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Proceedings Paper • Open Access

Signal processing for order 10 PM accuracy displacement metrology in real-world scientific applications
Author(s): Peter G. Halverson; Frank M. Loya

Paper Abstract

Projects such as the Space Interferometry Mission (SIM) [1] and Terrestrial Planet Finder (TPF) [2] rely heavily on sub-nanometer accuracy metrology systems to define their optical paths and geometries. The James Web Space Telescope (JWST) is using this metrology in a cryogenic dilatometer for characterizing material properties (thermal expansion, creep) of optical materials. For all these projects, a key issue has been the reliability and stability of the electronics that convert displacement metrology signals into real-time distance determinations. A particular concern is the behavior of the electronics in situations where laser heterodyne signals are weak or noisy and subject to abrupt Doppler shifts due to vibrations or the slewing of motorized optics. A second concern is the long-term (hours to days) stability of the distance measurements under conditions of drifting laser power and ambient temperature.

This paper describes heterodyne displacement metrology gauge signal processing methods that achieve satisfactory robustness against low signal strength and spurious signals, and good long-term stability. We have a proven displacement-measuring approach that is useful not only to space-optical projects at JPL, but also to the wider field of distance measurements.

Paper Details

Date Published: 21 November 2017
PDF: 8 pages
Proc. SPIE 10568, International Conference on Space Optics — ICSO 2004, 1056812 (21 November 2017); doi: 10.1117/12.2308008
Show Author Affiliations
Peter G. Halverson, Jet Propulsion Lab., California Institute of Technology (United States)
Frank M. Loya, Jet Propulsion Lab., California Institute of Technology (United States)


Published in SPIE Proceedings Vol. 10568:
International Conference on Space Optics — ICSO 2004
Josiane Costeraste; Errico Armandillo, Editor(s)

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