Image stabilization assembly for an optical system

DETAILED DESCRIPTION In the referenced patent, the optical tracking system includes a stabilization assembly having a mirror, pickoff and torquer.
The present invention recognizes that the mirror, pickoff and torquer comprise all of the elements necessary to create an inertial sensor, with the mirror being the proof mass.
The position of the mirror relative to the rigid block to which it is mounted is measured by the pickoff and the applied torque is known.
Therefore, the present invention contemplates causing the mirror to serve a dual purpose--(a) it is used as the control effector, effecting changes in the angular orientation of the line of sight by its motion, and (b) it is an integral part of the inertial sensor, providing a measure of the angular acceleration of the rigid block.
Thus, according to this invention, there is provided an assembly for rejecting environmental perturbations in an optical system which tracks a command line of sight.
The assembly comprises a mirror, a rigid block, means for flexibly coupling the mirror to the rigid block and providing two axes of rotational freedom for the mirror, torquer means for torquing the mirror about each of the axes, and pickoff means for sensing the angular position of the mirror relative to the rigid block about each of the axes and providing pickoff signals corresponding thereto.
The assembly further comprises control means receiving the pickoff signals and utilizing the dynamic properties of the mirror as coupled to the rigid block and the dynamic properties of the rigid block for providing a torquer signal for each of the axes to the torquer means.
The control means utilizes the mirror in conjunction with the torquer means and the pickoff means as an inertial sensor to provide a measure of the angular motion of the rigid block, and as a control effector to isolate the line of sight from unintentional, higher frequency rigid block motion (jitter or vibration) and to cause the optical system line of sight to track intentional, lower frequency rigid block motion (position commands)