Shipboard antenna pointing and alignment system

摘要

A mechanism for correcting for time-varying errors that affect the pointing accuracy of a shipboard mounted antenna employs a Kalman filter for realizing an optimal correction estimator through which inputs to the antenna aiming control hardware are adjusted. A series of coordinate system transformations, corrected by the Kalman filter error estimator, are carried out to provide a command input to an antenna pointing servo system. The servo control system produces a servo error signal representative of a deviation in the actual direction of the antenna pointing mechanism from the command input to the servo loop as defined by the corrected aiming signal. The actual direction in which the servo control system points the antenna is compared with a reference (the actual direction to the satellite). As a result of this comparison, a pointing deviation signal representative of any offset from the intended pointing direction is generated. Because this pointing deviation signal depends upon the output of the servo control mechanism, it inherently contains any error in that output. Such error is removed by subtracting the servo error signal from the pointing deviation signal and applying the resultant difference signal to the Kalman filter error estimator.