N13A-T001 TITLE: Naval Platform Aero-Optic Turbulence and Mitigation Methodology

TECHNOLOGY AREAS: Weapons

ACQUISITION PROGRAM: PMA-242

OBJECTIVE: Develop modeling and simulation capability to resolve negative effects of air flow pattern of naval aviation platforms such as the rotary and fixed winged aircraft.

DESCRIPTION: Past efforts in platform aero-optic effects have emphasized the development of tool sets via Modeling and Simulation (M&S) to visualize the problem, but mitigation of the negative effects has not been at the forefront of follow-on efforts. Comparing experimental data to simulations is very important to understanding the problem and will be essential to develop mitigation techniques. This topic is to address anticipated negative aero-optic effects on beam stability caused by main rotor downwash by developing modeling and simulation capability using techniques such as Computational Fluid Dynamics (CFD) to resolve the air flow pattern of naval aviation platforms such as rotary and fixed winged aircraft. This will include the aero-optical, aero-mechanical and atmospheric effects, and may include the modeling of adaptive-optic and beam-control systems, as well as the integrated effect of the platform fuselage, rotor wash and engine exhaust. The developed capability must be in sufficient resolution to predict the aero-optical effects to an aviation- based high energy laser (HEL) system.

This STTR will primarily focus on developing mitigation techniques required to support airborne HEL weapon systems on a variety of Naval aviation platforms. The performer is expected to address the following types of topics:

1) Integrated opto-mechanical design, incorporating an acquisition and tracking system and HEL laser.
2) Innovative adaptive optics or other phase control system for aero-optics and atmospheric aberration compensation.
3) Passive phase retrieval techniques for aberration determination, such as phase diversity.
4) Control of laser beam under platform jitter.

After development of techniques to predict/measure these aero-optic effects, the second area of research will be in the development of mitigation techniques to provide the maximum turbulence compensation for the various rotary and fixed winged aviation platforms of interest. The near-term objective will support an ongoing Future Naval Capability program involving the integration of a High Power Laser onto a rotary wing aircraft.

PHASE I: Develop aero-optical distortion methodology to predict performance characteristics of the HEL system as a function of atmospheric turbulence, platform downwash/exhaust, and platform vibration. Define system architecture, identify system hardware and functionality.

PHASE II: Develop and test mitigation aero-optical distortion methodologies. Perform aero-optical distortion measurements in a wind tunnel on a model system. Integrate passive optical aberration metrology and a compensation system and demonstrate in wind tunnel environment.

PHASE III: Develop hardware to demonstrate beam control system functionality and performance (aero-optic mitigation). Examine scaling issues related to these methods. Use methodology developed to reduce the negative aero optic effects on the HEL beam on naval aviation platforms.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Commercial aircraft contain an increasing number of instruments and communications equipment located in pods/blisters on the surface of the aircraft. Aero-optic effects from these pods could lead to equipment performance issues and degraded aerodynamics of the aircraft. The results of this topic could lead to mitigation strategies to improve performance and aircraft efficiency.

REFERENCES:
1. Thompson, W.E., & McManamon, P.F. (Eds.). (2012). Acquisition, tracking, pointing, and laser system technologies XXVI. Proceedings of SPIE, 8395. Retrieved from http://spie.org/x648.html?product_id=903342&origin_id=x648

2. Gilbert, K., & Otten, L. (Eds.). (1982). Aero-optical phenomena. Progress in Astronautics and Aeronautics, 80. New York: American Institute of Aeronautics and Astronautics, Inc., doi:10.2514/4.9781600863356