Patent ID: 6348889
Filing Date: 2002-02-19
Classification: G01S

Abstract:
A radar apparatus for being mounted on a subject vehicle comprising:a beam transmission means for radiating a radar beam as a transmission signal; a beam reception means for receiving a reception signal reflected from a target object which is within a radiation range of said radiated radar beam; and a processing unit for detecting a position of a target object from said transmission signal and said received reception signal, said processing unit comprising; a preceding vehicle judgement means for judging if a preceding vehicle travelling in front of the subject vehicle in approximately a same direction as the subject vehicle is same vehicle as previously detected, and a signal strength comparing means for comparing the signal strength of a reception signal reflected from said preceding vehicle, with a signal strength of a reception signal reflected from said preceding vehicle a comparison reference time prior, to thereby calculate a change amount in signal strength, and when said change amount calculated by said signal strength comparing means drops beyond a previously set threshold value and it is judged by said preceding vehicle judgement means that said preceding vehicle is the same vehicle, said processing unit diagnoses that detection sensitivity of the radar apparatus has dropped.