Backscatter from atmospheric aerosols and molecular nitrogen and oxygen causes “clutter” noise in direct detection ladar applications operating within the atmosphere. The backscatter clutter is more pronounced in multiple pulse, high PRF ladars where pulse-averaging is used to increase operating range. As more and more pulses are added to the wavetrain the backscatter increases. We analyze the imaging of a transmitted Gaussian laser-mode multi-pulse wave-train scatteried off of aerosols and molecules at the focal plane including angular-slew rate resulting from optical tracking, angular lead-angle, and bistatic-optics spatial separation. The defocused backscatter images, from those pulses closest to the receiver, are analyzed using a simple geometrical optics approximation. Methods for estimating the aerosol number density versus altitude and the volume backscatter coefficient of the aerosols are also discussed.

Date Published: 19 May 2015
PDF: 14 pages
Proc. SPIE 9465, Laser Radar Technology and Applications XX; and Atmospheric Propagation XII, 94650B (19 May 2015); doi: 10.1117/12.2176714

Published in SPIE Proceedings Vol. 9465:
Laser Radar Technology and Applications XX; and Atmospheric Propagation XII
Monte D. Turner; Linda M. Wasiczko Thomas; Gary W. Kamerman; Earl J. Spillar, Editor(s)