## 4 Experiment
### Wind Speed Measurement Experiment  
On 11 December 2024, the CDWL was placed outdoors at the location coordinates of 43.794713\({}^{\circ}\) N, 125.395189\({}^{\circ}\) E. Four radial wind speeds were measured by using a four-caliber optical antenna. To verify the accuracy of the measurement results of this CDWL prototype, a commercial CDWL was used as a control in the experiment, and the experimental scenario is shown in Figure 12. The model of the commercial CDWL is the Movelaser Molas NL200, and its specific parameters are shown in Table 2.  
Figure 11: Comparison of RMSE under different turntable rotation speeds. Figure 10: Comparison of actual and measured speeds for different window functions: (**a**) rectangular window; (**b**) 1 st HSCW; (**c**) 2 nd HSCW. The CDWL sets comprise one distance gate for each of the 64 sampling points, resulting in a total of 10 range gates. The echo signals collected from each distance gate were processed using the traditional RW and HSCW, with the spectral results accumulated 5000 times. The CDWL prototype was designed to divide a total of 10 range gates, each with a width of 38.6 m.  
The normalized incoherent accumulation spectra obtained at different range gates are shown in Figure 13. In Figure 13, the horizontal coordinates indicate the frequency points, with each point corresponding to 1.95 MHz. Here, the spectrum result is divided by the amplitude corresponding to the highest spectral line, and the spectrum is normalized for comparison and analysis. After taking the average of the spectrum accumulation results for 10 different sets of cycles, the variation in the SNR for different range gates is shown in Figure 14, where \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline Range/m & 50–200 \\ Measurement Layer & 10 \\ Wind Speed Accuracy/m\(\cdot\)s\({}^{-1}\) & 0.1 \\ Wind Speed Range/m\(\cdot\)s\({}^{-1}\) & \(-\)50–50 \\ Beam Structure & 4 beams, horizontal angle 30\({}^{\circ}\), vertical angle 25\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Molas NL200 parameters. Figure 12: Outdoor wind farm experimental scene. Figure 13: Normalized spectra of gates at different range gates. the horizontal coordinates indicate the individual range gates from near to far, and the vertical coordinates indicate the SNR. Through calculation, the SNR after adding the second-order HSCW and the first-order HSCW has increased by 2.06 dB and 1.52 dB, respectively, compared with that of the RW. A comparison of the four-caliber wind speed inversion results is presented in Figure 15.  
Figure 15a-d illustrate the comparison of radial wind speeds measured by each aperture of the four-caliber CDWL. The black, red, and blue curves represent the wind speed inversion results obtained by adding the RW, the first-order HSCW, and the second-order HSCW. Figure 14: Range gate SNR change. Figure 15: Retrieval results of wind speed in different line of sight directions: **(a)** upper left line of sight; **(b)** upper right line of sight; **(c)** lower left line of sight; **(d)** lower right line of sight. order HSCW, respectively. The brown curves represent the results of the wind speeds measured by the commercial CDWL. Due to the closer detection distance and higher spatial and temporal resolution of the commercial CDWL, only a portion of the points in the experimental system can be approximated (approximate points are located at 70 m, 110 m, 150 m, and 190 m). Then, these approximate points of the CDWL prototype were compared with the commercial CDWL (as shown by the brown dashed line in the figure), and the results showed that the CDWL prototype system with the added HSCW had greater consistency with the wind speed measurement results of the commercial CDWL.