Patent ID: 7164382
Filing Date: 2007-01-16
Classification: G01S

Abstract:
1. An on-vehicle radar system installed on a motor vehicle, comprising: a transmitting means for radiating as a transmission wave a signal having a constant frequency after pulse modulation; a receiving means for receiving as a reception wave a reflection wave resulting from reflection of said transmission wave at a target in every range gate set at a same interval as a pulse width of said transmission wave; an arithmetic means for detecting a range extending from said motor vehicle to said target on the basis of said reception wave; and an operation mode changeover means for changing over operation mode of said transmitting means and said arithmetic means between a pulse operation mode and an FMCW operation mode based on a frequency-modulated continuous wave at an appropriate timing, wherein in said pulse operation mode, said transmitting means radiates the signal of said constant frequency while said arithmetic means determines a range extending from said motor vehicle to said target on the basis of the range corresponding to said range gate, whereas in said FMCW operation mode, said transmitting means radiates a modulated wave whose frequency repetitively increases and decreases while said arithmetic means determines said range extending from said motor vehicle to said target and a relative velocity of said target on the basis of a frequency difference between the frequency of said transmission wave and the frequency of said reception wave, said arithmetic means being so designed as to compare the range corresponding to said range gate in said pulse operation mode with the range determined on the basis of the frequency difference between the frequency of said transmission wave and the frequency of said reception wave to thereby detect a range error due to aberration of modulation band width brought about by the frequency increasing and decreasing of said transmission wave in said FMCW operation mode, and wherein said arithmetic means is so arranged as to detect said range error on the basis of frequency difference components having substantially same amplitudes in adjacent range gates.