Laser satellite communication has become especially attractive in recent years. However, because the laser beam is very
narrow and there is a long distance between satellites, the laser communication channel is very sensitive to vibrations of
the optical platform. These vibrations cause optical jitter, leading to the reduction of received signals and bit-error rate
degradation. Consequently, optical jitter control with PAT (pointing acquisition and tracking) subsystems is a critical
problem in laser satellite communication. To compensate for the platform vibration effectively in realtime, in this paper,
an adaptive feedback control technique based on Youla-parameterization is presented, which can adapt to the current
disturbance acting on the laser beam by adjusting its parameters in realtime to maintain optimal performance. The main
idea is to use the well-known Youla parameterization formula to construct a feedback control scheme with the
guaranteed closed loop stability, and the feedback controller is a function of plant coprime factors and a free parameter Q.
For adaptive disturbance estimation, the free parameter Q is set to an adaptive finite impulse response (FIR) filter, the
coefficients of which are updated by a recursive least-squares (RLS) algorithm in realtime. It is shown in experiment that
the adaptive feedback control technique based on Youla-parameterization can reject the optical jitter caused by satellite
platform vibration effectively and improve the performance of the system.