Gravity distortion compensation via subreflector motion for 64m shaped Cassegrain antenna

On the degradation of electrical performance due to the main reflector deformation of large shaped Cassegrain antennas, a method for compensation by moving subreflector is presented. A group of best-fit paraboloids are found by least-square fitting the theoretical discrete data. The group of paraboloids are used to fit the deformed main reflector, with the constraint of all these focuses being in line. The best-fit parameters are optimized and the adjustments of subreflector are derived with the ratio of main reflector and subreflector. The adjustments at various attitudes are saved in a look-up table to real-time compensate for main reflector deformation. From the experimental verification on a 64m reflector antenna, satisfactory results are obtained and will be used in practice.