Outward atmospheric scintillation effects and inward atmospheric scintillation effects comparisons for direct detection ladar applications

Douglas G. Youmans

doi:10.1117/12.2050674

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9 June 2014 Outward atmospheric scintillation effects and inward atmospheric scintillation effects comparisons for direct detection ladar applications

Douglas G. Youmans

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Proceedings Volume 9080, Laser Radar Technology and Applications XIX; and Atmospheric Propagation XI; 90800C (2014) https://doi.org/10.1117/12.2050674
Event: SPIE Defense + Security, 2014, Baltimore, Maryland, United States

Abstract

Atmospheric turbulence produces intensity modulation or "scintillation" effects on both on the outward laser-mode path and on the return backscattered radiation path. These both degrade laser radar (ladar) target acquisition, ranging, imaging, and feature estimation. However, the finite sized objects create scintillation averaging on the outgoing path and the finite sized telescope apertures produce scintillation averaging on the return path. We expand on previous papers going to moderate to strong turbulence cases by starting from a 20kft altitude platform and propagating at 0° elevation (with respect to the local vertical) for 100km range to a 1 m diameter diffuse sphere. The outward scintillation and inward scintillation effects, as measured at the focal plane detector array of the receiving aperture, will be compared. To eliminate hard-body surface speckle effects in order to study scintillation, Goodman's M-parameter is set to 10⁶ in the analytical equations and the non-coherent imaging algorithm is employed in Monte Carlo realizations. The analytical equations of the signal-to-noise ratio (SNRp), or mean squared signal over a variance, for a given focal plane array pixel window of interest will be summarized and compared to Monte Carlo realizations of a 1m diffuse sphere.

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Douglas G. Youmans "Outward atmospheric scintillation effects and inward atmospheric scintillation effects comparisons for direct detection ladar applications", Proc. SPIE 9080, Laser Radar Technology and Applications XIX; and Atmospheric Propagation XI, 90800C (9 June 2014); https://doi.org/10.1117/12.2050674

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