In-flight Investigation of LIDAR based Clear Air Turbulence Detection DELICAT project 5B2. Thales Avionics Hervé Barny

Transcription

1 In-flight Investigation of LIDAR based Clear Air Turbulence Detection DELICAT project 5B2 Thales Avionics Hervé Barny

2 Different types of weather hazards WAKE VORTEX Caused by aircraft lift Any flight phase May be predicted to some accuracy Protection by aircraft separation WIND SHEAR Caused by thunderstorms Take off and landing phases Protection by weather radar or accelerometers TURBULENCE Caused by convection, shear instability or mountain waves Mainly in cruise flight Protection by weather radar if CONVECTION Protection by LIDAR if CLEAR : DELICAT 2

3 Convective / Clear Air Turbulence Thunderstorm Turbulence Turbulence associated with thunderstorms & cumulonimbus clouds Covered by state of the art weather radar Clear Air Turbulence High level turbulence typically associated with windshear Mountain wave Turbulence High or low level Turbulence associated with strong wind over mountains Not covered by existing technologies 3

4 Turbulence accidents Airlines need efficient Turbulence protection 58 passengers injured / year over USA Number of accidents grows 3 times faster than air traffic Situation will worsen, due to traffic increase Weather Radar ensures protection for convection but does not work in Clear Conditions (40% of turbulence accidents) There is a need for protection against Clear Air Turbulence 4

5 Operational protection against CAT Long Range: Avoidance by modification of trajectory Requires clearance from ATM : identification and localisation of hazardous area > 5 minutes before the turbulence encounter Out of range for the LIDAR: domain of weather forecasting Medium Range: Seat belts fasten Very efficient protection : 98% of injured passengers were not attached at the moment of the accident Protection requires 1 to 2 minutes before encounter Preliminary analysis in FP6 FLYSAFE Domain of turbulence detection : DELICAT Short Range: Actions on the flight controls Measurement of 3D air speed 0.5 to 1 s ahead of the aircraft Requires coupling with flight controls (critical system) Evaluated in FP5 AWIATOR 5

6 CAT detection parameter Turbulence affects the aircraft mainly through variations of vertical wind speed AOA then Cz variations vertical accelerations and torques Vertical wind speed cannot be directly measured at Medium Range Projection on Line Of Sight then Doppler shift is very low Vertical wind speed can be detected through air density fluctuations Fluctuations of LIDAR back-scattered energy (Rayleigh contribution, molecular back-scattering) 6

7 DELICAT Objectives Main objective: validate an advanced and new technology for medium-range detection of Clear Air Turbulence Second objective: analyse the integration of short-range range and medium-range functions Induced objective: improve the understanding of Clear Air Turbulence phenomenon, and the CAT forecasting capabilities 7

8 DELICAT Project G.A. n DELICAT = DEmonstration of LIdar based Clear Air Turbulence detection T0: April 1st, 2009, duration 3 years Project total cost: 5.6 M, EC contribution: 3.8 M 1. Thales 2. CNRS 3. DLR 4. Hovemere 5. Météo France 7. NLR 8. ONERA 9. INOE 10. Institute of Atmospheric Physics - IAP 11. Laser Diagnostic Instruments 12. Warsaw University ICM 13. EADS-IW 8

9 DELICAT Experiment The atmosphere on the flight path is analysed by the UV LIDAR (both molecular and aerosols energies recorded) The atmosphere on the flight path is analysed by the aircraft onboard sensors (accelerations and rotations, air temperature, airspeed) The data from the LIDAR and from the aircraft sensors, are compared off-line 9

10 DELICAT LIDAR The LIDAR includes 3 sub-assemblies Beam Steering to direct the laser beam on the flight path Receiver (Telescope, Mie / Rayleigh separation, photon counting & analogue PMT) UV Transmitter (Tripled Nd:YAG, 10 W, 100 Hz) 10

11 DELICAT Meteorological activities CAT are rare events not easily predicted Strong need for meteorological support to maximise the chances of CAT flight encounters Initial choice of flight region Short term / real time support during flight periods DUTTON ELLROD 1 BROWN ELLROD 2 11

12 DELICAT Test aircraft NLR s Cessna Citation II research aircraft Modifications to the aircraft Fairing to protect the folding mirror (to direct the laser beam on the flight path) Nose boom to measure accurately the wind direction Aircraft floor to support the LIDAR Cabin windows to let the laser beam in and out RVSM compliance demonstration is required 12

13 Thanks to the European Commission for the support to DELICAT Thank you for your attention Any question? 13