| 摘要 |
<p>44A radar arrangement (1) suitable for measuring the horizontal velocity v of an aircraft relative to the ground (2) comprises an high-frequency signal generator (10) including a transmitting aerial (9), a receiver including two aerials (12, 11) spaced a distance d apart along a line in the direction of the velocity to be measured and respective mixers (30, 31) and filters (32, 33), and a correlator (15) which determines the value ( tau =d/v) of the delay of the signals received at the rearmost aerial (11) relative to those received at the foremost (12) for which the correlation is a maximum. The signal generator (10) generates two linearly frequency-modulated waves (E2, E1) and is controlled by the correlator (15) so that the interval between E2 and E1 equals tau . The height H of the aircraft can also easily be determined, being directly proportional to the beat frequency at the output of the filters (32, 33).</p> |
