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A laboratory demonstration of two novel tactical beam control methods for correcting the effects of strong turbulence
including Beacon Anisoplanatism, and the combined effects of Beacon Anisoplanatism and Thermal Blooming,
respectively, were performed in SAIC's Tactical Beam Control Test-Bed. Both systems were tested with ratio of
aperture diameter to Fried parameter, D/r0, of up to 7, and ratio of beam spot size at the target to isoplanatic angle, θB/θo,
of up to 10. The first method was implemented in a Wavefront-based Stochastic Parallel Gradient Decent (WSPGD)
adaptive optics (AO) system, which uses an off-axis wavefront sensor (WFS) to provide feedback for a multi-dithering
beam control algorithm. The second method was implemented in a Hybrid WSPGD AO system, which incorporates the
WSPGD AO system with a conventional Phase Conjugate (PC) AO system. The Hybrid system uses an on-axis WFS to
generate initial deformable mirror commands and an off-axis WFS to generate additional commands that account for the
high frequency phase components removed from the wavefront of a laser return by Beacon Anisoplanatism. We
developed a low speed PC-based WSPGD controller, implemented designs of the WSPGD and Hybrid WSPGD AO
systems in SAIC's Test-Bed, and tested both AO systems in static and dynamic turbulence over a wide range of
turbulence conditions. A target-plane tracker was used to stabilize the line-of-sight in the AO corrected beam. Test
results show that the WSPGD AO system efficiently compensates the effects of Beacon Anisoplanatism for both static
and dynamic turbulence, providing a mean performance gain of 1.8 averaged over multiple turbulent realizations. We
also found in testing that the Hybrid WSPGD system efficiently compensates for Beacon Anisoplanatism in the presence
of Thermal Blooming - providing improved compensation for both Thermal Blooming and turbulence. In the presence
of strong Beacon Anisoplanatism with θB/θo of up to 10, the maximum performance gain is 4.9 and the mean
performance gain for multiple turbulence realizations is 2.1.
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