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Proceedings Paper

Turbulence effects in a horizontal propagation path close to ground: implications for optics detection
Author(s): Lars Sjöqvist; Lars Allard; Ove Gustafsson; Markus Henriksson; Magnus Pettersson
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Paper Abstract

Atmospheric turbulence effects close to ground may affect the performance of laser based systems severely. The variations in the refractive index along the propagation path cause effects such as beam wander, intensity fluctuations (scintillations) and beam broadening. Typical geometries of interest for optics detection include nearly horizontal propagation paths close to the ground and up to kilometre distance to the target. The scintillations and beam wander affect the performance in terms of detection probability and false alarm rate. Of interest is to study the influence of turbulence in optics detection applications. In a field trial atmospheric turbulence effects along a 1 kilometre horizontal propagation path were studied using a diode laser with a rectangular beam profile operating at 0.8 micrometer wavelength. Single-path beam characteristics were registered and analysed using photodetectors arranged in horizontal and vertical directions. The turbulence strength along the path was determined using a scintillometer and single-point ultrasonic anemometers. Strong scintillation effects were observed as a function of the turbulence strength and amplitude characteristics were fitted to model distributions. In addition to the single-path analysis double-path measurements were carried out on different targets. Experimental results are compared with existing theoretical turbulence laser beam propagation models. The results show that influence from scintillations needs to be considered when predicting performance in optics detection applications.

Paper Details

Date Published: 6 October 2011
PDF: 13 pages
Proc. SPIE 8187, Technologies for Optical Countermeasures VIII, 81870M (6 October 2011); doi: 10.1117/12.898171
Show Author Affiliations
Lars Sjöqvist, Swedish Defence Research Agency (Sweden)
Lars Allard, Swedish Defence Research Agency (Sweden)
Ove Gustafsson, Swedish Defence Research Agency (Sweden)
Markus Henriksson, Swedish Defence Research Agency (Sweden)
Magnus Pettersson, Swedish Defence Research Agency (Sweden)

Published in SPIE Proceedings Vol. 8187:
Technologies for Optical Countermeasures VIII
David H. Titterton; Mark A. Richardson, Editor(s)

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