Patent ID: 6924762

Claim:
A radar apparatus for a vehicle comprising: a transmitter working to emitting a transmit signal in the form of a radar wave which has a frequency so modulated as to increase, decrease, and be kept constant in sequence; a first and a second receiver circuit including a first and a second antenna located at a given interval away from each other, the first and second receiver circuits each working to receive a return of the radar wave from an object to produce receive signals and produce a first and a second beat signal each of which has a frequency corresponding to a difference in frequency between the transmit signal and a corresponding one of the receive signals, each of the first and second beat signals having a first frequency component in a modulated frequency-rising range wherein the frequency of the transmit signal increases, a second frequency component in a modulated frequency-falling range wherein the frequency of the transmit signal decreases, and a third frequency component in a constant modulated frequency range wherein the frequency of the transmit signal is kept constant; and a signal processor working to determine an angular direction of the object using the receive signals provided by said first and second receiver circuits, said signal processor including a first and a second angular direction determining section, the first angular direction determining section determining the angular direction of the object based on a phase difference between the first and second beat signals at a peak frequency that is at least one of frequencies of the first and second beat signals in at least one of the modulated frequency-rising and -falling ranges which have peaks, when peak frequencies that are frequencies of the first and second beat signals arising form a plurality of objects which have peaks in at least one of the modulated frequency-rising and -falling ranges overlap each other, the second angular direction determining section determining the angular direction of the object using a phase difference between the first and second beat signals at peak frequencies that are frequencies of the first and second beat signals in the constant modulated frequency range.