5 March 2003 Ultra-high resolution, absolute position sensors for cryostatic applications
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Recent advances in new technology, optical pattern recognition encoders at NASA have resulted in high speed, reliable, compact position sensors for use in cryostatic space flight mechanisms. New encoder scale patterns and image processing algorithms combine with digital signal processors (DSP) and field programmable gate array (FPGA) logic elements to enable encoders with conversion rates in excess of 1.5 kHz (suitable for high speed servo motion control for mechanisms), linear resolutions of less than 10 nm, and angular resolutions in the single digit milli-arcseconds in relatively compact packages. Fiber optic light guides allow encoders to function in cryostats with extremely low power dissipation. Ambient test data for fiber optic configurations suitable for cryogenic environments are presented. Cryostatic test capabilities under development are discussed. Potential applications exist for NGST and other infrared and sub-millimeter missions, such as fine guidance sensing, attitude control, mirror segment position sensing, and mirror scanning.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Douglas B. Leviton, Douglas B. Leviton, Brad Frey, Brad Frey, } "Ultra-high resolution, absolute position sensors for cryostatic applications", Proc. SPIE 4850, IR Space Telescopes and Instruments, (5 March 2003); doi: 10.1117/12.461799; https://doi.org/10.1117/12.461799

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