Design and test of laser anemometer based on continuous wave coherence detection

In order to implement measurement of the close wind field accurate and real-time, a laser anemometer based on CW coherence detection was designed with eye-safe band 1.55 m. The system optical path employed the all-fiber structure to enhance the operational stability. The telescope adopted a coaxial transmission structure with effective aperture of 70 mm and focusing distance of 80 m. The backscattered signals were processed by using the on-board programmable gate array chip on the A/D capture card and spectral centroid algorithm was also designed for wind velocity estimation. The anemometer realized high real-time and reliability. The long-term radial wind speed measurement results proved that the laser anemometer output signal was stable with a time resolution of 1 s and the lower limit of the wind measurement range was about 0.915 m/s. Compared with a calibrated pulsed coherent wind lidar, the correlation coefficient of wind speed data measured by the two devices was 0.997, the standard deviation was 0.090 m/s, and the maximum difference was 0.480 m/s.