| 摘要 |
A passive doppler differential ranging method for use with respect to an aircraft radar for determining the range, R, of a threat passively, includes the steps of mounting a first receiving antenna and a second receiving antenna on an aircraft and positioning the first and second antennas a known distance, d, apart from each other, and determining the azimuth angle alpha of the threat with respect to the aircraft at a first time to. A first differential doppler phase shift, DELTA phi , between the first and second antennas of a received signal transmitted by the threat at time to is then determined. The velocity of the aircraft is measured, and a second differential phase shift, DELTA phi 1, between the first and second antennas of a received signal transmitted by the threat at time t1 is then determined. The differential differential doppler phase shift, DELTA DELTA phi , is determined by subtracting the first differential doppler phase shift from the second differential doppler phase shift, and the range, R, of the threat at time t1 is then determined. The passive doppler differential ranging system includes two antennas and preferably includes an interferometer which is used to determine the differential doppler phase shift at time to.
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