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Adaptive DIT-Based Fringe Tracking and Prediction at IOTAAn automatic fringe tracking system has been developed and implemented at the Infrared Optical Telescope Array (IOTA). In testing during May 2002, the system successfully minimized the optical path differences (OPDs) for all three baselines at IOTA. Based on sliding window discrete Fourier transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on off-line data. Implemented in ANSI C on the 266 MHZ PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. Preliminary analysis on an extension of this algorithm indicates a potential for predictive tracking, although at present, real-time implementation of this extension would require significantly more computational capacity.
Document ID
20040161180
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Wilson, Edward
(Intellization Redwood Shores, CA, United States)
Pedretti, Ettore
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Bregman, Jesse
(NASA Ames Research Center Moffett Field, CA, United States)
Mah, Robert W.
(NASA Ames Research Center Moffett Field, CA, United States)
Traub, Wesley A.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Date Acquired
September 7, 2013
Publication Date
June 1, 2004
Publication Information
Publication: Proceedings of the SPIE Astronomical Telescopes and Instrumentation Symposium: New Frontiers in Stellar Interferometry
Volume: 5491
Issue: 173
Subject Category
Optics
Distribution Limits
Public
Copyright
Public Use Permitted.
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