CDS Lunchtime Seminar: Turbulence in Adaptive Optics Systems: Modeling, Estimation and Compensation

Prof. Angelo Cenedese (University of Padua, Italy)

ABSTRACT:  Turbulence phenomena emerge in communication systems due to the presence of a non-ideal transmissive medium that strongly affects the quality and limits the performance of data transmission.

A case study of interest is that of astronomical imaging from ground telescope:
In current and next generation of systems, in fact, Adaptive Optics (AO) are employed to correct the detrimental effects induced by the presence of atmospheric turbulence, that would strongly limit the actual resolution of the overall system. In this presentation, the whole problem is discussed, starting from the modal representation of turbulence, to the estimation of a suitable model, to the design of a compensation scheme for the AO system.

A layered model for the atmospheric turbulence is presented, based on the
definition of a Markov-Random-Field whose parameters are determined according to the turbulence statistics, and a procedure for the identification of the model is  designed that allows the estimation of both its static and dynamic characteristics. In this sense, the problem of turbulence estimation is formalized within the stochastic framework and conditions for the identifiability of the turbulence structure (numbers of layers, energies and velocities) are stated. Then, the information on the turbulence layers is employed to construct a linear predictor of the turbulence that can be used within a feedback control loop to compensate for the turbulent phase. The performance of the proposed approach is assessed by means of numerical results.
        


Angelo Cenedese (Laurea 1999, Ph.D 2004.) is currently Assistant Professor at the  Department of Engineering and Management of the University of Padova (Italy). He has held several visiting positions with international institutions: the JAERI  Institute, Naka, Japan (2000), the UKAEA-JET laboratory, Oxford, UK (2001-2004), General Atomics, SanDiego, CA (2004),
UCLA, Los Angeles, CA (2010). He has been and is currently involved in EU
Projects on control and diagnostics of nuclear fusion  devices, on methodologies for Adaptive Optics systems, on estimation and control in
distributed networked systems. His interests are in the fields of modeling,
control theory and its applications, active vision, sensor and actor networks, with particular attention to environmental monitoring and control, and surveillance  networks. He is co-author of more than 40 papers, and three international patent applications on the field of surveillance sensor networks are under submission.




http://automatica.dei.unipd.it/people/cenedese/research.html


===============================================
If you are interested in meeting with the speaker, please contact
Elisa Franco, elisaf (at) caltech.edu.