Simulation of Atmospheric Compensation for a Laser phased array in the presence of target speckle

Propagation of a laser beam from a phased array source through atmospheric turbulence to a target and techniques to compensate for this atmospheric turbulence are simulated. A large rough target is simulated which causes speckle on the returned light. This return is used as a beacon to command the phased array to correct for aberrations caused by the atmosphere; however, this target speckle degrades the performance of the compensation algorithm over that which could be achieved with an ideal beacon. One way to reduce this degradation is to repetitively apply this compensation and measurement procedure until convergence. If the light field scattered back from the target due to each element of the phased array can be independently measured, the relative phase between these transmitters can be removed. These two approaches are simulated and compared for a 127 element piston-only controlled phased array in a 10 km tactical engagement. Performance of these techniques is evaluated using Strehl ratio (peak intensity) metric.