Kalman filter based control for adaptive optics

While the first MultiConjugate Adaptive Optics (MCAO) experimental set-ups are presently under construction, a growing attention is paid to the control loop. This is indeed a key element in the optimization process, especially for MCAO systems. Different approaches have been proposed in recent articles for astronomical applications: simple integrator, Optimized Modal Gain Integrator and Kalman filtering. We study here Kalman filtering, which seems a very promising solution. We have already proposed and simulated in simple cases a formalized adaptation of Kalman filtering to Adaptive Optics (AO) and MCAO. (1-3) We wish now to characterize for the first time the frequential properties of this Kalman filter and to refine it so as to improve its robustness and performance, for instance in the presence of static aberrations and vibrations. Comparisons with classical controllers are proposed. Aliasing reduction could also be considered. In the near future, Kalman filter performance and robustness should be tested for realistic AO and MCAO configurations on a simulator and an experimental set-up.