A Dual Pulse Heterodyne Lidar for the Measurement of Atmospheric Velocity Turbulence

Previous Doppler lidar statistical measurements of mechanical turbulence have only been successful in discerning moderate to strong wind field turbulence. This limitation is related to the transmitter pulse duration which is restricted by both the available laser technology and the range resolution requirements. We propose a real time dual pulse speckle correlation technique which will overcome these limitations. The range resolution afforded by the proposed method is determined by the individual pulse durations wheras its sensitivity to light turbulence conditions is determined by the inter-pulse time delay. The unique dual transmitter Air Force Phillips Laboratory MAPM lidar provides an ideal opportunity to test this approach and demonstrate its sensitivity and utility. With only minor hardware modifications, this system would be capable of remote measurement of wind velocity dispersions less than 0.1 m/s and with a range resolution on the order of 50-100 m.