Linear Spatio-Temporal Prediction for Adaptive Optics Wavefront Reconstructors

Detailed computer simulations have been performed to evaluate the potential for spatio-temporal prediction of wavefront slope data from a Shack-Hartmann sensor to improve the imaging quality of an astronomical adaptive optics system by overcoming the effect of the inherent delay between sensing and correcting the wavefront phase error. Results of the simulations show that an improvement of a factor of at least 2 in the residual mean-square phase error can be achieved by extrapolating into the future on the basis of past wavefront measurements. Experiments will be conducted very shortly with actual data gathered at a 1.6 m telescope using a Shack-Hartmann sensor with 31-cm subapertures to test the simulations. Both the simulations and the experimental arrangement have been chosen to match closely the measured operating conditions of the adaptive optics system under construction for the 6.5 m MMT (Martin & Anderson 1995).