Onboard wake vortex localization with a coherent 1.5 µm Doppler LIDAR for aircraft in formation flight configuration

Abstract

An onboard LIght Detection And Ranging (LIDAR) sensor designed to track wake vortex created by aircraft in formation flight is presented. It uses short pulses (75 ns) to obtain a spatial resolution of ∼22.5 m required to resolve small-scale structures of vortices and a blind zone of 17.5 m to locate vortices next to the wing tip. Monte Carlo simulations show that vortex centers could be located within ±0.5 m. Flight tests were performed with two aircraft in formation flight configuration. The LIDAR, installed in the following aircraft, was able to measure, in real time (every 6 s), the air flow velocities induced by the vortices created by the leading aircraft. The software was used to determine the vortex centers. These measurements were coupled to global positioning system (GPS) measurements of the two aircraft positions to determine the falling velocity of the vortices and infer their circulations.