Analysis of GeMS tip-tilt on-sky data: LQG implementation for vibration rejections

Lucie Leboulleux; Gaetano Sivo; Rémy Juvénal; Caroline Kulcsár; Vincent Garrel; Henri François Raynaud; Jean Marc Conan; Cyril Petit; William Rambold; Pedro Gigoux; Eduardo Marin; Vanessa Montes; Cristian Moreno; Chad Trujillo

doi:10.20353/K3T4CP1131621

Analysis of GeMS tip-tilt on-sky data: LQG implementation for vibration rejections

Lucie Leboulleux, Gaetano Sivo, Rémy Juvénal, Caroline Kulcsár, Vincent Garrel, Henri François Raynaud, Jean Marc Conan, Cyril Petit, William Rambold, Pedro Gigoux, Eduardo Marin, Vanessa Montes, Cristian Moreno, Chad Trujillo

Research output: Contribution to conference › Paper › peer-review

1 Scopus citations

Abstract

Adaptive Optics (AO) systems aim at detecting and correcting for optical distortions induced by atmospheric turbulences on ground based telescopes astronomical images. They are also extremely sensitive to extraneous sources of perturbations such as vibrations, which degrade their performance. A new well defined vibration at 37Hz has been detected in January 2015 and is still currently affecting the Gemini South telescope secondary mirror. We show how its existence limits the performance of the operational systems at Gemini South: The Gemini Planet Imager (GPI) and the Gemini Multi-Conjugated AO system (GeMS). We further focus on how these vibrations are affecting GeMS performance and propose to implement the Tip-Tilt control strategy first tested on CANARY and routinely used on SPHERE. It combines identification of a sum of auto-regressive models of order 2 with a Linear Quadratic Gaussian (LQG) control. LQG is now routinely used for Tip-Tilt and focus control for GPI and has been successfully tested on all modes on CANARY. We show that the expected gain in performance brought by this LQG Tip-Tilt control strategy on GeMS compared with an Integral Controller is on the order of 15 to 20mas. The analysis was conducted in "replay mode" using GeMS Tip-Tilt on-sky data. This allows realistic performance assessment before implementation inside the Real-Time Computer (RTC) of GeMS and on-sky tests during the first semester of 2016.

Original language	English (US)
DOIs	https://doi.org/10.20353/K3T4CP1131621
State	Published - 2015
Externally published	Yes
Event	4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015 - Lake Arrowhead, United States Duration: Oct 26 2015 → Oct 30 2015

Conference

Conference	4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015
Country/Territory	United States
City	Lake Arrowhead
Period	10/26/15 → 10/30/15

Keywords

Adaptive optics
GeMS
Kalman filter
LQG
Multi conjugated adaptive optics
Optimal control
Vibrations rejection

ASJC Scopus subject areas

Control and Systems Engineering
Instrumentation
Electronic, Optical and Magnetic Materials
Space and Planetary Science
Astronomy and Astrophysics
Mechanical Engineering

Access to Document

10.20353/K3T4CP1131621

Cite this

Leboulleux, L., Sivo, G., Juvénal, R., Kulcsár, C., Garrel, V., Raynaud, H. F., Conan, J. M., Petit, C., Rambold, W., Gigoux, P., Marin, E., Montes, V., Moreno, C., & Trujillo, C. (2015). Analysis of GeMS tip-tilt on-sky data: LQG implementation for vibration rejections. Paper presented at 4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015, Lake Arrowhead, United States. https://doi.org/10.20353/K3T4CP1131621

Leboulleux, L, Sivo, G, Juvénal, R, Kulcsár, C, Garrel, V, Raynaud, HF, Conan, JM, Petit, C, Rambold, W, Gigoux, P, Marin, E, Montes, V, Moreno, C & Trujillo, C 2015, 'Analysis of GeMS tip-tilt on-sky data: LQG implementation for vibration rejections', Paper presented at 4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015, Lake Arrowhead, United States, 10/26/15 - 10/30/15. https://doi.org/10.20353/K3T4CP1131621

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title = "Analysis of GeMS tip-tilt on-sky data: LQG implementation for vibration rejections",

abstract = "Adaptive Optics (AO) systems aim at detecting and correcting for optical distortions induced by atmospheric turbulences on ground based telescopes astronomical images. They are also extremely sensitive to extraneous sources of perturbations such as vibrations, which degrade their performance. A new well defined vibration at 37Hz has been detected in January 2015 and is still currently affecting the Gemini South telescope secondary mirror. We show how its existence limits the performance of the operational systems at Gemini South: The Gemini Planet Imager (GPI) and the Gemini Multi-Conjugated AO system (GeMS). We further focus on how these vibrations are affecting GeMS performance and propose to implement the Tip-Tilt control strategy first tested on CANARY and routinely used on SPHERE. It combines identification of a sum of auto-regressive models of order 2 with a Linear Quadratic Gaussian (LQG) control. LQG is now routinely used for Tip-Tilt and focus control for GPI and has been successfully tested on all modes on CANARY. We show that the expected gain in performance brought by this LQG Tip-Tilt control strategy on GeMS compared with an Integral Controller is on the order of 15 to 20mas. The analysis was conducted in {"}replay mode{"} using GeMS Tip-Tilt on-sky data. This allows realistic performance assessment before implementation inside the Real-Time Computer (RTC) of GeMS and on-sky tests during the first semester of 2016.",

keywords = "Adaptive optics, GeMS, Kalman filter, LQG, Multi conjugated adaptive optics, Optimal control, Vibrations rejection",

author = "Lucie Leboulleux and Gaetano Sivo and R{\'e}my Juv{\'e}nal and Caroline Kulcs{\'a}r and Vincent Garrel and Raynaud, {Henri Fran{\c c}ois} and Conan, {Jean Marc} and Cyril Petit and William Rambold and Pedro Gigoux and Eduardo Marin and Vanessa Montes and Cristian Moreno and Chad Trujillo",

note = "Funding Information: Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Minist{\'e}rio da Ci{\^e}ncia, Tecnologia e Inova{\c c}{\~a}o (Brazil) and Ministerio de Ciencia, Tecnolog{\'i}a e Innovaci{\'o}n Productiva (Argentina).; 4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015 ; Conference date: 26-10-2015 Through 30-10-2015",

year = "2015",

doi = "10.20353/K3T4CP1131621",

language = "English (US)",

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TY - CONF

T1 - Analysis of GeMS tip-tilt on-sky data

T2 - 4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015

AU - Leboulleux, Lucie

AU - Sivo, Gaetano

AU - Juvénal, Rémy

AU - Kulcsár, Caroline

AU - Garrel, Vincent

AU - Raynaud, Henri François

AU - Conan, Jean Marc

AU - Petit, Cyril

AU - Rambold, William

AU - Gigoux, Pedro

AU - Marin, Eduardo

AU - Montes, Vanessa

AU - Moreno, Cristian

AU - Trujillo, Chad

N1 - Funding Information: Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

PY - 2015

Y1 - 2015

N2 - Adaptive Optics (AO) systems aim at detecting and correcting for optical distortions induced by atmospheric turbulences on ground based telescopes astronomical images. They are also extremely sensitive to extraneous sources of perturbations such as vibrations, which degrade their performance. A new well defined vibration at 37Hz has been detected in January 2015 and is still currently affecting the Gemini South telescope secondary mirror. We show how its existence limits the performance of the operational systems at Gemini South: The Gemini Planet Imager (GPI) and the Gemini Multi-Conjugated AO system (GeMS). We further focus on how these vibrations are affecting GeMS performance and propose to implement the Tip-Tilt control strategy first tested on CANARY and routinely used on SPHERE. It combines identification of a sum of auto-regressive models of order 2 with a Linear Quadratic Gaussian (LQG) control. LQG is now routinely used for Tip-Tilt and focus control for GPI and has been successfully tested on all modes on CANARY. We show that the expected gain in performance brought by this LQG Tip-Tilt control strategy on GeMS compared with an Integral Controller is on the order of 15 to 20mas. The analysis was conducted in "replay mode" using GeMS Tip-Tilt on-sky data. This allows realistic performance assessment before implementation inside the Real-Time Computer (RTC) of GeMS and on-sky tests during the first semester of 2016.

AB - Adaptive Optics (AO) systems aim at detecting and correcting for optical distortions induced by atmospheric turbulences on ground based telescopes astronomical images. They are also extremely sensitive to extraneous sources of perturbations such as vibrations, which degrade their performance. A new well defined vibration at 37Hz has been detected in January 2015 and is still currently affecting the Gemini South telescope secondary mirror. We show how its existence limits the performance of the operational systems at Gemini South: The Gemini Planet Imager (GPI) and the Gemini Multi-Conjugated AO system (GeMS). We further focus on how these vibrations are affecting GeMS performance and propose to implement the Tip-Tilt control strategy first tested on CANARY and routinely used on SPHERE. It combines identification of a sum of auto-regressive models of order 2 with a Linear Quadratic Gaussian (LQG) control. LQG is now routinely used for Tip-Tilt and focus control for GPI and has been successfully tested on all modes on CANARY. We show that the expected gain in performance brought by this LQG Tip-Tilt control strategy on GeMS compared with an Integral Controller is on the order of 15 to 20mas. The analysis was conducted in "replay mode" using GeMS Tip-Tilt on-sky data. This allows realistic performance assessment before implementation inside the Real-Time Computer (RTC) of GeMS and on-sky tests during the first semester of 2016.

KW - Adaptive optics

KW - GeMS

KW - Kalman filter

KW - LQG

KW - Multi conjugated adaptive optics

KW - Optimal control

KW - Vibrations rejection

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DO - 10.20353/K3T4CP1131621

M3 - Paper

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Y2 - 26 October 2015 through 30 October 2015

ER -

Analysis of GeMS tip-tilt on-sky data: LQG implementation for vibration rejections

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