<title>Active figure maintenance control using an optical truss laser metrology system for a space-based far-IR segmented telescope</title>

The USNO Astrometric Interferometer (USNOAI; a subarray of the Navy Prototype Optical Interferometer at Lowell Observatory) is presently under construction and expected to begin limited operations within a year. The main goal of the USNOAI observations is to provide a northern hemisphere catalog of several thousand stars with positions known to a few mas. In order to meet this requirement, a baseline laser metrology system must be employed to measure the three-dimensional motions of the baselines with an accuracy better than ~ 0.1 μm. The metrology scheme, as presently conceived, represents the largest and most complex high-resolution laser metrology system ever attempted.

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Laser interferometric high-precision geometry (angle and length) monitor for JASMINE

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308019315 ◽

2007 ◽

Vol 3 (S248) ◽

pp. 280-281

Author(s):

Y. Niwa ◽

K. Arai ◽

A. Ueda ◽

M. Sakagami ◽

N. Gouda ◽

...

Keyword(s):

Wave Front ◽

High Precision ◽

Small Scales ◽

Laser Metrology ◽

Laser Interferometric ◽

Metrology System

AbstractThe telescope geometry of JASMINE should be stabilized and monitored with the accuracy of about 10 to 100 pm or 10 to 100 prad of rms over about 10 hours. For this purpose, a high-precision interferometric laser metrology system is employed. Useful techniques for measuring displacements on extremely small scales are the wave-front sensing method and the heterodyne interferometrical method. Experiments for verification of measurement principles are well advanced.

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The USNO Astrometric Interferometer

Symposium - International Astronomical Union ◽

10.1017/s0074180900108137 ◽

1994 ◽

Vol 158 ◽

pp. 427-435

Author(s):

Donald J. Hutter

Keyword(s):

State Of The Art ◽

Naval Research ◽

Delay Lines ◽

Optical Interferometer ◽

Zeroth Order ◽

Matching Accuracy ◽

Naval Observatory ◽

Laser Metrology ◽

Fringe Tracking ◽

Metrology System

The U.S. Naval Observatory Astrometric Interferometer (USNOAI) will be the dedicated astrometric sub-array of the new Navy Prototype Optical Interferometer (NPOI) at Lowell Observatory, which is being built in collaboration with the Naval Research Laboratory. The USNOAI will be in operation on Anderson Mesa, near Flagstaff, Arizona, in late 1993. The instrument will incorporate four siderostats which will be located in a Y-shaped configuration, and will feature state-of-the-art delay lines, a real-time zeroth-order fringe tracking algorithm, a full-array laser metrology system to monitor baseline motion, and a limiting magnitude of 10. The instrument will be capable of simultaneous observations on six baselines, and will produce star positions accurate to a few mas. With it, we will be able to maintain the HIPPARCOS reference frame with matching accuracy over the next few decades.

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Development of ITER In-Vessel Viewing and Metrology Systems

Journal of Robotics and Mechatronics ◽

10.20965/jrm.1998.p0096 ◽

1998 ◽

Vol 10 (2) ◽

pp. 96-103

Author(s):

Kenjiro Obara ◽

◽

Satoshi Kakudate ◽

Masataka Nakahira ◽

Akira Ito

Keyword(s):

High Temperature ◽

Gamma Radiation ◽

Technology Development ◽

High Vacuum ◽

Inert Gas ◽

Design And Technology ◽

Home Team ◽

Laser Metrology ◽

Metrology System ◽

The U.S

The ITER in-vessel viewing system is vital for detecting and locating damage to in-vessel components such as the blankets and divertors and in monitoring and assisting in-vessel maintenance. This system must be able to operate at high temperature (200°C) under intense gamma radiation (-30 kGy/h) in a high vacuum or I bar inert gas. A periscope viewing system was chosen as a reference due to its clear, wide view and a fiberscope viewing system chosen as a backup for viewing in narrow confines. According to the ITER R&D program, both systems and a metrology system are being developed through the joint efforts of Japan, the U.S., and RF Home Teams. This paper outlines design and technology development mainly on periscope in-vessel viewing and laser metrology contributed by the Japan Home Team.

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The USNO Astrometric Optical Interferometer

Symposium - International Astronomical Union ◽

10.1017/s0074180900227782 ◽

1995 ◽

Vol 166 ◽

pp. 23-29

Author(s):

D.J. Hutter ◽

K.J. Johnston ◽

D. Mozurkewich

Keyword(s):

State Of The Art ◽

Tracking System ◽

Proper Motions ◽

Optical Interferometer ◽

Naval Observatory ◽

Operational Lifetime ◽

Visual Magnitude ◽

Laser Metrology ◽

Fringe Tracking ◽

Metrology System

The U.S. Naval Observatory Astrometric Optical Interferometer (AOI) began operation on Anderson Mesa, near Flagstaff, Arizona, in the autumn of 1994. The AOI incorporates four siderostats that are located in a Y-shaped configuration, and features a full-array laser metrology system to monitor baseline motion. The AOI incorporates state-of-the-art delay lines and a real-time fringe-tracking system. The AOI will have a limiting visual magnitude of 10, under typical observing conditions, and will produce star positions accurate to a few milliarcseconds (mas). With a planned operational lifetime of several decades, this instrument will be capable of maintaining the optical reference frame by improving the proper motions of thousands of the brighter HIPPARCOS stars through repeated observations.

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