1.5μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

Abstract

Lidar (Light detection and ranging) is a well established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5µm Lidars show that the technology is mature, offers great ease of use and is reliable and compact. A 1.5µm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems: it allows to measure remotely, outside aircraft aerodynamic disturbance, an absolute air speed (no need of calibration) with a great precision and in all aircraft flight domain.In the frame work of the EU AIM2 project, Onera task has consisted in the development and testing of a 1.5µm anemometer sensor for in-flight airspeed measurements. Objective of this work is to demonstrate that the 1.5µm Lidar sensor can increase the quality of the data acquisition procedure for the aircraft flight test certification. This paper presents the 1.5µm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully onboard the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft Flight Test Instrumentation (FTI) in the reference frame of the Iidar sensor head. Very good agreement of True Air Speed (TAS), Angle Of Sideslip (AOS) and Angle Of Attack (AOA) was observed.

On the development of flight-test equipment in relation to the aircraft spin

“…Secondly, although not new technology, the increasing availability of LIDAR systems allowed Augere et al [64] to develop a laser anemometer. This technique uses a single frequency laser, projected from on-board an aircraft, to reflect a light wave from natural aerosols in the atmosphere, through Mie scattering.…”

“…Therefore, using this method, it is possible to measure air speed, angle of attack, and sideslip angle in the freestream. This technique was shown to be accurate to 1 m/s for the true airspeed, and to 0.5 • for the flow angles in a study by Augere et al [64] based on flight test results using a Piaggio P180. A 3-axis wind LIDAR was also used on-board a Dauphin 6075 helicopter to show that the direct measurement of true airspeed is possible by considering the airflow outside of the influence of the helicopter rotors [65].…”

Optimization of a direct detection UV wind lidar architecture for 3D wind reconstruction at high altitude

“…Altitude air flow velocity measurements with atmospheric lidar have various applications, including weather forecasting (Baker et al, 1995(Baker et al, , 2014Bruneau and Pelon, 2021;Witschas et al, 2022), determining true air speed from aircraft (Augere et al, 2016), analyzing wind fields around High Altitude Platforms (Karabulut Kurt et al, 2021), and turbulence detection for Gust Load Alleviation (GLA) (Regan and Jutte, 2012;Fournier et al, 2022). GLA involves actively reducing the loads caused by air flow velocity on wings using actuators that modify the aerodynamic profile of the aircraft based on the direction and strength of the encountered wind.…”

“…1). The two wind components are then derived from the four projections using a linear least squares method (Augere et al, 2016). This assumes that the wind is homogeneous, so the projections measured on the different axes correspond to the same wind vector.…”

Robust molecular wind lidar with Quadri Mach-Zehnder interferometer and UV fiber laser for calibration/validation and future generation of Aeolus

“…The wind measurement with embedded atmospheric lidar have many applications such as gust load alleviation, [1][2][3][4] navigation aid for aircraft navigation 5 or high-altitude platform system, 6 weather forecasting improvement using wind measurements from spaceborne lidar. 7 The latter was realized during the ADM-Aeolus mission, launched in 2018, providing the first global wind profiles from space across the entire troposphere and lower stratosphere which led to a significant improvement in the weather forecast score.…”