Mixed H2/H∞ approach of full order state observer design for satellite attitude control system

This paper investigates the design method of full order state observer for satellite attitude control system using mixed H₂/H_∞ optimal approach. A linear system described by state space form is introduced first to state the problem of full order state observer design. The designed observer should meet the requirement of H₂ performance and H_∞ performance so that the disturbance would influence the observer as little as possible. Thus, we convert the satellite attitude control system to the same state space form, and deduce the mixed H₂/H_∞ approach based on linear matrix inequalities (LMIs). By solving LMIs, we can obtain the solution of corresponding convex optimization problem. Then, the observer gain can be decided. The simulation results based on satellite attitude control system show that the magnitude of observer error is 10^-6 rad/s within 10000s. We can conclude that the mixed H₂/H_∞ approach of full order state observer design is effective and the external disturbance has little influence on the observation error.