Abstract The radar has two antennas which radiate RF signals of different frequencies and whose radiation patterns overlap. The frequencies of the radiated signals are generated by amplitude-modulating a single RF signal with two low frequency signals. The signals received by one of the two antennas are evaluated by determining, in an evaluating device, the difference between the amplitudes of the RF signals of different frequency which are reflected from an object. A DC voltage signal proportional to the above difference is generated and the DC voltage signal is fed to a threshold circuit whose threshold is determined by a predetermined azimuth range. Therefore, it can be determined if the reflecting object is in the same road lane as a car equipped with the radar.
An anticollision radar for motor vehicles comprising: at least two antennas each radiating a radio frequency signal of different frequencies, said two antennas having overlapping radiation patterns; a first means coupled to said two antennas to amplitude modulate a single radio frequency signal with two low frequencies to generate said radio frequency signals of different frequencies. second means coupled to one of said two antennas to receive said radio frequency signals of different frequencies reflected from an object, to determine the difference between the amplitudes of said two radio frequency signals reflected from said object and to generate a direct current voltage proportional to said difference; and third means having a threshold determined by a predetermined azimuth range coupled to said second means, said third means being responsive to said voltage to indicate whether said object is in the same road lane as a motor vehicle equipped with said radar.
Claim 2
Dependent Claim
150 words
An anticollision radar for motor vehicles comprising: at least two antennas each radiating a radio frequency signal of different frequencies, said two antennas having overlapping radiation patterns; a first means coupled to said two antennas to amplitude modulate a single radio frequency signal with two low frequencies to generate said radio frequency signals of different frequencies. second means coupled to one of said two antennas to receive said radio frequency signals of different frequencies reflected from an object, to determine the difference between the amplitudes of said two radio frequency signals reflected from said object and to generate a direct current voltage proportional to said difference; and third means having a threshold determined by a predetermined azimuth range coupled to said second means, said third means being responsive to said voltage to indicate whether said object is in the same road lane as a motor vehicle equipped with said radar.