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.
Highlights
As the vortex core radius is typically few meters, positioning the wing tip of the following aircraft where the air flow velocity induced by the vortex is large and pushes the wing upward require a localization of the vortex center within about ±1 m at 25 m from the aircraft
Along the axis that go through the vortex center angle, the air flow induced by the vortex is perpendicular to the LIght Detection And Ranging (LIDAR) axis resulting in a constant velocity that minimize the standard deviation parameter
A LIDAR developed at ONERA is presented where short pulses were used to obtain a small spatial resolution (∼22.5 m) and a small blind zone length (∼18 m)
Summary
Measuring meter-scale air flow velocity structures is important for a wide variety of physics: (1) for meteorology to measure atmospheric turbulence [1,2,3,4,5], its effect on ocean elevation [5] and diffusion of pollutants in cities [6], (2) for airport to detect wind shear [7], vortices and measure their time of life [8,9,10], (3) for small airship that are sensitive to small-scale air flow velocity structures [11], (4) for wind turbine to optimize them according to the air flow velocity [12], (5) for drone transport, or (6) for airship to perform formation flight [13]. The wing tip is positioned 20 m to 30 m above the vortex center and not at the maximum air flow velocity for safety reasons This needs to be performed in real time to continuously position the following aircraft and avoid variation in drag reduction [Fig. 1(a)]. A LIDAR designed at ONERA is presented that enable to locate vortex centers within ±0.5 m at a distance down to 25 m It uses 75 ns FWHM (120 ns at -30 dB) pulse length that induce a blind zone of ∼17.5 m and a spatial resolution of ∼22.5 m. Formation flight tests were carried out where a leading aircraft seeded its wake vortices with smoke to enable the pilot of a second following aircraft to visually locate the vortex and increase the LIDAR signal. Coupled to global positioning system (GPS) measurements of the two aircraft positions, the circulation was inferred within ±4 % by measuring the falling velocity of the vortices and the distance between vortices
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
