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Proceedings Paper

Limitations Of Laser Transmission Measurements Due To Correlated Atmospheric Effects
Author(s): N. Menyuk; D. K. Killinger
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Paper Abstract

Single-ended atmospheric transmission measurements employing laser radiation backscattered from a remote target are subject to uncertainties due to large fluctuations of the backscattered signals. The magnitude of these fluctuations is dependent upon atmospheric effects, the type of ba.ckscattering target (specular or diffuse), and the nature of the detection system employed (heterodyne or direct). The measurement uncertainty is reduced (i. e. , the signal-to-noise ratio is increased) by signal averaging over a large number of pulses. For signal averaging over n independent measurermts, the standard deviation of the average value, and hence the measurement uncertainty, is expected to decrease as n-1/2. However, it has been found that both short-term and long-term changes in the atmosphere give rise to temporal correlation among successive laser return signals, and this correlation can significantly limit the improvement signal averaging makes in the accuracy of atmospheric transmission measurements. In this paper we give the results of several of our experiments which directly measured the limitations of signal averaging in reducing the standard deviation of laser signals backscattered from a specular or a diffusely reflecting target using both heterodyne- and direct-detection systems. These limitations are shown to be in agreement with a theory which takes the observed atmospherically induced temporal correlation into account.

Paper Details

Date Published: 12 July 1983
PDF: 5 pages
Proc. SPIE 0410, Laser Beam Propagation in the Atmosphere, (12 July 1983); doi: 10.1117/12.935752
Show Author Affiliations
N. Menyuk, Massachusetts Institute of Technology (United States)
D. K. Killinger, Massachusetts Institute of Technology (United States)

Published in SPIE Proceedings Vol. 0410:
Laser Beam Propagation in the Atmosphere
John Carl Leader, Editor(s)

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