Real-time clear sky turbulence detection method and system based on coherent laser

A detection system and detection method technology, applied in the field of forecasting and detection of clear-air turbulence, can solve the problems of small number of aerosol particles, weak scattering echo, and inability to apply Doppler lidar, so as to suppress backscatter interference, Enhance the echo signal energy and improve the effect of the farthest effective detection distance

Active Publication Date: 2020-12-25
XI'AN INST OF OPTICS & FINE MECHANICS - CHINESE ACAD OF SCI
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Problems solved by technology

However, clear-air turbulence occurs in clear, clean and transparent high altitudes, the number of aerosol particles is small, and the scattered echoes are extremely weak, which makes coherent Doppler lidar unusable in most cases.

Method used

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  • Real-time clear sky turbulence detection method and system based on coherent laser
  • Real-time clear sky turbulence detection method and system based on coherent laser
  • Real-time clear sky turbulence detection method and system based on coherent laser

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Embodiment Construction

[0032] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] The invention uses the intensity fluctuation of the atmospheric scattering signal of the coherent laser to detect the turbulence of the aircraft in the clear sky. The turbulence of the aircraft is caused by the flight of the aircraft in turbulence. The change of the load factor of the aircraft directly reflects the change of the lift force. If the lift force changes greatly, the turbulence must also be strong. The aircraft load factor variable equation is as follows:

[0034]

[0035] In the formula, Δn is the load factor variable, C y is the lift coefficient, S is the wing area, ρ is the air density, G is the gravity of the aircraft, α is the angle of attack of the aircraft in level flight, the airspeed is V, and w is the lateral wind speed. For a fixed aircraft, G / S is a given value, when the angle of attack is less than the criti...

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Abstract

The invention belongs to the field of clear air turbulence prediction and detection and relates to a coherent laser-based real-time clear air turbulence detection method and system. The coherent laser-based real-time clear air turbulence detection method and system can detect clear air turbulence intensity on an air line in real time and realize the purpose of clear air turbulence detection. In a testing process, two homologous ultraviolet laser beams which have been subjected to frequency modulation are emitted; with the emission angles of the light beams controlled, the light beams are adopted to detect a region with a distance R; during the detection, a path integral mode is adopted for the detection region, that is to say, a light beam converging area has a certain thickness deltaR; the converging point of the two light beams is made to perform one-dimensional or two-dimensional scanning in a vertical plane at different distances; with reverse thinking utilized, atmospheric parameters such as air density and wind speed do not need to be directly measured, instead, the characteristic of laser scattering signal fluctuation caused by atmospheric turbulence is utilized to determine whether clear air turbulence exists in front of an aircraft, and therefore, the influence of complicated relations between the atmospheric parameters on the accuracy of clear air turbulence detection is avoided.

Description

technical field [0001] The invention belongs to the field of forecast and detection of clear-air turbulence, and in particular relates to a real-time clear-air turbulence detection method and system based on a coherent laser. Background technique [0002] Clear-air turbulence refers to the turbulence that occurs at an altitude above 6,000 meters and has nothing to do with convective clouds. It is composed of vortex airflows of different scales that change with time, and the direction of turbulence is dissipation from large scale to small scale. If the aircraft enters the turbulent region, the large-scale vortex will cause the aircraft to rise and fall violently, and the small-scale vortex will destroy the original balance of aerodynamic force and moment, causing the aircraft to produce irregular motion, that is, "clear sky turbulence". Turbulence intensity is related to aircraft size, airspeed, air density, horizontal and vertical wind shear, horizontal and vertical temperat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S17/95G01W1/02
CPCG01S17/95G01W1/02Y02A90/10
Inventor 刘辉罗秀娟陈明徕张羽赵晶
Owner XI'AN INST OF OPTICS & FINE MECHANICS - CHINESE ACAD OF SCI
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