Abstract

Experiments have shown the reward adaptive optics provides in improving the resolution of ground-based astronomical telescopes.^1-2 A critical contributor to adaptive optics system performance is the reconstruction algorithm that converts wavefront sensor (WFS) measurements into the deformable mirror (DM) actuator commands.^3-4 Minimum variance reconstruction algorithms have been developed extensively to optimize the performance of adaptive optics systems given specific atmospheric conditions.^5-7 These algorithms depend on atmospheric parameters which are seldom known exactly and are constantly fluctuating. This is especially true for systems incorporating multiple WFS beacons that require knowledge of the wind speed profile, the vertical distribution of atmospheric turbulence, and the intensity of the wavefront sensing beacons to calculate the optimal reconstructor.⁷ This uncertainty and continual changing of atmospheric conditions implies that an optimal degree of turbulence compensation cannot be achieved or maintained over long time intervals with static reconstructor coefficients. A need exists for a method of updating these coefficients in real time based on actual closed-loop performance.

© 1995 Optical Society of America