A radar suppresses a dc component so as to improve the precision in processing a signal that belongs to a low-frequency band. The radar comprises a mixer that mixes a transmitted signal and a received signal, and an A/D converter that analog-to-digital converts an output signal of the mixer. The radar further includes: a removing unit that removes a dc voltage component by subtracting a predetermined removal voltage value from output data of the A/D converter; and an analyzing unit that Fourier-...

A signal processing unit detects the azimuthal direction of a target in accordance with the phase difference between signals received by two receiving antennas. Then, by sequentially switching plural transmitting antennas having mutually different beam directions with a switching device, received signals are obtained using each of the transmitting antennas.

A radar of the present invention has: (1) an antenna unit for transmitting a radio wave and receiving a reflected wave of the radio wave; (2) rotating means for rotating the antenna unit about an axis along a direction of transmitting the radio wave; and (3) control means for detecting an azimuth of a target from the reflected wave, the azimuth using the axis as a reference and being defined in a plane determined from a posture of the antenna unit and the axis.

A transmission wave is transmitted to a target from a transmission section. A receiving section receives a wave reflected from the target as a received wave. A conversion section converts a time difference between the transmission time at which a transmission wave is transmitted and the receiving time at which a received wave is received in to a voltage. The thus-obtained voltage is subjected to analog-to-digital conversion by means of a processing circuit, whereby a distance is computed.

A radar includes a transmission signal processing system, a reception signal processing system, an auxiliary signal processing system, a transmission-signal input unit, and a search determination unit. The transmission signal processing system transmits a transmission signal. The reception signal processing system receives and processes a reflected wave at a target. The auxiliary signal processing system is separate from the reception signal processing system and has the same configuration as at...

An FM-CW radar detects at least one of the relative distance and the relative speed of a predetermined object based on the frequencies of projection portions observed in the frequency spectrums of beat signals in an ascending-modulation section and a descending-modulation section, where the projection portions are generated by one and the same object. The radar determines the moving speed of a predetermined moving object such as a vehicle or the like having the radar mounted thereon, and the fre...

A method of guiding an object by means of a radar information field, wherein a field is created comprising a beam which has a generally annular cross sectional region defining a central null in the field, controlling the beam so that the null is directed towards a destination or target, and positioning said object in or at a defined position relative to the null, said object including an antenna and receiver means responsive to the signal strength difference between the annular region of the inf...

A radar wherein, in accordance with a peak frequency f1[t-nT] of a first projecting portion at a predetermined timing t-nT, a center frequency fr[t] of peak frequencies of first and second projecting portions at a current measurement timing t is predicted, and f1[t] and f2[t] in which (f1[t]+f2[t])/2 approximates the predicted fr[t] is extracted as a pair candidate. In addition, f1[t] and f2[t] in which Doppler shift frequency is substantially equal to a Doppler shift frequency calculated from t...

A radar wherein a first threshold value is determined in accordance with the intensity of background noise; second threshold values are set in a fixed frequency area around base portions of peaks in the frequency spectrum; the higher one of these second threshold values is adopted as a decisive threshold value in each FFT bin; and a peak exceeding this threshold value is considered a target peak and detected. Thus, the target peak caused by the reflected wave from a target included in the freque...

A radar device precisely detects a target in short time intervals by detecting a true peak frequency with high accuracy via a calculation which does not require a large amount of computation. A discrete frequency spectrum of a beat signal multiplied by a window function is determined, and values of signal strength at two discrete frequencies which are, respectively, higher and lower than a peak frequency of the discrete frequency spectrum of the beat signal and which are adjacent to the peak fre...