NO2 receiving and transmitting integrated telemetering device and method based on semiconductor laser

Abstract

The invention discloses a semiconductor laser-based NO2 transceiving integrated telemetering device and a semiconductor laser-based NO2 transceiving integrated telemetering method. The device comprises a transceiving integrated laser emission system, a telescope system and a data receiving system, the laser emitting system comprises a semiconductor laser, the semiconductor laser is connected with a laser driving module, and a laser beam emitted by the semiconductor laser sequentially passes through a collimating lens, a beam splitter prism and a spectrograph; the telescope system comprises a right-angle reflecting prism, a secondary mirror and a primary mirror; the right-angle reflecting prism is placed in the direction of the reflected light and is fixed on the same mounting frame with the secondary mirror; the data receiving system comprises a photoelectric detector; the photoelectric detector is connected with a data processing module; the laser emission system and the telescope system adopt a transmit-receive integrated design, an emission light path and a reception light path are concentric, and the system has the characteristics of compact structure, high stability and easy maintenance, and is more suitable for remote measurement of atmospheric NO2 concentration at night.

Description

Technical Field

[0001] The present invention relates to the field of optical remote sensing technology for emission flux of pollution sources, and in particular to a semiconductor laser-based NO2 transceiver integrated remote sensing device and method. Background Art

[0002] Nitrogen dioxide (NO2) is a pollutant gas, which has the following three main hazards. First, nitrogen dioxide itself is toxic and can cause significant health effects. Second, when the concentration of nitrogen dioxide in the air is high, reddish-brown photochemical smog will appear, which affects vehicle travel and traffic safety to a certain extent. Third, nitrogen dioxide can react with water and oxygen to produce nitric acid, causing nitric acid rain, which causes serious damage to soil, water bodies, forests, buildings, etc. Therefore, there is an urgent need to master the concentration of urban atmospheric pollutants, especially the observation data at night.

[0003] At present, the main optical remote sensing methods for NO2 include long-range differential absorption spectroscopy (LP-DOAS), multi-axis differential absorption spectroscopy (DOAS), tunable diode absorption spectroscopy (TDLAS) and differential absorption lidar (DIAL), but these methods have their limitations. The light source used in long-range differential absorption spectroscopy is a broadband thermal light source, which has low energy utilization and requires the setting of cooperative targets; the light source used in multi-axis differential absorption spectroscopy is scattered light from the sun, which cannot be measured at night; the tunable diode absorption spectroscopy requires modulation, demodulation and peak sweeping of the wavelength, which has high requirements for laser modulation; the differential absorption lidar system is complex, bulky, and the key components are expensive. Summary of the invention

[0004] The main purpose of the present invention is to provide a NO2 transceiver integrated telemetry device and method based on semiconductor laser, aiming to solve the existing technical problems.

[0005] To achieve the above-mentioned object, the present invention provides a semiconductor laser-based NO2 transceiver integrated telemetry device, comprising a transceiver integrated laser emission system, a telescope system and a data receiving system;

[0006] The laser emission system comprises a semiconductor laser, which is connected to a laser driving module, and the laser driving module controls the semiconductor laser to emit laser light. The laser beam emitted by the semiconductor laser passes through a collimating lens, a beam splitter prism and a spectrometer in sequence, and the laser beam passes through the beam splitter prism and is divided into a transmitted light and a reflected light, wherein the transmitted light is directed toward the spectrometer, and the reflected light is directed toward a right-angle reflecting prism;

[0007] The telescope system comprises a right-angle reflecting prism, a secondary mirror and a primary mirror, wherein the right-angle reflecting prism is placed in the direction of the reflected light and is fixed on the same mounting frame as the secondary mirror, and the right-angle reflecting prism reflects the reflected light of the beam splitter prism twice, so that the secondary reflected light is coaxial with the telescope system, and the direction of the secondary reflected light is the target object;

[0008] The data receiving system is connected to the telescope system. The data receiving system includes a photoelectric detector. The photoelectric detector is placed on the focal plane of the telescope system and is connected to a data processing module.

[0009] Furthermore, the collimating lens is an aspherical lens, which is placed on a high-precision slide, and the distance between the collimating lens and the semiconductor laser is controlled by the slide.

[0010] Furthermore, the beam splitting ratio of the beam splitting prism is 70:30, wherein, of the laser beam passing through the collimating lens, 70% of the laser beam is reflected and directed to the right-angle reflection prism of the telescope system, and 30% of the laser beam is transmitted and directed to the spectrometer.

[0011] Furthermore, the right-angle reflection prism, the secondary mirror and the primary mirror are arranged in sequence, the right-angle reflection prism is close to the target direction, the primary mirror is close to the photoelectric detector direction, and the primary mirror, the secondary mirror and the right-angle reflection prism constitute a Cassegrain telescope for amplifying the target reflected light.

[0012] Furthermore, the laser driving module includes a constant current driving module and a temperature control module, which are used to control the optical signal output by the semiconductor laser.

[0013] Furthermore, the semiconductor laser is a high-power tunable semiconductor laser, which is used to generate detection light corresponding to the detection of NO2 molecules in the atmosphere.

[0014] The NO2 transceiver integrated telemetry method based on semiconductor laser uses the telemetry device as mentioned above, and specifically includes the following steps:

[0015] Adjusting the position and angle of the collimating lens and semiconductor laser so that the collimated light is coaxial with the telescope system and is aligned with the target object;

[0016] The laser driving module is used to control the output wavelength of the semiconductor laser to be located at the NO2 absorption peak λ on Laser at

[0017] The output laser passes through the beam splitter prism, the transmitted light is monitored by the spectrometer for output wavelength, and the reflected light hits the right-angle reflecting prism of the telescope system;

[0018] The reflected light is reflected again by the right-angle reflection prism, and the secondary reflected light hits the target object to produce target reflected light;

[0019] The target reflected light is gathered by the primary mirror and the secondary mirror onto the photosensitive surface of the photodetector, which converts it into a voltage signal output and collects and processes it through the data processing module and the industrial computer;

[0020] The laser driving module is used to control the output wavelength of the semiconductor laser to be located at the NO2 absorption valley λ off Laser at

[0021] The received target reflected light signals of the two bands are differentially processed to obtain the average concentration of NO2.

[0022] Furthermore, the wavelength detected by the photodetector is λ on The optical power is P(λ on ,z), with a wavelength of λ off The optical power is P(λ off ,z); the processing steps of the data processing module include:

[0023] According to the differential absorption equation under the wide spectrum state, it can be concluded that:

[0024]

[0025] Among them, P0 is the output light power of the laser; K is the system constant of the instrument; β(λ) is the scattering of the laser of this wavelength by aerosols and other air components in the atmosphere; η(λ) is the reflectivity of the target to the laser; α s (λ) is the absorption rate of laser by non-cooperative target; α aer (λ) is the absorption of the laser of this wavelength by the aerosol and other air components in the atmosphere; σ(λ,T) is the absorption cross section of the gas to be measured at wavelength λ; N is the concentration of the gas to be measured;

[0026] After normalization, the differential absorption signal is obtained, which is expressed by the following formula:

[0027]

[0028] According to the measurement distance z, the average concentration of NO2 in this distance can be calculated using the following fitting formula:

[0029]

[0030] The beneficial effects of the present invention are embodied in:

[0031] The laser emission system and telescope system of the present invention adopt an integrated transmitting and receiving design, and the transmitting optical path and the receiving optical path are concentric. They have the characteristics of compact structure, high stability and easy maintenance, and are more suitable for remote sensing of atmospheric NO2 concentration at night.

[0032] The present invention can realize remote sensing of atmospheric NO2 concentration at a single end without complicated inversion analysis, and each component can be replaced. It has good application prospect and is worthy of wide promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the optical path of the NO2 transceiver integrated remote sensing device based on semiconductor laser of the present invention;

[0034] Figure 2 It is a flow chart of the telemetry method of the present invention.

[0035] Description of reference numerals:

[0036] 1. Laser emission system; 101. Laser driving module; 102. Semiconductor laser; 103. Collimating lens; 104. Beam splitter; 105. Spectrometer; 2. Telescope system; 201. Right-angle reflecting prism; 202. Secondary mirror; 203. Primary mirror; 3. Data receiving system; 301. Photoelectric detector; 302. Data processing module; 303. Industrial computer. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] See also Figure 1 The present invention provides a semiconductor laser-based NO2 transceiver integrated telemetry device, comprising a transceiver integrated laser emission system 1, a telescope system 2 and a data receiving system 3;

[0039] The laser emission system 1 includes a semiconductor laser 102, which is connected to a laser driving module 101. The laser driving module 101 controls the semiconductor laser 102 to emit laser light. The laser beam emitted by the semiconductor laser 102 passes through a collimating lens 103, a beam splitter prism 104, and a spectrometer 105 in sequence. The laser beam passes through the beam splitter prism 104 and is divided into a transmitted light and a reflected light. The transmitted light is directed toward the spectrometer 105, and the reflected light is directed toward a right-angle reflecting prism 201.

[0040] The telescope system 2 includes a right-angle reflecting prism 201, a secondary mirror 202 and a primary mirror 203. The right-angle reflecting prism 201 is placed in the direction of the reflected light and is fixed on the same mounting frame as the secondary mirror 202. The right-angle reflecting prism 201 reflects the reflected light of the beam splitter prism 104 twice, so that the secondary reflected light is coaxial with the telescope system 2, and the direction of the secondary reflected light is the target object 4.

[0041] The data receiving system 3 is connected to the telescope system 2, and includes a photoelectric detector 301, which is placed on the focal plane of the telescope system 2 and connected to a data processing module 302. The data receiving system 3 also includes an industrial computer 303 for controlling the telemetry device.

[0042] The laser emission system and telescope system of the present invention adopt an integrated transmitting and receiving design, and the transmitting optical path and the receiving optical path are concentric. They have the characteristics of compact structure, high stability and easy maintenance, and are more suitable for remote sensing of atmospheric NO2 concentration at night.

[0043] The present invention can realize remote sensing of atmospheric NO2 concentration at a single end without complicated inversion analysis, and each component can be replaced. It has good application prospect and is worthy of wide promotion.

[0044] In one embodiment, the collimating lens 103 is an aspherical lens, which is placed on a high-precision slide, and the slide is used to control the distance between the collimating lens 103 and the semiconductor laser 102. This embodiment is arranged in this way to achieve the adjustment of the collimating effect.

[0045] In one embodiment, the beam splitting ratio of the beam splitting prism 104 is 70:30, wherein 70% of the laser light passing through the collimating lens 103 is reflected to the right-angle reflecting prism 201 of the telescope system 2 , and 30% of the laser light is transmitted to the spectrometer 105 .

[0046] In one embodiment, the right-angle reflection prism 201, the secondary mirror 202 and the primary mirror 203 are arranged in sequence, the right-angle reflection prism 201 is close to the target direction, the primary mirror 203 is close to the photodetector 301, and the primary mirror 203, the secondary mirror 202 and the right-angle reflection prism 201 constitute a Cassegrain telescope for magnifying the target reflected light.

[0047] Specifically, the laser driving module 101 includes a constant current driving module and a temperature control module, which are used to control the optical signal output by the semiconductor laser.

[0048] Specifically, the semiconductor laser 102 is a high-power tunable semiconductor laser, which is used to generate detection light corresponding to the detection of NO2 molecules in the atmosphere.

[0049] Specifically, the photodetector 301 is a photodiode or a photomultiplier tube, which is used to convert light signals into voltage signals for collection and processing by the data processing module.

[0050] See also Figure 2 The present invention also provides a semiconductor laser-based NO2 transceiver integrated telemetry method, using the telemetry device as described above, specifically including the following steps:

[0051] (1) adjusting the position and angle of the collimating lens 103 and the semiconductor laser 102 so that the collimated light is coaxial with the telescope system 2 and is aligned with the target object 4;

[0052] (2) The laser driving module 101 is used to control the output wavelength of the semiconductor laser 102 to be located at the NO2 absorption peak λ on Laser at

[0053] (3) The output laser passes through the beam splitter prism 104, the transmitted light passes through the spectrometer 105 to monitor the output wavelength, and the reflected light hits the right-angle reflection prism 201 of the telescope system 2;

[0054] (4) The reflected light is reflected again by the right-angle reflection prism 201, and the secondary reflected light hits the target object 4 to generate target reflected light;

[0055] (5) The target reflected light is converged by the primary mirror 203 and the secondary mirror 202 onto the photosensitive surface of the photodetector 301, and is converted into a voltage signal output by the photodetector 301, which is collected and processed by the data processing module 302 and the industrial computer 303;

[0056] (6) The laser driving module 101 is used to control the output wavelength of the semiconductor laser 102 to be located at the NO2 absorption valley λ off Laser at

[0057] (7) The received target reflected light signals of the two bands are differentially processed to obtain the average concentration of NO2.

[0058] In one embodiment, the wavelength detected by the photodetector 301 is denoted as λ on The optical power is P(λ on ,z), with a wavelength of λ off The optical power is P(λ off ,z); The processing steps of the data processing module 302 include,

[0059] According to the differential absorption equation under the wide spectrum state, it can be concluded that:

[0060]

[0061] Among them, P0 is the output light power of the laser; K is the system constant of the instrument; β(λ) is the scattering of the laser of this wavelength by aerosols and other air components in the atmosphere; η(λ) is the reflectivity of the target to the laser; α s (λ) is the absorption rate of laser by non-cooperative target; α aer (λ) is the absorption of the laser of this wavelength by the aerosol and other air components in the atmosphere; σ(λ,T) is the absorption cross section of the gas to be measured at wavelength λ; N is the concentration of the gas to be measured;

[0062] After normalization, the differential absorption signal is obtained, which is expressed by the following formula:

[0063]

[0064] According to the measurement distance z, the average concentration of NO2 in this distance can be calculated using the following fitting formula:

[0065]

[0066] The present invention can realize remote measurement of atmospheric NO2 concentration at night with a single end. The present invention has the characteristics of compact device structure, high stability and easy maintenance. Through the above calculation method, the calculation efficiency is greatly improved, and the calculation is stable and reliable.

[0067] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0068] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A semiconductor laser-based NO2 transceiver integrated telemetry device, characterized in that: It comprises a laser transmitting system (1), a telescope system (2) and a data receiving system (3); The laser emission system (1) comprises a semiconductor laser (102), the semiconductor laser (102) is connected to a laser driving module (101), the laser driving module (101) controls the semiconductor laser (102) to emit laser light, the laser light beam emitted by the semiconductor laser (102) passes through a collimating lens (103), a beam splitter prism (104), and a spectrometer (105) in sequence, the laser light beam passes through the beam splitter prism (104) and is divided into transmitted light and reflected light, the transmitted light is directed toward the spectrometer (105), and the reflected light is directed toward a right-angle reflecting prism (201); The telescope system (2) comprises a right-angle reflection prism (201), a secondary mirror (202) and a primary mirror (203); the right-angle reflection prism (201) is placed in the direction of the reflected light and is fixed on the same mounting frame as the secondary mirror (202); the right-angle reflection prism (201) re-reflects the reflected light of the beam splitter prism (104) so ​​that the re-reflected light is coaxial with the telescope system (2); and the direction of the re-reflected light is the target object (4); The data receiving system (3) is connected to the telescope system (2), and the data receiving system (3) comprises a photoelectric detector (301). The photoelectric detector (301) is placed on the focal plane of the telescope system (2), and the photoelectric detector (301) is connected to a data processing module (302).

2. The semiconductor laser-based NO2 transceiver integrated remote sensing device as claimed in claim 1, characterized in that: The collimating lens (103) is a non-spherical lens and is placed on a high-precision slide. The distance between the collimating lens (103) and the semiconductor laser (102) is controlled by the slide.

3. The semiconductor laser-based NO2 transceiver integrated remote sensing device as claimed in claim 1, characterized in that: The beam splitting ratio of the beam splitting prism (104) is 70:30, wherein 70% of the laser light passing through the collimating lens (103) is reflected and directed to the right-angle reflection prism (201) of the telescope system (2), and 30% of the laser light is transmitted and directed to the spectrometer (105).

4. The semiconductor laser-based NO2 transceiver integrated remote sensing device as claimed in claim 1, characterized in that: The right-angle reflection prism (201), the secondary mirror (202), and the primary mirror (203) are arranged in sequence, the right-angle reflection prism (201) is close to the direction of the target object, the primary mirror (203) is close to the direction of the photoelectric detector (301), and the primary mirror (203), the secondary mirror (202), and the right-angle reflection prism (201) form a Cassegrain telescope for magnifying the reflected light of the target.

5. The semiconductor laser-based NO2 transceiver integrated remote sensing device as claimed in claim 1, characterized in that: The laser driving module (101) comprises a constant current driving module and a temperature control module, and is used to control the optical signal output by the semiconductor laser.

6. The semiconductor laser-based NO2 transceiver integrated remote sensing device as claimed in claim 1, characterized in that: The semiconductor laser (102) is a high-power tunable semiconductor laser, used to generate detection light corresponding to the detection of NO2 molecules in the atmosphere.

7. A semiconductor laser-based NO2 transceiver integrated telemetry method, characterized in that: Using the remote sensing device as described in any one of claims 1 to 6, specifically The following steps are included: Adjusting the position and angle of the collimating lens (103) and the semiconductor laser (102) so that the collimated light is coaxial with the telescope system (2) and is aligned with the target object (4); The laser driving module (101) is used to control the semiconductor laser (102) to output a wavelength located at the NO2 absorption peak λ on Laser at The output laser passes through the beam splitter prism (104), the transmitted light is monitored by the spectrometer (105) for output wavelength, and the reflected light is hit on the right-angle reflection prism (201) of the telescope system (2); The reflected light is reflected again by the right-angle reflection prism (201), and the secondary reflected light hits the target object (4) to generate target reflected light; The target reflected light is converged by the primary mirror (203) and the secondary mirror (202) onto the photosensitive surface of the photodetector (301), and is converted into a voltage signal output by the photodetector (301), and is collected and processed by the data processing module (302) and the industrial computer (303); The laser driving module (101) is used to control the semiconductor laser (102) to output a wavelength located at the NO2 absorption valley λ off Laser at The received target reflected light signals of the two bands are differentially processed to obtain the average concentration of NO2.

8. The semiconductor laser-based NO2 transceiver integrated remote sensing method according to claim 7, characterized in that: The wavelength detected by the photodetector (301) is λ on The optical power is P(λ on ,z), with a wavelength of λ off The optical power is P(λ off ,z); the processing steps of the data processing module (302) include: According to the differential absorption equation under the wide spectrum state, it can be concluded that: Among them, P0 is the output light power of the laser; K is the system constant of the instrument; β(λ) is the scattering of the laser of this wavelength by aerosols and other air components in the atmosphere; η(λ) is the reflectivity of the target to the laser; α s (λ) is the absorption rate of laser by non-cooperative target; α aer (λ) is the absorption of the laser of this wavelength by the aerosol and other air components in the atmosphere; σ(λ,T) is the absorption cross section of the gas to be measured at wavelength λ; N is the concentration of the gas to be measured; After normalization, the differential absorption signal is obtained, which is expressed by the following formula: According to the measurement distance z, the average concentration of NO2 in this distance can be calculated using the following fitting formula:

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