Abstract: A radar system mounted on a vehicle includes a first radar and a second radar, each having a transmitter-receiver and a signal processor. The transmitter-receiver transmits radar waves to detect objects such as another vehicle or other obstacles. An operating cycle period T1, T2 and a transmission time X1, X2 during which the radar waves are transmitted are set in both radars to satisfy the formula: K·T2+X2+X1?T1?(K+1)·T2?X2?X1 under a condition that T1>T2, where K is a positive integer. By setting both radars in this manner, interference between two radars is avoided without using additional devices in the radar system, and a high detection accuracy is realized.

Abstract: Apparatus and method are disclosed for estimating direction of an arrival wave, such as radio or acoustic waves. A correlation matrix of an arrival wave is computed, and matrices for obtaining eigenvalues and eigenvectors are produced. Column norms of the matrix, which is subject to a Householder transformation, are computed. Whether a maximum value of the column norms is the same as or lower than a predetermined threshold is judged. A Householder transformation of the matrix is performed only if the maximum value of the column norms is determined to be greater than or equal to the threshold, and not when the maximum value of the column norms is less than the threshold. The eigenvectors and the eigenvalues of the correlation matrix are obtained by further implementing the Householder transformation. The number of arrival waves is judged from the number of times the Householder transformation is performed.

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: An FMCW radar device executes a frequency analysis for a beat signal in a frequency increase interval and a frequency decrease interval, to obtain frequency components in a predetermined high frequency range exceeding a frequency range corresponding to a target detection frequency range within which a target object for detection should be detected. Then the FMCW radar device calculates a value related to a sum of intensities of frequency components within the high frequency range respectively for each of the frequency increase interval and the frequency decrease interval. In the case that one of the calculated integrals is larger than a threshold, the FMCW radar device determines that the FMCW radar device is interfered with by a nearby radar device.

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 o a computed CAPON phase information.

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: In a system, a frequency-modulating unit is configured to frequency-modulate a radar wave signal within a predetermined frequency modulation range from bottom to top so that a frequency of the frequency-modulated radar wave changes in time. The rate of frequency change of the radar wave signal in time is set to F0/Tf. The F0 represents a center frequency in the frequency modulation range. The Tf represents the predetermined constant time. A mixing unit is configured to mix the transmitted frequency-modulated radar wave signal and the reflection signal to obtain a beat signal. The beat signal is based on a frequency difference between a frequency of the transmitted radar wave signal and that of the reflection signal. A sweeping unit is configured to sweep the beat signal within the frequency modulation range from one of the bottom and the top to the other thereof to obtain a frequency component of the beat signal.

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: A radar signal processor has means for outputting a predetermined observation signal from a reflected wave caught by an array element, 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 which is a sample value of a correlation matrix 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, and means for selecting the reflected wave in a predetermined arrival direction power of which is to be estimated and a reflected wave in an azimuth adjacent to the arrival direction of the reflected wave and for computing and determining the array response matrix as an adjacent azimuth array response matrix, having only these reflected waves as elements in order to estimate the power of the reflected wa

Abstract: Occurrence of interference is detected using sampled amplitude data obtained by oversampling a beat signal. It is detected by comparing the absolute value (|VD|) of variation in the sampled data with a threshold value (TH). When interference occurs, a wideband signal is superposed on the beat signal, and this disturbs the signal waveform of the beat signal to drastically varies its amplitude. Therefore, occurrence of interference can be detected without fail regardless of the scheme on which a radar as the source of an interference wave is based and even when the amplitude of the interference wave is low. In addition, when low-frequency noise is superposed on the beat signal, erroneous detection of occurrence of interference can be prevented.

Abstract: A radar signal processor has observation means, for receiving a reflected wave from a target and for outputting a predetermined observation signal, means for extracting distance component, for extracting a distance component corresponding to a distance from the each observation signal, means for estimating, for collecting respective distance components and for computing and estimating an estimated value of a corresponding correlation matrix with a forgetting factor as a parameter by a method for estimating correlation matrix with exponential smoothing, means for estimating a presence of a target or a movement state of the target on the basis of the respective estimated values of the correlation matrices, and means for determining forgetting factor, for respectively computing and determining the forgetting factors corresponding to the distances, and for respectively outputting the computed and determined.

Abstract: Occurrence of interference is detected using sampled amplitude data obtained by oversampling a beat signal. It is detected by comparing the absolute value (|VD|) of variation in the sampled data with a threshold value (TH). When interference occurs, a wideband signal is superposed on the beat signal, and this disturbs the signal waveform of the beat signal to drastically varies its amplitude. Therefore, occurrence of interference can be detected without fail regardless of the scheme on which a radar as the source of an interference wave is based and even when the amplitude of the interference wave is low. In addition, when low-frequency noise is superposed on the beat signal, erroneous detection of occurrence of interference can be prevented.

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.

Abstract: A radar device (2) includes plural transmission antennas and plural reception antennas. The reception antennas constitute a reception-side antenna portion (20) and are arranged at an interval of d. The transmission antennas constitute a transmission-side antenna portion (18) and are arranged at an interval of d?=d×(n?1). The path length at which the electric wave is reflected from a target is identical between channels A9 and B1, and seventeen kinds of channels (A1 to A8, A9 or B1, B2 to B9) which are different in path length by every fixed distance are achieved. The data of the channels (A1 to A9 and B1 to B9) using different transmission antennas are respectively collected in different measuring cycles, and an error based on the time difference between the measuring cycles is corrected on the basis of a correction value calculated from the data of the channels A9, B1.

Abstract: A radar system mounted on a vehicle includes a first radar and a second radar, each having a transmitter-receiver and a signal processor. The transmitter-receiver transmits radar waves to detect objects such as another vehicle or other obstacles. An operating cycle period T1, T2 and a transmission time X1, X2 during which the radar waves are transmitted are set in both radars to satisfy the formula: K·T2+X2+X1?T1?(K+1)·T2?X2?X1 under a condition that T1>T2, where K is a positive integer. By setting both radars in this manner, interference between two radars is avoided without using additional devices in the radar system, and a high detection accuracy is realized.

Abstract: Apparatus has means for computing correlation matrix of arrival wave, means for producing a matrix for obtaining eigenvalues and a matrix for obtaining eigenvectors, means for computing column norms on the matrix which is a subject for Householder transformation, means for judging whether a maximum value of the column norms is the same as or lower than a predetermined threshold, means for repeating Householder transformation on the matrix only if the maximum value of the column norms is judged not to be the same or not to be lower, means for breaking Householder transformation if the maximum value is the same as or lower, means for further implementing Householder transformation and for obtaining the eigenvectors and the eigenvalues of the correlation matrix, and means for judging the number of the arrival waves from the implementation times of Householder transformation.

Abstract: An FMCW radar device executes a frequency analysis for a beat signal in a frequency increase interval and a frequency decrease interval, to obtain frequency components in a predetermined high frequency range exceeding a frequency range corresponding to a target detection frequency range within which a target object for detection should be detected. Then the FMCW radar device calculates a value related to a sum of intensities of frequency components within the high frequency range respectively for each of the frequency increase interval and the frequency decrease interval. In the case that one of the calculated integrals is larger than a threshold, the FMCW radar device determines that the FMCW radar device is interfered with by a nearby radar device.

Abstract: An apparatus for detecting a direction of a target is provided. The apparatus transmits and receives radio waves through a plurality of transmission/reception channels causing a phase difference in signals to be received through the transmission/reception channels and calculates the direction based on the phase difference. The apparatus comprises a direction calculating device, range determining device, and direction correcting device. The direction calculating device calculates the direction of the target based on the phase difference in the received signals on the assumption that the phase difference is within a range of ?? to +? [rad]. The range determining device determines that the target exists in any of azimuthal angle ranges each corresponding to ranges defined by (2m?1) ? to (2m+1) ? [rad] (m is an integer). The direction correcting device corrects the direction according to a range-determined result.

Abstract: An apparatus for detecting a direction of a target is provided. The apparatus transmits and receives radio waves through a plurality of transmission/reception channels causing a phase difference in signals to be received through the transmission/reception channels and calculates the direction based on the phase difference. The apparatus comprises a direction calculating device, range determining device, and direction correcting device. The direction calculating device calculates the direction of the target based on the phase difference in the received signals on the assumption that the phase difference is within a range of ?? to +? [rad]. The range determining device determines that the target exists in any of azimuthal angle ranges each corresponding to ranges defined by (2m?1)? to (2m+1)? [rad] (m is an integer). The direction correcting device corrects the direction according to a range-determined result.

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.