A LiDAR system for atmospheric temperature and humidity profiling

Abstract

The invention discloses an atmospheric temperature and humidity profile laser radar system, which is characterized by comprising: an industrial computer, a laser emission system, a receiving spectroscopic system and a data acquisition system; the laser emission system comprises a laser and an optical guide component, the laser is electrically connected to the industrial computer, and the optical guide component guides the laser emitted by the laser into the atmosphere; the receiving spectroscopic system comprises a telescope, an optimization component and a spectroscopic component, the optimization component collimates the optical signal received by the telescope and then divides it into five groups of optical signals by the spectroscopic component; the data acquisition system comprises an acquisition card and five groups of photoelectric sensors electrically connected to the acquisition card, each group of photoelectric sensors corresponds to a group of optical signals, and the acquisition card is electrically connected to the industrial computer. The invention overcomes the shortcomings of the prior art and can realize the detection of vertical spatial distribution of temperature and the detection of temperature boundary layer.

Description

Technical Field

[0001] The invention belongs to the technical field of laser radars, and in particular relates to an atmospheric temperature and humidity profile laser radar system. Background Art

[0002] Lidar (Light Detection And Ranging) uses laser as light source and detects echo signals generated by the interaction between laser and atmosphere to remotely sense the atmosphere. It has high-precision distance resolution capability. The interaction between laser and atmosphere will produce radiation signals containing information about gas atoms, molecules, atmospheric aerosol particles and clouds. The corresponding inversion method can be used to obtain information about atmospheric components such as gas atoms, molecules, atmospheric aerosol particles and clouds.

[0003] At the same time, LiDAR can obtain information such as atmospheric temperature profile, atmospheric humidity profile, and ozone profile. It is an indispensable monitoring device in the meteorological and environmental protection industries, and its application prospects are becoming more and more extensive. The distribution of atmospheric boundary layer temperature profile is closely related to atmospheric phenomena such as atmospheric inversion and urban heat island, and is an important parameter for atmospheric forecasting. The temperature profile Raman LiDAR system is of great significance to the changing laws of atmospheric inversion characteristics and urban heat island effect in the boundary layer. Temperature profile Raman LiDAR mainly uses the Raman backscattering signals of nitrogen and oxygen in the atmosphere to invert the temporal and spatial distribution of temperature profiles in the atmosphere. Summary of the invention

[0004] In order to achieve synchronous measurement of atmospheric temperature and humidity profiles, the present invention provides an atmospheric temperature and humidity profile laser radar system.

[0005] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0006] An atmospheric temperature and humidity profile laser radar system, characterized by comprising:

[0007] Industrial computer, laser emission system, receiving spectroscopic system and data acquisition system;

[0008] The laser emission system comprises a laser and an optical guide component, wherein the laser is electrically connected to an industrial control machine, and the optical guide component guides the laser emitted by the laser into the atmosphere;

[0009] The receiving spectroscopic system comprises a telescope, an optimization component and a spectroscopic component. The optimization component collimates the optical signal received by the telescope and then the spectroscopic component divides the optical signal into five groups of optical signals.

[0010] The data acquisition system comprises an acquisition card and five groups of photoelectric sensors electrically connected to the acquisition card, each group of photoelectric sensors corresponds to a group of optical signals, and the acquisition card is electrically connected to an industrial control computer.

[0011] Furthermore, the optical guiding assembly includes a reflector 1, a beam expander and a reflector 2. The reflector 1 reflects the laser light emitted by the laser to the beam expander, and after being expanded by the beam expander, the laser light is reflected into the atmosphere by the reflector 2.

[0012] Furthermore, the beam expander has a beam expansion factor of at least 3 times and a light transmittance of ≥95%.

[0013] Furthermore, the beam expander has a beam expansion factor of 5 times.

[0014] Furthermore, the laser is an ultraviolet laser with a single pulse energy greater than 150 mJ and a wavelength of 355 nm.

[0015] Furthermore, the optimization component includes a grating, a third reflector and a collimating lens. The light signal received by the telescope is processed by the grating and then transmitted by the third reflector to the collimating lens for collimation processing; the light splitting component includes a color separator one, a color separator two, a filter one, a color separator three, a filter four and a filter five which are sequentially arranged on the light path, wherein the color separator one splits the light signal into two paths, one of which is filtered by the filter six to obtain a first group of light signals, the color separator two splits the light signal from the color separator one into two paths, one of which is filtered by the filter seven to obtain a second group of light signals, the filter one splits the light signal from the color separator two into two paths, one of which is a third group of light signals, the color separator three splits the light signal from the filter one into two paths, one of which is filtered by the filter two and the filter three to obtain a fourth group of light signals, and the filter four and the filter five filter the light signal from the color separator three to obtain a fifth group of light signals.

[0016] Further, the wavelength of the first group of optical signals is 407 nm, the wavelength of the second group of optical signals is 386.7 nm, the wavelength of the third group of optical signals is 354.7 nm, the wavelength of the fourth group of optical signals is 354.05 nm, and the wavelength of the fifth group of optical signals is 353.2 nm.

[0017] Furthermore, the photoelectric sensor is composed of a photomultiplier tube and a converging lens arranged in front of the photomultiplier tube, and the converging lens converges the light signal to the photomultiplier tube.

[0018] Compared with the prior art, the implementation effects of the present invention are as follows: the system of the present invention separates the optical signals received by the telescope, thereby realizing the separation of optical signals with wavelengths of 353.2nm, 354.05nm, 354.7nm, 386.7nm and 407.5nm, so that the system can obtain accurate atmospheric temperature and humidity contour lines with stable results, and can realize the detection of vertical spatial distribution of temperature and detection of temperature boundary layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the system of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See attached Figure 1 A laser 1 of an atmospheric temperature and humidity profile laser radar system emits a laser of a specific wavelength. The laser wavelength of the system is 355nm, and the single pulse energy is greater than 160mJ. After the high-energy laser is emitted, it is first reflected by a reflector 2 to the entrance of a beam expander 3. The beam expansion multiple of the beam expander is 5 times, and the transmittance is ≥95%. After the beam expander, the beam divergence angle is optimized, and the laser reaches a reflector 4. The laser is emitted into the atmosphere through the reflector 4, interacts with atmospheric molecules, and a Raman effect occurs, which excites backscattered light signals with wavelengths of 353.2nm, 354.05nm, 354.7nm, 386.7nm and 407.5nm.

[0022] The backscattered light signal is received by the telescope 5 and first reaches the aperture 6. The telescope adopts an aspherical large-aperture Cassegrain system and an aspherical primary mirror, which makes the diffuse light spot in the field of view small enough. The aperture is 16 inches and can receive sufficiently strong scattered signals. After passing through the aperture 6, the strong sunlight is suppressed, and the effective light signal is reflected by the reflector three 7 to the collimating lens 20. The collimating lens is composed of two groups of lenses. The optical signals of each wavelength are optimized through the collimating lens and then pass through the receiving spectroscopic system.

[0023] See also Figure 1, the effective light signal, after optimization, first reaches the color separation plate 10, after the color separation plate 10, the 407nm light signal is reflected to the filter six 18, and then converged to the photomultiplier tube 91 through the converging lens 81, converted into a corresponding electrical signal, and the first group of signals is obtained; at the same time, the remaining wavelength signals after the color separation plate 10 are transmitted to the color separation plate 2 11, and then the 386.7nm light signal is reflected to the filter seven 19 through the color separation plate 2 11, and then converged to the photomultiplier tube 2 92 through the converging lens 2 82, and converted into a corresponding electrical signal to obtain the second group of signals; the remaining three groups of signals are transmitted to the filter 12; using the light angle, the light signal with a wavelength of 354.7nm is transmitted to the converging lens 3 83, and then Then, the optical signals are converged to the photomultiplier tube three 93 through the converging lens three 83 and converted into corresponding electrical signals to obtain the third group of signals; then, the remaining two groups of optical signals pass through the filter one 12 and reach the color separator three 13, and the filter two 14 and the filter three 15 are used to make the 354.05nm optical signal reach the converging lens four 84 at the end, and after passing through the converging lens four 84, the 354.05nm signal reaches the photomultiplier tube five 95 and is converted into corresponding electrical signals to obtain the fourth group of signals; at the same time, the last group of 353.2nm optical signals pass through the filter four 16 and the filter five 17 and reach the converging lens five 85, and then after passing through the converging lens five 85, they are converged to the photomultiplier tube four 94 and converted into corresponding electrical signals to obtain the fifth group of signals.

[0024] The above five groups of signals are collected by a high-speed acquisition card 21, which uses a six-channel 100M acquisition card, and then transmitted to an industrial computer 22, which is powered by an external power supply. The industrial computer 22 processes the signals collected by the acquisition card 21, and obtains the humidity profile by inverting the first and second groups of signals; and obtains the temperature profile by inverting the third, fourth and fifth groups of signals.

[0025] Since the wavelengths of the third, fourth and fifth groups of signals differ very little, the system separates optical signals of different wavelengths by combining filter one 12, filter two 14, filter three 15, filter four 16 and filter five 17, through angle offset and the difference in refractive index of lasers of different wavelengths. The angle between filter one 12 and filter two 14 is 12°, the angle between filter two 14 and filter three 15 is 8°, and the angle between filter four 16 and filter five 17 is 7°.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An atmospheric temperature and humidity profile laser radar system, characterized in that: include: Industrial computer, laser emission system, receiving spectroscopic system and data acquisition system; The laser emission system comprises a laser and an optical guide component, wherein the laser is electrically connected to an industrial control machine, and the optical guide component guides the laser emitted by the laser into the atmosphere; The receiving spectroscopic system comprises a telescope, an optimization component and a spectroscopic component. The optimization component collimates the optical signal received by the telescope and then the spectroscopic component divides the optical signal into five groups of optical signals. The data acquisition system includes an acquisition card and five groups of photoelectric sensors electrically connected to the acquisition card, each group of photoelectric sensors corresponds to a group of light signals, and the acquisition card is electrically connected to the industrial control computer; The optimization component includes a grating, a third reflector and a collimating lens. The optical signal received by the telescope is processed by the grating and then transmitted by the third reflector to the collimating lens for collimation processing; the light splitting component includes a color splitter plate 1, a color splitter plate 2, a filter plate 1, a color splitter plate 3, a filter plate 4 and a filter plate 5 which are sequentially arranged on the optical path, wherein the color splitter plate 1 splits the optical signal into two paths, one of which is filtered by the filter plate 6 to obtain a first group of optical signals, the color splitter plate 2 splits the optical signal from the color splitter plate 1 into two paths, one of which is filtered by the filter plate 7 to obtain a second group of optical signals, the filter plate 1 splits the optical signal from the color splitter plate 2 into two paths, one of which is a third group of optical signals, the color splitter plate 3 splits the optical signal from the filter plate 1 into two paths, one of which is filtered by the filter plate 2 and the filter plate 3 to obtain a fourth group of optical signals, and the filter plate 4 and the filter plate 5 filter the optical signal from the color splitter plate 3 to obtain a fifth group of optical signals; The included angle between filter one and filter two is 12°, the included angle between filter two and filter three is 8°, and the included angle between filter four and filter five is 7°.

2. The atmospheric temperature and humidity profile laser radar system according to claim 1, characterized in that: The optical guiding assembly comprises a first reflector, a beam expander and a second reflector. The first reflector reflects the laser light emitted by the laser to the beam expander, and after being expanded by the beam expander, the laser light is reflected into the atmosphere by the second reflector.

3. The atmospheric temperature and humidity profile laser radar system according to claim 2, characterized in that: The beam expander has a beam expansion multiple of at least 3 times and a light transmittance of ≥95%.

4. The atmospheric temperature and humidity profile laser radar system according to claim 2, characterized in that: The beam expander has a beam expansion factor of 5 times.

5. The atmospheric temperature and humidity profile laser radar system according to claim 1, characterized in that: The laser is an ultraviolet laser with a single pulse energy greater than 150mJ and a wavelength of 355nm.

6. The atmospheric temperature and humidity profile laser radar system according to claim 1, characterized in that: The wavelength of the first group of optical signals is 407 nm, the wavelength of the second group of optical signals is 386.7 nm, the wavelength of the third group of optical signals is 354.7 nm, the wavelength of the fourth group of optical signals is 354.05 nm, and the wavelength of the fifth group of optical signals is 353.2 nm.

7. The atmospheric temperature and humidity profile laser radar system according to claim 1, characterized in that: The photoelectric sensor is composed of a photomultiplier tube and a converging lens arranged in front of the photomultiplier tube, and the converging lens converges the light signal to the photomultiplier tube.

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