Advanced control of low order modes in laser guide star multi-conjugate adaptive optics systems

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DOIResolve DOI: http://doi.org/10.1117/12.926872
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TypeArticle
Proceedings titleProceedings of SPIE - The International Society for Optical Engineering
ConferenceAdaptive Optics Systems III, 1 July 2012 through 6 July 2012, Amsterdam
ISSN0277-786X
ISBN9780819491480
Volume8447
Article number84471S
SubjectAdvanced control; Anisoplanatism; Atmospheric tomography; Double integrator; Kalman-filtering; Laser guide star; Low order; Lower bounds; Modal gain; Multi-conjugate adaptive optics systems; Parameter optimisation; Thirty Meter Telescope; Lasers; Mineralogy; Optimization; Stars
AbstractLaser-guide-star-based multi-conjugate adaptive optics (MCAO) systems require natural guide-stars to measure tilt and tilt-anisoplanatism modes. This paper focuses on the parameter optimisation of sub-optimal integrator-based controllers using a single and a double integrator (baseline option) to drive the low-order loop of NFIRAOS, the 1st light MCAO system for the Thirty-Meter Telescope. The minimum-variance (MV) controller is outlined, against which integrators are compared. Simulations using ∼500 asterisms considered in sky-coverage simulations for the TMT show that the double integrator gives competitive results thoughout the range of asterisms and magnitudes considered. It is shown that using an optimal modal gain integrator can further improve the performance with respect to using an averaged gain for all of part of the modes. However, it is outperformed by the MV controller, in particular for asterisms with relatively dim stars (lower bound is magnitude 22 in H-band) requiring low temporal frame-rates (as low as 16Hz) to integrate more flux. Over all the cases tested, an average of ∼100 nm rms (23 nm rms median) improvement can be achieved with the MV. The MV further increases by 15% the probability of working below the 50th-percentile residual of the double integrator. © 2012 SPIE.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Herzberg Institute of Astrophysics (HIA-IHA)
Peer reviewedYes
NPARC number21269178
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Record identifier14337dcd-f395-43c7-8ad2-58e594044b2d
Record created2013-12-12
Record modified2016-05-09
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