A Trajectory Preprocessor for Antenna Pointing

S. R. TylerGround Antennas and Facilities EngineeringSectionA trajectory-preprocessing algorithm has been devised which matches antennaangular position, velocity, and acceleration to those of a target. This eliminatesvibrations of the antenna structure caused by discontinuities in velocity and ac-celeration commands, and improves antenna-pointing performance by constrainingantenna motion to a linear regime. The algorithm permits faster acquisition timesand preserves antenna-tracking capability in situations where there would otherwisebe an unacceptably sudden change in antenna velocity or acceleration. A simulationof DSS 13 shows that thb preprocessor would reduce servo error to I mdeg duringacquisition of a low-Earth-orbiting satellite.