High-altitude air Rayleigh scattering wind-warm syndrome laser radar

Abstract

The invention discloses a high-altitude air Rayleigh scattering wind-warm syndrome laser radar which is used for high-altitude air sounding. The laser radar comprises a laser emitting unit (1), a receiving telescope (2), an optical fiber (3), a frequency discrimination unit (4) and a data acquiring and processing unit (5), wherein output frequency of emitting laser adopts atomic absorption for frequency stabilization; and the frequency discrimination unit can adopt three channels of the same atom for frequency discrimination, respectively obtains strengths of full spectrum, left edge spectrum and right edge spectrum of an echo spectrum, and can simultaneously obtain air density, temperature and wind field. The invention has the advantages of strong inhibition capacity of background light, high frequency discrimination precision, small detection error and stable and reliable work.

Description

Technical field: [0001] The invention relates to laser radars, in particular to high-altitude atmospheric detection laser radars. Background technique: [0002] With the extension of human activities to space, high-altitude atmospheric conditions, especially the wind field, have a greater impact on space vehicles. However, as the altitude of the atmosphere increases, the aerosols gradually decrease, the Mie scattered echo light gradually decreases, and the proportion of the Rayleigh scattered echo light produced by smaller molecules gradually increases. This not only weakens the lidar echo, but also due to the influence of the kinetic energy of molecules and atoms, the spectrum of the echo optical signal has a large spectral broadening compared with the line width of the emitted laser, which increases the difficulty of detecting the high-altitude Rayleigh scattering wind field. [0003] The literature "Research Progress of Doppler Wind LiDAR" (Journal of Atmospheric and Env...

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Problems solved by technology

[0004] The double-edge frequency discrimination technology of F-P etalon (document "Research on Rayleigh Scattering Wind Lidar Receiver" Infrared and Laser Engineering, 2008, Volume 37, Supplement, Page 120-124) is to combine two F-P etalons The transmission peaks are respectively set at the two edges of the Rayleigh scattering echo spectrum. Because the echo spectrum will shift left and right due to the change of wind speed, the light intensity passing through the two F-P etalons will change. According to the two F-P standard The wind direction and wind speed can be determined by the light intensity difference of the tool. This technology has high frequency discrimination sensitivity, but the F-P etalon is expensive and sensitive to temperature and mechanical vibration. The frequency discrimination error caused by environmental changes is large, which affects the Detection accuracy

[0005] Iodine molecular absorption edge frequency discrimination technology (document "Comparison of hyperspectral iodine molecule and double-edge Doppler wind lidar technology" Journal of Ocean University of China, 2004, 34(3): 489~49) is to set the laser frequency to make One edge of the Rayleigh scattering echo spectrum is placed on the edge of the iodine molecular absorption spectrum. When the echo spectrum is shifted left and right due to the change of the wind field, the light intensity passing through the iodine molecular absorption cell will change. According to the size of the change The wind direction and wind speed can be determined. Since the iodine molecular absorption spectrum with stable spectral line position is used to discriminate the echo light and stabilize the frequency of the emitted laser, the frequency discrimination error is reduced and the detection accuracy is improved. However, only one edge detection can be used , affecting the frequency discrimination sensitivity

[0006] Wisconsin University utilizes high spectral resolution lidar (document "Demonstration of a high-spectral-resolution lidar based on aniodine absorption filter" Optics Letters, 1994, 19 (3): 1) adopts iodine molecular absorption filter for frequency discrimination, the laser Radar can detect atmospheric temperature, but not the wind field of the atmosphere

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