Retrieval Of Wind Field Characteristics Based On Lidar Measurement

The detection of complex wind field such as wind shear and turbulence is an important content in the field of aviation safety.At present,the main detection methods include hydrogen pilot balloon,anemometer,wind profiler radar,and lidar.Pilot balloon and lidar are important ways to accurately detect large-scale wind fields in clear sky conditions.Based on the needs of airport wind field detection,this paper realizes the detection of three-dimensional wind field,wind shear and turbulence based on two detection methods of pilot ball and lidar and data assimilation methods.The first work is the accurate retrieval method of wind field based on multitheodolite.First,the multiple theodolites are used to detect the height and azimuth information obtained by the hydrogen balloon,and then the precise trajectory and speed information of the hydrogen balloon are obtained through the extended Kalman filter algorithm.Finally,the dynamic analysis of the hydrogen balloon is carried out.Based on the equation of motion,The accurate inversion of the speed of the hydrogen balloon to the background wind field speed has improved the accuracy of wind direction and wind speed by more than 50% compared with the traditional method.The second work is based on the joint detection method of lidar and pilot balloon and the acquisition method of multi-wind field features.Alternately adopt multiple PPI scanning methods with specific altitude angles,and realize the inversion of the threedimensional wind field from the radial wind speed through the 3D-VPP method;in order to improve the accuracy of the wind field in the vertical direction and key airspace,on this basis,based on the principle of variational method,Assimilate the observation data of the air sounding ball into the lidar data.The advantages of high data rate and wide coverage of lidar,as well as the advantages of convenient operation and high accuracy of the air sounding ball,are brought into play to realize the accurate detection and inversion of the three-dimensional wind field of the airport.The third work is a multi-feature retrieval method based on wind field observations.In the glideslope area at 3° altitude,the value of F-factor is used to evaluate the existence of wind shear;the 35.3° altitude cone scan is used to calculate the turbulence energy using partial Fourier decomposition algorithm;the uniform turbulence assumption is used to calculate the radial velocity structure Function to estimate the distribution of turbulent dissipation rate in the region.Simulations and airport experiments verify that this method has good performance for the detection and inversion of wind shear and turbulence around the airport.These three works in this paper have realized the accurate observation and retrieval of the three-dimensional wind field,and the obtained wind field has high accuracy and strong timeliness.Among them,the multi-theodolite method can realize the rapid,accurately and convenient detection and accurate inversion of the vertical wind field at the high altitude of the airport.The scanning method based on lidar and the assimilation of the air sounding ball method can effectively take into account the space coverage,time and space resolution and robustness.It can not only realize the key detection of the aircraft glide path area,but also realize the accuracy of the near-field turbulence intensity Perception can also realize the inversion of a large-scale three-dimensional wind field.The inversion of multi-characteristic parameters of the wind field provides data support for quantifying wind shear and turbulence intensity for flight safety management.