Half angle mechanism for a heliostat

摘要

An improved heliostat device for an electrooptical system in which a mirror is gimbaled in two axes for line-of-sight direction and stabilization. A half angle drive system is connected to the mirror for controlling azimuth rotation of the mirror relative to the stable body from which the mirror is mounted. The half angle drive system comprises a N-2N-speed synchro transmitter-receiver pair, with the N-speed synchro control transmitter mounted on the stable body axis, and the 2N-speed control receiver mounted on the mirror axis. This synchro transmitter-receiver pair is operable with a null error signal controlling mirror drive such that the angular rotation of the mirror is one-half that of the angular rotation of the stable body.