Accelerometer assisted high bandwidth control of tip-tilt mirror for precision pointing stability

Pointing stability that defines acceptable displacement of an observation target on the optical detector during the exposure time in a satellite telescope system largely dominates the quality of the image. This research proposes a new control approach to improve pointing stability using a tip-tilt mirror. While conventional control systems for a tip-tilt mirror use feedback error signals obtained from the optical detector, the signal loses enough bandwidth to compensate for high frequency disturbances when pointing at a dark reference guide star. This paper presents a control system subsidiarily using accelerometers to generate high bandwidth feedforward control references to a tip-tilt mirror by properly identifying transfer function between acceleration and pointing displacement. The numerical simulation and experiments using a disturbance source and a tip-tilt mirror verifies feasibility of this method.