In an airborne radar system, moving ground targets are identified on a cathode ray tube (CRT) display and their motion tracked to allow precise delivery of air-to-ground weapons. Target location errors, due to the effect of target motion upon the doppler frequency of the received radar signals, are significantly reduced. The target's radial velocity with respect to the electrical boresight of the system antenna is determined and a corresponding frequency adjustment is made to the processed signal in order to locate the target accurately on the display so as to lie in precise correspondence with its displayed stationary surroundings. The measurement of target radial velocity also provides a precise interferometer antenna referenced azimuth angle estimate to be used for relative range and azimuth weapon guidance, independent of usually large angle errors arising from clutter effects within the field of view of the antenna, and of other hardware and navigational error sources associated with absolute angle measurement systems.
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