Lidar system for wind measurement

Abstract

A lidar system adapted to perform a wind measurement related to a focal zone (ZF) of a laser beam (F) emitted by the system. The system comprises time control means (40) for the laser beam adapted to place this laser beam in the form of successive laser pulses such that each laser pulse has a single length greater than or equal to twice the Rayleigh length (lR) divided by the propagation velocity of the laser pulse in the atmosphere and less than 20 [mu] s. Advantageously, the individual length of each laser pulse is between 0.2 and 5 times the coherence time of the effective atmosphere in the focal region. The lidar system provides a better spectral CNR ratio at an equivalent spatial resolution than the spectral CNR ratio of a system at a current technology development level.

Description

technical field

[0001] This specification relates to a Lidar (LIDAR) system suitable for performing anemometric measurements, and a measurement process using this system. Background technique

[0002] LiDAR systems, or "Light Detection and Ranging", are well known and used in many applications, in particular for making anemometric measurements. For anemometric velocity measurements, the laser beam is backscattered by particles suspended in the air (such as aerosols or solid particles) and carried by the air flow. Next, the component of the wind speed parallel to the laser beam is inferred from the frequency shift due to the Doppler effect. However, several reasons limit the performance of existing lidar systems for anemometric velocity measurements. Among these reasons, one of the biggest constraints is the small value of the CNR spectral ratio (representing the spectral "carrier-to-noise ratio"), which is written as the CNR_sp ratio and is the ratio of the maximum amplitu...

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