A Raman LiDAR system for measuring aerosols and atmospheric temperature

Abstract

A Raman laser radar system for measuring aerosol and atmospheric temperature, comprising: emitting a laser beam generated by a laser into the atmosphere through a laser emitting device; a signal receiving device receiving a high-altitude echo signal and a low-altitude echo signal generated after the laser beam interacts in the atmosphere, converting the high-altitude echo signal and the low-altitude echo signal into corresponding first and second electrical signals respectively, and sending the first and second electrical signals to a data acquisition device; the data acquisition device acquires the first and second electrical signals sent by the signal receiving device and converts them into acquisition data that conforms to a preset data format, and sends the acquisition data to a signal processing device; the signal processing device receives the acquisition data sent by the data acquisition device, and calculates the temperature information and aerosol information corresponding to the acquisition data. The problem that the aerosol and atmospheric temperature information cannot be accurately calculated based on the signals received by the laser radar system due to the limited detection capability of the laser radar system is solved.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a Raman laser radar system for measuring aerosol and atmospheric temperature. Background Art

[0002] In the field of meteorology, temperature plays an important role in atmospheric circulation and plays an important role in the study of meteorology, atmospheric radiation, thermodynamics, cloud formation, precipitation, etc. The measurement of aerosols can help monitor and evaluate the sources, types and development changes of pollutants in the air, and play an important role in environmental monitoring and biosafety. When using a traditional lidar system to obtain a single-branch spectrum signal, the echo signal has a large bandwidth and a large number of noise signals, and it is impossible to detect signals at high altitudes. Therefore, the detection capability of the lidar system is low, resulting in the aerosol and atmospheric temperature calculated based on the signals received by the lidar system being inaccurate. Summary of the invention

[0003] The main technical problem solved by the present invention is that due to the limited detection capability of the laser radar system, the aerosol and atmospheric temperature information calculated based on the signals received by the laser radar system is not accurate enough.

[0004] According to the first aspect, in one embodiment, a Raman laser radar system for measuring aerosol and atmospheric temperature is provided, wherein the Raman laser radar system includes a laser emitting device, a signal receiving device, a data acquisition device, and a signal processing device;

[0005] The laser emitting device is used to emit the laser beam generated by the laser into the atmosphere;

[0006] The signal receiving device is used to receive the high-altitude echo signal and the low-altitude echo signal generated after the laser beam interacts in the atmosphere, convert the high-altitude echo signal and the low-altitude echo signal into corresponding first electrical signals and second electrical signals, respectively, and send the first electrical signal and the second electrical signal to the data acquisition device;

[0007] The data acquisition device is used to acquire the first electrical signal and the second electrical signal sent by the signal receiving device, convert the first electrical signal and the second electrical signal into acquisition data conforming to a preset data format, and send the acquisition data to the signal processing device;

[0008] The signal processing device is used to receive the collected data sent by the data collection device and calculate the temperature information and aerosol information corresponding to the collected data.

[0009] In some embodiments, the signal receiving device includes a first receiving device and a second receiving device, the first receiving device is used to receive the high-altitude echo signal and convert it into a corresponding first electrical signal, and the second receiving device is used to receive the low-altitude echo signal and convert it into a corresponding second electrical signal; wherein the first receiving device includes a first Cassegrain telescope, a first collimation module, a first beam splitter, a first spectroscope, a first elastic module, a first high-order pure rotational Raman signal processing module and a first low-order pure rotational Raman signal processing module;

[0010] The first electrical signal includes the electrical signal output by the first elastic module, the electrical signal corresponding to the first high-order pure rotational Raman signal processing module, and the electrical signal corresponding to the first low-order pure rotational Raman signal processing module;

[0011] The first Cassegrain telescope is used to receive the high-altitude echo signal generated after the laser beam interacts in the atmosphere;

[0012] The first collimation module is used to perform collimation processing on the high-altitude echo signal to obtain a collimated high-altitude echo signal;

[0013] The first beam splitter is used to divide the collimated high-altitude echo signal into a first echo signal and a second echo signal according to light intensity, send the first echo signal to the first elastic module, and send the second echo signal to the first beam splitter;

[0014] The first spectroscope is used for dividing the received second echo signal into a third echo signal and a fourth echo signal according to light intensity, sending the third echo signal to the first high-order pure rotational Raman signal processing module, and sending the fourth echo signal to the first low-order pure rotational Raman signal processing module;

[0015] The first elastic module includes a first filter, a first lens and a first photomultiplier tube, and the first elastic module is used to receive the first echo signal, filter the first echo signal using the first filter and the first lens, and focus the filtered first echo signal on the first photomultiplier tube to convert it into an electrical signal output by the first elastic module;

[0016] The first high-order pure rotational Raman signal processing module includes a first interferometer and a second photomultiplier tube, and the first high-order pure rotational Raman signal processing module is used to receive the third echo signal, filter the third echo signal using the first interferometer, focus the filtered third echo signal on the second photomultiplier tube, and convert it to obtain an electrical signal corresponding to the first high-order pure rotational Raman signal processing module;

[0017] The first low-order pure rotational Raman signal processing module includes a second interferometer and a third photomultiplier tube. The first low-order pure rotational Raman signal processing module is used to receive the fourth echo signal, filter the fourth echo signal using the second interferometer, focus the filtered fourth echo signal on the third photomultiplier tube, and convert it to obtain an electrical signal corresponding to the first low-order pure rotational Raman signal processing module.

[0018] In some embodiments, the second receiving device includes a second Cassegrain telescope, a second collimation module, a second beam splitter, a second spectroscope, a second elastic module, a second high-order pure rotational Raman signal processing module, and a second low-order pure rotational Raman signal processing module;

[0019] The second electrical signal includes the electrical signal output by the second elastic module, the electrical signal corresponding to the second high-order pure rotational Raman signal processing module, and the electrical signal corresponding to the second low-order pure rotational Raman signal processing module;

[0020] The second Cassegrain telescope is used to receive the low-altitude echo signal generated after the laser beam interacts in the atmosphere;

[0021] The second collimation module is used to perform collimation processing on the low-altitude echo signal to obtain a collimated low-altitude echo signal;

[0022] The second beam splitter is used to divide the collimated low-altitude echo signal into a fifth echo signal and a sixth echo signal according to light intensity, send the fifth echo signal to the second elastic module, and send the sixth echo signal to the second beam splitter;

[0023] The second spectroscope is used for dividing the received sixth echo signal into a seventh echo signal and an eighth echo signal according to light intensity, sending the seventh echo signal to the second high-order pure rotational Raman signal processing module, and sending the eighth echo signal to the second low-order pure rotational Raman signal processing module;

[0024] The second elastic module includes a second filter, a second lens and a fourth photomultiplier tube, and the second elastic module is used to receive the fifth echo signal, filter the fifth echo signal by using the second filter and the second lens, and focus the filtered fifth echo signal on the fourth photomultiplier tube to convert it into an electrical signal output by the second elastic module;

[0025] The second high-order pure rotational Raman signal processing module includes a third interferometer and a fifth photomultiplier tube, and the second high-order pure rotational Raman signal processing module is used to receive the seventh echo signal, filter the seventh echo signal using the third interferometer, focus the seventh echo signal after filtering onto the fifth photomultiplier tube, and convert it to obtain an electrical signal corresponding to the second high-order pure rotational Raman signal processing module;

[0026] The second low-order pure rotational Raman signal processing module includes a fourth interferometer and a sixth photomultiplier tube. The second low-order pure rotational Raman signal processing module is used to receive the eighth echo signal, filter the eighth echo signal using the fourth interferometer, focus the filtered eighth echo signal onto the sixth photomultiplier tube, and convert it to obtain an electrical signal corresponding to the second low-order pure rotational Raman signal processing module.

[0027] In some embodiments, a high-voltage gating module is provided on the first photomultiplier tube, the second photomultiplier tube and the third photomultiplier tube; the high-voltage gating module is used to cut off the low-altitude echo signal in the filtered echo signal before the first photomultiplier tube, the second photomultiplier tube and the third photomultiplier tube receive the filtered echo signal.

[0028] In some embodiments, a heat dissipation module is provided on the first interferometer and the second interferometer; wherein the heat dissipation module includes a heat dissipation fan and a temperature sensor, the temperature sensor is used to detect the real-time temperature of the environment in which the first interferometer and the second interferometer are located, and the heat dissipation fan is used to perform heat dissipation treatment on the first interferometer and the second interferometer when the real-time temperature is greater than or equal to a preset temperature threshold.

[0029] In some embodiments, the data acquisition device includes a data acquisition instrument, wherein the data acquisition instrument has an analog signal acquisition mode and a photon counting acquisition mode.

[0030] In some embodiments, the laser emitting device includes a laser, a beam expander, and a reflector assembly;

[0031] The laser is used to generate a laser beam;

[0032] The beam expander is used to convert the laser beam generated by the laser into a laser beam that meets the target reference requirements; the target reference requirements include energy density requirements, beam waist radius requirements and divergence angle requirements;

[0033] The reflector group comprises a reflector, and the reflector is used to emit a laser beam meeting a target reference requirement vertically into the atmosphere.

[0034] In some embodiments, the reflector assembly further includes an electrically controlled two-dimensional adjustment platform, and the electrically controlled two-dimensional adjustment platform is used to adjust the orientation of the reflector so that the laser beam is emitted vertically into the atmosphere.

[0035] In some embodiments, the Raman laser radar system further includes a system security device, which includes a cooling module, a voltage-stabilized power supply module, and a temperature and humidity control module;

[0036] The cooling module includes an internal circulation water cooler and an external circulation water cooler, wherein the internal circulation water cooler is used to take away the heat generated by the laser during operation and control the operating temperature of the laser, and the external circulation water cooler is used to dissipate the heat in the internal circulation water cooler into the atmosphere;

[0037] The voltage-stabilized power supply module is used to provide a stable voltage for the laser;

[0038] The temperature and humidity control module is used to control the temperature and humidity of the environment in which the Raman lidar system is located to comply with a preset operating temperature range and a preset operating humidity range.

[0039] In some embodiments, the Raman laser radar system further includes a system control device, which includes a laser control module, a high-voltage excitation module, a temperature-controlled power supply module, a photomultiplier tube power supply module, a timing control module, and a photomultiplier tube gating module;

[0040] The laser control module is used to control the startup of the laser, monitor the operating status of the laser, and record the cause of the failure of the laser when the laser fails;

[0041] The high-voltage excitation module is used to send a high-voltage electrical signal to the laser to excite the laser to generate laser light;

[0042] The temperature-controlled power supply module is used to provide power input for the heat dissipation module in the signal receiving device;

[0043] The photomultiplier tube power module is used to provide power input for the first photomultiplier tube, the second photomultiplier tube, the third photomultiplier tube, the fourth photomultiplier tube, the fifth photomultiplier tube and the sixth photomultiplier tube in the signal receiving device;

[0044] The timing control module is used to control the working timing of the Raman laser radar system;

[0045] The photomultiplier tube gating module is used to control the working states of the first photomultiplier tube, the second photomultiplier tube, the third photomultiplier tube, the fourth photomultiplier tube, the fifth photomultiplier tube and the sixth photomultiplier tube in the signal receiving device.

[0046] According to the Raman lidar system for measuring aerosols and atmospheric temperature of the above-mentioned embodiment, since the signal receiving device is used to receive the high-altitude echo signal and the low-altitude echo signal generated after the laser light beam interacts in the atmosphere, the Raman lidar system can detect high-altitude and low-altitude signals and improve the detection capability. Therefore, the corresponding temperature information and aerosol information calculated based on the signals detected by the Raman lidar system are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the structure of a Raman lidar system for measuring aerosol and atmospheric temperature in one embodiment of the present application;

[0048] Figure 2 This is a schematic structural diagram of a Raman lidar system for measuring aerosol and atmospheric temperature in another embodiment of the present application;

[0049] Figure 3 A comparison diagram of temperature profiles measured by a Raman lidar system and radio data in one embodiment;

[0050] Figure 4 The figure is a comparison diagram of the aerosol backscattering coefficient profile measured by a Raman lidar system according to an embodiment and the theoretical value. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0052] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0053] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0054] Please refer to Figure 1 , Figure 1 The schematic diagram is a structural diagram of a Raman lidar system for measuring aerosol and atmospheric temperature according to an embodiment of the present invention. The Raman lidar system 10 includes a laser emitting device 11, a signal receiving device 12, a data acquisition device 13 and a signal processing device 14.

[0055] Please refer to Figure 2 , Figure 2 The structure diagram of a Raman laser radar system for measuring aerosol and atmospheric temperature in an embodiment is shown. In the Raman laser radar system 10, the laser emitting device 11 includes a laser 111, a beam expander 112 and a reflector group 113. The signal receiving device 12 includes a first receiving device 121 and a second receiving device 122, wherein the first receiving device 121 includes a first Cassegrain telescope 121a, a first collimating module 121b, a first beam splitter 121c, a first beam splitter 121d, a first elastic module 121e, a first high-order pure rotation Raman signal processing module 121f and a first low-order pure rotation Raman signal processing module 121g. At the same time, the Raman laser radar system 10 also includes a system security device 15, wherein the system security device 15 includes a cooling module 151, a voltage-stabilized power supply module 152 and a temperature and humidity control module 153. The Raman laser radar system 10 further includes a system control device 16, wherein the system control device 16 includes a laser control module 161, a high voltage excitation module 162, a temperature control power module 163, a photomultiplier tube power module 164, a timing control module 165, and a photomultiplier tube gating module 166. The Raman laser radar system 10 further includes a data storage device 17.

[0056] In some embodiments, the laser emitting device 11 includes a laser 111, a beam expander 112, and a reflector group 113. The laser 111 is used to generate a laser beam, and the wavelength of the laser beam can be 1064nm. The laser beam can pass through an internal amplifier and a doubled frequency crystal to emit a laser beam with a single pulse energy of about 700mJ, a wavelength of 532.6nm, and a spot diameter of 8mm. The energy density of the laser beam is reduced by the beam expander 112, the spot diameter is increased, and the divergence angle is reduced. Therefore, the beam expander 112 can convert the laser beam generated by the laser 111 into a laser beam that meets the target reference requirements, wherein the target reference requirements include energy density requirements, beam waist radius requirements, and divergence angle requirements. The reflector group 113 includes a reflector, or the reflector group 113 may also include an electrically controlled two-dimensional adjustment table, wherein the reflector emits a laser beam that meets the target reference requirements vertically into the atmosphere, and the electrically controlled two-dimensional adjustment table is controlled by a drive motor and a computer, which can adjust the orientation of the reflector so that the laser beam is emitted vertically into the atmosphere and increase the receiving efficiency of the signal receiving device 12.

[0057] In some embodiments, the signal receiving device 12 is used to receive the high-altitude echo signal and the low-altitude echo signal generated after the laser light beam interacts in the atmosphere, convert the high-altitude echo signal and the low-altitude echo signal into corresponding first electrical signals and second electrical signals respectively, and send the first electrical signals and the second electrical signals to the data acquisition device 13.

[0058] In some embodiments, the signal receiving device 12 includes a first receiving device 121 and a second receiving device 122. The first receiving device 121 receives the high-altitude echo signal and converts it into a corresponding first electrical signal, and the second receiving device 122 receives the low-altitude echo signal and converts it into a corresponding second electrical signal. The sizes of the Cassegrain telescopes in the first receiving device 121 and the second receiving device 122 are different, and the rest of the structures are the same. The first receiving device 121 and the second receiving device 122 may be provided with a 1m Cassegrain telescope and a 0.3m Cassegrain telescope, respectively.

[0059] In some embodiments, the signal receiving device 12 is not limited to the Cassegrain telescope, nor is it limited to two receiving devices. The signal receiving device can also be expanded. For example, a channel for receiving information such as water vapor, three-phase water and fluorescence can be set.

[0060] In some embodiments, the first receiving device 121 includes a first Cassegrain telescope 121a, a first collimating module 121b, a first beam splitter 121c, a first beam splitter 121d, a first elastic module 121e, a first high-order pure rotational Raman signal processing module 121f, and a first low-order pure rotational Raman signal processing module 121g. The first electrical signal includes an electrical signal output by the first elastic module 121e, an electrical signal corresponding to the first high-order pure rotational Raman signal processing module 121f, and an electrical signal corresponding to the first low-order pure rotational Raman signal processing module 121g.

[0061] In some embodiments, the laser beams interact with each other in the atmosphere and generate echo signals. The first Cassegrain telescope 121a can receive the high-altitude echo signals generated by the interaction of the laser beams in the atmosphere, and collimate the received high-altitude echo signals through the first collimation module 121b to obtain the collimated high-altitude echo signals. The first beam splitter 121c divides the collimated high-altitude echo signals into the first echo signal and the second echo signal according to the light intensity, and sends the first echo signal to the first elastic module 121e, and sends the second echo signal to the first beam splitter 121d. The first beam splitter 121d divides the received second echo signal into the third echo signal and the fourth echo signal according to the light intensity, and sends the third echo signal to the first high-order pure rotational Raman signal processing module 121f, and sends the fourth echo signal to the first low-order pure rotational Raman signal processing module 121g.

[0062] In some embodiments, the first elastic module 121e includes a first filter, a first lens and a first photomultiplier tube. The first filter and the first lens are used to filter the received first echo signal, and the filtered first echo signal is focused on the first photomultiplier tube to convert the optical signal into an electrical signal, thereby obtaining the electrical signal output by the first elastic module 121e.

[0063] In some embodiments, the first high-order pure rotational Raman signal processing module 121f includes a first interferometer and a second photomultiplier tube, and the first interferometer is used to filter the received third echo signal, and the filtered third echo signal is focused on the second photomultiplier tube, and the optical signal is converted into an electrical signal, thereby obtaining an electrical signal corresponding to the first high-order pure rotational Raman signal processing module 121f. The filtered third echo signal can be focused on the second photomultiplier tube through a lens.

[0064] In some embodiments, the first low-order pure rotational Raman signal processing module 121g includes a second interferometer and a third photomultiplier tube. The second interferometer is used to filter the received fourth echo signal, and the filtered fourth echo signal is focused on the third photomultiplier tube to convert the optical signal into an electrical signal, thereby obtaining an electrical signal corresponding to the first low-order pure rotational Raman signal processing module 121g.

[0065] In some embodiments, since the proportion of pure rotational Raman signals in the echo signal is too low, it is extremely easy for other invalid signals to pass through by only using a filter to filter, resulting in a reduction in the detection distance, etc. Therefore, a first interferometer and a second interferometer are respectively set in the first high-order pure rotational Raman signal processing module 121f and the first low-order pure rotational Raman signal processing module 121g as filtering devices to filter out invalid signals, thereby improving the accuracy of filtering.

[0066] In some embodiments, a high-voltage gating module is provided on the first photomultiplier tube, the second photomultiplier tube and the third photomultiplier tube, and the high-voltage gating module is controlled by a high-voltage power supply. Before the first photomultiplier tube, the second photomultiplier tube and the third photomultiplier tube receive the echo signal after filtering, the high-voltage gating module cuts off the low-altitude echo signal in the echo signal after filtering, thereby preventing the low-altitude echo signal from being too strong and causing the photomultiplier tube to be saturated, thereby increasing the service life of the photomultiplier tube.

[0067] In some embodiments, since the first interferometer and the second interferometer are extremely sensitive to the ambient temperature, a heat dissipation module is also provided on the first interferometer and the second interferometer, and the heat dissipation module can control the ambient temperature of the interferometer in real time to ensure the normal and stable operation of the system. The heat dissipation module includes a heat dissipation fan and a temperature sensor, and the temperature sensor can detect the real-time temperature of the environment in which the first interferometer and the second interferometer are located. The heat dissipation fan can perform heat dissipation processing on the first interferometer and the second interferometer when the real-time temperature is greater than or equal to a preset temperature threshold, so as to reduce the ambient temperature of the first interferometer and the second interferometer.

[0068] In some embodiments, the second receiving device 122 includes a second Cassegrain telescope 122a, a second collimating module 122b, a second beam splitter 122c, a second beam splitter 122d, a second elastic module 122e, a second high-order pure rotational Raman signal processing module 122f, and a second low-order pure rotational Raman signal processing module 122g. The second electrical signal includes an electrical signal output by the second elastic module 122e, an electrical signal corresponding to the second high-order pure rotational Raman signal processing module 122f, and an electrical signal corresponding to the second low-order pure rotational Raman signal processing module 122g. It is worth noting that, except for the size of the Cassegrain telescope, the other structures of the first receiving device 121 and the second receiving device 122 are the same. The second receiving device 122 can receive the low-altitude echo signal generated by the interaction of the laser beam in the atmosphere and convert it into a corresponding second electrical signal, which will not be repeated here.

[0069] In some embodiments, the data acquisition device 13 is used to acquire the first electrical signal and the second electrical signal sent by the signal receiving device 12, convert the first electrical signal and the second electrical signal into acquisition data that conforms to a preset data format, and send the acquisition data to the signal processing device 14. The data acquisition device 13 can be a data acquisition instrument, which has an analog signal acquisition mode and a photon counting acquisition mode. The data acquisition instrument is used to acquire data, and the acquired data is saved in a computer, which can convert the acquired data into a recognizable .dat file.

[0070] In some embodiments, the signal processing device 14 receives the collected data sent by the data collection device 13, and calculates the temperature information and aerosol information corresponding to the collected data.

[0071] In some embodiments, the temperature information corresponding to the collected data is calculated using the following formula:

[0072] ,

[0073] Where T represents temperature information, A and B represent constants, which can be calibrated by radiosonde data, and P J Represents the pure rotational Raman signal of low-order quantum numbers in the collected data, Represents the pure rotational Raman signal of higher-order quantum numbers in the acquired data.

[0074] In some embodiments, the aerosol information corresponding to the collected data is calculated by the following formula:

[0075] ,

[0076] Where F(J,T) represents the rotational partition function of the molecule, represents the differential scattering cross section, J represents the rotational quantum number before the Raman scattering is emitted, represents the rotational quantum number after Raman scattering, The expression representing the backscattering system of nitrogen molecules with different rotational quantum numbers is: represents the aerosol backscattering coefficient corresponding to the collected data, and Represent the system constants of each channel respectively, and Respectively represent the echo signal strength of each channel, and are the backscattering coefficients of the molecules, represents the molecular backscattering cross section, P0 and P J Indicates the echo signal of each channel.

[0077] In some embodiments, ,in, The expression of the backscattering system of nitrogen molecules with different rotational quantum numbers, n(z) represents the molecular number density, F(J,T) represents the rotational partition function of the molecule, and its physical meaning represents the percentage of molecules in the rotational quantum state J at temperature T. Represents the differential scattering cross section, whose size is only related to the rotational quantum number.

[0078] In some embodiments, ,

[0079] Where F(J,T) represents the rotational partition function of the molecule, represents the statistical weight factor, I represents the nuclear self-selected quantum number, h represents Planck's constant, c represents the speed of light, B0 represents the rotation constant, k represents the Boltzmann constant, T represents the temperature, and J represents the rotational quantum state.

[0080] In some embodiments, the calculation of the echo signal strength may refer to the following formula:

[0081] ,

[0082] in, represents the echo signal strength, E0 represents the power of the laser, c is the speed of light, represents the width of the laser pulse emitted by the laser, A represents the receiving area of ​​the telescope, represents the optical efficiency of each channel, O(z) represents the overlap factor, represents the backscattering coefficient, represents the atmospheric transmittance of the photon during its round trip, and z represents the molecule.

[0083] In some embodiments, the aerosol backscattering coefficient expression after calibrating the system constant is:

[0084] ,

[0085] in, represents the calibrated aerosol backscattering coefficient, represents the backscattering coefficient of the molecule, represents the rotational partition function of molecule z, represents the rotational partition function of molecule z0, and Respectively represent the echo signal intensity of molecule z in each channel, and Respectively represent the echo signal intensity of molecule z0 in each channel.

[0086] In some embodiments, the Raman laser radar system 10 further includes a system security device 15, which includes a cooling module 151, a voltage-stabilized power supply module 152, and a temperature and humidity control module 153. Among them, the cooling module 151 includes an internal circulation water cooler and an external circulation water cooler. The internal circulation water cooler takes away the heat generated by the laser during operation and controls the operating temperature of the laser to be kept below a preset temperature. The external circulation water cooler exchanges heat with the water tank of the internal circulation water cooler through a pipeline, and dissipates the heat in the internal circulation water cooler into the atmosphere. The voltage-stabilized power supply module 152 is used to provide a stable voltage for the laser, thereby reducing the fluctuation of the output laser power, thereby improving the overall performance of the Raman laser radar system 10. At the same time, the system can be ensured to work stably when the instantaneous power failure of the extreme time causes the laser to shut down or the computer to restart, or when the voltage or power fluctuates, the system can be ensured to work stably, effectively preventing the irreversible damage to the equipment caused by sudden power failure. The temperature and humidity control module 153 controls the temperature and humidity of the environment in which the Raman laser radar system 10 is located to meet the preset working temperature range and the preset working humidity range. Among them, the temperature and humidity control module 153 includes a dehumidifier and an air conditioner, which can ensure the working environment of the Raman lidar system 10. Since components such as the beam expander and the electrically controlled reflector are extremely sensitive to the temperature and humidity in the environment, therefore, when the temperature is high or the air humidity is high in the working environment, the temperature and humidity are controlled to avoid affecting the normal operation of the Raman lidar system 10, extend the service life of the system equipment and ensure the system detection performance.

[0087] In some embodiments, the Raman laser radar system 10 further includes a system control device 16, wherein the system control device 16 includes a laser control module 161, a high voltage excitation module 162, a temperature control power module 163, a photomultiplier tube power module 164, a timing control module 165, and a photomultiplier tube gating module 166. The laser control module 161 can control the laser to start working, monitor the operating status of the laser, and when the laser fails, record the cause of the failure of the laser. The high voltage excitation module 162 can send a high voltage electrical signal to the laser to excite the laser to generate laser. The temperature control power module 163 can provide power input for the heat dissipation module in the signal receiving device 12. The photomultiplier tube power module 164 provides power input for the first photomultiplier tube, the second photomultiplier tube, the third photomultiplier tube, the fourth photomultiplier tube, the fifth photomultiplier tube, and the sixth photomultiplier tube in the signal receiving device 12. The timing control module 165 controls the working timing of the Raman laser radar system 10 to ensure the overall stable and orderly operation of the system. The photomultiplier tube gating module 166 controls the working states of the first photomultiplier tube, the second photomultiplier tube, the third photomultiplier tube, the fourth photomultiplier tube, the fifth photomultiplier tube, and the sixth photomultiplier tube in the signal receiving device 12 .

[0088] In some embodiments, the Raman lidar system 10 also includes a data storage device 17, wherein the data storage device 17 also includes a data display module, and the data storage device 17 is used to store the collected data in the data acquisition device, and when receiving a data display request sent by the user, the collected data is displayed in real time on the data display module.

[0089] Please refer to Figure 3 and Figure 4 In some embodiments, Figure 3 Including the comparison between the relationship between temperature and altitude under the 0.3m aperture telescope data, the relationship between temperature and altitude under the 1m aperture telescope data, and the relationship between temperature and altitude under the radio data measured by the Raman laser radar system 10, Figure 4 It represents the comparison between the inversion result between the backscattering coefficient and the altitude measured by the Raman laser radar system 10 and the theoretical result between the backscattering coefficient and the altitude.

[0090] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0091] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A Raman lidar system for measuring aerosols and atmospheric temperature, characterized in that: The Raman laser radar system includes a laser emitting device, a signal receiving device, a data acquisition device and a signal processing device; The laser emitting device is used to emit the laser beam generated by the laser into the atmosphere; The signal receiving device is used to receive the high-altitude echo signal and the low-altitude echo signal generated after the laser beam interacts in the atmosphere, and convert the high-altitude echo signal and the low-altitude echo signal into corresponding first electrical signals and second electrical signals respectively, and send the first electrical signal and the second electrical signal to the data acquisition device; the signal receiving device includes a first receiving device and a second receiving device, the first receiving device is used to receive the high-altitude echo signal and convert it into a corresponding first electrical signal, and the second receiving device is used to receive the low-altitude echo signal and convert it into a corresponding second electrical signal; wherein the first receiving device includes a first Cassegrain telescope, a first collimation module, a first beam splitter, a first spectroscope, a first elastic module, a first high-order pure rotational Raman signal processing module and a first low-order pure rotational Raman signal processing module; The first electrical signal includes the electrical signal output by the first elastic module, the electrical signal corresponding to the first high-order pure rotational Raman signal processing module, and the electrical signal corresponding to the first low-order pure rotational Raman signal processing module; The first Cassegrain telescope is used to receive the high-altitude echo signal generated after the laser beam interacts in the atmosphere; The first collimation module is used to perform collimation processing on the high-altitude echo signal to obtain a collimated high-altitude echo signal; The first beam splitter is used to divide the collimated high-altitude echo signal into a first echo signal and a second echo signal according to light intensity, send the first echo signal to the first elastic module, and send the second echo signal to the first beam splitter; The first spectroscope is used for dividing the received second echo signal into a third echo signal and a fourth echo signal according to light intensity, sending the third echo signal to the first high-order pure rotational Raman signal processing module, and sending the fourth echo signal to the first low-order pure rotational Raman signal processing module; The first elastic module includes a first filter, a first lens and a first photomultiplier tube, and the first elastic module is used to receive the first echo signal, filter the first echo signal using the first filter and the first lens, and focus the filtered first echo signal on the first photomultiplier tube to convert it into an electrical signal output by the first elastic module; The first high-order pure rotational Raman signal processing module includes a first interferometer and a second photomultiplier tube, and the first high-order pure rotational Raman signal processing module is used to receive the third echo signal, filter the third echo signal using the first interferometer, focus the filtered third echo signal on the second photomultiplier tube, and convert it to obtain an electrical signal corresponding to the first high-order pure rotational Raman signal processing module; The first low-order pure rotational Raman signal processing module includes a second interferometer and a third photomultiplier tube, and the first low-order pure rotational Raman signal processing module is used to receive the fourth echo signal, filter the fourth echo signal using the second interferometer, focus the filtered fourth echo signal on the third photomultiplier tube, and convert it to obtain an electrical signal corresponding to the first low-order pure rotational Raman signal processing module; The data acquisition device is used to acquire the first electrical signal and the second electrical signal sent by the signal receiving device, convert the first electrical signal and the second electrical signal into acquisition data conforming to a preset data format, and send the acquisition data to the signal processing device; The signal processing device is used to receive the collected data sent by the data collection device and calculate the temperature information and aerosol information corresponding to the collected data.

2. The Raman laser radar system according to claim 1, characterized in that: The second receiving device includes a second Cassegrain telescope, a second collimation module, a second beam splitter, a second spectroscope, a second elastic module, a second high-order pure rotational Raman signal processing module and a second low-order pure rotational Raman signal processing module; The second electrical signal includes the electrical signal output by the second elastic module, the electrical signal corresponding to the second high-order pure rotational Raman signal processing module, and the electrical signal corresponding to the second low-order pure rotational Raman signal processing module; The second Cassegrain telescope is used to receive the low-altitude echo signal generated after the laser beam interacts in the atmosphere; The second collimation module is used to perform collimation processing on the low-altitude echo signal to obtain a collimated low-altitude echo signal; The second beam splitter is used to divide the collimated low-altitude echo signal into a fifth echo signal and a sixth echo signal according to light intensity, send the fifth echo signal to the second elastic module, and send the sixth echo signal to the second beam splitter; The second spectroscope is used for dividing the received sixth echo signal into a seventh echo signal and an eighth echo signal according to light intensity, sending the seventh echo signal to the second high-order pure rotational Raman signal processing module, and sending the eighth echo signal to the second low-order pure rotational Raman signal processing module; The second elastic module includes a second filter, a second lens and a fourth photomultiplier tube, and the second elastic module is used to receive the fifth echo signal, filter the fifth echo signal by using the second filter and the second lens, and focus the filtered fifth echo signal on the fourth photomultiplier tube to convert it into an electrical signal output by the second elastic module; The second high-order pure rotational Raman signal processing module includes a third interferometer and a fifth photomultiplier tube, and the second high-order pure rotational Raman signal processing module is used to receive the seventh echo signal, filter the seventh echo signal using the third interferometer, focus the seventh echo signal after filtering onto the fifth photomultiplier tube, and convert it to obtain an electrical signal corresponding to the second high-order pure rotational Raman signal processing module; The second low-order pure rotational Raman signal processing module includes a fourth interferometer and a sixth photomultiplier tube. The second low-order pure rotational Raman signal processing module is used to receive the eighth echo signal, filter the eighth echo signal using the fourth interferometer, focus the filtered eighth echo signal onto the sixth photomultiplier tube, and convert it to obtain an electrical signal corresponding to the second low-order pure rotational Raman signal processing module.

3. The Raman laser radar system according to claim 1, characterized in that: The first photomultiplier tube, the second photomultiplier tube and the third photomultiplier tube are provided with a high-voltage gating module; the high-voltage gating module is used to cut off the low-altitude echo signal in the filtered echo signal before the first photomultiplier tube, the second photomultiplier tube and the third photomultiplier tube receive the filtered echo signal.

4. The Raman laser radar system according to claim 1, characterized in that: The first interferometer and the second interferometer are provided with a heat dissipation module; wherein the heat dissipation module includes a heat dissipation fan and a temperature sensor, the temperature sensor is used to detect the real-time temperature of the environment in which the first interferometer and the second interferometer are located, and the heat dissipation fan is used to perform heat dissipation processing on the first interferometer and the second interferometer when the real-time temperature is greater than or equal to a preset temperature threshold.

5. The Raman laser radar system according to claim 1, characterized in that: The data acquisition device comprises a data acquisition instrument, wherein the data acquisition instrument has an analog signal acquisition mode and a photon counting acquisition mode.

6. The Raman laser radar system according to claim 1, characterized in that: The laser emitting device comprises a laser, a beam expander and a reflector group; The laser is used to generate a laser beam; The beam expander is used to convert the laser beam generated by the laser into a laser beam that meets the target reference requirements; the target reference requirements include energy density requirements, beam waist radius requirements and divergence angle requirements; The reflector group comprises a reflector, and the reflector is used to emit a laser beam meeting a target reference requirement vertically into the atmosphere.

7. The Raman laser radar system according to claim 6, characterized in that: The reflector assembly also includes an electrically controlled two-dimensional adjustment platform, which is used to adjust the orientation of the reflector so that the laser beam is emitted vertically into the atmosphere.

8. The Raman laser radar system according to claim 1, characterized in that: The Raman laser radar system also includes a system protection device, which includes a cooling module, a voltage-stabilized power supply module and a temperature and humidity control module; The cooling module includes an internal circulation water cooler and an external circulation water cooler, wherein the internal circulation water cooler is used to take away the heat generated by the laser during operation and control the operating temperature of the laser, and the external circulation water cooler is used to dissipate the heat in the internal circulation water cooler into the atmosphere; The voltage-stabilized power supply module is used to provide a stable voltage for the laser; The temperature and humidity control module is used to control the temperature and humidity of the environment in which the Raman lidar system is located to comply with a preset operating temperature range and a preset operating humidity range.

9. The Raman laser radar system according to claim 1, characterized in that: The Raman laser radar system also includes a system control device, which includes a laser control module, a high-voltage excitation module, a temperature control power supply module, a photomultiplier tube power supply module, a timing control module, and a photomultiplier tube gating module; The laser control module is used to control the startup of the laser, monitor the operating status of the laser, and record the cause of the failure of the laser when the laser fails; The high-voltage excitation module is used to send a high-voltage electrical signal to the laser to excite the laser to generate laser light; The temperature-controlled power supply module is used to provide power input for the heat dissipation module in the signal receiving device; The photomultiplier tube power module is used to provide power input for the first photomultiplier tube, the second photomultiplier tube, the third photomultiplier tube, the fourth photomultiplier tube, the fifth photomultiplier tube and the sixth photomultiplier tube in the signal receiving device; The timing control module is used to control the working timing of the Raman laser radar system; The photomultiplier tube gating module is used to control the working states of the first photomultiplier tube, the second photomultiplier tube, the third photomultiplier tube, the fourth photomultiplier tube, the fifth photomultiplier tube and the sixth photomultiplier tube in the signal receiving device.

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