Aircraft Wake Vortex Recognition Method Based On Doppler Lidar

As a modern emerging industry,civil aviation has developed rapidly with the support of the government.The resulting problem of airspace capacity saturation has become a bottleneck affecting the development of the air-transport industry.Many domestic researchers have focused on the study of the reduction of aircraft wake turbulence separation.They hope that reduce the wake turbulence separation while ensuring flight safety by studying the dissipation regulation of aircraft wake vortex and combining the airport environment to predict the wake vortex dissipation time.The wake vortex belongs to atmospheric turbulence and is invisible to the eye.The study of the dissipation mechanism of the wake vortex must complete the detection of the wake vortex.At present,the mainstream tool for wake vortex detection is the coherent Doppler lidar,which describes the vortex change by detecting the velocity variation of the wake vortex.The coherent Doppler lidar detection mode of the wake vortex is mostly RHI display,which is difficult to be recognized by the controller.If the wake vortex in the detected data can be automatically recognized by the computer,the control efficiency can be improved.This paper is based on the coherent Doppler lidar detection of aircraft wake vortex,systematically analyzes the aerodynamic characteristics and spatio-temporal evolution characteristics of the aircraft wake vortex.The radial velocity model of the wake vortex and the Doppler characteristics of the wake vortex is got by the classic wake vortex velocity model and the principle of Doppler lidar detection of wake vortex.Finally,three kinds of wake vortex recognition methods are proposed to complete the automatic recognition of the wake vortex of the measured data and form wake vortex recognition platform.The main results include the following three aspects:Firstly,the aerodynamic characteristics and spatiotemporal evolution characteristics of the aircraft wake vortex are analyzed.The formation mechanism and dissipation characteristics of the aircraft wake vortex are studied.Based on the classic vortex velocity model,the distribution regulation of the tangential velocity of the wake vortex is studied.The analytical expression of the tangential velocity distribution model of the wake vortex is proposed at last.Secondly,the detection principle and wake vortex recognition methods of coherent Doppler lidar are studied.According to the lidar detection principle and the vortex tangential velocity model,the radial vortex echo velocity model is established,and the Doppler characteristics of the wake vortex are analyzed.Based on this,the wake vortex recognition method based on template matching,the wake vortex recognition method based on pattern recognition and the multi-feature fusion wake vortex recognition method are proposed.Finally,the wake vortex recognition platform is constructed according to the three recognition methods proposed in this paper.The recognition platform is designed based on the wake vortex recognition process,and the measured wind field data is used for recognition and verification.The research results of the thesis can not only recognize the wake vortex of the aircraft conveniently,but also display the analysis results intuitively for further analysis of the wake vortex,and can use the recognition results to assist controller's decision-making and improve the airport operation's efficiency.