Performance evaluation and estimation of a laser time-of-flight velocimeter

Using a low power (less than 1 W) CW argon-ion laser, the concepts of single particle photon-burst correlation and detection sensitivity are examined and applied to a laser time-of-flight velocimeter. A scaling law, including the effects of turbulence, for performance evaluation and estimation of the velocimeter in terms of the signal particle arrival rate is developed theoretically and verified experimentally in the laboratory and field. The effect of atmospheric turbulence on the laser beam radius was investigated both theoretically and experimentally. Using the turbulence induced beam radius and the aerosol size distribution constants determined from the scaling law at short ranges, the predicted signal particle arrival rate at a long range of 500 m is found to be comparable to the experimental rates at this range at night. If a higher laser power is used and signal photon bursts from several signal particles arriving at the same time are analyzed properly, this type of laser velocimeter should be suitable for routine wind speed measurements for a range up to 1000 m.