Circulation retrieval of wake vortex in fog with an upward-looking monostatic radar

Detection and parameter retrieval of aircraft wake vortices have attracted much attention in air traffic management and related fields. In foggy weather conditions, the scattering of a wake vortex is mainly determined by the fog drops carried by the velocity field of the wake. By taking the fog drops' property of weak inertia into account, a new theoretical method to retrieve the circulation of a wake vortex generated in fog is proposed in this paper. In the method, an upward-looking monostatic radar is employed to obtain the Doppler velocities of radar cells along the symmetric line of the wake vortex, and then the circulation can be obtained through a very simple expression with respect to the Doppler velocities and the length of the radar cells. Numerical simulation results verify the good performance of the method.