Three-wavelength eight-channel Raman-meter temperature and humidity laser radar detection system

Abstract

The invention discloses a Raman-meter temperature and humidity laser radar detection system with three wavelengths and eight channels. The Raman-meter temperature and humidity laser radar detection system comprises a transmitting system, a receiving system, a data acquisition and processing system and a computer control system. Laser signals with the wavelengths of 355 nm and 532 nm are combined with a dynamic background light intensity adjusting mechanism, so that the signal sensitivity under the conditions of strong background light in the daytime and low background light at night is ensured. The light splitting module adopts a high-performance narrow-band optical filter and a multilayer medium coated dichroic mirror which are arranged at a preset inclination angle and cooperate with an achromatic lens group of the collimation system, so that efficient light beam transmission and accurate separation of multi-wavelength signals are realized, spectral crosstalk is remarkably reduced, and the system detection precision, the environment adaptability and the data processing reliability are improved; the method is suitable for all-weather and multi-scene atmosphere detection.

Description

Technical Field

[0001] The present invention relates to the field of laser radar detection technology, and in particular to a three-wavelength eight-channel Raman-Mie temperature and humidity laser radar detection system. Background Art

[0002] Raman-Mie temperature and humidity lidar is an active remote sensing device based on the interaction between laser and atmospheric molecules. It can be used to detect the vertical distribution characteristics of atmospheric aerosol, water vapor content and temperature, and is widely used in weather forecasting, environmental monitoring and atmospheric science research. Its working principle is to transmit multi-wavelength lasers into the atmosphere, receive echo signals after scattering with atmospheric molecules, and analyze signal characteristics through inversion algorithms to obtain target parameters. However, due to background light interference in the atmosphere, multi-wavelength signal crosstalk and insufficient multi-channel accuracy, the detection stability and accuracy of existing technologies in complex environments are still greatly limited.

[0003] At present, the industry usually adopts the following methods to improve the detection performance of LiDAR: 1. Optimize the ability to suppress background light interference: Use fixed attenuation plates or simple optical filters to reduce the interference of daytime background light on echo signals. However, this method has poor adaptability during the day and at night. Fixed attenuation plates may cause loss of weak signals, and simple filters have limited efficiency in dynamic environments.

[0004] 2. Improve the separation accuracy of optical signals: Use narrow-band filters in the spectrometer module to separate multi-wavelength signals. However, unreasonable arrangement of filters can easily cause spectral crosstalk between channels, affecting the accuracy and consistency of multi-channel signals.

[0005] 3. Enhance data inversion capability: Analyze atmospheric parameters through a single parameter inversion algorithm (such as based only on the Raman signal intensity ratio or the intensity change of a single scattering signal). However, this method lacks accuracy in multi-parameter joint detection and is difficult to meet the needs of detecting multi-dimensional characteristics of the atmosphere.

[0006] In order to make up for the above shortcomings, the industry has tried to use the method of dynamically adjusting the attenuation plate to adapt to the background light of multiple scenes, using higher-precision filter design to reduce crosstalk, or developing more complex inversion algorithms to improve accuracy. However, these methods still have new problems in practical applications: the equipment structure of the dynamically adjusted attenuation plate is complex and the response speed is limited, making it difficult to accurately control in real-time monitoring; the design of high-precision filters increases the complexity of the system, and its arrangement angle is not compatible with the signal, which can easily lead to signal energy loss; complex inversion algorithms require a large amount of signal input and high computing power, which usually leads to reduced computing efficiency due to hardware limitations, making it difficult to achieve real-time detection.

[0007] Therefore, how to break through the bottleneck of the existing technology and achieve high-precision, high-stability and multi-scenario adaptability detection performance through precise optical design, deep integration of signal dynamic adjustment and inversion algorithm in a multi-wavelength lidar detection system has become a technical problem to be solved by the present invention. Summary of the invention

[0008] The technical problem solved by the present invention is to provide a three-wavelength eight-channel Raman-Mie temperature and humidity lidar detection system in response to the defects existing in the above-mentioned prior art, so as to solve the problems of insufficient background light interference suppression, multi-wavelength signal crosstalk and low multi-parameter detection accuracy proposed in the above-mentioned background technology.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A three-wavelength eight-channel Raman-Mi temperature and humidity laser radar detection system, including a transmitting system, a receiving system, a data acquisition and processing system, and a computer control system; The transmitting system comprises a multi-wavelength pulse laser, a beam shaping module and a spectroscopic module. The multi-wavelength pulse laser emits laser beams of two wavelengths, 355 nm and 532 nm. The beam shaping module compresses the beam divergence angle to be less than or equal to 0.1 mrad and adjusts the light spot coverage range. Then, the spectroscopic module adjusts the 355 nm beam to the center of the secondary mirror of the telescope for coaxial emission, and the 532 nm beam is emitted off-axis near the edge of the telescope barrel, so as to minimize the detection blind spot of the system. An imaging detection device is used to observe whether the natural background light presents a uniform and complete light spot after passing through the telescope and subsequent channels, so as to perform auxiliary measurement of the coaxiality of each lens of the spectroscopic channel. The receiving system includes a reflective telescope, a spectroscopic module, a high-performance narrowband filter and a steering gear attenuation device. The field of view of the reflective telescope is designed to be 0.1-0.3 mrad, and the divergence angle of the laser in the transmitting system is designed to be smaller than the field of view of the receiving telescope to ensure effective reception of the echo signal after the laser interacts with the atmosphere; The optical splitting module separates the received optical signal into 532P channel, 532S channel, 407 water vapor Raman channel, 386 nitrogen Raman channel, 355P channel, 355S channel, high-order temperature Raman channel and low-order temperature Raman channel according to wavelength and polarization state through a dichroic mirror, a polarizer and a high-performance narrow-band filter. The high-order and low-order temperature Raman channel optical splitting modules match the central wavelength of each channel in the optical path by adjusting the tilt angle of the filter; The steering gear attenuation device comprises a background light intensity detection module and a steering gear driving device communicating with the background light intensity detection module, wherein the steering gear driving device drives the attenuation sheet arranged in the optical path to adjust the angle, and the angle adjustment logic is dynamically controlled by a computer control system according to the background light intensity signal to adapt to different light intensity conditions and realize all-weather detection during the day and at night; The data acquisition and processing system includes a photoelectric signal processing module, an analog-to-digital conversion module and a data storage module; The photoelectric signal processing module is connected to each channel detector of the receiving system and is used to convert the optical signal output by the detector into an electrical signal; The analog-to-digital conversion module is arranged at the rear end of the photoelectric signal processing module, and is used to convert the analog electrical signal into a digital signal; The data storage module is arranged at the back end of the analog-to-digital conversion module, and is used to store the collected digital signals and transmit the digital signals to the computer control system; The data acquisition and processing system transmits the optical signal data obtained from the detectors of each channel of the receiving system, and provides the computer control system with multi-wavelength digital signals of 532nm, 355nm Raman signals and 355, 532nm Mie scattering signals based on intensity changes, time delays and spectral characteristics; The computer control system utilizes the intensity ratio of the 532nm and 355nm Raman signals, the water vapor content formula and the ratio of the high-order and low-order rotational Raman lines at 355nm, combined with the extinction coefficient of the 355 and 532nm Mie scattering signals, to invert and generate the mass concentration distribution of aerosols, the vertical distribution characteristics of water vapor content and temperature, and monitors and controls the operating status of each system in real time.

[0010] As a further solution of the present invention, the receiving system also includes a collimation system, which includes at least one achromatic lens group. The achromatic lens group is arranged along the optical path between the reflecting telescope and the spectroscopic module. The achromatic lens group is used to collimate the echo signal received by the reflecting telescope, and the diameter of the collimated light beam is controlled within the light aperture range of the spectroscopic module.

[0011] As a further solution of the present invention, the receiving system also includes a pinhole aperture, which is arranged between the reflecting telescope and the collimation system to limit the field of view of the receiving telescope to within the range of 0.1-0.3 mrad.

[0012] As a further solution of the present invention, the tilt angle refers to an angle between the incident angle of the light signal and the normal direction of the filter surface, which is 0° to 10°.

[0013] As a further solution of the present invention, the servo drive device includes a motor drive assembly and an attenuation plate mounting frame, the attenuation plate mounting frame is arranged perpendicular to the optical path through the motor drive assembly, and a plurality of attenuation plates with different strengths are provided on the attenuation plate mounting frame.

[0014] As a further solution of the present invention, the data acquisition and processing system includes a photoelectric signal processing module, an analog-to-digital conversion module and a data storage module; the photoelectric signal processing module is connected to each channel detector of the receiving system, and is used to convert the optical signal output by the detector into an electrical signal; the analog-to-digital conversion module is arranged at the back end of the photoelectric signal processing module, and is used to convert the analog electrical signal into a digital signal; the data storage module is arranged at the back end of the analog-to-digital conversion module, and is used to store the collected digital signal and transmit it to the computer control system for subsequent data processing.

[0015] As a further solution of the present invention, the inversion algorithm of the computer control system comprises the following steps: Step 1, input processing: receiving the intensity of 355nm and 532nm Mie scattering signals, the intensity, time delay and spectral characteristics of 355nm and 532nm Raman scattering signals transmitted by the data acquisition and processing system; Step 2, atmospheric aerosol inversion: Based on the intensity change and height distribution of the 355 and 532 nm scattering signals, the vertical distribution of the mass concentration of atmospheric aerosols is inverted using the extinction coefficient of the echo signal; Step 3, water vapor content inversion: using the intensity ratio of the 355nm Raman scattering signal and combining it with the gas Raman scattering formula, the vertical distribution of water vapor is inverted; Step 4, temperature inversion: Based on the ratio of high-order and low-order rotational Raman lines of the 355nm Raman scattering signal and the molecular rotational Raman scattering formula, the vertical distribution of temperature is inverted; Step 5, output results: generate vertical distribution characteristic data of aerosol mass concentration distribution, water vapor content and temperature, and display them through a visual interface.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The multi-wavelength laser signal (355nm and 532nm) is organically combined with the dynamic adjustment mechanism of the background light intensity. The angle and intensity of the attenuation plate are adjusted in real time through the servo attenuation device, which not only ensures the effective capture of weak signals under strong background light during the day, but also optimizes the sensitivity of signals under low background light at night, while avoiding the problem of insufficient adaptability of static attenuation plate adjustment in the existing technology. The combination of this dynamic adjustment mechanism and multi-wavelength signals ensures that the system can maintain high detection accuracy and stability in all weather and multiple scenarios.

[0017] 2. By combining the high-performance narrow-band filters and dichroic mirrors of the spectrometer module with the achromatic lens group of the collimation system, a full chain of precise control from beam collimation to wavelength selection is formed in the optical path. The collimation system optimizes the beam divergence angle to match the aperture of the spectrometer module to ensure efficient transmission of beam energy; the filters are arranged at a predetermined tilt angle and combined with a multi-layer dielectric coated dichroic mirror to significantly reduce spectral crosstalk between channels and improve the separation accuracy of multi-wavelength signals.

[0018] 3. The high-precision data acquisition module is integrated with the multi-parameter joint inversion algorithm. Based on the 355nm and 532nm Raman signal intensity ratio, the high-order and low-order rotation spectral line ratio, and the 355 and 532nm Mie scattering signal extinction coefficients, the vertical distribution characteristics of aerosol mass concentration distribution, water vapor content, and temperature are jointly inverted through the input of multi-wavelength digital signals. Compared with the inversion methods of each single parameter in the prior art, the present invention realizes the efficient joint detection of atmospheric parameters through the synchronous inversion design of multi-wavelength and multi-parameter signals, which significantly improves the detection accuracy and data consistency.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 Schematic diagram of the system architecture of the present invention.

[0022] Figure 2 It is a schematic diagram of the optical path detection tooling of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0024] See also Figure 1 — Figure 2In an embodiment of the present invention, a three-wavelength eight-channel Raman-Mi temperature and humidity laser radar detection system includes a transmitting system, a receiving system, a data acquisition and processing system, and a computer control system; The transmitting system comprises a multi-wavelength pulse laser, a beam shaping module and a spectroscopic module. The multi-wavelength pulse laser emits laser beams of two wavelengths, 355 nm and 532 nm. The beam shaping module compresses the beam divergence angle to be less than or equal to 0.1 mrad and adjusts the light spot coverage range. Then, the spectroscopic module adjusts the 355 nm beam to the center of the secondary mirror of the telescope for coaxial emission, and the 532 nm beam is emitted off-axis near the edge of the telescope barrel, so as to minimize the detection blind spot of the system. An imaging detection device is used to observe whether the natural background light presents a uniform and complete light spot after passing through the telescope and subsequent channels, so as to perform auxiliary measurement of the coaxiality of each lens of the spectroscopic channel. The receiving system includes a reflective telescope, a spectroscopic module, a high-performance narrowband filter and a steering gear attenuation device. The field of view of the reflective telescope is designed to be 0.1-0.3 mrad, and the divergence angle of the laser in the transmitting system is designed to be smaller than the field of view of the receiving telescope to ensure effective reception of the echo signal after the laser interacts with the atmosphere; The optical splitting module separates the received optical signal into 532P channel, 532S channel, 407 water vapor Raman channel, 386 nitrogen Raman channel, 355P channel, 355S channel, high-order temperature Raman channel and low-order temperature Raman channel according to wavelength and polarization state through a dichroic mirror, a polarizer and a high-performance narrow-band filter. The high-order and low-order temperature Raman channel optical splitting modules match the central wavelength of each channel in the optical path by adjusting the tilt angle of the filter; The steering gear attenuation device comprises a background light intensity detection module and a steering gear driving device communicating with the background light intensity detection module, wherein the steering gear driving device drives the attenuation sheet arranged in the optical path to adjust the angle, and the angle adjustment logic is dynamically controlled by a computer control system according to the background light intensity signal to adapt to different light intensity conditions and realize all-weather detection during the day and at night; The data acquisition and processing system includes a photoelectric signal processing module, an analog-to-digital conversion module and a data storage module; The photoelectric signal processing module is connected to each channel detector of the receiving system and is used to convert the optical signal output by the detector into an electrical signal; The analog-to-digital conversion module is arranged at the rear end of the photoelectric signal processing module, and is used to convert the analog electrical signal into a digital signal; The data storage module is arranged at the back end of the analog-to-digital conversion module, and is used to store the collected digital signals and transmit the digital signals to the computer control system; The data acquisition and processing system transmits the optical signal data obtained from the detectors of each channel of the receiving system, and provides the computer control system with multi-wavelength digital signals of 532nm, 355nm Raman signals and 355, 532nm Mie scattering signals based on intensity changes, time delays and spectral characteristics; The computer control system utilizes the intensity ratio of the 532nm and 355nm Raman signals, the water vapor content formula and the ratio of the high-order and low-order rotational Raman lines at 355nm, combined with the extinction coefficient of the 355 and 532nm Mie scattering signals, to invert and generate the mass concentration distribution of aerosols, the vertical distribution characteristics of water vapor content and temperature, and monitors and controls the operating status of each system in real time.

[0025] As a further solution of the present invention, the receiving system also includes a collimation system, which includes at least one achromatic lens group. The achromatic lens group is arranged along the optical path between the reflecting telescope and the spectroscopic module. The achromatic lens group is used to collimate the echo signal received by the reflecting telescope, and the diameter of the collimated light beam is controlled within the light aperture range of the spectroscopic module.

[0026] As a further solution of the present invention, the receiving system also includes a pinhole aperture, which is arranged between the reflecting telescope and the collimation system to limit the field of view of the receiving telescope to within the range of 0.1-0.3 mrad.

[0027] As a further solution of the present invention, the tilt angle refers to an angle between the incident angle of the light signal and the normal direction of the filter surface, which is 0° to 10°.

[0028] As a further solution of the present invention, the servo drive device includes a motor drive assembly and an attenuation plate mounting frame, the attenuation plate mounting frame is arranged perpendicular to the optical path through the motor drive assembly, and a plurality of attenuation plates with different strengths are provided on the attenuation plate mounting frame.

[0029] As a further solution of the present invention, the data acquisition and processing system includes a photoelectric signal processing module, an analog-to-digital conversion module and a data storage module; the photoelectric signal processing module is connected to each channel detector of the receiving system, and is used to convert the optical signal output by the detector into an electrical signal; the analog-to-digital conversion module is arranged at the back end of the photoelectric signal processing module, and is used to convert the analog electrical signal into a digital signal; the data storage module is arranged at the back end of the analog-to-digital conversion module, and is used to store the collected digital signal and transmit it to the computer control system for subsequent data processing.

[0030] As a further solution of the present invention, the inversion algorithm of the computer control system comprises the following steps: Step 1, input processing: receiving the intensity of 355nm and 532nm Mie scattering signals, the intensity, time delay and spectral characteristics of 355nm and 532nm Raman scattering signals transmitted by the data acquisition and processing system; Step 2, atmospheric aerosol inversion: Based on the intensity change and height distribution of the 355 and 532 nm scattering signals, the vertical distribution of the mass concentration of atmospheric aerosols is inverted using the extinction coefficient of the echo signal; Step 3, water vapor content inversion: using the intensity ratio of the 355nm Raman scattering signal and combining it with the gas Raman scattering formula, the vertical distribution of water vapor is inverted; Step 4, temperature inversion: Based on the ratio of high-order and low-order rotational Raman lines of the 355nm Raman scattering signal and the molecular rotational Raman scattering formula, the vertical distribution of temperature is inverted; Step 5, output results: generate vertical distribution characteristic data of aerosol mass concentration distribution, water vapor content and temperature, and display them through a visual interface.

[0031] It can be understood by those skilled in the art that all devices, components and modules involved in the present invention are known in the prior art, or can be realized by conventional design and manufacturing means in the art. For example, the multi-wavelength pulse laser, beam shaping module and spectrometer module included in the transmitting system of the present invention are all common optical components in the field of laser radar, which can be realized by mature design methods and manufacturing processes in the prior art; the reflective telescope, high-performance narrow-band filter and servo attenuation device in the receiving system are also common hardware components in the existing optical system design, and their principles and implementation methods have been widely used in the art. In addition, the optoelectronic signal processing module, analog-to-digital conversion module and data storage module used in the data acquisition and processing system are also widely used electronic modules in current atmospheric detection equipment, and have mature implementation schemes. The specific implementation and technical scheme of the present invention are only for the purpose of clearly explaining the purpose and effect of the present invention, and are not the only restrictions on its composition and implementation.

[0032] Embodiment 1: This embodiment provides a specific application scenario and implementation method of a three-wavelength, eight-channel Raman-Mie temperature and humidity lidar detection system, which is used to solve the problems of strong background light interference, significant spectral signal crosstalk, and low multi-parameter joint detection accuracy in complex environments.

[0033] In an environmental monitoring project in a large city, it is necessary to obtain atmospheric aerosol distribution, water vapor content and vertical temperature distribution characteristics in real time for air quality assessment and pollution source tracing. This scenario faces the challenges of strong sunlight background interference during the day and weak signals at night that are susceptible to noise. At the same time, the monitoring point is located in a highly polluted area, with high aerosol concentration and complex distribution. Existing single-wavelength radars or systems based on static adjustment cannot meet the needs of accurate detection.

[0034] To this end, this system uses multi-wavelength (355nm and 532nm) lasers as light sources, combined with a dynamically adjusted servo attenuation device and a high-precision multi-wavelength signal processing module, to achieve high-precision detection in multiple scenarios. The specific implementation is as follows: The multi-wavelength pulse laser generates two wavelengths of laser light, 355nm and 532nm, of which 355nm and 532nm are used for atmospheric Raman scattering detection. The beam divergence angle is compressed to less than or equal to 0.1mrad through the beam shaping module, and the spot coverage range is adjusted to ensure that the laser beam can efficiently penetrate the atmosphere and reduce the detection blind area. The light beam is emitted coaxially or off-axis through the spectroscopic module to form a uniform and efficient spatial distribution, which is suitable for the detection of high-concentration aerosol areas.

[0035] The system receives echo signals generated by atmospheric Raman scattering and Mie scattering. The design field of view of the reflective telescope is 0.1-0.3mrad. Combined with the pinhole aperture set between the telescope and the collimation system, it accurately limits the receiving field of view and suppresses unnecessary background light interference. The collimation system further collimates the echo signal, optimizes the beam diameter through the achromatic lens group to match the aperture of the spectrometer module, and improves the signal transmission efficiency.

[0036] After the echo signal enters the spectrometer, it is classified by wavelength through a dichroic mirror, and the 532nm and 355nm Raman signals are separated from the 532nm Mie scattering signal. The high-performance narrow-band filter is arranged at a predetermined tilt angle (the angle between the incident angle and the normal line of the filter surface is 0° to 10°), combined with multi-layer dielectric coating technology, to optimize the transmittance of the target wavelength to more than 90%, suppress the out-of-band spectral transmittance to within 10^-5, effectively reduce the spectral crosstalk between adjacent channels, and improve the accuracy of multi-wavelength signal separation.

[0037] The steering gear attenuation device adjusts the angle and intensity of the attenuation sheet in real time. The system collects real-time ambient light intensity data through the background light intensity detection module. Under high background light conditions during the day, it automatically switches to a strong attenuation sheet or a medium attenuation sheet to suppress interference signals; under low background light conditions at night, it switches to no attenuation sheet or a weak attenuation sheet to ensure the sensitive capture of weak signals. This dynamic adjustment capability significantly enhances the system's all-weather and multi-scenario adaptability.

[0038] The multi-wavelength signal output by the receiving system is converted into an electrical signal by the optoelectronic signal processing module, and is processed by the analog-to-digital conversion module and transmitted to the data storage module. The system combines the extinction coefficients of the 355 and 532nm Mie scattering signals, the intensity ratio of the 355nm and 532nm Raman signals, and the ratio of the 355nm rotational Raman spectral lines, and generates the vertical distribution characteristic data of aerosol mass concentration distribution, water vapor content and temperature based on the joint inversion algorithm. Specifically: the extinction coefficients of the 355 and 532nm Mie scattering signals are used to invert the vertical distribution of the mass concentration of atmospheric aerosols; based on the intensity ratio of the 355nm and 532nm Raman signals, combined with the gas Raman scattering formula, the vertical distribution of water vapor is inverted; based on the 355nm and 532nm Raman signal intensity ratio, combined with the gas Raman scattering formula, the vertical distribution of temperature is inverted. The data acquisition system is equipped with an optical path detection tooling, which uses a spot test device to detect the shape of each channel signal spot in real time, and uses an energy analysis module to analyze the energy distribution uniformity of the optical signal, providing dynamic calibration support for spectral reception accuracy and signal consistency.

[0039] In this embodiment, through the coordinated application of three-wavelength laser signals and dynamically adjusted background light adaptation mechanism, optical path collimation and precision spectroscopic design, and joint inversion algorithm, the system shows high sensitivity and high precision under both strong background light during the day and low background light at night. Compared with the existing technology, this embodiment significantly reduces the impact of spectral crosstalk on signal accuracy, overcomes the bottleneck of low inversion accuracy of a single parameter, and realizes efficient joint detection of atmospheric aerosols, water vapor and temperature, providing a reliable technical solution for atmospheric detection in complex environments.

[0040] Embodiment 2: In a mountain environment monitoring project, in order to study the air quality and meteorological changes under complex terrain conditions, it is necessary to obtain the vertical distribution characteristics of atmospheric aerosol distribution, water vapor content and temperature in real time. Due to the fact that mountainous areas are cloudy and foggy and the light changes rapidly, the background light intensity is seriously disturbed during the day, and the low temperature at night causes the light signal to attenuate. Traditional single-wavelength or static adjustment systems cannot provide stable and accurate data support in such a changing environment.

[0041] Aiming at the above-mentioned complex scenarios, this system realizes high-precision, all-weather atmospheric detection capabilities through innovative design. The specific implementation is as follows: The transmitting system uses two wavelength lasers, 355nm and 532nm, of which 355nm is used to obtain water vapor Raman and molecular rotation Raman signals, and 532nm is used to detect aerosol and Mie scattering signals. The beam shaping module compresses the beam divergence angle to less than or equal to 0.1mrad through an achromatic lens and a beam expander, ensuring that the beam has high energy density and stability when penetrating the mountainous atmosphere. The coaxial and off-axis emission modes of the beam are adjusted through the spectroscopic module. The 355nm beam is coaxially emitted to reduce the detection blind area, and the 532nm beam is off-axis emitted to enhance the aerosol signal detection effect. The receiving system adopts a reflective telescope design with a field of view of 0.1-0.3mrad. Combined with a pinhole aperture to limit the receiving angle, it reduces the introduction of background light and improves the signal-to-noise ratio of the echo signal. The optical signal is collimated by the collimation system to ensure that the beam diameter matches the aperture of the subsequent spectroscopic module. The spectroscopic module uses a dichroic mirror and a high-performance narrow-band filter to perform multi-channel separation of the optical signal. The filter is arranged at a predetermined tilt angle (0° to 10°) and uses multi-layer coating technology to ensure that the spectral transmittance is as high as 90% or more, and the out-of-band suppression ratio is as low as 10^-5, effectively avoiding the channel crosstalk problem in the complex spectral environment of the mountainous atmosphere. The servo attenuation device is combined with the background light intensity detection module to achieve real-time dynamic adjustment through a computer control system. Under strong background light conditions during the day, the servo automatically switches to a high-intensity attenuation plate to suppress the interference of the solar background light; under low light conditions at night, the servo switches to a mode without attenuation plates to ensure the integrity and sensitivity of the echo signal. This mechanism can adapt to the needs of drastic changes in light intensity during the day and night in mountainous areas, so that the system still has high stability and reliability in complex light environments.

[0042] The data acquisition and processing system collects, stores and processes the received multi-wavelength signals in real time. The optical signal output by the detector is converted into an electrical signal through the photoelectric signal processing module, and a multi-wavelength digital signal is formed after being processed by the analog-to-digital conversion module. The spot distribution and energy uniformity of each optical channel are calibrated in combination with the optical path detection tooling. The computer control system generates the vertical distribution characteristic data of aerosol distribution, water vapor content and temperature in mountainous areas based on the joint inversion algorithm by inputting the 532nm Mie scattering signal, the 355nm and 532nm Raman signal intensity ratio and the 355nm molecular rotation Raman spectrum ratio. This joint inversion method not only improves the accuracy of multi-parameter detection in mountainous areas, but also effectively compensates for the problem of reduced signal intensity under low temperature conditions.

[0043] In this embodiment, by combining the technical means of three-wavelength laser emission, precise reception and signal processing with the dynamic background light adjustment mechanism, the system shows excellent signal adaptability and detection accuracy under complex lighting conditions in mountainous areas. Compared with traditional technologies, this system significantly reduces the data error caused by background light intensity interference in mountainous areas, optimizes the separation and inversion effect of multi-wavelength signals, and realizes the stable detection of multiple parameters such as aerosols, water vapor and temperature, providing reliable scientific data support for atmospheric environment monitoring in mountainous areas.

[0044] Embodiment 3: This embodiment combines Figure 1 The system structure diagram and two parts of the component schematic diagram specifically explain the practical application and working principle of a three-wavelength eight-channel Raman-Mie temperature and humidity lidar detection system.

[0045] In this embodiment, the system consists of a transmitting system, a receiving system, a data acquisition and processing system, and a computer control system, and uses multi-wavelength laser signals and precise optical design to achieve efficient detection of multiple parameters of the atmosphere.

[0046] As shown in the figure, the transmitting system includes a multi-wavelength pulse laser, a beam shaping module and a spectrometer module. The multi-wavelength pulse laser generates laser beams of two wavelengths, 355nm and 532nm. The beam divergence angle is compressed to less than 0.1mrad by the beam shaping module, and the spot coverage range is adjusted by the achromatic lens. The shaped beam enters the spectrometer module, and the beam is separated and guided by the dichroic mirror 1 and the reflector 1. The 532nm beam is emitted through the off-axis arrangement of the spectrometer module, and the 355nm beam is coaxially emitted through the center of the secondary mirror of the telescope. This design can not only optimize the detection range, but also effectively reduce the laser blind area.

[0047] The receiving system is shown in the figure, including the primary mirror, secondary mirror, pinhole diaphragm, collimation system and spectrometer module. The optical signal is received by the primary mirror and secondary mirror of the reflecting telescope, and the field of view of the telescope is limited to 0.1-0.3mrad through the pinhole diaphragm to suppress background light and noise signals and enhance the signal-to-noise ratio of the echo signal. The signal is further adjusted by the collimation system and enters the spectrometer module. The spectrometer module uses a dichroic mirror 2 and a high-performance narrow-band filter to perform multi-channel separation of the optical signal, and divides the 355nm and 532nm laser signals into multiple optical channels such as 532P, 532S, 355P, and 355S.

[0048] A servo attenuation device is set in the receiving path of the system. The layout of its attenuation plates is shown in the schematic diagram of the components in the figure. It contains multiple attenuation plates of different strengths (numbered 1 to 4), which are dynamically switched by the servo drive. Specifically: Under strong background light conditions during the day, the system uses the background light intensity detection module to monitor the light environment in real time, and selects appropriate attenuation plates to insert into the optical path (such as strong attenuation plates or medium attenuation plates) according to the light intensity signal to suppress the interference of strong background light on the echo signal. Under low background light conditions at night, the servo drive device automatically switches to no attenuation plates or weak attenuation plates to ensure the sensitive capture capability of weak signals. This dynamic adjustment capability combined with the precision optical path design enables the system to achieve high signal-to-noise ratio signal detection in different scenarios, significantly enhancing the adaptability to multiple scenarios.

[0049] The received multi-channel signals are converted into electrical signals by the optoelectronic signal processing module, and then formed into digital signals by the analog-to-digital conversion module, and then transmitted to the computer control system for inversion processing. The system uses a joint inversion algorithm, combined with the intensity ratio of the 532nm Mie scattering signal, the 355nm and 532nm Raman signals, and the ratio of the high-order and low-order rotational Raman lines of 355nm, to generate the vertical distribution characteristics of aerosol mass concentration, water vapor content and temperature. The processed data is output in real time through a visual interface to provide users with clear atmospheric detection information.

[0050] This embodiment uses the precise optical path design, dynamic adjustment mechanism and coordinated optimization of data acquisition and inversion algorithms as shown in the figure, so that the system can effectively suppress background light interference, reduce spectral crosstalk, and accurately obtain the vertical distribution characteristics of atmospheric aerosols, water vapor and temperature in complex light environments. Especially in a variable environment (such as day and night or highly polluted areas), this system shows excellent detection accuracy and stability, providing reliable technical support for atmospheric environment monitoring.

[0051] In the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "setting", "connection", "fixation", "screw-on" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0052] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit of the present invention or based on the present features. Therefore, the embodiments should be regarded as exemplary and non-restrictive from all points of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A three-wavelength eight-channel Raman-Mi temperature and humidity laser radar detection system, including a transmitting system, a receiving system, a data acquisition and processing system, and a computer control system, characterized in that: The transmitting system comprises a multi-wavelength pulse laser, a beam shaping module and a spectroscopic module. The multi-wavelength pulse laser emits laser beams of two wavelengths, 355 nm and 532 nm. The beam shaping module compresses the beam divergence angle to be less than or equal to 0.1 mrad and adjusts the light spot coverage range. Then, the spectroscopic module adjusts the 355 nm beam to the center of the secondary mirror of the telescope for coaxial emission, and the 532 nm beam is emitted off-axis near the edge of the telescope barrel, so as to minimize the detection blind spot of the system. An imaging detection device is used to observe whether the natural background light presents a uniform and complete light spot after passing through the telescope and subsequent channels, so as to perform auxiliary measurement of the coaxiality of each lens of the spectroscopic channel. The receiving system includes a reflective telescope, a spectroscopic module, a high-performance narrowband filter and a steering gear attenuation device. The field of view of the reflective telescope is designed to be 0.1-0.3 mrad, and the divergence angle of the laser in the transmitting system is designed to be smaller than the field of view of the receiving telescope to ensure effective reception of the echo signal after the laser interacts with the atmosphere; The optical splitting module separates the received optical signal into 532P channel, 532S channel, 407 water vapor Raman channel, 386 nitrogen Raman channel, 355P channel, 355S channel, high-order temperature Raman channel and low-order temperature Raman channel according to wavelength and polarization state through a dichroic mirror, a polarizer and a high-performance narrow-band filter. The high-order and low-order temperature Raman channel optical splitting modules match the central wavelength of each channel in the optical path by adjusting the tilt angle of the filter; The steering gear attenuation device comprises a background light intensity detection module and a steering gear driving device communicating with the background light intensity detection module, wherein the steering gear driving device drives the attenuation sheet arranged in the optical path to adjust the angle, and the angle adjustment logic is dynamically controlled by a computer control system according to the background light intensity signal to adapt to different light intensity conditions and realize all-weather detection during the day and at night; The data acquisition and processing system includes a photoelectric signal processing module, an analog-to-digital conversion module and a data storage module; The photoelectric signal processing module is connected to each channel detector of the receiving system and is used to convert the optical signal output by the detector into an electrical signal; The analog-to-digital conversion module is arranged at the rear end of the photoelectric signal processing module, and is used to convert the analog electrical signal into a digital signal; The data storage module is arranged at the back end of the analog-to-digital conversion module, and is used to store the collected digital signals and transmit the digital signals to the computer control system; The data acquisition and processing system transmits the optical signal data obtained from the detectors of each channel of the receiving system, and provides the computer control system with multi-wavelength digital signals of 532nm, 355nm Raman signals and 355, 532nm Mie scattering signals based on intensity changes, time delays and spectral characteristics; The computer control system utilizes the intensity ratio of the 532nm and 355nm Raman signals, the water vapor content formula and the ratio of the high-order and low-order rotational Raman lines at 355nm, combined with the extinction coefficient of the 355 and 532nm Mie scattering signals, to invert and generate the mass concentration distribution of aerosols, the vertical distribution characteristics of water vapor content and temperature, and monitors and controls the operating status of each system in real time.

2. The three-wavelength eight-channel Raman-Mi temperature and humidity laser radar detection system according to claim 1 is characterized in that: The receiving system also includes a collimation system, which includes at least one achromatic lens group. The achromatic lens group is arranged along the optical path between the reflecting telescope and the spectroscopic module. The achromatic lens group is used to collimate the echo signal received by the reflecting telescope, and the diameter of the collimated beam is controlled within the light aperture range of the spectroscopic module.

3. The three-wavelength eight-channel Raman-Mi temperature and humidity lidar detection system according to claim 2 is characterized in that: The receiving system also includes a pinhole aperture, which is arranged between the reflecting telescope and the collimating system and is used to limit the field angle of the receiving telescope to the range of 0.1-0.3 mrad.

4. The three-wavelength eight-channel Raman-Mi temperature and humidity lidar detection system according to claim 1 is characterized in that: The tilt angle refers to the angle between the incident angle of the light signal and the normal direction of the filter surface, which is 0° to 10°.

5. The three-wavelength eight-channel Raman-Mi temperature and humidity lidar detection system according to claim 1 is characterized in that: The steering gear driving device comprises a motor driving assembly and an attenuation plate mounting frame. The attenuation plate mounting frame is arranged perpendicular to the optical path through the motor driving assembly. A plurality of attenuation plates with different strengths are arranged on the attenuation plate mounting frame.

6. The three-wavelength eight-channel Raman-Mi temperature and humidity lidar detection system according to claim 1 is characterized in that: The data acquisition and processing system includes a photoelectric signal processing module, an analog-to-digital conversion module and a data storage module; the photoelectric signal processing module is connected to each channel detector of the receiving system, and is used to convert the optical signal output by the detector into an electrical signal; the analog-to-digital conversion module is arranged at the back end of the photoelectric signal processing module, and is used to convert the analog electrical signal into a digital signal; the data storage module is arranged at the back end of the analog-to-digital conversion module, and is used to store the collected digital signal and transmit it to the computer control system for subsequent data processing.

7. The three-wavelength eight-channel Raman-Mi temperature and humidity lidar detection system according to claim 1 is characterized in that: The inversion algorithm of the computer controlled system comprises the following steps: Step 1, input processing: receiving the intensity of 355nm and 532nm Mie scattering signals, the intensity, time delay and spectral characteristics of 355nm and 532nm Raman scattering signals transmitted by the data acquisition and processing system; Step 2, atmospheric aerosol inversion: Based on the intensity change and height distribution of the 355 and 532 nm scattering signals, the vertical distribution of the mass concentration of atmospheric aerosols is inverted using the extinction coefficient of the echo signal; Step 3, water vapor content inversion: using the intensity ratio of 355nm and 532nm Raman scattering signals, combined with the gas Raman scattering formula, the vertical distribution of water vapor is inverted; Step 4, temperature inversion: Based on the ratio of high-order and low-order rotational Raman lines of the 355nm Raman scattering signal and the molecular rotational Raman scattering formula, the vertical distribution of temperature is inverted; Step 5, output results: generate vertical distribution characteristic data of aerosol mass concentration distribution, water vapor content and temperature, and display them through a visual interface.

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