DEmonstration of LIdar based Clear Air Turbulence detection

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Performances objectives

The FP6 FLYSAFE project has defined technical objective regarding Clear Air Turbulence detection. These objectives are defined in term of Missed Alarm Rate (MAR) and False Alarm Rate (FAR), for a given turbulence level, at a given distance. Once the installation constraints (such as available power from the aircraft, diameter of receiver telescope) and overall requirements (resolution, altitude, integration distance) are defined, the expected performances mainly depends on the available laser source power and detection efficiency:

- For a 1 step of technology development (corresponding to commercially available laser sources and detection devices, suitable for equipment integration, within a 3 to 4 years time frame)

  • Laser power equal to 2 W
  • Detection efficiency over 40%

The achievable objective is to detect turbulence with a level Moderate or greater (as defined by ICAO standards) at a distance at least equal to 15 km and a Missed Alarm Rate lower than 40%. This corresponds to a 1 minute before encounter warning, allowing protection for passengers and crews through seats fasten.

- For a 2nd step of technology development (corresponding to commercially available laser sources and detection devices, suitable for equipment integration, within a 5 to 10 years time frame)

  • Laser power equal to 10 W
  • Detection efficiency over 80%

The achievable objective is to detect turbulence with a level Moderate or greater at a distance at least equal to 15 km and a Missed Alarm Rate lower than 10%, or at 30 km and a Missed Alarm Rate lower than 40%. This corresponds to a 1 or 2 minutes before encounter warning.

Operational objectives

DELICAT will validate an advanced and new technology for medium-range detection of Clear Air Turbulence at a distance ahead of the aircraft allowing efficient protection of passengers and crew by taking appropriate actions in the cabin (fasten seat belts, fixing objects, etc). This technology, combined in single equipment performing both-short range and medium-range turbulence protection, will provide a very efficient turbulence protection for air transport customers and crewmembers.

30% to 40% of turbulence accidents are not directly linked to convective phenomenon, and so cannot be detected even by state of the art weather radar. In opposition, those accidents can be avoided by the use of this UV LIDAR turbulence protection equipment, which will then allow a reduction of the number of turbulence accidents roughly by the same factor (30% to 40%).

Other objectives of the DELICAT project


Objectives regarding LIDAR system architecture

The LIDAR mock up will include all the basic functionalities of future medium range detection LIDAR equipment, even though those functionalities will have a lower maturity level (for example, signal processing will be performed off line instead of in real time).

In addition, a specific task will be dedicated to the analysis of the integration of short-range and medium-range functions, in order to ensure that the design of the architecture of future commercial detection equipment is optimum with respect to both applications (short range being the concept tested within the frame of the FP5 AWIATOR project).

Induced objective: Improvement of Clear Air Turbulence Forecasting

The main objective of DELICAT is to validate the turbulence detection during flight experiments through turbulent conditions. This requires the recording of data during encounters with CAT. Those events being rare will require essential support from the met services to the planning of actual encounters with regions likely to contain significant turbulence.

  • Selection of the most favourable phenomena: thunderstorm-induced, shear stress or mountain wave
  • Selection of the most favourable location and time (strategic flight campaign planning)
  • Short term support to flight tests (tactical support)

In return, the analysis of the data collected during the flight tests and their comparison with forecasting situations as well as with other observation sources such as satellites will allow improving the understanding of Clear Air Turbulence atmospheric phenomenon and also improving the CAT forecasting capabilities of European met services providers. This will result in optimised CAT-safe flight plans and optimum 4-D aircraft trajectories.