Aeronautics Application of Direct-Detection Doppler Wind Lidar: An Adapted Design Based on a Fringe-Imaging Michelson Interferometer as Spectral Analyzer

Abstract

We report on the development of a novel direct-detection Doppler wind lidar (DD-DWL) within the strong requirements of an aeronautic feed-forward control application for gust load alleviation (GLA). This DD-DWL is based on fringe imaging of the Doppler-shifted backscatter of ultraviolet laser pulses in a field-widened Michelson interferometer (FW-FIMI) using a fast linear photodetector. The double approach of detailed simulation and demonstrator development is validated by field measurements with reference wind sensing instrumentation. These experiments allow us to establish wind determination precision at a high repeat rate, short range resolution and close distance of approximately 0.5 m/s, which is in accordance with the dedicated simulations. These findings lead us to the conclusion that this FW-FIMI-based Doppler wind lidar is a pertinent development meeting the special requirements of this aeronautics application. Second, the developed simulators are well suited (given their validation) to be used in the overall and full analysis as well as the optimization of the lidar-based GLA control scheme.