A comparison of inertial line-of-sight stabilization techniques using mirrors

Mirrors are commonly used to stabilize images and point the line-of-sight (LOS) for a variety of electro-optical applications such as surveillance, target tracking and laser pointing. However, the law of reflection introduces an inherent 2:1 relationship in the axis perpendicular to the LOS that must be addressed. Because of this relationship, simply stabilizing the mirror in inertial space will not stabilize the LOS. Also, the 2:1 relationship renders the mirror stabilization configuration particularly susceptible to base motions. Presented are several different techniques that use a combination of mechanisms and inertial / relative-motion sensors that can be used to deal with these limitations. The techniques are described along with a discussion of the characteristics and tradeoffs associated with each.