US Patent 7339517 Radar

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 frequency spectrum of a beat signal is surely detected and detection accuracy of the target is increased.