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Centro de Astrofísica da Universidade do Porto

Physical optics modeling of sky coverage for TMT NFIRAOS with advanced LQG controller

L. Wang, L. Gilles, B. Ellerbroek, C. M. Correia

Abstract
We have implemented the linear quadratic Gaussian (LQG) controller in our physical optics sky coverage simulator (MAOS) for the Thirty Meter Telescope (TMT) Narrow Field InFrared Adaptive Optics System (NFIRAOS) aimed for improved correction of tip/tilt and plate scale modes. The LQG controller has a built-in capability to correct narrow frequency vibrations that are above the closed loop bandwidth of the system and is a very desirable solution for this application. The LQG controller is tuned with the combined power spectral density (PSD) of turbulence, wind shake, and vibration computed from the telemetry. We will show how LQG performs for various telescope/instrument vibration spectral (such as broadband or drifting peaks). We will also show the performance and sky coverage of LQG in comparison with single or double integrator controllers for correcting low order atmospheric turbulence with a set of up to three tip/tilt(/focus) natural guide star wavefront sensors. We found that the LQG controller reduces the median sky coverage wavefront error by 25 nm in quadrature. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Adaptive Optics Systems IV
(Eds.) E. Marchetti, L. M. Close, J.-P. Véran

SPIE
Vol. 9148,
2014

>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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