A Coherent LiDAR for Simultaneous Detection of Atmospheric Wind Velocity and Depolarization Ratio

Abstract

The invention discloses coherent laser radar for simultaneously detecting atmosphere wind speed and the depolarization ratio. The coherent laser radar mainly comprises a light source emitting module (L), polarization frequency mixing modules (S and P) and a signal processing module 15. Echo signals are divided into S polarization light and P polarization light through polarization beam splitters in the polarization frequency mixing modules (S and P), liner polarization local oscillator light is converted into circular polarization light through a quarter-wave plate, the circular polarization light is divided into S polarization light and P polarization light through the polarization beam splitters, and the S polarization light, the P polarization light and signal light in a corresponding polarization state are subjected to frequency beating. According to the scheme, the utilization rate of the echo signals of the coherent wind measuring laser radar can be increased, and the performance of the coherent wind measuring laser radar can be improved; the signals in different polarization states are measured, the depolarization ratio of aerosol is measured, and detection of the coherent wind measuring laser radar on the condition of the aerosol is achieved.

Description

technical field [0001] The invention relates to the technical field of laser radar, in particular to a coherent laser radar for simultaneously detecting atmospheric wind speed and depolarization ratio. Background technique [0002] Accurate atmospheric wind field measurement is of great significance for detecting atmospheric pollution, obtaining military environmental intelligence, improving aerospace safety, improving the accuracy of weather forecasts, and improving climate models. Wind lidar is an effective means of wind field measurement, which can be divided into direct detection wind lidar and coherent detection wind lidar. The direct detection wind measurement lidar uses an optical discriminator to convert the Doppler frequency shift information into the relative change of energy, and realizes the measurement of the atmospheric wind field; the coherent detection wind measurement lidar uses the coherence between the atmospheric echo signal and the local oscillator laser...

AI Technical Summary

Problems solved by technology

[0006] 1) In the coherent wind lidar system, one of the necessary conditions for the coherent beat frequency is that the signal light and the local oscillator light are in the same polarization state, but due to the aerosol depolarization effect, the echo signal is no longer linearly polarized light, thus As a result, the polarization state of part of the echo signal of the traditional coherent wind lidar is different from that of the local oscillator laser, so the echo signal is lost

[0007] 2) Because the depolarization ratio is related to the aerosol situation, the traditional coherent wind lidar signal cannot reflect the aerosol situation

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