A Lidar For Remote Sensing Of Optical Turbulence

Atmospheric turbulence affects the performance of missile defense platforms, such as the Airborne Laser (ABL). To understand the results of laser propagation tests on both the horizontal and inclined propagation paths, and to validate atmospheric turbulence prediction models, the vertical profile of the refractive index structure parameter is required. There is no current accepted lidar method for measuring profiles of the refractive index structure parameter. The differential image motion (DIM) has been established as the best way to measure the Fried parameter for "seeing" using a star or laser source. A new concept was proposed, DIM lidar, for measuring vertical profiles of the refractive index structure parameter. The lidar has the transmitter and receiver at the same end of the optical path and uses a pulsed lidar, atmospheric backscatter, and a range-gated receiver. A proof-of-concept test was performed and the experimental results validated the DIM lidar concept and showed that the refractive index structure parameter can be accurately measured.