Fast Wavefront Sensing for Mitigating Aero-Optical Effects

Aero-optical and aero-mechanical disturbances are a significant obstacle to implementing and operating HELWS on aircraft platforms. Aero-optic aberrations present near the beam director will generally produce significant spreading of the outgoing HEL beam at the target if their effects are not addressed somehow. One method to compensate aero-optic disturbances is to use AO control as part of the airborne HELWS BCS design. Presently, conventional AO systems struggle to compensate aero-optics because the characteristic frequencies of aero-optic disturbances (1?10 kHz) are too fast for AO systems with COTS camera-based sensing solutions to be effective. The development of novel high-speed WFS solutions that can measure aero-optic disturbances at sample rates greater than 100 kHz is a critical step towards being able to overcome the current frame-rate limitations of state-of-the-art AO systems. Results from our Phase I activities indicate that a prototype photodiode WFS concept that we call FPS-AO will meet the preliminary frame rate and sensitivity, and SWaP requirements specified at the outset of the program.