This paper describes the first successful attempt to detect wake vortices axially using an on-board infrared pulsed Doppler LiDAR. On-board axial detection is more complex than the classic ground-based tangential approach, because the axial air speed in vortices is low and the atmospheric particle density is reduced, yielding a poorer SNR. To provide meaningful results in such unfavorable conditions we have developed a new flexible signal processing method based on a two-primitive model fitting the spectrum of the Doppler return. This new spectral estimation successfully detects wake vortices with an admissible SNR that is lower than other on-board state-of-the-art approaches. It was validated through flight tests.
Douxchamps, D., Lugan, S., Verschueren, Y., Mutuel, L., Macq, B., & Chihara, K. (2008). On-Board Axial Detection of Wake Vortices using a 2-mu m LiDAR. IEEE Transactions on Aerospace and Electronic Systems, 44(4), 1276-1290. https://doi.org/10.1109/TAES.2008.4667709 (Original work published 2008)