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Results of the NFIRAOS RTC trade study

Véran, Jean-Pierre and Boyer, Corrine and Ellerbroek, Brent L. and Gilles, Luc and Herriot, Glen and Kerley, Daniel A. and Ljusic, Zoran and McVeigh, Eric A. and Prior, Robert and Smith, Malcolm and Wang, Lianqi (2014) Results of the NFIRAOS RTC trade study. In: Adaptive Optics Systems IV. Proceedings of SPIE. No.9148. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 91482F. ISBN 9780819496164.

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With two large deformable mirrors with a total of more than 7000 actuators that need to be driven from the measurements of six 60x60 LGS WFSs (total 1.23Mpixels) at 800Hz with a latency of less than one frame, NFIRAOS presents an interesting real-time computing challenge. This paper reports on a recent trade study to evaluate which current technology could meet this challenge, with the plan to select a baseline architecture by the beginning of NFIRAOS construction in 2014. We have evaluated a number of architectures, ranging from very specialized layouts with custom boards to more generic architectures made from commercial off-the-shelf units (CPUs with or without accelerator boards). For each architecture, we have found the most suitable algorithm, mapped it onto the hardware and evaluated the performance through benchmarking whenever possible. We have evaluated a large number of criteria, including cost, power consumption, reliability and flexibility, and proceeded with scoring each architecture based on these criteria. We have found that, with today’s technology, the NFIRAOS requirements are well within reach of off-the-shelf commercial hardware running a parallel implementation of the straightforward matrix-vector multiply (MVM) algorithm for wave-front reconstruction. Even accelerators such as GPUs and Xeon Phis are no longer necessary. Indeed, we have found that the entire NFIRAOS RTC can be handled by seven 2U high-end PC-servers using 10GbE connectivity. Accelerators are only required for the off-line process of updating the matrix control matrix every ~10s, as observing conditions change.

Item Type:Book Section
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Additional Information:© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE).
Group:Thirty Meter Telescope
Subject Keywords:Adaptive optics, real-time computing, real-time control
Series Name:Proceedings of SPIE
Issue or Number:9148
Record Number:CaltechAUTHORS:20180619-155416736
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Official Citation:Jean-Pierre Véran, Corinne Boyer, Brent L. Ellerbroek, Luc Gilles, Glen Herriot, Daniel A. Kerley, Zoran Ljusic, Eric A. McVeigh, Robert Prior, Malcolm Smith, Lianqi Wang, "Results of the NFIRAOS RTC trade study", Proc. SPIE 9148, Adaptive Optics Systems IV, 91482F (21 July 2014); doi: 10.1117/12.2057323;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87242
Deposited By: George Porter
Deposited On:19 Jun 2018 23:15
Last Modified:11 Oct 2019 04:11

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