Patent ID: 7064704

Claim:
A radar apparatus operative to selectively filter ambiguous echoes, comprising: a transmitter operative to transmit electromagnetic pulses in varying pulse repetition intervals; range gates operative to receive energy impulses reflected by at least one object; a Doppler filter operative to work with an impulse function response having a length that is significantly shorter than a predetermined number of periods and thereby to produce for a received impulse a number of outgoing impulses, wherein upon the appearance in the radar of a representative single impulse for a plurality of echoes, the Doppler filter emits an output impulse that is significantly shorter than the output impulse signal caused by a first of the echoes; and at least one threshold device that, irrespective of the amplitudes of the representative single impulses, generates fewer incidences of threshold exceeding than a corresponding first-time-around impulse, thus producing output impulses for a plurality of pulse intervals, with the radar being operative to ascertain the differences between the incidences of threshold exceeding and to use these as the basis for the filtering.