Boundary Doppler Lidar based on multi-beam Fizeau Interferometer

摘要

A direct-detection Doppler lidar for planetary boundary layer wind field measurement utilizing multi-beam Fizeau interferometer (MFI) is proposed. Fringe imaging and edge techniques are popular methods of incoherent wind speed measurement. In boundary layer, where aerosol backscattering is strong, it is good to measure wind velocity with fringe imaging technique. Fabty-Perot interferometers (FPI) are standard instruments in former incoherent lidar. Their performance is restricted from detector channels. However, linear fringes of MFI can be measured directly by linear detector, for example, charge coupled device (CCD). The MFI consists of two flat plates which assembled much like a FPI, but wedged by a small angle. Through three PZTs fixed on one plate, the plates spacing can be tuned and the wedge angle can be adjusted. The physical properties of the MFI are discussed in this paper. The factors affecting the measurement of Doppler frequency shift and the correction methods are analyzed and presented. A set of practical system parameters is proposed. The numerical simulation of system performance is implemented. Under different parameters of MFI, error of horizontal wind speed is compared in boundary layer. It shows that the error can be less than 1m/s using the optimized parameters of MFI.