Description: The evolution of the National Airspace System via the Next Generation Air Transportation System program depends on enabling new operational concepts to increase efficiency. Decreasing the spacing between aircraft on takeoff and landing would increase the throughput of airports. On-board sensing capability for wake vortices could allow aircraft to operate with reduced spacings. Wake vortices can be detected by a lidar located on the aircraft, but such a system needs to be small, lightweight, rugged, and require minimal maintenance. The Phase I program showed the feasibility of an intrinsically low-cost, coherent lidar that would be suitable for deployment on commercial airliners for axial wake vortex detection. The Low-Cost Lidar Test Bed was used to demonstrate measurement of aerosol returns. The program also assessed the feasibility of using the lidar for remote detection of clear air turbulence and volcanic ash clouds. The program developed a conceptual design for a prototype system that would be fabricated and ground tested in the Phase II program. The Phase II program will design and fabricate an engineering prototype compact coherent Doppler lidar and demonstrate it by measuring ambient wind fields at nearby venues.

Benefits: NASA applications mostly relate to flight safety: wind shear, vortex, and CAT detection. The low-cost through simplicity design approach may be attractive for high-reliability applications.

Non-NASA applications also relate to flight safety: wind shear, vortex, and CAT detection. The low-cost through simplicity design approach may be attractive for high-reliability applications. Other commercial applications include regional air quality monitoring. This application would combine a coherent wind-sensing lidar with a pollution monitoring DIAL system to measure pollution fluxes rather than just concentrations. This data could then be used to force compliance with pollution-reduction regulations, or could provide early warning of a hazardous release. Another application is wind field mapping for wind turbine farm site assessment, as well as forward looking wind monitoring from the turbine nacelle itself for optimization of wind turbine operation.