Analysis and test the performance of the coherent doppler lidar using a prism wedge in the scanning mode

The scanner is an important unit of the Coherent Doppler wind Lidar (CDWL) for long range detection. In the compact telescope system, a prism wedge rotating around the optical axis is often added to realize conical scanning of the laser beam. For the focused CDWL, the prism wedge can produce astigmatism in the measuring light, which will change the energy distribution in the detection space. Based on the geometric optics technique, the relation between the wedge parameters and the beam propagation status is analyzed in this paper. A modified range weighting function is also constructed by using the collection efficiency mode. A CDWL with 100 m focused distance was employed in the wind measurement experiments. Compared the measurement data from the CDWL with the anemometer at 50 m and 100 m height at the wind tower, the result indicates that the CDWL detection data is closer to the wind field at 50 m height, which is consistent with theoretical analysis. The optimized wedge parameters and the modified range weighting function are helpful for the further development of the miniaturized and lightweight CDWL.