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Proceedings Paper

Active suppression of acoustically induced jitter for the airborne laser
Author(s): Roger M. Glaese; Eric H. Anderson; Paul C. Janzen
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Paper Abstract

The Airborne Laser (ABL) system has extremely tight jitter requirements. Acoustic disturbances, such as those caused by the pressure recovery system of the high power laser, are a significant jitter source. Several technologies may be appropriate for reducing the acoustically induced jitter. The first choice for mitigation will be passive approaches, such as acoustic blankets. There is, however, some uncertainty whether these approaches will provide sufficient attenuation and there is concern about the weight of these approaches. A testbed that captured the fundamental physics of the ABL acoustically induced optical jitter problem was developed. This testbed consists of a flexure-mounted mirror exposed to an acoustic field that is generated outside a beam tube and then propagates within the tube. Both feedback and adaptive feedforward control topologies were implemented on the testbed using either of two actuators (a fast steering mirror and a secondary acoustic speaker located near the precision mirror), and a variety of sensors (microphones measuring the acoustic disturbance, accelerometers and microphones mounted on the precision optic, and an optical position sensing detector). This paper summarizes the results from these control topologies for reducing the acoustically induced jitter with some control topologies achieving in excess of 40 dB jitter reduction at a single frequency. This work was performed under an SBIR Phase I funded by the Air Force Research Laboratory Space Vehicles Directorate.

Paper Details

Date Published: 21 July 2000
PDF: 14 pages
Proc. SPIE 4034, Laser Weapons Technology, (21 July 2000); doi: 10.1117/12.391865
Show Author Affiliations
Roger M. Glaese, CSA Engineering, Inc. (United States)
Eric H. Anderson, CSA Engineering, Inc. (United States)
Paul C. Janzen, CSA Engineering, Inc. (United States)

Published in SPIE Proceedings Vol. 4034:
Laser Weapons Technology
Todd D. Steiner; Paul H. Merritt, Editor(s)

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