Heterodyne lidar returns in the turbulent atmosphere: performance evaluation of simulated systems

Simulations of beam propagation in three-dimensional random media were used to study the effects of atmospheric refractive turbulence on coherent lida r performance. By use of the two-beam model, the lidar return is expressed in terms of the overlap integral of the transmitter and the virtual (back-p ropagated) local oscillator beams at the target, reducing the problem to on e of computing irradiance along the two propagation paths. This approach pr ovides the tools for analyzing laser radar with general reactive turbulence conditions beam truncation at the antenna aperture, beam-angle misalignmen t, and arbitrary transmitter and receiver configurations. Simplifying assum ptions used in analytical studies, were tested and treated as benchmarks fo r determining the accuracy of the simulations. The simulation permitted cha racterization of the effect on lidar performance of the analytically intrac table return variance that results from turbulent fluctuations as well as o f the heterodyne optical power and system-antenna efficiency. (C) 2000 Opti cal Society of America OCIS codes: 030.1670, 010.3640, 010.1300, 010.1330.