Green Function Inversion for Deep Atmospheric Turbulence Compensation

Optical Physics Company demonstrated the feasibility of Green''s Function Inversion (GFI) to accomplish high quality hit spot formation even under conditions of severe scintillation during the Phase I study. GFI provides many solutions with good strehl over a wide range of target area which can be selected to place and maintain the hit spot in a desired location. The sensing technique has been extended to utilize "intensity only" data to allow implementation conformal to the aircraft skin. This SBIR Phase II project will demonstrate the GFI technique in the laboratory. This lab demo is a moderate fidelity simulation of the turbulence and sensing architecture of GFI during an LT1 (Low Tactical 1) engagement. Hartmann sensors will be used to produce data identical to a conformal array of sensors. The aimpoint selection and maintenance process that allow the system to keep the hit spot in the desired region of the target and maintain a good strehl ratio during the burn will be verified. Anchoring the lab test results to the simulation model will provide a powerful tool which can be used to model the GFI architecture under many different engagement conditions to quantify its performance envelope. BENEFIT: GFI beam control is well suited to phasing and correcting a conformal array of HEL fiber lasers through turbulence. Besides the air-to-air engagements, the technique also applies well to air-to-ground and ground-to-air scenarios, as well as applications such as imaging and aim point maintenance through long horizontal paths. The speckle processing used in GFI is well suited to HEL diagnostics in that the quality of the hit spot can be measured in real-time. Northrop Grumman Space Technologies (NGST) is our strategic partner in this effort which provides an excellent pathway for technology insertion.