Title
Absolute distance metrology for space interferometers
Author
Swinkels, B.L.
Wendrich, T.J.
Bhattacharya, N.
Wielders, A.A.
Braat, J.J.M.
Technisch Physische Dienst TNO - TH
Contributor
Warmbein, B. (editor)
Publication year
2004
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. This metrology system consists of various sub-systems to monitor distances, angles and speeds. Our research focuses on one of these 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 building a frequency sweeping interferometer. It is operated by first measuring a phase in the interferometer, sweeping a tunable laser over a known frequency interval and finally measuring 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. We plan on actively stabilizing the wavelength at the endpoints of the sweep on a Fabry-Perot cavity using the Pound-Drever-Hall technique. In this way the unknown distance is directly referenced to the length of the Fabry-Perot cavity.
Subject
Space & Scientific Instrumentation
Industrial Innovation
Amplitude modulation
Large scale systems
Laser tuning
Measurements
Natural frequencies
Space applications
Space telescopes
Complex metrology systems
Frequency sweeping interferometry (FSI)
Tunable lasers
Interferometers
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TNO identifier
237808
ISSN
0379-6566
Source
Proceedings of the 5th International Conference on Space Optics, ICSO 2004, 30 March - 2 April 2004, Toulouse, France (554), 559-561
Bibliographical note
Ook gepresenteerd op: Semiconductor Lasers and Laser Dynamics Conference, 27-30 April 2004, Strasbourg, France
Document type
conference paper