Scintillation De-Correlation Times – Measurements and Analysis

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Authors
  1. Potvin, G.
  2. Dion, D.
  3. Forand, J.L.
Corporate Authors
Defence R&D Canada - Valcartier, Valcartier QUE (CAN)
Abstract
The detection of distant targets depends critically on the strength and the temporal correlation of scintillation. The performance of optical systems, such as SIRIUS and SEOSS, can be improved through a better understanding of scintillation properties in the surface layer. To this end, scintillation data were obtained using an SLS20 laser scintillometer at an outdoor test site at DRDC Valcartier. The data were taken during both day and night periods in May and June 2003. Meteorological data (wind, temperature, humidity) were also taken over these periods. De-correlation times obtained from the scintillation data were then compared with the times deduced using wind data and Clifford’s theory, which only uses the wind component transverse to the propagation path of the laser, and substantial differences were observed. This is because Clifford’s original theory does not take into account the effects of the inner scale of turbulence or the wind’s longitudinal component with respect to the propagation path. Much smaller differences are obtained when Clifford’s theory is modified to include the inner scale, as measured by the SLS20 scintillometer. Although the inner scale estimates are subject to error, especially at night, considerable improvement occurs. The principal remaining source of error between the measured and estimated timescales is the inability of Clifford’s theory to take the longitudinal wind component into account. A simple theoretical model has been devel

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Keywords
Electromagnetic wave propagation;Laser equipment;Atmospheric turbulence
Report Number
DRDC-VALCARTIER-TR-2004-035 — Technical Report
Date of publication
01 Nov 2004
Number of Pages
44
DSTKIM No
CA025126
CANDIS No
522689
Format(s):
CD ROM

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