Analysis of measurement error of wind lidar caused by propagation properties of Gaussian beam

The Fabry–Perot Etalon (FPE) is widely used in Doppler wind lidar as frequency discriminator and its performance is certainly affected by the propagation properties of Gaussian beam. The divergence angle of lidar returns affected by the quality factor M2 and magnification of beam expander (MBE) of outgoing laser is firstly discussed. Also, the corresponding sensitivity of system on wind velocity is analyzed. The numerical results show that the divergence angle of lidar returns and FPE transmission varied with height, the resulting sensitivity of system is decreased and the wind velocity error is relatively steady in the far field. Consequently, for the wind lidar using FPE as frequency discriminator, it is supposed that the outgoing laser with both lower beam quality factor M2 and higher MBE are requested, in particularly, the system calibration due to FPE instability must be considered in the near field.