A vehicle radar system extracts peak frequencies fbu and fbd of respective beat
signals B1 to B9 representing the frequency difference between a
transmission signal fs and a plurality of received signals fr1 to fr9.
The phase difference of respective beat signals B1 to B9 at the peak
frequencies fbu and fbd is converted into a frequency signal. In the case of reflection
from a close range road surface or raindrops, the phase difference of each beat
signal is irregular. The peak frequency intensity of a converted frequency signal
is small. This system compares the peak frequency intensity of the converted frequency
signal with predetermined criterion intensity. Then, the system identifies an objective
with a close range road surface or raindrops when the peak frequency intensity
of the converted frequency signal is not larger than the predetermined criterion intensity.
