Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published April 2013 | Published
Journal Article Open

Increased sky coverage with optimal correction of tilt and tilt-anisoplanatism modes in laser-guide-star multiconjugate adaptive optics

Abstract

Laser-guide-star multiconjugate adaptive optics (MCAO) systems require natural guide stars (NGS) to measure tilt and tilt-anisoplanatism modes. Making optimal use of the limited number of photons coming from such, generally dim, sources is mandatory to obtain reasonable sky coverage, i.e., the probability of finding asterisms amenable to NGS wavefront (WF) sensing for a predefined WF error budget. This paper presents a Strehl-optimal (minimum residual variance) spatiotemporal reconstructor merging principles of modal atmospheric tomography and optimal stochastic control theory. Simulations of NFIRAOS, the first light MCAO system for the thirty-meter telescope, using ∼500 typical NGS asterisms, show that the minimum-variance (MV) controller delivers outstanding results, in particular for cases with relatively dim stars (down to magnitude 22 in the H-band), for which low-temporal frame rates (as low as 16 Hz) are required to integrate enough flux. Over all the cases tested ∼21  nm  rms median improvement in WF error can be achieved with the MV compared to the current baseline, a type-II controller based on a double integrator. This means that for a given level of tolerable residual WF error, the sky coverage is increased by roughly 10%, a quite significant figure. The improvement goes up to more than 20% when compared with a traditional single-integrator controller.

Additional Information

© 2013 Optical Society of America. Received December 6, 2012; revised January 25, 2013; accepted January 25, 2013; posted January 29, 2013 (Doc. ID 181273); published March 11, 2013. The authors thank Caroline Kulcsár and Henri-François Raynaud for fruitful discussions regarding the upsampled MV controller.

Attached Files

Published - josaa-30-4-604.pdf

Files

josaa-30-4-604.pdf
Files (604.8 kB)
Name Size Download all
md5:4e4bd7f3743d21800e398e8f92a2f753
604.8 kB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 23, 2023