Parameter Estimation Of Wake Vortex In Foggy Weather Based On Single Or Double Station Radars

The wake vortex is an inherent aerodynamics phenomenon for an aircraft in flight. Since the wake vortex may pose serious impact to a following aircraft, the real-time detection of wake vortex has become a key issue in the fields of aviation safety and so on, and the circulation is an important parameter to measure the strength of wake vortex. In cloudy and mist conditions, radar is believed to have a relatively good detection performance due to the enhanced backscattering from cloud droplets. Under this background, the radar characteristics and circulation estimation of aircraft wake vortex in foggy and cloudy weather has been studied in this thesis. Here follows the three aspects of the thesis:The first aspect is the study of modeling of radar characteristic of wake vortex under cloudy and foggy conditions, which can be divided into two smaller aspects: 1) Motion characteristics of droplets in wake vortex. Firstly, macroscopic and microscopic parameters of cloud and fog has been simply introduced to describe its weak inertia characteristic. 2) Rader echo simulation of wake vertices in cloudy weather. Firstly, radar scattering model of cloudy droplets is established to analyze the radar detectability of wake vortex. Then Doppler characteristics and velocity characteristics of wake vortex in different radar resolution has been adopted by simulation and data processing.The second aspect is the estimation of wake vortex based on one station radar. Firstly, the Doppler characteristic of the wake vortex is simulated and analyzed based on one station radar. Then, a simple mapping algorithm is proposed to estimate circulation by using linear regression equation. In order to get the accurate circulation value, relationship between integral results and circulation has been analyze in geometry level. Performance of the algorithm is believed to be good according to the simulated results.The third aspect is the velocity field inversion and circulation estimation of wake vortex based on two station radar. the millimeter radar doppler characteristics of the wake vortex is simulated and analyzed on the combination of typical wake vortex aerodynamics model and electromagnetic scattering model. And then, a grid mapping method is proposed to estimate the velocity and circulation of wake vortex.The study of the thesis is innovate and of great value.