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Reference : UMR8109-YANCLE-004
Workplace : MEUDON
Date of publication : Friday, December 07, 2018
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 February 2019
Proportion of work : Full time
Remuneration : Based on experience (cf. CNRS salary grids), for ex. from 2600€ to 3000€ monthly for someone with no experience
Desired level of education : PhD
Experience required : Indifferent
The proposed research topic concerns the single conjugate adaptive optics (SCAO) system of MICADO-MAORY at the European Extremely Large Telescope (ELT). It aims to define, model and evaluate the performance of algorithms for the real-time optical correction of the effect of mechanical vibrations induced in the structure of the instruments and the movement of the telescope under the effect of the wind load. These activities will focus primarily on tip-tilt modes, and possibly on some higher orders.
Using the team's numerical simulation tools and control laws developed as part of this research, it will also consist in establishing the SCAO error budget to derive the SCAO system performance.
The wind load on the ELT will make its huge structure oscillate and shake with a much greater amplitude than the degradation of the image quality due to turbulence, and following a modeled and known broad temporal spectrum. There will be in addition various sources of excitation such as motors, fans, cryo-generators present around the instrument which will produce mechanical vibrations in the structures. The induced optical effect will mainly be on tip / tilt aberrations but perhaps also on other modes. Perceived by the SCAO system, they will degrade its performances if nothing is done to compensate for them.
Strategies for identifying and correcting these tip / tilt errors have already been implemented for the current generation of AO system (for example Kalman filter or more generally LQG method). Starting from this existing, it will be necessary to elaborate a strategy specific to the MICADO-MAORY SCAO system and to develop the corresponding algorithms while respecting a balance subjected to three constraints: efficiency of the correction, compatibility with the numerical real-time aspects, and robustness of the identification strategy of the phenomena to be corrected with respect to the very great variety and potential variability of the observation conditions. After getting started with our AO COMPASS simulation code (https://anr-compass.github.io/compass/), the post-holder will implement these algorithms and optimize them while measuring their performance. This work will feed the design of the SCAO real-time computer.
More generally, the post-holder will work on the establishment of the overall error budget of the MICADO-MAORY SCAO mode, starting from the work already done as part of the preliminary design phase and integrating the results obtained for tip / tilt correction.
- PhD in physics, related to adaptive optics or control theory / automatic
- Adaptive optics simulations
- Python language
- A knowledge of the CUDA language would be a plus
- Technical English
LESIA, department of the Observatoire de Paris and laboratory of the CNRS, is one of the largest French research laboratories in astrophysics (about 12% of the discipline). The laboratory has more than 240 agents including about 130 permanent positions. The primary purpose of LESIA is:
- the design and production of space and ground-based instrumentation;
- the exploitation and scientific interpretation of the observations of the instruments made in our laboratory;
- the development of advanced techniques implemented in ground-based as well as space instruments.
LESIA is located on the Meudon site of the Observatoire de Paris.
The recruited person will be integrated into the ELT MICADO project team and will be integrated into the “Pôle Haute Résolution Angulaire en Astrophysique”.
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