Abstract: An object recognition apparatus performs a sweep of a scanned region by transmitting scanning wave beams at respective scan angles and successive timings, derives a received-wave signal strength value and reflection location corresponding to each scan wave beam during the sweep, and assigns a set of mutually adjacent reflection locations as a segment. A corresponding range value of the segment is calculated, expressing an estimated distance of a detected object. A threshold value is derived in accordance with the segment range, a region of the segment in which the signal strength values exceed the threshold value is extracted, and the width of the extracted region is designated as the width of the detected object.

Abstract: An object recognition apparatus performs a sweep of a scanned region by transmitting scanning wave beams at respective scan angles and successive timings, derives a received-wave signal strength value and reflection location corresponding to each scan wave beam during the sweep, and assigns a set of mutually adjacent reflection locations as a segment. A corresponding range value of the segment is calculated, expressing an estimated distance of a detected object. A threshold value is derived in accordance with the segment range, a region of the segment in which the signal strength values exceed the threshold value is extracted, and the width of the extracted region is designated as the width of the detected object.

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 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 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: 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 radar apparatus is provided which is designed to form digital beams using beat signals each of which is produced by one of a plurality of receivers and analyze the frequency of the beat signals in units of the beams for obtaining data such as the distance to, relative speed, and azimuth of a target. The apparatus performs the complex Fourier Transform twice on beat signals in time series and space series along the array of receiving antennas to derive results of the frequency analysis in units of the beams, thereby resulting in simplified structure and decrease in operation load of the apparatus.

Abstract: A radar apparatus is provided which is capable of discriminating between azimuth angles of two or more targets moving side by side close to each other. The radar apparatus provides antenna beams which partially overlap with each other to define a plurality of monopulse areas and processes input signals produced in each of the monopulse areas to obtain angular direction data. The radar apparatus determines a time-sequential variation in angular direction data in each of the monopulse areas and determines the angular direction data whose variation is within a preselected allowable range as being effective in determining the angular direction of each target correctly.

Abstract: A radar apparatus is provided which includes a transmitter, a receiver, and a signal processor. The transmitter produces a transmit signal which is so modulated in frequency as to change with time cyclically and transmits the transmit signal as a radar wave. The receiver selectively establishes communication with one of receiving antennas and changes the communications with the receiving antennas in sequence in a cycle shorter than a cycle of a change in the frequency of the transmit signal to supply a series of signal components of input signals produced by the receiving antennas. The receiver mixes the series of signal components with a local signal having the same frequency as that of the transmit signal to produce a beat signal. The signal processor samples the beat signal to analyze frequency components thereof to determine the distance to, relative speed and azimuth of a target.

Abstract: An aperture antenna suitable for a radar system of an automotive vehicle is provided which includes three or more primary radiators and a feeding circuit. The feeding circuit is designed to supply electromagnetic signals to adjacent two of the primary radiators through discrete feeders to radiate in phase electromagnetic waves and to extract signals received by the two of the primary radiators separately. This enables the radiation of radar waves over a wider area without increasing the radiation power.

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: 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: An FM-CW radar which is suitable for automotive anti-collision systems, for example, is provided. This radar outputs a radar signal in the form of a triangular wave whose frequency is increased at a given rate and decreased at a given rate. A receiver receives a wave reflected from a target to produce a beat signal and takes the Fourier transform of the beat signal to determine peak frequency components thereof showing peaks in a frequency spectrum. The receiver also determines phases of the peak frequency components and selects at least one from the peak frequency components in a frequency-rising range wherein the frequency of the radar signal is increased and at least one from the peak frequency components in a frequency-falling range wherein the frequency of the radar signal is decreased which show substantially the same phase to pair them for determining the distance to and relative speed of the target based on the frequency of the paired peak frequency components.

Abstract: In an FM-CW radar system, a beat signal is frequency-analyzed for selecting ascending-side beat frequencies and descending-side beat frequencies for a plurality of targets. By pairing the ascending-side and descending-side beat frequencies one by one from each side, all possible combinations thereof are prepared. Based on these beat frequency combinations, beat frequency combinations after a given time are predicted, respectively. If an ascending-side beat frequency and a descending-side beat frequency of the predicted beat frequency combination are found in ascending-side beat frequencies and descending-side beat frequencies of a beat signal selected after the given time, respectively, or in the neighborhood of them, respectively, the predicted beat frequency combination of the found ascending-side and descending-side beat frequencies is set as a correct beat frequency combination. A further correct beat frequency combination/combinations can be set in the same manner.