of two objects moving relatively to each other. The apparatus includes a circuit for effecting a direct spread modulation with respect to a transmission carrier signal using modulation codes; an antenna unit for transmitting the modulated carrier signal toward the other of the two objects and for receiving a reflection wave therefrom; a circuit for demodulating the received reflection wave signal using the transmission carrier signal; a circuit for making correlation between the demodulated output signal and a signal having the same code as that of the modulation code and having a phase delayed by a predetermined time; a unit for extracting a Doppler frequency component contained in a signal which has been propagated through a propagation path existing in a specified distance range; and a circuit for properly processing the extracted Doppler frequency component.

Abstract: The invention provides a circuit for analyzing backscatter-modulated RF signals received from a remote transponder to determine whether the transponder is stationary or moving toward the reader or away from it and, if moving, the rate at which the transponder is coming or going. The circuit of the invention can be integrated with existing readers of the type described in U.S. Pat. No. 4,739,328 and requires only a single antenna. In response to the signal received from a transponder, the invention circuit generates three signals, each having a different phase. By analyzing the pattern and frequency of signal state changes in the three signals, the invention can determine the transponder's speed and direction of movement.

Abstract: A tristatic radar tracking system is disclosed in which two remote transmitters and a radar receiver use a method for combining measurements of the Doppler frequency shift and angle of arrival of two signals scattered by a moving target to derive parameters of the target's trajectory through space.

Abstract: In a process and device for the angular discrimination of targets by airborne radar, the angular position of a point on the ground is ascertained as a function of the Doppler frequency of an echo signal relating to the point under consideration, as determined by passband filtering the echo signals.The Doppler frequencies are selected by a bank of filters and an angular determination is made by analyzing signals including a signal representing the position in the bank of that filter selecting the Doppler frequency of the echo signal, and a reference frequency subject to closed loop control and representing the true Doppler frequency of the ground. Means are provided for maintaining data relating to the position and the range of the target constant during the process of analysis.

Abstract: A system for deriving direct digital indications of frequency and phase difference between two incoming pulse trains adaptable for collision avoidance systems or the like.A pair of radar beams 152 and 152A are directed toward a target 153 and corresponding beams 154 and 154A returning therefrom are detected. A digital difference circuit 110 forms a pulse train 66 from the Doppler shift frequencies of each beam pair having a repetition rate functionally related to the difference in magnitude of the shift frequencies. Pulses from the pulse train are counted as a function of time. Visual indications thereof on display 144 are correlative to target position relative to beams 152 and 152A.

Abstract: A traffic radar unit capable of looking past the lead vehicle of oncoming traffic and discovering and identifying a violator employs master and slave antennas having diverging boresights that provide overlapping relative power density radiation patterns. The radar return signal from a target of interest is received by each antenna to produce two independent Doppler signals of the same frequency which are processed by respective master and slave signal processing channels. In the illustrated embodiment, a reference boresight is established in the overlapped patterns such that a target position along the reference boresight occurs at the time that the amplitudes of the two Doppler signals are equal. Controllable high pass filters whose passbands are shifted upwardly in response to return signals of increasing amplitude attenuate stronger, lower frequency interfering signals.