High doppler rate high altitude capability coherent pulsed doppler radar altimeter

Abstract From the Canadian patent

A pulse Doppler radar altimeter designed to resolve the ambiguous range problem associated with the use of a pulse repetition interval which is less , than the, aircraft altitude includes a radar transmitter configured to transmit first and second, series of pulses where the first series has a pulse repetition interval slightly different, from the pulse repetition interval of the second series. At a time when the first series, is being transmitted, the receiver electronics including a range gate and a tracker, searches for ground returns and positions the range gate in time coincidence with the, detected ground return. Control then shifts so that the second series of pulses is, …