Laser Doppler velocimeter for vehicle application with improved signal-to-noise ratio

Laser Doppler velocimeter (LDV) with improved signal-to-noise ratio (SNR) is presented to measure the vehicle velocity. A novel optical structure named split-reuse type configuration is developed to improve the SNR of LDV. Reference measurements were provided by measuring the outer surface of a precision single-axis turntable. Under these conditions, the measurement uncertainty of the instrument is better than 0.56 % with 95 % confidence interval. The split-reuse type LDV has been tested with an automobile on the open road, and the measurement results are comparing with the results of a precision spatial filter velocimeter, which verify the feasibility of split-reuse type LDV to measure the self-velocity of vehicle.