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Simulations of closed-loop wavefront reconstruction for multiconjugate adaptive optics on giant telescopes

Ellerbroek, Brent L. and Vogel, C. R. (2003) Simulations of closed-loop wavefront reconstruction for multiconjugate adaptive optics on giant telescopes. In: Astronomical Adaptive Optics Systems and Applications. Proceedings of SPIE. No.5169. Society of Photo-Optical Instrumentation Engineers , Bellingham, WA, pp. 206-217. ISBN 9780819450425. https://resolver.caltech.edu/CaltechAUTHORS:20181217-161905888

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Abstract

The multi-conjugate adaptive optics (MCAO) systems proposed for future giant telescopes will require new, computationally efficient, concepts for wavefront reconstruction due to their very large number of deformable mirror (DM) actuators and wavefront sensor (WFS) measurements. Preliminary versions of such reconstruction algorithms have recently been developed, and simulations of MCAO systems with 9000 or more DM actuators and 33000 or more WFS measurements are now possible using a single desktop computer. However, the results obtained to date are limited to the case of open-loop wavefront reconstruction, and more work is needed to develop computationally efficient reconstructors for the more realistic case of a closed-loop MCAO system that iteratively measures and corrects time-varying wavefront distortions. In this paper, we describe and investigate two reconstruction concepts for this application. The first approach assumes that knowledge of the DM actuator command vector and the DM-to-WFS influence matrix may be used to convert a closed-loop WFS measurement into an accurate estimate of the corresponding open-loop measurement, so that a standard open-loop wavefront reconstructor may be applied. The second approach is a very coarse (but computationally efficient) approximation to computing the minimum variance wavefront reconstructor for the residual wavefront errors in a closed-loop AO system. Sample simulation results are presented for both concepts with natural guide star (NGS) AO and laser guide star (LGS) MCAO systems on 8- and 32-meter class telescopes. The first approach yields a stable control loop with closed-loop performance comparable to the open-loop estimation accuracy of the classical minimum variance reconstructor. The second approach is unstable when implemented in a type I servo system.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.506580DOIArticle
Additional Information:© 2003 Society of Photo-Optical Instrumentation Engineers. The New Initiatives Office is a partnership between two divisions of the Association of Universities for Research in Astronomy (AURA), Inc.: The National Optical Astronomy Observatory (NOAO) and the Gemini Observatory. NOAO is operated by AURA under a cooperative agreement with the National Science Foundation (NSF). The Gemini Observatory is operated by AURA under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil) and CONICET (Argentina).
Group:Thirty Meter Telescope
Funders:
Funding AgencyGrant Number
Association of Universities for Research in Astronomy (AURA)UNSPECIFIED
National Optical Astronomy Observatory (NOAO)UNSPECIFIED
Gemini ObservatoryUNSPECIFIED
NSFUNSPECIFIED
Particle Physics and Astronomy Research Council (United Kingdom)UNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)UNSPECIFIED
Australian Research CouncilUNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)UNSPECIFIED
Subject Keywords:Multi-conjugate adaptive optics; wavefront reconstruction; extremely large telescopes
Series Name:Proceedings of SPIE
Issue or Number:5169
Record Number:CaltechAUTHORS:20181217-161905888
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20181217-161905888
Official Citation:Brent L. Ellerbroek, Curtis R. Vogel, "Simulations of closed-loop wavefront reconstruction for multiconjugate adaptive optics on giant telescopes," Proc. SPIE 5169, Astronomical Adaptive Optics Systems and Applications, (24 December 2003); doi: 10.1117/12.506580
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91877
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:18 Dec 2018 17:57
Last Modified:03 Oct 2019 20:39

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