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Proceedings Paper

Identification of the focal plane wavefront control system using E-M algorithm
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Paper Abstract

In a typical focal plane wavefront control (FPWC) system, such as the adaptive optics system of NASA’s WFIRST mission, the efficient controllers and estimators in use are usually model-based. As a result, the modeling accuracy of the system influences the ultimate performance of the control and estimation. Currently, a linear state space model is used and calculated based on lab measurements using Fourier optics. Although the physical model is clearly defined, it is usually biased due to incorrect distance measurements, imperfect diagnoses of the optical aberrations, and our lack of knowledge of the deformable mirrors (actuator gains and influence functions). In this paper, we present a new approach for measuring/estimating the linear state space model of a FPWC system using the expectation-maximization (E-M) algorithm. Simulation and lab results in the Princeton’s High Contrast Imaging Lab (HCIL) show that the E-M algorithm can well handle both the amplitude and phase errors and accurately recover the system. Using the recovered state space model, the controller creates dark holes with faster speed. The final accuracy of the model depends on the amount of data used for learning.

Paper Details

Date Published: 1 September 2017
PDF: 15 pages
Proc. SPIE 10400, Techniques and Instrumentation for Detection of Exoplanets VIII, 1040028 (1 September 2017); doi: 10.1117/12.2274835
Show Author Affiliations
He Sun, Princeton Univ. (United States)
N. Jeremy Kasdin, Princeton Univ. (United States)
Robert Vanderbei, Princeton Univ. (United States)

Published in SPIE Proceedings Vol. 10400:
Techniques and Instrumentation for Detection of Exoplanets VIII
Stuart Shaklan, Editor(s)

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