Passive Optical Monitor for Atmospheric Turbulence and Windspeed
RESEARCH SUPPORT INSTRUMENTS INC LANHAM MD
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Measurement of atmospheric turbulence conditions is critical for predicting the performance of a free-space optical laser communication FSO lasercomm link. A Cn2 monitor based on angle-of-arrival AOA fluctuations has been built for characterization of atmospheric conditions at the NRL FSO Lasercomm Test Facility across the Chesapeake Bay. The monitor used existing lights in various locations as point sources for determining AOA fluctuations. Real time analysis of the AOA fluctuations was performed to determine the power spectrum of the fluctuations every few seconds. This additional power spectrum information allows much greater understanding of atmospheric conditions including estimation of average wind speed based on frequency shifts in the power spectrum distribution. The performance of the monitor was tested over short paths by comparison to a commercial scintillometer. In addition the monitor was used at other sites to determine atmospheric conditions at a variety of locations. Results of these experiments are presented.
- Atmospheric Physics