Abstract: A plurality of array antenna elements are divided in terms of a set constituted of an optionally selected L number of groups. The spaces between the array antenna elements are determined by obtaining a greatest common divisor of the set as a greatest common divisor of inter-group element spaces, the set having, as components, greatest common divisors of inter-element spaces of the individual L number of groups in the set, obtaining a greatest common divisor of inter-group element for every number L equal to or less than the maximum number of incoming waves by changing the number L of group components, and allowing a direction not to be caused in the radar scanning region by a number equal to or more than L+1, on the basis of the greatest common divisor of inter-group element spaces for every number L of group components, the direction being linearly dependent on an incoming wave corresponding to the greatest common divisor of inter-group element spaces.

Abstract: A technology for providing an arrival direction estimation apparatus which can greatly reduce the calculation amount in spectrum calculation and can perform precise direction estimation without setting short frequency division in spectrum calculation is disclosed.

Abstract: The array antenna includes a feed line, and a plurality of radiating element sections arranged at a predetermined arranging interval in a first direction, each of the radiating element sections including at least one radiating element fed a traveling wave through the feed line. The inter-element line length as a length of the feed line between each succeeding two of the radiating element sections is longer than the arranging interval in the first direction.

Abstract: A radar apparatus has a plurality of receiving antennas and an array transmitting antenna controlled to successively vary the direction of a transmitted beam within a range which includes a target detection range of directions. The direction of any target within the target detection range is detected based on a phase difference between incident reflected waves of adjacent receiving antennas. To eliminate false targets resulting from aliasing, each detected target is authenticated based upon closeness of its detected direction to the current transmitted beam direction. The receiving antennas and transmitting antenna are configured to exclude directions of grating lobes of the transmitted beam from the detection range, and thereby suppress effects of received reflected waves that originate from grating lobes.

Abstract: In a FM-CW or CW radar apparatus, when interference components are contained in channel signals obtained as beat signals from array antenna elements of respective channels, and the interference components result from directly receiving transmitted CW radar waves from an external source, phase shifting is applied to each of the channel signals to shift respective phases of the interference components of the respective channels to a condition corresponding to reception of interference waves from a predetermined direction. The interference components are then eliminated, and reverse phase shifting is applied to restore remaining components of the channel signals to their original phase condition.

Abstract: A target object detection apparatus periodically executes a transmit/receive operation to transmit radar waves and obtain received signals from resultant incident reflected waves from respective target objects. An individual correlation matrix of received signal values is derived for each one of a fixed plurality of successive transmit/receive operations, with the transmission frequency being changed at successive operations. Individual correlation matrices derived from respective transmit/receive operations are time-averaged to obtain an average correlation matrix for use in obtaining target object information such as direction or velocity, with effects of correlation between respective incident waves being suppressed.

Abstract: An electronic scanning radar apparatus has a cutting portion for cutting receiving data which is comprised of N numbers of data for each channel into two more short time data having M (<N) numbers of data in a time direction for each channel, an inverse matrix estimator for computing and estimating an inverse matrix of the time series correlation matrix from the short time data, and a phase information producing portion for computing CAPON phase information out of the estimated inverse matrix of the time series correlation matrix in order to detect a distance, an azimuth and a relative speed of a target on the basis of a computed CAPON phase information.

Abstract: A FMCW-type radar device generates snapshot data from a beat signal that represents a received condition of the radar device every modulation period. Auto-correlation matrices generated by the snapshot data every modulation period are averaged every set of plural periods. The radar device calculates the target azimuth of a target object such as a preceding vehicle based on the averaged auto-correlation matrix based on MUSIC (MUltiple SIgnal Classification) method. This averaging is performed by weighting average based on an amount of mixed noise (or an interference amount) contained in the snapshot data in each modulation period. A weighting coefficient to be applied to the auto-correlation matrix in each modulation period is set to a value corresponding to the amount of mixed noise, namely, the interference amount of this modulation period. The weighting coefficient becomes large when the interference amount is small, and on the other hand, becomes small when it is large.

Abstract: A plurality of array antenna elements are divided in terms of a set constituted of an optionally selected L number of groups. The spaces between the array antenna elements are determined by obtaining a greatest common divisor of the set as a greatest common divisor of inter-group element spaces, the set having, as components, greatest common divisors of inter-element spaces of the individual L number of groups in the set, obtaining a greatest common divisor of inter-group element for every number L equal to or less than the maximum number of incoming waves by changing the number L of group components, and allowing a direction not to be caused in the radar scanning region by a number equal to or more than L+1, on the basis of the greatest common divisor of inter-group element spaces for every number L of group components, the direction being linearly dependent on an incoming wave corresponding to the greatest common divisor of inter-group element spaces.

Abstract: A target detecting apparatus mounted on a vehicle has an electronically agile radar detecting a beat signal indicating a difference in frequency between transmission and reception signals and producing a time series of N reception data from the beat signal, a determining unit determining search areas placed at different ranges of distance from the vehicle while considering a running state of the vehicle and determining a data length for each search area, an extracting unit extracting (N?M+1) time series of short time data, respectively, having the data length corresponding to M reception data from the N reception data for each search area, a producing unit producing phase information from the short time data for each search area, and a detecting unit determining a target distance and a target bearing from the phase information and detecting a target from the target distance and the target bearing.

Abstract: A sampled beat signal RD is split into a plurality of short-time data SD in the time direction, for each of antenna elements. Interference component frequency of an interference wave is detected from a frequency spectrum of the short-time data SD. A digital beam forming process is performed for the interference component frequency of the interference wave to extract a peak of the electrical power of an azimuth direction and estimate an absolute value of an incoming direction of interference components. Based on the absolute value of the incoming direction of the estimated interference components, a filter for suppressing the interference components is operated to suppress the interference components.

Abstract: A target object detection apparatus periodically executes a transmit/receive operation to transmit radar waves and obtain received signals from resultant incident reflected waves from respective target objects. An individual correlation matrix of received signal values is derived for each one of a fixed plurality of successive transmit/receive operations, with the transmission frequency being changed at successive operations. Individual correlation matrices derived from respective transmit/receive operations are time-averaged to obtain an average correlation matrix for use in obtaining target object information such as direction or velocity, with effects of correlation between respective incident waves being suppressed.

Abstract: In a FM-CW or CW radar apparatus, when interference components are Contained in channel signals obtained as beat signals from array antenna elements of respective channels, and the interference components result from directly receiving transmitted CW radar waves from an external source, phase shifting is applied to each of the channel signals to shift respective phases of the interference components of the respective channels to a condition corresponding to reception of interference waves from a predetermined direction. The interference components are then eliminated, and reverse phase shifting is applied to restore remaining components of the channel signals to their original phase condition.

Abstract: A radar signal processor is disclosed having an observation mechanism for receiving a reflected wave from a target and for outputting a predetermined observation signal. The processor extracts a distance component corresponding to a distance from each observation signal. The processor further collects the respective distance components and computes an estimated value of a corresponding correlation matrix with a forgetting factor as a parameter using a method for estimating correlation matrix with exponential smoothing. The processor further estimates the presence or movement state of the target on the basis of the respective estimated values of the correlation matrices and outputs the computed values.

Abstract: A sampled beat signal is cut out into two or more short time data in a time direction concerning each antenna component. From a frequency spectrum of the short time data, an interference element frequency of an interference wave is detected. From the interference element frequency of the interference wave, two or more candidates of the frequency before aliasing of the interference wave are produced, and phase correction is executed on each candidate. Digital Beamforming is executed on the corrected frequency so as to extract maximum peaks of the power of an azimuth direction, and the frequency candidate showing the maximum peak power is selected and the arrival azimuth of the interference element is estimated. A filter for suppressing the interference element is applied on the short time data from the estimated arrival azimuth of the interference element so as to suppress the interference element.

Abstract: A radar apparatus includes a receiving means that receives a reflected signal, a beat signal generation means that generates beat signals based on the reflected signal, a correlation matrix generation means that calculates correlation matrices based on the beat signals, a storing means that stores previous correlation matrices, an addition means that calculates addition correlation matrices by adding the correlation matrices to the previous correlation matrices, a detection means that detects a frequency component satisfying a predetermined condition by using the beat signals, an extraction means that extracts an extraction matrix corresponding to the detected frequency from the addition correlation matrices, and a direction calculation means that calculates a direction of the object with respect to the radar apparatus based on the extraction matrix.

Abstract: A radar apparatus includes a receiving means that receives a reflected signal, a beat signal generation means that generates beat signals based on the reflected signal, a correlation matrix generation means that calculates correlation matrices based on the beat signals, a storing means that stores previous correlation matrices, an addition means that calculates addition correlation matrices by adding the correlation matrices to the previous correlation matrices, a detection means that detects a frequency component satisfying a predetermined condition by using the beat signals, an extraction means that extracts an extraction matrix corresponding to the detected frequency from the addition correlation matrices, and a direction calculation means that calculates a direction of the object with respect to the radar apparatus based on the extraction matrix.

Abstract: A radar signal processor has observation means for outputting a predetermined observation signal from a reflected wave, means for extracting an observation signal component concerning a target from the observation signal, means for computing a sample correlation matrix showing a correlation characteristic between the observation means from the observation signal components, means for estimating power of the reflected wave from the sample correlation matrix, and an array response matrix which is comprised of response vectors of the reflected waves. When estimating the power, an adjacent azimuth array response matrix having only the reflected waves of a predetermined arrival direction which power is to be estimated and the reflected waves of an azimuth adjacent to the reflected wave as elements is determined so as to estimate the power of the reflected wave.

Abstract: A radar device uses a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave. An incoming wave estimation process stores a threshold for each beat frequency of the beat signal, and distinguishes the incoming wave in a signal space from the incoming wave in a non-signal space using the threshold. The estimation process facilitates an accurate estimation of the incoming wave in MUSIC method, ESPRIT method or the like.

Abstract: A radar transceiver of an on-vehicle radar transmits and receives a radar wave. Objects ahead of a vehicle having the on-vehicle radar are sensed based on the reflected radar wave reflected from the objects. A target vehicle to be monitored is extracted from the sensed objects based on the reflected radar wave. Also, a blind spot object, which is present in a blind spot of the target vehicle is extracted from the sensed objects based on the reflected radar wave.