Abstract: A signal processing circuit detects, at a plurality of different timing points, a first and a second distance of an oncoming vehicle approaching a vehicle including the radar apparatus and detects a first and a second component of a relative velocity of the vehicle in the radar-apparatus direction. A distance of closest approach of the oncoming vehicle to the vehicle appears when the vehicle and the oncoming vehicle pass each other side by side. The signal processing circuit computes the distance of closest approach on the basis of a formula indicating that a relative velocity given by the first distance, the distance of closest approach, and the first component of a relative velocity in the radar-apparatus direction is equal to a relative velocity given by the second distance, the distance of closest approach, and the second component of a relative velocity in the radar-apparatus direction.

Abstract: A frequency spectrum of a beat signal of a transmission signal and a reception signal is determined. Whether or not the number of peaks exceeding a noise threshold in the frequency spectrum exceeds a predetermined number is determined. According to the determination result, presence or absence of interference on the beat signal is detected. If “interference exists”, the threshold for extraction of target peaks that appear on the frequency spectrum is increased. This allows detection of presence or absence of a spike noise to be superposed on the beat signal to be performed more certainly, thereby enabling processing according to presence or absence of interference.

Abstract: A beat signal normalizing section in a correction control section normalizes a group of sampling data of an input beat signal in one processing group. A phase amount measuring section calculates an amount of phase change of each sampling data. A correction control value calculating section compares the actually measured amount of phase change of each sampling data with an ideal amount of phase change of each sampling data and generates correction voltage data such that the actually measured amount of phase change matches with the ideal amount of phase change. Correction control data provided as the correction voltage data at each sampling time is applied to a transmission control section. The transmission control section generates transmission control data based on the correction control data and applies the transmission control data to a VCO through a DAC.

Abstract: To prevent erroneous tracking of a false target, increase reliability of target tracking, enhance continuous tracking of a real target, and thereby prevent erroneous target recognition and improve the recognition accuracy, a target is tracked on the basis of detection information that is included in detection information obtained at a plurality of different measurement time points and is estimated to have resulted from one and the same reflector; tracking reliability indicating a likelihood that a target currently being tracked has resulted from one and the same reflector is determined; and a recognition condition required for recognizing a real target is set according to the tracking reliability or its change.

Abstract: A radar wherein, in response to an increase in the level of noise appearing in a frequency spectrum caused by interference being superimposed on a beat signal, peaks exceeding a threshold are extracted as target peaks in an ordinary state and a predetermined number of peaks in descending order starting from the peak having the highest peak value are extracted in the case where interference occurs.

Abstract: An OCT technique that permits tomographic observation of biological body parts that are difficult to restrain, and also provides a tomographic observation technique for the observation of a constrainable part that does not require constraint and thus removes a burden on the biological body. A wavelength-tunable light generator (wavelength-tunable light source) is employed as the light source of the optical coherence tomography device. The wavelength-tunable light generator has a wave number tunable range width of at least 4.7×10?2 ?m?1 and an emitted-light frequency width of no more than 13 GHz, for example, and is capable of changing the wave number stepwise at wave number intervals of no more than 3.1×10?4 ?m?1 and time intervals of no more than 530 ?s.

Abstract: A radar system transmits a beam of detection radio waves with a predetermined azimuth width, receives a reflected wave from a target, changes a central azimuth of the beam, and detects the distribution of reception signal strengths at predetermined angular intervals and for each predetermined distance. Then, when the reception signal strength distribution associated with changes in azimuth is expressed in rectangular coordinates, an azimuth corresponding to a vertex of an isosceles triangle that approximates the reception signal strength distribution and has an azimuth width, which is determined by the beam azimuth width, as its base is detected as the central azimuth of the target.

Abstract: The present invention provides an OCT technique that permits tomographic observation of a biological body parts that is difficult to restrain and also provides a tomographic observation technique for the observation of a constrainable part that does not require constraint and remove the burden from biological body. A wavelength-tunable light generator (wavelength-tunable light source) is employed as the light source of the optical coherence tomography device. The wavelength-tunable light generator has a wave number tunable range width of at least 4.7×10?2 ?m?1 and an emitted-light frequency width of no more than 13 GHz, for example, and includes means capable of changing the wave number stepwise at wave number intervals of no more than 3.1×10?4 ?m?1 and time intervals of no more than 530 ?s.

Abstract: A beat signal normalizing section in a correction control section normalizes a group of sampling data of an input beat signal in one processing group. A phase amount measuring section calculates an amount of phase change of each sampling data. A correction control value calculating section compares the actually measured amount of phase change of each sampling data with an ideal amount of phase change of each sampling data and generates correction voltage data such that the actually measured amount of phase change matches with the ideal amount of phase change. Correction control data provided as the correction voltage data at each sampling time is applied to a transmission control section. The transmission control section generates transmission control data based on the correction control data and applies the transmission control data to a VCO through a DAC.

Abstract: The present invention provides an OCT technique that permits tomographic observation of a biological body parts that is difficult to restrain and also provides a tomographic observation technique for the observation of a constrainable part that does not require constraint and remove the burden from biological body. A wavelength-tunable light generator (wavelength-tunable light source) is employed as the light source of the optical coherence tomography device. The wavelength-tunable light generator has a wave number tunable range width of at least 4.7×10?2 ?m?1 and an emitted-light frequency width of no more than 13 GHz, for example, and includes means capable of changing the wave number stepwise at wave number intervals of no more than 3.1×10?4 ?m?1 and time intervals of no more than 530 ?s.

Abstract: A radar that detects whether spike noise due to an interference with a transmission signal from an object vehicle is superimposed on a beat signal obtained from the transmission signal and a reception signal. When the spike noise is detected, a threshold for extracting a peak from a frequency spectrum is temporarily increased. Normally, a threshold (TH0) is set not so as to extract background noise as a target peak. When the spike noise is detected, a noise floor level (NFL) of the frequency spectrum is determined on the basis of the maximum absolute value of the spike noise, and a threshold (TH1) higher by a predetermined amount ?L than the threshold TH0 is set. This allows a proper target peak to be accurately extracted without mistakenly extracting many peaks caused by the noise as the target peaks.

Abstract: A signal processing circuit detects, at a plurality of different timing points, a first and a second distance of an oncoming vehicle approaching a vehicle including the radar apparatus and detects a first and a second component of a relative velocity of the vehicle in the radar-apparatus direction. A distance of closest approach of the oncoming vehicle to the vehicle appears when the vehicle and the oncoming vehicle pass each other side by side. The signal processing circuit computes the distance of closest approach on the basis of a formula indicating that a relative velocity given by the first distance, the distance of closest approach, and the first component of a relative velocity in the radar-apparatus direction is equal to a relative velocity given by the second distance, the distance of closest approach, and the second component of a relative velocity in the radar-apparatus direction.

Abstract: A radar system transmits a beam of detection radio waves with a predetermined azimuth width, receives a reflected wave from a target, changes a central azimuth of the beam, and detects the distribution of reception signal strengths at predetermined angular intervals and for each predetermined distance. Then, when the reception signal strength distribution associated with changes in azimuth is expressed in rectangular coordinates, an azimuth corresponding to a vertex of an isosceles triangle that approximates the reception signal strength distribution and has an azimuth width, which is determined by the beam azimuth width, as its base is detected as the central azimuth of the target.

Abstract: In a radar apparatus, IF beat signals are detected in a first section and a second section serving as two adjacent frequency up-modulation sections of a transmitted wave. Frequency conversions such as FFTs are performed on the IF beat signals so that the frequency spectra are obtained. Subsequently, peak frequencies are detected from the frequency spectra in the corresponding sections, and the phase difference between the peak frequencies is determined. Since the phase difference calculated in this manner depends on the relative moving distance ?r during the interval between the first section and the second section, the relative moving distance ?r, the relative distance, and the relative velocity at this moment can be calculated from the phase difference.

Abstract: A radar apparatus wherein transmission beams are set such that reception intensities corresponding to the transmission beams are gradually reduced from a center direction toward an edge direction of a scanning-angle range. For example, when a vehicle serving as a target is located in the center direction of a transmission beam, the reception-signal intensity corresponding to an adjacent transmission beam is set higher than the reception intensity in the center direction corresponding to the transmission beam. When the scanning-angle distributions of reception-signal intensities corresponding to transmission beams are detected, a scanning angle exhibiting a peak reception-signal intensity is nearer the center of the scanning-angle range than the azimuth angle at which the target is actually located. Thus, a peak reception-signal intensity corresponding to a target located in a region that is a predetermined amount outside the scanning-angle range of a transmission beam appears inside the scanning-angle range.

Abstract: A radar for detecting a target wherein a standard deviation of the amplitude of a beat signal from a transmission signal and a reception signal is determined for a predetermined period. A threshold is determined by adding a predetermined value to the standard deviation or by multiplying the standard deviation by a predetermined coefficient. The presence or absence of interference on the beat signal is detected according to the presence or the absence of an amplitude greater than the threshold. For example, an amplitude exceeding the standard deviation×2 is considered a spike noise (SPN), i.e., as “presence of interference”. The threshold used for detecting peaks appearing on a frequency spectrum is then increased. This allows detection of the presence or the absence of a spike noise superposed on the beat signal to be performed more certainly, thereby enabling processing according to the presence or the absence of interference.

Abstract: The present invention provides an OCT technique that permits tomographic observation of a biological body parts that is difficult to restrain and also provides a tomographic observation technique for the observation of a constrainable part that does not require constraint and remove the burden from biological body. A wavelength-tunable light generator (wavelength-tunable light source) is employed as the light source of the optical coherence tomography device. The wavelength-tunable light generator has a wave number tunable range width of at least 4.7×10?2 ?m?1 and an emitted-light frequency width of no more than 13 GHz, for example, and includes means capable of changing the wave number stepwise at wave number intervals of no more than 3.1×10?4 ?m?1 and time intervals of no more than 530 ?s.

Abstract: A radar including a target measurement component, a differential velocity calculator and an overall velocity determination portion. The target measurement component transmits and receives an electromagnetic wave over a detection range repeatedly at measurement intervals to measure a position of a target in the detection range and measure a Doppler velocity of the target based on a Doppler shift of the electromagnetic wave reflected from the target. The differential velocity calculator determines a differential velocity of the target based on a change in position of the target during consecutive measurement intervals. The overall velocity determination portion determines a current overall velocity by calculating a weighted average of the Doppler velocity, the differential velocity, and a previously determined overall velocity.

Abstract: A radar wherein, in response to an increase in the level of noise appearing in a frequency spectrum caused by interference being superimposed on a beat signal, peaks exceeding a threshold are extracted as target peaks in an ordinary state and a predetermined number of peaks in descending order starting from the peak having the highest peak value are extracted in the case where interference occurs.

Abstract: A radar that detects whether spike noise due to an interference with a transmission signal from an object vehicle is superimposed on a beat signal obtained from the transmission signal and a reception signal. When the spike noise is detected, a threshold for extracting a peak from a frequency spectrum is temporarily increased. Normally, a threshold (TH0) is set not so as to extract background noise as a target peak. When the spike noise is detected, a noise floor level (NFL) of the frequency spectrum is determined on the basis of the maximum absolute value of the spike noise, and a threshold (TH1) higher by a predetermined amount ?L than the threshold TH0 is set. This allows a proper target peak to be accurately extracted without mistakenly extracting many peaks caused by the noise as the target peaks.