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Proceedings Paper

Absolute distance metrology for space interferometers
Author(s): Bas L. Swinkels; Thijs J. Wendrich; Nandini Bhattacharya; Arno A. Wielders; Joseph J.M. Braat
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Paper Abstract

Space interferometers consisting of several free flying telescopes, such as the planned Darwin mission, require a complex metrology system to make all the components operate as a single instrument. Our research focuses on one of its sub-systems that measures the absolute distance between two satellites with high accuracy. For Darwin the required accuracy would be in the order of 10 μm over 250 meter. To measure this absolute distance, we are currently exploring the frequency sweeping interferometry technique. Its measurement principle is to first measure a phase in the interferometer, sweep a tunable laser over a known frequency interval and finally measure a second phase. By also counting the number of fringes during the sweep it is possible to determine the absolute path length difference without ambiguities. The wavelength at the endpoints of the sweep is stabilized on a Fabry-Perot cavity. In this way the unknown distance is directly referenced to the length of the Fabry-Perot cavity.

Paper Details

Date Published: 29 September 2004
PDF: 5 pages
Proc. SPIE 5495, Astronomical Structures and Mechanisms Technology, (29 September 2004); doi: 10.1117/12.551270
Show Author Affiliations
Bas L. Swinkels, Technische Univ. Delft (Netherlands)
Thijs J. Wendrich, Technische Univ. Delft (Netherlands)
Nandini Bhattacharya, Technische Univ. Delft (Netherlands)
Arno A. Wielders, TNO TPD (Netherlands)
Joseph J.M. Braat, Technische Univ. Delft (Netherlands)

Published in SPIE Proceedings Vol. 5495:
Astronomical Structures and Mechanisms Technology
Joseph Antebi; Dietrich Lemke, Editor(s)

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