All-day biological aerosol fluorescence laser radar system

Abstract

The embodiment of the invention discloses an all-day biological aerosol fluorescence laser radar system, and the system comprises a rotary table; the central control assembly is adaptively arranged on the rotary table; the laser assembly is adaptively arranged on the rotary table and is used for generating pulse laser under the control of the central control assembly; the reflecting mirror assembly is adaptively arranged on the rotary table and is used for reflecting the pulse laser and fluorescent light generated by the biological aerosol under the induction of the pulse laser; the signal acquisition assembly is arranged on the rotary table, is connected with the central control assembly and is used for acquiring optical signals; the illuminometer is adaptively arranged on the rotary table, is connected with the central control assembly and is used for detecting the sunlight illumination intensity; the Beidou positioning assembly is adaptively arranged on the rotary table, is connected with the central control assembly and is used for determining the relative position of the sun; wherein the rotary table, the reflector assembly and the signal acquisition assembly are arranged to be in a coaxial state. The test gain of the radar system can be adjusted according to the test area so as to adapt to different illumination conditions, and safe and accurate detection can be carried out under different illumination conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of bioaerosol detection, and in particular relates to a full-day bioaerosol fluorescent laser radar system. Background Art

[0002] Bioaerosols in the troposphere can absorb shorter wavelengths of light, which can affect the ecological balance. In recent years, many scholars at home and abroad have conducted a lot of research in the field of bioaerosols and achieved relatively mature research results. Among them, the use of laser radar to remotely measure bioaerosols and determine their particle number density and other characteristics is one of the current research hotspots. Bioaerosols can produce fluorescence under the induction of lasers, while non-biological aerosols cannot. Therefore, aerosol bioaerosols can be detected by a laser radar system based on laser-induced fluorescence.

[0003] Fluorescence laser radar is mainly composed of lasers, telescopes, spectroscopic systems, computers and some auxiliary tools. It realizes the detection and analysis of bioaerosols based on the combination of laser induced fluorescence technology and laser radar technology. The fluorescence spectra of biological particles (fungi, viruses) and non-biological particles (smog, dust) have fixed characteristic forms. The fluorescence spectrum of the aerosol to be tested is collected using ultraviolet laser induced fluorescence (UV-LIF, Ultraviolet Laser Induced Fluorescence) technology. By analyzing and deducing with the existing data, the type of biological particles can be inferred.

[0004] Most of the existing laser radars used for environmental bioaerosol detection are vehicle-mounted laser radars, which can achieve three-dimensional scanning detection, but the operation is relatively cumbersome, and a separate gimbal is required to control the reflector. In addition, it is impossible to determine whether the light intensity is reasonable, and it cannot rule out the influence of factors such as strong sunlight on the detection results of the radar system. Detection is usually carried out in dark environments on cloudy days or at night. Summary of the invention

[0005] In view of this, some embodiments disclose a 24-hour bioaerosol fluorescence lidar system, the system comprising:

[0006] Turntable;

[0007] A central control component, adapted to be arranged on a turntable;

[0008] A laser assembly, adapted to be arranged on a turntable, and used to generate pulsed laser under the control of a central control assembly;

[0009] A reflector assembly is adapted to be arranged on a turntable and is used to reflect the pulsed laser and the fluorescence generated by the bioaerosol under the induction of the pulsed laser;

[0010] A signal acquisition component is arranged on a turntable and connected to the central control component for collecting optical signals;

[0011] A light meter is mounted on a turntable and connected to the central control component to detect the intensity of sunlight;

[0012] Beidou positioning component, which is adapted to be set on the turntable and connected to the central control component, is used to determine the relative position of the sun;

[0013] Among them, the turntable, the reflector assembly, and the signal acquisition assembly are set to a coaxial state.

[0014] In some embodiments of the all-weather bioaerosol fluorescent lidar system disclosed, the reflector assembly includes:

[0015] A small reflector, adapted to the laser assembly and used for reflecting the pulsed laser;

[0016] The large reflector is adapted to the small reflector and the signal collection component, and is used to reflect the pulsed laser after being reflected by the small reflector, and is used to reflect the fluorescence induced by the pulsed laser irradiating the bioaerosol, and reflect the fluorescence to the signal collection component.

[0017] Some embodiments disclose a 24-hour bioaerosol fluorescence lidar system, wherein the signal acquisition component comprises:

[0018] A telescope, adapted to be set with the large reflector, for collecting optical signals;

[0019] A spectrometer unit, adapted to the telescope, for receiving and processing optical signals collected by the telescope;

[0020] The data acquisition unit is connected to the light-splitting unit and is used to acquire data transmitted by the light-splitting unit and transmit the acquired data to the central control component.

[0021] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, the spectroscopic unit includes:

[0022] A first dichroic mirror; a meter signal photoelectric detector is arranged in the direction of the reflected light of the first dichroic mirror, and the meter signal photoelectric detector is arranged to be connected to the data acquisition card;

[0023] A second dichroic mirror, disposed in the transmission light direction of the first dichroic mirror;

[0024] A first fluorescence photoelectric detector is arranged in the direction of the reflected light of the second dichroic mirror, and the first fluorescence photoelectric detector is connected to the data acquisition card;

[0025] A second fluorescence photoelectric detector is arranged in the projection light direction of the second dichroic mirror, and the second fluorescence photoelectric detector is arranged to be connected with the data acquisition card.

[0026] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, the light meter is adapted to be arranged in front of the telescope to detect the intensity of sunlight at the front end of the telescope;

[0027] The test signal-to-noise ratio of the lidar system is determined based on the measurement results of the light meter and the data collected by the signal acquisition component; the test signal-to-noise ratio is calculated according to the following formula:

[0028]

[0029] Among them, η pmt is the detection efficiency of the photodetector; e is the electron charge, in C; h is Planck's constant, in j·s; c is the speed of light, in m·s -1 ;Ω0 is the receiving field angle of the telescope, in sr;Δλ is the filter bandwidth, in nm;B is the frequency bandwidth of the photodetector, in Hz;S b , solar background light parameters; n is the total number of laser pulses; P(R) is the light signal intensity of the photodetector at a distance R; A0 is the receiving area of ​​the telescope; i d is the photodetector noise current; Y -SNR (R) is the test signal-to-noise ratio.

[0030] The all-day bioaerosol fluorescent lidar system disclosed in some embodiments adjusts the test gain of the radar system according to the test signal-to-noise ratio and the sunlight intensity, specifically including increasing the test gain of the radar system in a test interval with high light intensity and low test signal-to-noise ratio, and reducing the test gain of the radar system in a test interval with low light intensity and high test signal-to-noise ratio.

[0031] In some embodiments, the all-day bioaerosol fluorescent laser radar system disclosed sets three illumination thresholds according to the illumination intensity, wherein the relationship between the first illumination threshold Lux1, the second illumination threshold Lux2, and the third illumination threshold Lux3 is Lux1<Lux2<Lux3;

[0032] According to the illumination threshold and the test signal-to-noise ratio, four test areas are set, including:

[0033] The area with light intensity less than Lux1 and good test signal-to-noise ratio is the first test area;

[0034] The area where the illumination intensity is between Lux1 and Lux2 and the test signal-to-noise ratio is qualified is the second test area;

[0035] The area with illumination between Lux2 and Lux3 and poor test signal-to-noise ratio is the third test area;

[0036] The area with illuminance greater than Lux3 and very poor test signal-to-noise ratio is divided into the fourth test area.

[0037] The all-day bioaerosol fluorescent lidar system disclosed in some embodiments is adjusted to a small gain in the first test area, to a medium gain in the second test area, to a high gain in the third test area, and in the fourth test area, the radar system is turned off and monitoring is stopped.

[0038] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, the front end of the telescope is adapted to be provided with an electronic shutter structure.

[0039] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, in the fourth test area, the electronic shutter is closed without closing the radar system.

[0040] The all-day bioaerosol fluorescent lidar system disclosed in the embodiment of the present invention uses a Beidou positioning component to determine the relative position of the lidar system and the sun, further determines a test area of ​​the radar system according to light intensity and a test signal-to-noise ratio of the system, and adjusts the test gain of the radar system according to different characteristics of the test area to adapt to different lighting conditions. Under different lighting conditions, the bioaerosol can be effectively and reliably measured, and the lidar system can be protected from being damaged under strong sunlight, thereby increasing the service life of the radar laser system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Example 1 Schematic diagram of the composition of the all-day bioaerosol fluorescence lidar system;

[0042] Figure 2 Schematic diagram of the composition of the spectroscopic unit of Example 2.

[0043] Reference numerals

[0044] 1 Turntable 2 Central control components

[0045] 3 Laser component 4 Signal acquisition component

[0046] 5 Reflector assembly 6 Light meter

[0047] 7 Beidou positioning component 31 pulse laser

[0048] 32 Beam expander 41 Data acquisition unit

[0049] 42 Telescope 43 Spectroscopic unit

[0050] 51 Small reflector 52 Large reflector

[0051] 100 Bioaerosol Cloud DETAILED DESCRIPTION

[0052] The word "embodiment" used herein as an "exemplary" does not necessarily mean that any embodiment described is superior or better than other embodiments. Performance index tests in the embodiments of the present invention are performed using conventional test methods in the art unless otherwise specified. It should be understood that the terms described in the embodiments of the present invention are only used to describe specific implementation methods and are not intended to limit the contents disclosed in the embodiments of the present invention.

[0053] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which the embodiments of the present invention belong; other experimental methods and technical means not specifically specified in the embodiments of the present invention refer to experimental methods and technical means commonly used by ordinary technicians in the field.

[0054] The terms "substantially" and "approximately" used herein are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. The numerical data represented or presented in the range format herein are used only for convenience and brevity, and should therefore be flexibly interpreted as including not only the values ​​clearly listed as the limits of the range, but also all independent values ​​or sub-ranges contained in the range. For example, the numerical range of "1-5%" should be interpreted as including not only the clearly listed values ​​of 1% to 5%, but also the independent values ​​and sub-ranges within the range shown. Therefore, independent values ​​such as 2%, 3.5% and 4% and sub-ranges such as 1%-3%, 2%-4% and 3%-5% are included in this numerical range. This principle also applies to the range of only one numerical value. In addition, such an interpretation applies regardless of the width of the range or the characteristics described.

[0055] In this document, including in the claims, transitional words such as "comprises," "includes," "with," "having," "containing," "involving," "accommodating," etc. are understood to be open-ended, i.e., meaning "including but not limited to." Only the transitional words "consisting of" and "composed of" are closed transitional words.

[0056] In order to better illustrate the present invention, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

[0057] Under the premise of no conflict, the technical features disclosed in the embodiments of the present invention may be arbitrarily combined, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present invention.

[0058] In some embodiments, a 24-hour bioaerosol fluorescence lidar system comprises:

[0059] Turntable: Usually, the turntable is installed on the system bracket or system base, and can rotate in a set manner to drive the radar system to detect at different angles.

[0060] The central control component is adapted to be set on the turntable; generally, the central control component is the information processing and test control center of the radar system, for example, it controls the turntable to rotate according to the set method, controls the laser component to provide pulsed laser that meets the test needs, processes the information of the light meter and Beidou positioning component, processes the information collected by the data set acquisition card, etc., and performs intelligent control of the laser radar system to realize automatic detection of bioaerosols around the clock;

[0061] A laser assembly, adapted to be arranged on a turntable, and used to generate pulsed laser under the control of a central control assembly;

[0062] A reflector assembly is adapted to be arranged on a turntable and is used to reflect the pulsed laser and the fluorescence generated by the bioaerosol under the induction of the pulsed laser;

[0063] A signal acquisition component is arranged on a turntable and connected to the central control component for collecting optical signals;

[0064] The light meter is adapted to be set on the turntable and connected to the central control component to detect the intensity of sunlight. Usually, the optical signal collected by the signal acquisition component includes not only the fluorescence induced by the laser, but also sunlight. Since the intensity of sunlight is too high or the optical device of the signal acquisition component is damaged, and the sunlight has a large spectral radiation in various light bands, it has a great influence on the detection process of the laser radar system, thereby affecting the detection accuracy and service life of the laser radar system. Therefore, the light meter is used to detect the intensity of sunlight, so as to adjust the radar system according to the light intensity to prevent damage to the optical device.

[0065] The Beidou positioning component is adapted to be set on the turntable and connected to the central control component to determine the relative position of the sun. Generally, the Beidou positioning component can determine the geographic coordinate position of the laser radar system, and further combined with astronomical ephemeris data, such as solar declination and Greenwich hour angle, the position of the sun at a specific time and place can be calculated. Further, the scanning test direction of the radar system can be adjusted according to the position of the sun.

[0066] The turntable, reflector assembly, and signal acquisition assembly are set to be coaxial. The core components of the laser radar are set to be coaxial, and the coaxial detection system of the laser radar formed can avoid the overlapping factors existing in the non-coaxial system, reduce the optical cost, and reduce the signal loss.

[0067] Some embodiments disclose an all-day bioaerosol fluorescent lidar system, in which a coaxial bioaerosol lidar is placed on a gimbal, a light meter is fixed in the light emitting cavity of the radar system, and a Beidou positioning module is located at the bottom of the light emitting cavity; after the radar system is started, Beidou positioning locates the current position and provides the positioning radar system with further information to determine the position and direction of the sun; during the gimbal rotation and scanning process, the light meter is always testing the light intensity of the environment, further judging the test environment, and adjusting the system to a suitable test state, such as adjusting the high-voltage gain of the radar system photoelectric detector to prevent the sunlight from being too strong, affecting the measurement data and damaging optical devices such as telescopes, thereby improving the accuracy of the measurement data.

[0068] In some embodiments of the all-weather bioaerosol fluorescent lidar system disclosed, the reflector assembly includes:

[0069] A small reflector, adapted to the laser assembly and used for reflecting the pulsed laser;

[0070] The large reflector is adapted to the small reflector and the signal collection component, and is used to reflect the pulsed laser after being reflected by the small reflector, and is used to reflect the fluorescence induced by the pulsed laser irradiating the bioaerosol, and reflect the fluorescence to the signal collection component.

[0071] Some embodiments disclose a 24-hour bioaerosol fluorescence lidar system, wherein the signal acquisition component comprises:

[0072] A telescope, adapted to be set with the large reflector, for collecting optical signals;

[0073] A spectrometer unit, adapted to the telescope, for receiving and processing optical signals collected by the telescope;

[0074] The data acquisition unit is connected to the light-splitting unit and is used to acquire data transmitted by the light-splitting unit and transmit the acquired data to the central control component.

[0075] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, the spectroscopic unit includes:

[0076] A first dichroic mirror; a meter signal photoelectric detector is arranged in the direction of the reflected light of the first dichroic mirror, and the meter signal photoelectric detector is arranged to be connected to the data acquisition card;

[0077] A second dichroic mirror, disposed in the transmission light direction of the first dichroic mirror;

[0078] A first fluorescence photoelectric detector is arranged in the direction of the reflected light of the second dichroic mirror, and the first fluorescence photoelectric detector is connected to the data acquisition card;

[0079] A second fluorescence photoelectric detector is arranged in the projection light direction of the second dichroic mirror, and the second fluorescence photoelectric detector is arranged to be connected with the data acquisition card.

[0080] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, the light meter is adapted to be arranged in front of the telescope to detect the intensity of sunlight at the front end of the telescope;

[0081] The test signal-to-noise ratio of the lidar system is determined based on the measurement results of the light meter and the data collected by the signal acquisition component; the test signal-to-noise ratio is calculated according to the following formula:

[0082]

[0083] Among them, η pmt is the detection efficiency of the photodetector; e is the electron charge, in C; h is Planck's constant, in j·s; c is the speed of light, in m·s -1 ;Ω0 is the receiving field angle of the telescope, in sr;Δλ is the filter bandwidth, in nm;B is the frequency bandwidth of the photodetector, in Hz;S b , solar background light parameters; n is the total number of laser pulses; P(R) is the light signal intensity of the photodetector at a distance R; A0 is the receiving area of ​​the telescope; i d is the photodetector noise current; Y -SNR (R) is the test signal-to-noise ratio.

[0084] For the test process of the LiDAR system including the photodetector, the signal-to-noise ratio is an important parameter of the data performance index. For the photodetector, the signal-to-noise ratio generated at the photocathode is expressed as:

[0085]

[0086] Among them, i n is the noise generated by the photocathode; i s is the fluorescence signal current; i b is the background noise current; i d is the detector noise current; B is the frequency bandwidth of the detector, in Hz; e is the electron charge, in C; the fluorescence signal enters the photodetector, and the fluorescence signal current generated at the photocathode is i s :

[0087] i s =P(R)η pmt e(λ2 / hc)

[0088] Among them, η pmt is the detection efficiency of the photodetector; e is the electron charge, in C; h is Planck's constant, in j·s; c is the speed of light, in m·s -1 ;

[0089] Long-distance detection fluorescence laser radar mainly relies on high-energy ultraviolet lasers and uses synchronous accumulation technology to improve the signal-to-noise ratio of the detector; the sky background radiation generates a photoelectron flow on the photocathode of the photodetector. b :

[0090] i b =S b Ω0A0Δλη pmt e(λ / hc)

[0091] Where Ω0 is the receiving field angle of the telescope, in sr; Δλ is the filter bandwidth, in nm; a large number of echo signals are accumulated and averaged to obtain the test signal-to-noise ratio Y -SNR (R).

[0092] Generally speaking, the energy intensity of the fluorescence radar echo signal is related to the detection distance R, and the entire signal-to-noise ratio parameter is related to the solar background light parameter S b There is a certain relationship between the signal-to-noise ratio and Y -SNR (R) The calculation formula shows that the greater the light intensity, the smaller the signal-to-noise ratio, and the worse the system detection performance. Therefore, the measurement results of the radar system can be divided into four states according to the system signal-to-noise ratio, namely, the excellent signal-to-noise ratio state a1, the qualified state a2, the poor state a3, and the very poor state a4. The very poor state a4 is not suitable for measurement operations.

[0093] The all-day bioaerosol fluorescent lidar system disclosed in some embodiments adjusts the test gain of the radar system according to the test signal-to-noise ratio and the sunlight intensity, specifically including increasing the test gain of the radar system in a test interval with high light intensity and low test signal-to-noise ratio, and reducing the test gain of the radar system in a test interval with low light intensity and high test signal-to-noise ratio.

[0094] In some embodiments, the all-day bioaerosol fluorescent lidar system disclosed sets three illumination thresholds according to the light intensity, wherein the relationship among the first illumination threshold Lux1, the second illumination threshold Lux2, and the third illumination threshold Lux3 is Lux1<Lux2<Lux3; generally, the illumination threshold can be determined according to the detection results and actual test experience, and then the radar system is set using the determined threshold, and the measurement process of the radar system is controlled using the set threshold; in some embodiments, the average illumination value measured under normal sunlight is set as the third threshold Lux3, the average illumination value measured on a cloudy day is set as Lux2, and the average illumination value measured at night is set as the first threshold Lux1;

[0095] According to the illumination threshold and the test signal-to-noise ratio, four test areas are set, including:

[0096] The area with light intensity less than Lux1 and good test signal-to-noise ratio is the first test area;

[0097] The area where the illumination intensity is between Lux1 and Lux2 and the test signal-to-noise ratio is qualified is the second test area;

[0098] The area with illumination between Lux2 and Lux3 and poor test signal-to-noise ratio is the third test area;

[0099] The area with illuminance greater than Lux3 and very poor test signal-to-noise ratio is divided into the fourth test area.

[0100] Some embodiments disclose an all-day bioaerosol fluorescent lidar system, which adjusts the high-voltage gain of the radar system's photodetector according to the test area determined based on the light illumination threshold and the test signal-to-noise ratio. In the first test area, it is adjusted to a small gain, in the second test area, it is adjusted to a medium gain, in the third test area, it is adjusted to a high gain, and in the fourth test area, the radar system is turned off and monitoring is stopped.

[0101] In the all-day bioaerosol fluorescent lidar system disclosed in some embodiments, the front end of the telescope is adapted to be provided with an electronic shutter structure. Generally, an electronic shutter structure is provided at the front end of the telescope, and when the sunlight intensity is too large, for example, when the light intensity is greater than a third threshold, the electronic shutter structure is closed to seal the front end of the telescope to prevent sunlight from entering the telescope and thereby damaging the optical device of the signal collection component.

[0102] In the all-day bioaerosol fluorescent laser radar system disclosed in some embodiments, in the fourth test area, the electronic shutter is closed but the radar system is not closed. In some embodiments, the radar system is not closed when the electronic shutter is closed. When the scanning direction of the radar system is turned to a direction with suitable sunlight intensity under the drive of the turntable, the electronic shutter can be opened and the radar system can perform scanning detection.

[0103] The technical details are further illustrated below in conjunction with embodiments.

[0104] Example 1

[0105] Figure 1 This is a schematic diagram of the testing principle of the all-day bioaerosol fluorescent lidar system disclosed in Example 1.

[0106] In Example 1, a bioaerosol fluorescence lidar system is used throughout the day, such as Figure 1 As shown, including:

[0107] Turntable 1, central control component 2 is adapted to be arranged on the turntable 1, laser component 3 includes pulse laser 31 and beam expander 32, which are arranged horizontally above central control component 2 on turntable 1, laser component 3 is arranged to be connected with central control component 2, and generates pulse laser under the control of central control component 2;

[0108] The reflector assembly 5 includes a small reflector 51 and a large reflector 52, which are adapted to be arranged on a turntable, wherein the small reflector 51 is arranged in the laser beam irradiation direction downstream of the beam expander 32, and is at an angle of 145° with the horizontal direction, and reflects the laser beam reflected from the beam expander 32 to extend upward in the vertical direction; the large reflector 52 is arranged above the small reflector 51, and is at an angle of 45° with the horizontal direction, and reflects the laser beam extending vertically upward to the horizontal direction; a bioaerosol cloud 100 may be arranged in the horizontal direction of the laser beam reflection; when detecting the bioaerosol, the pulsed laser The pulse laser reflected by 31 is irradiated on the small reflector 51 after passing through the beam expander 32. Under the reflection of the small reflector 51, the pulse laser is irradiated vertically upward to the large reflector 52, and is extended horizontally under the reflection of the large reflector 52, and reacts with the bioaerosol cloud 100 to generate fluorescence under the induction of the pulse laser; the generated fluorescence is irradiated on the large reflector 52, and is reflected by the large reflector 52 and irradiated vertically downward to the telescope 42, and the north telescope 42 collects and enters the spectroscopic unit 43 and the information acquisition unit 41 for processing respectively, and the obtained signal enters the central control component 2 for further processing and analysis;

[0109] The signal collection component 4 is arranged on the turntable 1 and connected to the central control component 2 for collecting optical signals; wherein the signal collection component 4 includes a telescope 42, which is arranged below the large reflector 52, and the setting direction of the telescope 42 forms an angle of 145° with the large reflector 52; a spectroscopic unit 43 is arranged below the telescope 42, and can receive optical signals entering the telescope 42; and a data collection unit 41 is arranged to be connected to the spectroscopic unit 43;

[0110] The light meter 6 is adapted to be arranged on the turntable 1, located above the telescope 42, and connected to the central control component 2, and is used to detect the sunlight intensity above the telescope 42; the Beidou positioning component 7 is adapted to be arranged on the turntable, located above the telescope 42, and connected to the central control component 2, and is used to determine the relative position of the sun and the radar system;

[0111] Among them, the turntable 1, the reflector assembly 5, the signal acquisition assembly 4, and the central control assembly 2 are set to a coaxial state.

[0112] The laser radar system disclosed in Example 1 is used to perform all-day scanning and detection of bioaerosols, such as Figure 1 As shown, the detection method includes:

[0113] When the system is started, the turntable drives the radar system to scan and detect bioaerosols in the horizontal direction;

[0114] Beidou positioning component 7 determines the geographical coordinates of the system in real time, and the central control component 2 determines the direction of the sun relative to the radar system based on the geographical coordinates;

[0115] The light meter 6 measures the sunlight intensity in real time;

[0116] The central control component 2 controls the laser component 3 to emit a pulsed laser. The pulsed laser irradiates the bioaerosol cloud 100 under the continuous reflection of the reflection component 5, inducing the bioaerosol particles to produce fluorescence. The generated fluorescence enters the telescope 42 together with the background light signal under the continuous emission of the reflection component 5, and enters the central control component 2 after being collected and processed by the signal acquisition component 4. The central control component 2 determines the test area of ​​the radar system according to the set processing method, based on the relative direction between the radar and the sun, the light intensity, and the test signal-to-noise ratio, and adjusts the test gain of the radar system according to the test area, and then performs real-time scanning and monitoring of the bioaerosol under appropriate test conditions.

[0117] Example 2

[0118] Figure 2 This is a schematic diagram of the composition of the spectroscopic unit disclosed in Example 2.

[0119] In Example 2, the spectroscopic unit of the all-day bioaerosol fluorescent lidar system includes:

[0120] A first dichroic mirror BS1; a meter signal photodetector PMT1 is arranged in the reflected light direction of the first dichroic mirror BS1, and a first filter LF1 and a first light-transmitting lens FL1 are arranged in sequence between the first dichroic mirror BS1 and the meter signal photodetector PMT1; the meter signal photodetector PMT1 is arranged to be connected to a data acquisition card;

[0121] A second dichroic mirror BS2 is arranged in the transmission light direction of the first dichroic mirror BS1; a first fluorescence photodetector PMT2 is arranged in the reflection light direction of the second dichroic mirror BS2, and a second filter LF2 and a second light-transmitting lens FL2 are arranged in sequence between the second dichroic mirror BS2 and the first fluorescence photodetector PMT2; the first fluorescence photodetector PMT2 is arranged to be connected to a data acquisition card;

[0122] In the projection light direction of the second dichroic mirror BS2, a third filter LF3, a third light-transmitting lens FL3 and a second fluorescence photodetector PMT3 are sequentially arranged, and the second fluorescence photodetector PMT3 is arranged to be connected to a data acquisition card;

[0123] During the test, the optical signal transmitted from the telescope to the spectroscopic unit is split by the first dichroic mirror BS1; the short-wave light is reflected by the first dichroic mirror BS1 and then received by PMT1 after passing through the first filter LF1 and the first transmission lens FL1; the short-wave light that passes through the first dichroic mirror BS1 is reflected by the second dichroic mirror BS2, and then received by PMT2 after passing through the second filter LF2 and the second transmission lens FL2;

[0124] The long-wave light is projected onto the first dichroic mirror BS1 and then split by BS2. The long-wave light that passes through the second dichroic mirror BS2 is received by PMT3 after passing through the third filter LF3 and the third light-transmitting lens FL3.

[0125] The signals received by the three photoelectric detectors PMT1, PMT2, and PMT3 are transmitted to the data acquisition card for data processing, and finally the data are transmitted to the central control component for storage and processing.

[0126] Usually, PMT is used to detect weak light, and the obtained signal needs to be adjusted through circuit amplification and high voltage. Therefore, PMT itself usually has a gain range. For example, the high voltage can be adjusted within the range of 500 to 1100V. When 500V high voltage is applied to PMT, no signal may be seen, but when 900V high voltage is applied, a weak signal may be seen.

[0127] For the spectroscopic unit disclosed in Example 2, when adjusting the gain, the fluorescence signal of the PMT1-meter signal detector is relatively strong. In order to facilitate data comparison operations, the high-voltage gain of the channel can be kept unchanged. The overall measurement gain of the radar system can be adjusted by simply adjusting the gain of PMT2 and PMT3.

[0128] In Example 2, the average illuminance measured under normal sunlight is set as the third threshold Lux3, the average illuminance measured on a cloudy day is set as Lux2, and the average illuminance measured at night is set as the first threshold Lux1;

[0129] According to the illumination threshold and the test signal-to-noise ratio, four test areas are set, and the high-voltage gain is adjusted according to the different test areas, where:

[0130] The area with light intensity less than Lux1 and good test signal-to-noise ratio is the first test area; PMT1, PMT2, and PMT3 are all adjusted to small gain;

[0131] The area where the illumination intensity is between Lux1 and Lux2 and the test signal-to-noise ratio is qualified is the second test area. PMT1 is adjusted to a small gain, and PMT2 and PMT3 are adjusted to a medium gain.

[0132] The area with illumination between Lux2 and Lux3 and poor test signal-to-noise ratio is the third test area; PMT1 is adjusted to a small gain, and PMT2 and PMT3 are adjusted to a large gain;

[0133] The area with illuminance greater than Lux3 and very poor test signal-to-noise ratio is classified as the fourth test area. The system stops scanning, cuts off power to protect the system, and alarms.

[0134] The all-day bioaerosol fluorescent lidar system disclosed in the embodiment of the present invention uses a Beidou positioning component to determine the relative position of the lidar system and the sun, further determines a test area of ​​the radar system according to light intensity and a test signal-to-noise ratio of the system, and adjusts the test gain of the radar system according to different characteristics of the test area to adapt to different lighting conditions. Under different lighting conditions, the bioaerosol can be effectively and reliably measured, and the lidar system can be protected from being damaged under strong sunlight, thereby increasing the service life of the radar laser system.

[0135] The technical solutions disclosed in the embodiments of the present invention and the technical details disclosed in the embodiments are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, replacements or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the protection scope of the claims of the present invention.

Claims

1. All-day bioaerosol fluorescence lidar system, characterized by: include: Turntable; A central control component adapted to be arranged on the turntable; A laser component, adapted to be arranged on the turntable, and used to generate pulsed laser under the control of the central control component; A reflector assembly, adapted to be arranged on the turntable, and used to reflect the pulsed laser and the fluorescence generated by the bioaerosol under the induction of the pulsed laser; A signal collection component is arranged on the turntable and connected to the central control component, and is used to collect optical signals; A light meter, adapted to be arranged on the turntable and connected to the central control assembly, for detecting the intensity of sunlight; A Beidou positioning component is adapted to be arranged on the turntable and connected to the central control component, and is used to determine the relative position of the sun; Wherein, the turntable, the reflector assembly, and the signal acquisition assembly are arranged in a coaxial state.

2. The all-day bioaerosol fluorescent laser radar system according to claim 1, characterized in that: The reflector assembly comprises: A small reflector, adapted to the laser assembly and used to reflect the pulsed laser; The large reflector is respectively adapted to the small reflector and the signal collection component, and is used to reflect the pulsed laser after being reflected by the small reflector, and is used to reflect the fluorescence induced by the pulsed laser irradiating the bioaerosol, and reflect the fluorescence to the signal collection component.

3. The all-day bioaerosol fluorescent laser radar system according to claim 2, characterized in that: The signal acquisition component comprises: A telescope, adapted to be arranged with the large reflecting mirror, for collecting optical signals; A spectroscopic unit, adapted to the telescope, for receiving and processing optical signals collected by the telescope; The data acquisition unit is connected to the light-splitting unit and is used to acquire data transmitted by the light-splitting unit and transmit the acquired data to the central control component.

4. The all-day bioaerosol fluorescent laser radar system according to claim 3 is characterized in that: The light splitting unit comprises: A first dichroic mirror; a meter signal photoelectric detector is provided in the reflected light direction of the first dichroic mirror, and the meter signal photoelectric detector is connected to the data acquisition card; A second dichroic mirror, arranged in the transmission light direction of the first dichroic mirror; A first fluorescence photoelectric detector is arranged in the direction of the reflected light of the second dichroic mirror, and the first fluorescence photoelectric detector is arranged to be connected to the data acquisition card; A second fluorescence photodetector is arranged in the projection light direction of the second dichroic mirror, and the second fluorescence photodetector is arranged to be connected with the data acquisition card.

5. The all-day bioaerosol fluorescent laser radar system according to claim 4, characterized in that: The light meter is adapted to be arranged in front of the telescope, and is used to detect the sunlight intensity at the front end of the telescope; Determine the test signal-to-noise ratio of the lidar system based on the measurement results of the light meter and the data collected by the signal acquisition component; The test signal-to-noise ratio is calculated according to the following formula: Among them, η pmt is the detection efficiency of the photodetector; e is the electron charge, in C; h is Planck's constant, in j·s; c is the speed of light, in m·s -1 ;Ω0 is the receiving field angle of the telescope, in sr;Δλ is the filter bandwidth, in nm;B is the frequency bandwidth of the photodetector, in Hz;S b , solar background light parameters; n is the total number of laser pulses; P(R) is the light signal intensity of the photodetector at a distance R; A0 is the receiving area of ​​the telescope; i d is the photodetector noise current; Y -SNR (R) is the test signal-to-noise ratio.

6. The all-day bioaerosol fluorescent laser radar system according to claim 5, characterized in that: The test gain of the radar system is adjusted according to the test signal-to-noise ratio and the sunlight intensity. Specifically, the test gain of the radar system is increased in the test range where the light intensity is high and the test signal-to-noise ratio is low, and the test gain of the radar system is reduced in the test range where the light intensity is low and the test signal-to-noise ratio is high.

7. The all-day bioaerosol fluorescent laser radar system according to claim 6, characterized in that: Three illumination thresholds are set according to the illumination intensity, wherein the relationship among the first illumination threshold Lux1, the second illumination threshold Lux2, and the third illumination threshold Lux3 is Lux1<Lux2<Lux3; According to the illumination threshold and the test signal-to-noise ratio, four test areas are set, including: The area with light intensity less than Lux1 and good test signal-to-noise ratio is the first test area; The area where the illumination intensity is between Lux1 and Lux2 and the test signal-to-noise ratio is qualified is the second test area; The area with illumination between Lux2 and Lux3 and poor test signal-to-noise ratio is the third test area; The area with illuminance greater than Lux3 and very poor test signal-to-noise ratio is divided into the fourth test area.

8. The all-day bioaerosol fluorescent laser radar system according to claim 7, characterized in that: In the first test area, adjust to small gain, in the second test area, adjust to medium gain, in the third test area, adjust to high gain, and in the fourth test area, turn off the radar system and stop monitoring.

9. The all-day bioaerosol fluorescent laser radar system according to claim 8, characterized in that: The front end of the telescope is adapted to be provided with an electronic shutter structure.

10. The all-day bioaerosol fluorescent laser radar system according to claim 9, characterized in that: In the fourth test area, the electronic shutter was closed without shutting down the radar system.

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