18 April 2005 Free space optical alignment system using GPS
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This paper presents results from an ongoing effort at the University of Oklahoma to develop a real-time active alignment system for free-space optical communication system. An initial prototype of a FSO active alignment system using Global Positioning System (GPS) sensors, two gimbals, and point-to-point spread spectrum RF communication is described. The positions of both FSO transceivers are exchanged over the radio frequency (RF) communication link. A controller uses the exchanged information to calculate azimuth and elevation bearings to achieve initial alignment between the transceivers. The gimbals are used to steer the beams. The paper also presents a binary scan algorithm developed to expedite the initial alignment process. The algorithm incorporates power measurements as feed back to the original transceiver for comparison. In minimizing convergence time, simulation results confirm that the algorithm performs better than raster scan, spiral scan, and raster spiral scan algorithms, all of which are used in laser satellite communications. The results also show that the initial design is not able to achieve real-time alignment. For real-time alignment, different augmenting technologies (for example, steering mirrors) should be considered.
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Wee-Leong Saw, Hazem H. Refai, and James J. Sluss Jr. "Free space optical alignment system using GPS", Proc. SPIE 5712, Free-Space Laser Communication Technologies XVII, (18 April 2005); Logo
Cited by 11 scholarly publications and 2 patents.
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Free space optics


Global Positioning System


Raster graphics

Optical alignment


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