Portable multi-gas laser telemetering device

Abstract

The utility model discloses a portable multi-gas laser telemetering device, which comprises a light source module used for generating n infrared laser beams for detecting n target gases in a target detection area and outputting a synchronizing signal, n being greater than or equal to 2; the beam combining module is used for combining the n infrared laser beams into one beam; the collimation module is used for carrying out collimation to obtain a collimated light beam; the light collection and detection module is used for emitting the collimated light beam to a target detection area, collecting an infrared light laser beam diffusely reflected by any reflector and converting the infrared light laser beam into an electric signal; the distance measuring module is used for measuring the distance between the system and any reflecting object and outputting a distance signal to the signal processing module; the signal processing module is used for processing the collected synchronizing signal, the electric signal and the distance signal to obtain an average concentration value of each target gas; and the power supply module is used for supplying power to each module. The gas sensor is easy to carry, is not limited by a light path, and can be used for simultaneously and remotely detecting multiple gases.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas detection devices, and in particular relates to a portable multi-gas laser telemetry device. Background Art

[0002] To this day, oil, gas and various mineral resources still occupy a vital position in production and life. In the process of mining, processing, transportation and storage of oil, gas and various mineral resources, it is inevitable to produce various dangerous gases such as flammable and explosive methane, acetylene or toxic hydrogen sulfide. When these gases leak, if they are not discovered and handled in time, it will cause immeasurable losses. However, these gases are usually colorless and odorless. When a leak occurs, it is difficult for workers to detect them by themselves and they need to use relevant monitoring equipment. At present, whether it is traditional detection instruments such as semiconductor sensors, electrochemical sensors, etc., or new optical detection methods such as absorption spectroscopy methods and photoacoustic spectroscopy methods based on multiple reflection gas cells, they are mainly based on point measurement and can only respond to changes in gas concentration in a small range. This point measurement method cannot detect at a long distance, and it cannot help workers avoid risks, let alone quickly detect the source of the leak. Therefore, in recent years, the research and development of portable telemetry devices for hazardous gases has attracted much attention.

[0003] Optical-based gas detection methods have natural advantages in achieving long-distance remote sensing. Among them, the tunable semiconductor laser absorption spectroscopy technology based on absorption spectroscopy has the advantages of high sensitivity, strong selectivity, strong anti-interference ability, and relatively simple and stable structure. It has been widely used in the field of gas remote sensing; however, in existing portable remote sensing products, most of them detect a single component of methane, and there are almost no devices for simultaneous detection of multiple gases. Utility Model Content

[0004] The utility model aims to provide a portable multi-gas laser remote sensing device.

[0005] The utility model mainly adopts the following technical solutions:

[0006] A portable multi-gas laser telemetry device comprises: a light source module, which is used to generate n infrared laser beams for detecting n kinds of target gases in a target detection area and output a synchronization signal, wherein n≥2; a beam combining module, which is arranged in front of the light source module and is used to combine the n infrared laser beams into one beam; a collimating module, which is connected to the beam combining module and is used to collimate the light beam output by the beam combining module to obtain a collimated light beam; a light collecting and detecting module, which is used to emit the collimated light beam to the target detection area and collect the infrared laser beam diffusely reflected from any reflective object in the target detection area and convert it into an electrical signal; a distance measuring module, which is used to emit a visible light laser to detect the target gas in the target detection area; Indicating the target detection area and measuring the distance between the light source position in the ranging module and the arbitrary reflector, and outputting a distance signal to a signal processing module; a signal processing module, which is connected to the light source module, the light collection and detection module and the ranging module, and is used to process the collected synchronization signal output by the light source module, the electrical signal output by the light collection and detection module and the distance signal output by the ranging module to obtain the average concentration value of each target gas in the target detection area; and a power supply module, which is connected to the light source module, the beam combining module, the collimation module, the light collection and detection module, the ranging module and the signal processing module to supply power.

[0007] The beneficial effects of the utility model include: the portable multi-gas laser telemetry device of the utility model is based on the principle of gas absorption spectrum detection, is easy to carry and is not limited by the optical path, can detect multiple gases at a long distance at the same time, for example, can realize rapid detection of multiple dangerous gases such as methane and acetylene, and is used for a series of tasks such as leakage warning and leakage point investigation in petrochemical production.

[0008] The preferred embodiment of the present invention also has the following further beneficial effects:

[0009] (1) Multiple semiconductor lasers are used, with the central wavelength concentrated in the near-infrared band. The lasers use a time-division multiplexing strategy to emit light intermittently in sequence to avoid mutual interference between signals and achieve synchronous measurement.

[0010] (2) The optimized optical path design and high-sensitivity photoelectric detector can detect weak scattered light. Combined with wavelength modulation technology, the system has long-distance telemetry capabilities.

[0011] (3) The laser rangefinder is used to obtain the measurement optical path, so that the entire device can measure the average concentration value of the target gas along the path, while the visible light laser helps to confirm the detection area.

[0012] (4) A double-layer structure is adopted. The gas detection-related optical path of the second layer is integrated into a whole. The coaxial optical path arrangement, reflective collimation and beam collection scheme make the entire device very versatile and can be used for detection in a large spectral range. The first layer is mainly related electronic devices, and the use of optical fiber output lasers makes it easy to integrate more lasers for multiplexing and realize synchronous remote sensing of multiple gases.

[0013] (5) The system is highly integrated and easy to expand, is portable, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of a portable multi-gas laser telemetry device according to an embodiment of the utility model.

[0015] The following are the descriptions of the reference numerals:

[0016] 1. Function generator, 2. Cable, 3. First laser, 4. First laser controller, 5. First support plate, 6. First laser base, 7. First temperature controller, 8. Second temperature controller, 9. Second laser base, 10. Second laser controller, 11. Second laser, 12. Fiber combiner, 13. Microprocessor, 14. Second support plate, 15. Laser rangefinder, 16. Fiber jumper, 17. Reflective collimator, 18. Off-axis parabolic reflector with hole, 19. Any reflector, 20. Target detection gas, 21. Collimated beam, 22. Retroreflected beam, 23. Bandpass filter, 24. Photodetector, 25. Power module, 26. Phase-locked amplifier, 27. Visible light laser. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. This embodiment takes the simultaneous detection of methane and acetylene as an example, and the detection of more other gases can be expanded on the basis of this embodiment. It should be noted that the description of the specific embodiments here is only an explanation of the present invention, not a limitation. It should also be noted that, for the convenience of description, only the core parts related to the present invention are drawn in the accompanying drawings.

[0018] The utility model provides a portable multi-gas laser telemetry device in a specific embodiment, which includes: a light source module, which is used to generate n infrared laser beams for detecting n target gases in a target detection area and output a synchronization signal, wherein n≥2; a beam combining module, which is arranged in front of the light source module and is used to combine the n infrared laser beams into one beam; a collimating module, which is connected to the beam combining module and is used to collimate the light beam output by the beam combining module to obtain a collimated light beam; a light collection and detection module, which is used to emit the collimated light beam to the target detection area, and collect the infrared laser beam diffusely reflected from any reflective object in the target detection area, and convert it into an electrical signal; a distance measuring module, which is used to emit the collimated light beam to the target detection area, and collect the infrared laser beam diffusely reflected from any reflective object in the target detection area, and convert it into an electrical signal; and a distance measuring module, which is used to emit the collimated light beam to the target detection area. The invention relates to a method for manufacturing a target gas detection system comprising: emitting visible light laser to indicate the target detection area and measuring the distance between the light source position in the ranging module and the arbitrary reflector, and outputting a distance signal to a signal processing module; a signal processing module connected to the light source module, the light collection and detection module and the ranging module, and used for processing the collected synchronization signal output by the light source module, the electrical signal output by the light collection and detection module and the distance signal output by the ranging module to obtain the average concentration value of each target gas in the target detection area; and a power supply module connected to the light source module, the beam combining module, the collimation module, the light collection and detection module, the ranging module and the signal processing module to supply power.

[0019] In a preferred embodiment, the portable multi-gas laser telemetry device is composed of two layers, wherein the light source module, the signal processing module and the power module are integrated in the first layer (the first layer is used for system control), the collimation module, the light collection and detection module and the distance measurement module are integrated in the second layer (the second layer is used for the emission and reception of laser beams, etc.), and the beam combining module is integrated in the first layer or the second layer. Laser and signal transmission can be performed between the modules of the two layers through devices such as optical fibers and signal lines.

[0020] In a preferred embodiment, the first layer has a first support plate, the second layer has a second support plate, the light source module, the signal processing module and the power supply module are integrated on the first support plate to form a whole, the collimation module, the light collection and detection module and the ranging module are integrated on the second support plate to form a whole, and the beam combining module is integrated on the first support plate or the second support plate.

[0021] In a preferred embodiment, the light source module includes a function generator and n infrared laser beam generating units (n≥2, i.e., one infrared laser beam generating unit corresponds to the detection of one gas), the function generator is used to generate n modulated drive signals (one modulated drive signal corresponds to the detection of one gas) to be transmitted to the n infrared laser beam generating units to generate n infrared laser beams for detecting n target gases in the target detection area, and the function generator is also used to generate a synchronization signal to be transmitted to the signal processing module. Preferably, the modulated drive signal is composed of a low-frequency sawtooth wave superimposed with a high-frequency sine wave, and a time division multiplexing mode is adopted.

[0022] In a preferred embodiment, each infrared laser beam generating unit includes a laser controller, a temperature controller and a laser; the laser controller is connected to the function generator and the laser, and is used to receive the modulated drive signal generated by the function generator and convert it into an input current of the laser; the temperature controller is connected to the laser, and is used to control the laser at a predetermined operating temperature; the laser is used to receive the input current and generate an infrared laser beam of a corresponding wavelength.

[0023] In a preferred embodiment, the beam combining module is a fiber optic combiner, which is connected to the laser and is used to combine the n infrared laser beams from the laser into one beam; the collimation module is a reflective collimator, which is connected to the output port of the fiber optic combiner and is used to collimate the divergent light beam output by the fiber optic combiner to obtain a collimated light beam.

[0024] In a preferred embodiment, the light collection and detection module includes a perforated off-axis parabolic reflector, a bandpass filter and a photodetector; the axis of the perforated off-axis parabolic reflector is provided with a small hole larger than the diameter of the collimated light beam, and the reflective collimator is coaxially arranged with the perforated off-axis parabolic reflector to allow the collimated light beam to pass through the small hole and be emitted toward the target detection area; the perforated off-axis parabolic reflector is used to collect and converge the infrared laser beam diffusely reflected by the target detection area and transmit it to the photodetector after passing it through the bandpass filter; the photodetector is used to convert the light beam into an electrical signal and transmit it to the signal processing module.

[0025] In a preferred embodiment, the signal processing module includes a phase-locked amplifier and a microprocessor; the phase-locked amplifier is connected to the function generator and the photodetector, and is used to receive the synchronization signal output by the function generator and the electrical signal output by the photodetector, and is used to demodulate the electrical signal output by the photodetector with the synchronization signal output by the function generator as a reference, and then output a harmonic signal to the microprocessor; the microprocessor is connected to the function generator, the phase-locked amplifier and the ranging module, and is used to process the harmonic signal, the synchronization signal output by the function generator and the distance signal output by the ranging module to obtain the average concentration value of each target gas in the target detection area.

[0026] In a preferred embodiment, each infrared laser beam generating unit further comprises a laser base, and the laser is mounted on the laser base.

[0027] In a preferred embodiment, the ranging module includes a laser rangefinder and a visible light laser, wherein the visible light laser is used to emit visible light laser to indicate the target detection area, and the laser rangefinder is used to measure the distance between the light source position of the visible light laser and the arbitrary reflective object, and output a distance signal to the signal processing module.

[0028] In a preferred embodiment, the portable multi-gas laser remote sensing device further comprises a display, which is used to display and monitor the average concentration value of each target gas output by the microprocessor and relevant monitoring information of the laser.

[0029] The present invention is further described below by taking the simultaneous detection of methane and acetylene as an example.

[0030] like Figure 1As shown, it is a schematic diagram of the structure of a portable multi-gas laser telemetry device provided by an embodiment of the utility model, which includes: a light source module, a beam combining module, a collimation module, a light collection and detection module, a distance measurement module, a signal processing module and a power module, wherein the portable multi-gas laser telemetry device is composed of two layers, wherein the light source module, the beam combining module, the signal processing module and the power module are integrated on the first support plate 5 and are located on the first layer, and the collimation module, the light collection and detection module and the distance measurement module are integrated on the second support plate 14 and are located on the second layer. The light source module includes a function generator 1 and two infrared laser beam generating units, wherein the first infrared laser beam generating unit includes a first laser controller 4, a first temperature controller 7, a first laser base 6, and a first laser 3 (specifically a semiconductor laser with optical fiber output); the second infrared laser beam generating unit includes a second laser controller 10, a second temperature controller 8, a second laser base 9 and a second laser 11 (specifically a semiconductor laser with optical fiber output). The function generator 1 can be connected to each infrared laser beam generating unit (specifically, connected to a corresponding laser controller) via a cable 2 .

[0031] The function generator 1 generates a first modulated drive signal and a second modulated drive signal, as well as a synchronization signal; the first modulated drive signal and the second modulated drive signal are composed of a low-frequency sawtooth wave superimposed on a high-frequency sine wave, and the drive signal adopts a time-division multiplexing mode, and the first modulated drive signal and the second modulated drive signal are respectively used to realize that the wavelength and energy of the first laser 3 and the second laser 11 change in the form of a low-frequency sawtooth wave superimposed on a high-frequency sine wave. At the same time, the time-division multiplexing drive mode is used in the portable multi-gas laser telemetry device of the utility model, so only one photodetector 24 can be used to simultaneously detect two sequentially excited laser beams without mutual interference of signals.

[0032] The first laser controller 4 and the second laser controller 10 receive the corresponding first modulation drive signal and the second modulation drive signal and convert them into input currents of the first laser 3 and the second laser 11; the first temperature controller 7 and the second temperature controller 8 are used to control the working temperature of the first laser 3 and the second laser 11; the first laser 3 and the second laser 11 are respectively installed on the corresponding first laser base 6 and the second laser base 9, and after receiving the corresponding input currents, they generate infrared laser beams of corresponding wavelengths, and the infrared laser beams can be transmitted through the coupled single-mode optical fiber; in this example, the central wavelengths of the two infrared laser beams are 1651nm and 1531.6nm, respectively, to detect the absorption spectra of methane and acetylene. The synchronization signal generated by the function generator 1 is transmitted to the microprocessor 13 and the phase-locked amplifier 26.

[0033] The beam combining module is a fiber beam combiner 12 (in this example, the fiber beam combiner 12 is located in the first layer. In other examples, the fiber beam combiner 12 can also be flexibly configured in the second layer or other positions), and the collimation module is a reflective collimator 17. The fiber beam combiner 12 can be connected to the first laser 3 and the second laser 11 through an optical fiber jumper 16 to combine the infrared laser beams of different wavelengths from the first laser 3 and the second laser 11 into the same beam; at the same time, this solution realizes the transmission of the laser from the first layer to the second layer, and makes the device very flexible. The connection and relative position relationship between the second layer and the first layer will not be restricted by the optical path; the reflective collimator 17 is connected to the output port of the fiber beam combiner 12, and the divergent laser beam output by the fiber beam combiner 12 is collimated to obtain a collimated beam 21. The reflective collimator 17 in this example has a very high reflectivity in a wide spectral range, which can reduce energy loss.

[0034] The light collection and detection module includes an off-axis parabolic reflector with a hole 18, a bandpass filter 23 and a photodetector 24; a small hole larger than the diameter of the collimated light beam 21 is opened on the axis of the off-axis parabolic reflector with a hole 18, and the reflective collimator 17 is coaxially arranged with the off-axis parabolic reflector with a hole 18 to allow the collimated light beam 21 to pass through the small hole smoothly and emit the collimated light beam 21 to the target detection area; when there is a target detection gas 20 in the target detection area, the laser beam will interact with the gas, and the light intensity at a specific wavelength will be attenuated, and then when the laser beam hits any reflective object 19 (such as a wall, the ground, etc.) in the target detection area, diffuse reflection will occur, and a part of the scattered light (i.e., the reflected light beam 22) will be collected and converged by the off-axis parabolic reflector with a hole 18 and transmitted to the photodetector 24 after passing through the bandpass filter 23; the photosensitive area of ​​the photodetector 24 is adjusted to the convergence point of the light beam to realize the conversion of the laser into an electrical signal, and then the electrical signal is transmitted to the phase-locked amplifier 26 through the wire beam. In this example, the photodetector 24 has a very high sensitivity in the target detection band, and can detect weak scattered light. The bandpass filter 23 has a very high attenuation on light outside the target detection range, which can greatly reduce the interference of ambient light on the signal and improve the measurement signal-to-noise ratio. The above components of the light collection and detection module can be fixed as a whole after the optical path is adjusted, thereby enhancing the stability of the entire telemetry device.

[0035] The ranging module includes a laser rangefinder 15 and a visible light laser 27; the visible light laser 27 emits a visible light laser to indicate the target detection area of ​​the portable multi-gas laser telemetry device, and the laser rangefinder 15 is used to measure the distance from the light source position of the visible light laser 27 to any reflective object 19, and transmit the measured distance to the signal processing module in the form of an electrical signal.

[0036] The signal processing module includes a lock-in amplifier 26 and a microprocessor 13; the lock-in amplifier 26 receives the synchronization signal from the function generator 1 and the signal from the photodetector 24. The lock-in amplifier 26 uses the synchronization signal of the function generator 1 as a reference, demodulates the signal from the photodetector 24, extracts the harmonic component, and outputs the harmonic signal to the microprocessor 13. The microprocessor 13 receives multiple signals such as the synchronization signal of the function generator 1, the harmonic signal of the lock-in amplifier 26, and the distance signal of the laser rangefinder 15, and obtains the concentration value of the current detected gas after processing. In this example, specifically, since the detected laser intensity will fluctuate greatly with the telemetry distance, the properties of the reflecting surface and the detection angle in telemetry, the first harmonic normalization method is used in this example to eliminate the influence of energy fluctuations; in this method, the phase-locked amplifier 26 simultaneously obtains the first harmonic (1f) and the second harmonic (2f) signals, and transmits them to the microprocessor 13 for further processing; the microprocessor 13 calculates 2f / 1f, and selects the peak value of the harmonic signal in combination with the synchronization signal from the function generator 1, brings it into the calibrated linear relationship function written in advance into the microprocessor 13, and calculates the product of the concentration and the distance on the absorption path; further, this product is divided by the distance obtained from the laser rangefinder 15, and the average concentration of the gas to be measured on the path can be obtained. The output of the microprocessor 13 can be connected to a display (not shown) to monitor the concentration in real time. At the same time, the relevant monitoring information of the laser, such as the laser temperature, can also be displayed on the display.

[0037] The power module is battery powered, providing the required power for each component. For example, the power module can include a 24V high-performance lithium battery and a transformer module to power the entire device; the battery power supply makes the entire device portable and can be moved at any time to detect the target gas in the area that needs to be detected.

[0038] The working process of the utility model is as follows:

[0039] In the actual measurement process, first start the power module to start powering each component; the function generator 1 generates a pre-set first modulation drive signal and a second modulation drive signal, which are respectively used for modulating the first laser controller 4 and the second laser controller 10. It should be noted that the first laser 3 and the second laser 11 have no output at this time; turn on the first temperature controller 7 and the second temperature controller 8, and check the temperature monitoring to confirm that the temperature of the first laser 3 and the second laser 11 is controlled at the set working temperature; after the first laser 3 and the second laser 11 are stabilized at the target temperature, start the first laser controller 4 and the second laser controller 10 and the photodetector 24, and the first laser 3 and the second laser 11 generate infrared lasers of different wavelengths. beam, and the beam is modulated in a form consistent with the preset waveform; the device is rotated to the direction to be inspected, and when there is a target detection gas in the path, the infrared laser beam will be absorbed to a certain extent by methane or acetylene molecules in a specific band; finally, the laser is reflected in all directions by any reflector 19 at the far end, and a part of the reflected light will be collected and converged by the off-axis parabolic reflector 18 with holes and then reach the photosensitive surface of the photodetector 24 through the bandpass filter 23. The photodetector 24 converts the detected light intensity signal into a voltage signal and transmits it to the phase-locked amplifier 26; the phase-locked amplifier 26 outputs a harmonic signal to the microprocessor 13 after demodulating the voltage signal, and the microprocessor 13 outputs the concentration result and transmits it to the display for display.

[0040] In the preferred embodiment of the utility model, the central wavelength of the infrared laser beam is concentrated in the near-infrared band, and related devices such as semiconductor lasers, optical fibers, photodetectors, etc. are relatively mature and easy to obtain. Combined with the optical structure integrated as a whole in the second layer and the expandable light source driving scheme, the device of the utility model can realize the synchronous detection of multiple gases. The above is an explanation based on the synchronous detection of methane and acetylene as an example. When detecting more gases, it can be achieved by multiplexing more lasers (i.e. increasing the number of infrared laser beam generating units), and the overall structure does not need to be changed too much.

[0041] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For technicians in the technical field to which the present invention belongs, several equivalent substitutions or obvious variations can be made without departing from the concept of the present invention, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A portable multi-gas laser telemetry device, characterized in that: include: A light source module, which is used to generate n infrared laser beams for detecting n types of target gases in a target detection area and output a synchronization signal, wherein n≥2; A beam combining module, which is arranged in front of the light source module and is used to combine the n infrared laser beams into one beam; A collimating module, connected to the beam combining module, and configured to collimate the light beam output by the beam combining module to obtain a collimated light beam; A light collection and detection module, which is used to emit the collimated light beam to the target detection area, collect the infrared light laser beam diffusely reflected from any reflective object in the target detection area, and convert it into an electrical signal; A distance measuring module, used for emitting visible light laser to indicate the target detection area and measuring the distance between the light source position in the distance measuring module and the arbitrary reflective object, and outputting a distance signal to a signal processing module; a signal processing module connected to the light source module, the light collection and detection module and the distance measurement module, and configured to process the collected synchronization signal output by the light source module, the electrical signal output by the light collection and detection module and the distance signal output by the distance measurement module to obtain an average concentration value of each target gas in the target detection area; and A power supply module is connected to the light source module, the beam combining module, the collimating module, the light collecting and detecting module, the ranging module and the signal processing module to provide power.

2. The portable multi-gas laser telemetry device according to claim 1, characterized in that: The portable multi-gas laser telemetry device consists of two layers, wherein the light source module, the signal processing module and the power supply module are integrated in the first layer, the collimation module, the light collection and detection module and the ranging module are integrated in the second layer, and the beam combining module is integrated in the first layer or the second layer.

3. The portable multi-gas laser telemetry device according to claim 1 or 2, characterized in that: The light source module includes a function generator and n infrared laser beam generating units. The function generator is used to generate n modulated driving signals to be transmitted to the n infrared laser beam generating units respectively to generate n infrared laser beams for detecting n types of target gases in a target detection area. The function generator is also used to generate a synchronization signal to be transmitted to the signal processing module.

4. The portable multi-gas laser telemetry device according to claim 3, characterized in that: Each infrared laser beam generating unit includes a laser controller, a temperature controller and a laser; The laser controller is connected to the function generator and the laser, and is used to receive the modulated driving signal generated by the function generator and convert it into an input current of the laser; The temperature controller is connected to the laser and is used to control the laser at a predetermined operating temperature; The laser is used to receive the input current and generate an infrared laser beam of a corresponding wavelength.

5. The portable multi-gas laser telemetry device according to claim 4, characterized in that: The beam combining module is a fiber optic combiner, which is connected to the laser and is used to combine the n infrared laser beams from the laser into one beam; the collimation module is a reflective collimator, which is connected to the output port of the fiber optic combiner and is used to collimate the divergent light beam output by the fiber optic combiner to obtain a collimated light beam.

6. The portable multi-gas laser telemetry device according to claim 5, characterized in that: The light collection and detection module includes an off-axis parabolic reflector with a hole, a bandpass filter and a photodetector; the off-axis parabolic reflector with a hole has a small hole on its axis that is larger than the diameter of the collimated light beam, and the reflective collimator is coaxially arranged with the off-axis parabolic reflector with a hole so as to allow the collimated light beam to pass through the small hole and be emitted toward the target detection area; the off-axis parabolic reflector with a hole is used to collect and converge the infrared light laser beam diffusely reflected by the target detection area and transmit it to the photodetector after passing it through the bandpass filter; the photodetector is used to convert the light beam into an electrical signal and transmit it to the signal processing module.

7. The portable multi-gas laser telemetry device according to claim 6, characterized in that: The signal processing module includes a lock-in amplifier and a microprocessor; The lock-in amplifier is connected to the function generator and the photodetector, and is used to receive the synchronization signal output by the function generator and the electrical signal output by the photodetector, and is used to demodulate the electrical signal output by the photodetector with the synchronization signal output by the function generator as a reference, and then output a harmonic signal to the microprocessor; The microprocessor is connected to the function generator, the phase-locked amplifier and the distance measurement module, and is used to process the harmonic signal, the synchronization signal output by the function generator and the distance signal output by the distance measurement module to obtain the average concentration value of each target gas in the target detection area.

8. The portable multi-gas laser telemetry device according to claim 4, characterized in that: Each infrared laser beam generating unit further comprises a laser base, and the laser is mounted on the laser base.

9. The portable multi-gas laser telemetry device according to claim 2, characterized in that: The first layer has a first support plate, the second layer has a second support plate, the light source module, the signal processing module and the power supply module are integrated on the first support plate to form a whole, the collimation module, the light collection and detection module and the ranging module are integrated on the second support plate to form a whole, and the beam combining module is integrated on the first support plate or the second support plate.

10. The portable multi-gas laser telemetry device according to claim 7, characterized in that: The distance measuring module includes a laser rangefinder and a visible light laser, wherein the visible light laser is used to emit a visible light laser to indicate the target detection area, and the laser rangefinder is used to measure the distance between the light source position of the visible light laser and the arbitrary reflective object, and output a distance signal to the signal processing module; The portable multi-gas laser remote sensing device also includes a display, which is used to display and monitor the average concentration value of each target gas output by the microprocessor and relevant monitoring information of the laser.

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