Relative air humidity measuring system for meteorological monitoring

Abstract

The embodiment of the utility model provides an air relative humidity measuring system for meteorological monitoring. The air relative humidity measuring system comprises a power supply unit, a measuring unit, a processing unit and a communication unit, the processing unit comprises a power supply circuit, a laser driving control circuit, a measuring circuit, a temperature compensating circuit and a processor; the measuring unit comprises a laser, a gas chamber, a detector, a gas pressure sensor and a temperature sensor, the laser driving control circuit drives the laser to provide near-infrared laser, the near-infrared laser emitted by the laser is transmitted to the gas chamber through an optical fiber, the gas chamber converts the near-infrared laser transmitted by the optical fiber into spatial light, the spatial light irradiates gas to be measured in the gas chamber, and the gas to be measured is measured. And the signal is coupled to the detector. The relative air humidity measurement system for meteorological monitoring provided by the embodiment of the utility model has the advantages of strong environmental adaptability, large measuring range and high precision, and can meet the measurement requirement of the meteorological monitoring field on the relative air humidity.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of meteorological monitoring, and particularly relates to an air relative humidity measurement system for meteorological monitoring. Background Art

[0002] Air relative humidity is a physical quantity used to represent the water vapor content in the air and can reflect the water vapor content and humidity level in the air. Air relative humidity has an important impact on human comfort. When the air relative humidity is too low, people will feel dry mouth, dry tongue, and even symptoms such as sore throat, hoarseness, and nosebleeds, and are prone to catching colds. Meteorological departments conduct regular observations of air relative humidity every day, including daily average air relative humidity, monthly average air relative humidity, annual average air relative humidity, accumulated annual average air relative humidity, etc. These air relative humidity observation data are of great significance for meteorological forecasting and climate research. Therefore, equipment that can accurately detect air relative humidity is of great significance for meteorological monitoring.

[0003] In the field of meteorological monitoring, the performance requirements for air relative humidity measurement equipment are relatively high, which is mainly limited by the working environment of meteorological monitoring. In the field of meteorological monitoring, the working temperature of the measurement equipment is -40°C to 60°C, the working humidity is 10%RH to 100%RH, and the air pressure range is 550 hPa to 1060 hPa. Existing air humidity measurement equipment based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) often has a limited range, low measurement accuracy, and is difficult to meet the requirements of the working environment in the field of meteorological monitoring. Summary of the Invention

[0004] The embodiment of the utility model provides an air relative humidity measurement system for meteorological monitoring, and provides a large-range and high-precision measurement system that can meet the requirements of the working environment of meteorological monitoring.

[0005] The embodiment of the utility model provides an air relative humidity measurement system for meteorological monitoring, including: a power supply unit, a measurement unit, a processing unit, and a communication unit. The power supply unit is used to supply power to the measurement system, and the communication unit is used for communication between the measurement system and the host computer;

[0006] The processing unit includes a power supply circuit, a laser driver control circuit, a measurement circuit, a temperature compensation circuit, and a processor. The input end of the power supply circuit is connected to the power supply unit, and the output ends of the power supply circuit are respectively connected to the laser driver control circuit, the measurement circuit, the temperature compensation circuit, and the processor. The power supply circuit is used to convert the electric energy provided by the power supply unit into the electric energy required by each load;

[0007] The measurement unit includes a laser, a gas chamber, a detector, a barometric pressure sensor, and a temperature sensor. The laser is connected to a laser driving and control circuit. The gas chamber is respectively connected to the laser and the detector. The laser driving and control circuit drives the laser to provide a near-infrared laser. The near-infrared laser emitted by the laser is transmitted to the gas chamber through an optical fiber. The gas chamber converts the near-infrared laser transmitted by the optical fiber into spatial light, irradiates the gas to be measured in the gas chamber, and couples it to the detector.

[0008] The input ends of the measurement circuit are respectively connected to the detector, the barometric pressure sensor, and the temperature sensor. The output end of the measurement circuit is connected to the input end of the temperature compensation circuit. The output end of the temperature compensation circuit is connected to the processor. The processor is connected to the communication unit.

[0009] In some embodiments, the laser is a distributed feedback laser with a central wavelength of 1392.5 nm.

[0010] In some embodiments, the gas chamber is provided with a diffuse reflection lens.

[0011] In some embodiments, the detector uses a PIN photodiode.

[0012] In some embodiments, the measurement circuit includes an acquisition circuit, an amplification and modulation circuit, and an A / D conversion circuit connected in sequence.

[0013] In some embodiments, the temperature compensation circuit uses a thermistor as a temperature compensation component.

[0014] In some embodiments, the barometric pressure sensor uses a silicon resonant barometric pressure sensor.

[0015] In some embodiments, the temperature sensor is a platinum resistance temperature sensor.

[0016] In some embodiments, the communication unit is connected using an RS-232 interface.

[0017] In some embodiments, the power supply unit uses a 9V - 15V DC power supply.

[0018] The air relative humidity measurement system for meteorological monitoring provided by the embodiment of the present utility model includes: a power supply unit, a measurement unit, a processing unit, and a communication unit. The power supply unit is used to supply power to the measurement system, and the communication unit is used for communication between the measurement system and the host computer. The processing unit includes a power supply circuit, a laser driver control circuit, a measurement circuit, a temperature compensation circuit, and a processor. The input end of the power supply circuit is connected to the power supply unit, and the output ends of the power supply circuit are respectively connected to the laser driver control circuit, the measurement circuit, the temperature compensation circuit, and the processor. The power supply circuit is used to convert the electric energy provided by the power supply unit into the electric energy required by each load. The measurement unit includes a laser, a gas chamber, a detector, a barometric pressure sensor, and a temperature sensor. The laser is connected to the laser driver control circuit, the gas chamber is respectively connected to the laser and the detector. The laser driver control circuit drives the laser to provide near-infrared laser. The near-infrared laser emitted by the laser is transmitted to the gas chamber through an optical fiber. The gas chamber converts the near-infrared laser transmitted by the optical fiber into spatial light, irradiates the gas to be measured in the gas chamber, and couples it to the detector. The input ends of the measurement circuit are respectively connected to the detector, the barometric pressure sensor, and the temperature sensor. The output end of the measurement circuit is connected to the input end of the temperature compensation circuit. The output end of the temperature compensation circuit is connected to the processor. The processor is connected to the communication unit. The air relative humidity measurement system for meteorological monitoring provided by the embodiment of the present utility model has strong environmental adaptability, a large measurement range, and high accuracy, and can meet the measurement requirements of the air relative humidity in the meteorological monitoring field. Description of the Drawings

[0019] The drawings here are incorporated into the description and form a part of this description, showing embodiments in line with the present utility model, and are used together with the description to explain the principles of the present utility model.

[0020] Figure 1 It is a schematic structural diagram of the air relative humidity measurement system for meteorological monitoring provided by an embodiment of the present utility model;

[0021] Figure 2 It is a schematic structural diagram of the barometric pressure sensor provided by an embodiment of the present utility model;

[0022] Figure 3 It is a schematic diagram of the gas chamber and its diffuse reflection structure provided by an embodiment of the present utility model.

[0023] Description of the reference numerals:

[0024] 10 - Power supply unit; 20 - Measurement unit; 30 - Processing unit; 40 - Communication unit; 201 - Laser; 202 - Gas chamber; 203 - Detector; 204 - Air pressure sensor; 205 - Temperature sensor; 301 - Power supply circuit; 302 - Laser drive control circuit; 303 - Measurement circuit; 304 - Temperature compensation circuit; 305 - Processor; 3031 - Acquisition circuit; 3032 - Amplification and modulation circuit; 3033 - A / D conversion circuit; 2021 - Fixed end of diffuse mirror; 2022 - Installation end of detector collimator.

[0025] Through the above-mentioned drawings, specific embodiments of the present invention have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed embodiments

[0026] The present invention will be further described in detail below in conjunction with the drawings through specific embodiments. Similar elements in different embodiments are labeled with related similar element numbers. In the following embodiments, many details are described to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification to avoid the core part of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0027] In addition, the features, operations, or characteristics described in the specification can be combined in any appropriate manner to form various embodiments. At the same time, the steps or actions in the method description can also be reordered or adjusted in an obvious manner by those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0028] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. And the "connection" and "coupling" mentioned in this application, unless otherwise specified, both include direct and indirect connection (coupling).

[0029] Figure 1 It is a structural schematic diagram of an air relative humidity measurement system for meteorological monitoring provided by an embodiment of the present invention. AsFigure 1 As shown in Figure 1 , the relative air humidity measurement system for meteorological monitoring provided by the embodiments of the present utility model may include: a power supply unit 10, a measurement unit 20, a processing unit 30, and a communication unit 40. The power supply unit 10 is used to supply power to the measurement system, and the communication unit 40 is used for communication between the measurement system and the host computer; the measurement unit 20 is used to obtain physical quantities such as temperature, air pressure, and gas absorption rate; the processing unit 30 is used to determine the relative air humidity according to the physical quantities such as temperature, air pressure, and gas absorption rate obtained by the measurement unit 20. In some optional embodiments, the power supply unit 10 uses a 9V - 15V DC power supply. Specifically, a 9V - 15V DC power supply can be used for power supply, and the hardware circuit is configured with an external input power conversion function to convert it into various power supplies required inside the measurement system. In some embodiments, the communication unit 40 is connected using an RS - 232 interface. The communication unit 40 is used for communication between the measurement system and the host computer, including receiving the instruction information from the host computer and sending the relative air humidity information generated by the processing unit 30 to the host computer, and transmitting data and status information to the observation software in the way of connecting with RS - 232.

[0030] The processing unit 30 includes a power supply circuit 301, a laser driver control circuit 302, a measurement circuit 303, a temperature compensation circuit 304, and a processor 305. The input end of the power supply circuit 301 is connected to the power supply unit 10. The power supply circuit 301 can use a high - precision LDO chip to convert the external input power into the power required for the internal circuit. The output end of the power supply circuit 301 is respectively connected to the laser driver control circuit 302, the measurement circuit 303, the temperature compensation circuit 304, and the processor 305. The power supply circuit 301 is used to convert the electric energy provided by the power supply unit 10 into the electric energy required by each load. The processor 305 can adopt a Cortex processor 305 integrated with an MCU control unit, a data memory, a program memory, a driving circuit, a clock, etc., and is the core component of the instrument. The processor 305 processes the gas absorption curve through an algorithm inside to obtain the water vapor absorption peak value and calculates the corresponding water vapor concentration.

[0031] The measurement unit 20 includes a laser 201, a gas chamber 202, a detector 203, a barometric pressure sensor 204, and a temperature sensor 205, whose function is to convert the physical quantity of the observed element into a digital signal and transmit it to the processing unit 30. The laser 201 is connected to the laser drive control circuit 302. The gas chamber 202 is respectively connected to the laser 201 and the detector 203. The laser drive control circuit 302 drives the laser 201 to provide near-infrared laser with a wavelength corresponding to the near-infrared absorption of water vapor, and humidity is measured by wavelength scanning. The near-infrared laser emitted by the laser 201 is transmitted to the gas chamber 202 through an optical fiber. The gas chamber 202 converts the near-infrared laser transmitted by the optical fiber into spatial light, irradiates the gas to be measured in the gas chamber 202, and couples it to the detector 203, and then the subsequent water vapor concentration inversion calculation is carried out through subsequent circuit processing. In some alternative embodiments, the detector 203 may employ a PIN photodiode.

[0032] The input end of the measurement circuit 303 is respectively connected to the detector 203, the barometric pressure sensor 204, and the temperature sensor 205. The output end of the measurement circuit 303 is connected to the input end of the temperature compensation circuit 304. The output end of the temperature compensation circuit 304 is connected to the processor 305. The processor 305 is connected to the communication unit 40. In some embodiments, the measurement circuit 303 includes an acquisition circuit 3031, an amplification and modulation circuit 3032, and an A / D conversion circuit 3033 connected in sequence, which are used to realize signal acquisition, amplification, modulation, and the conversion from analog quantity to digital quantity. Specifically, the amplification and modulation circuit 3032 converts the current signal on the detector 203 into an appropriate voltage signal, removes noise through the modulation circuit, and finally the A / D conversion circuit 3033 performs A / D conversion to obtain the gas absorption curve. In some embodiments, the temperature compensation circuit 304 uses a thermistor as the temperature compensation component, and specifically, the measurement result can be automatically calibrated and corrected according to the ambient temperature through the thermistor.

[0033] In some alternative embodiments, the laser drive control circuit 302 may further include a laser temperature control circuit and a laser drive circuit. Among them, the laser temperature control circuit is used to ensure that the laser 201 operates at the temperature corresponding to the water vapor absorption wavelength and always maintains a constant temperature in outdoor high and low temperature environments; the laser drive circuit scans the output wavelength of the laser 201 near the water vapor absorption wavelength through current control, in cooperation with the water vapor inversion algorithm.

[0034] In some alternative embodiments, the air relative humidity measurement system for meteorological monitoring may further include a monitoring circuit for detecting and monitoring the internal voltage, temperature, and other internal states of the measurement system.

[0035] The air relative humidity measurement system for meteorological monitoring provided by the embodiment of the utility model has strong environmental adaptability, a large measurement range and high precision, and can meet the measurement requirements of the meteorological monitoring field for air relative humidity.

[0036] On the basis of the above embodiment, in order to further improve the measurement accuracy, in the air relative humidity measurement system for meteorological monitoring provided by this embodiment, the laser 201 uses a distributed feedback laser with a central wavelength of 1392.5 nm. Specifically, a distributed feedback laser (DFB) with a 14-pin butterfly package from Nanoplus, Germany can be selected. It is a tunable single-mode coupled laser with a central wavelength of 1392.5 nm. This wavelength band has a strong water vapor absorption peak and a background gas. To realize the temperature control of the laser and ensure that the output of the central wavelength is not interfered by the environment and remains at the target value. In order to cooperate with the dual-wavelength measurement method adopted in this application, in this embodiment, according to the characteristics of the DFB laser, the drive current can be adjusted at different control temperatures, and the central wavelength of the laser can be changed by 0.033 nm / mA. Considering the water vapor absorption spectrum line and the drive circuit design comprehensively, the wavelength difference between the two wavelengths of this system is 0.7 nm, that is, the first wavelength is 1392.5 nm and the second wavelength is 1391.8 nm.

[0037] Specifically, the experimental equipment used in this embodiment includes: a GRZ5300 low-temperature dew point generator (dew point range -70 to 40 °C), an MBW373 digital dew point meter, a sensor to be calibrated, an experimental tooling, and a constant temperature box. The dew point generator generates a target stable humidity environment, the dew point meter provides accurate environmental humidity values, the experimental tooling cooperates with the dew point generator to ensure that the sensor is not interfered by external humidity, and the constant temperature box realizes the function of preventing condensation at high temperature dew points. Calibration points are selected between an absolute humidity of 50 to 245,600 PPM. After conversion to dew point, this patent selects 7 points of -30, -25, -20, -5, 10, 30, and 40 °C. Finally, the calibration results are analyzed, and 50 to 300 PPM is classified as low concentration, 300 to 75,000 PPM is classified as conventional concentration, and 75,000 to 245,600 PPM is classified as high concentration. The measurement range of the first wavelength of 1392.5 nm is 50 to 75,600 PPM, and the measurement range of the second wavelength of 1391.8 nm is 75,000 to 245,600 PPM. Among them, the switching thresholds for the direct method and the harmonic method are 300 and 400 PPM, and the switching thresholds for the first wavelength and the second wavelength are 74,400 PPM and 75,600 PPM. From the direction of increasing humidity, the harmonic method of the first wavelength is used for 50 to 400 PPM, the direct method of the first wavelength is used for 401 to 75,600, and the second wavelength is used for 75,601 to 245,600 PPM; from the direction of decreasing humidity, the second wavelength is measured for 245,600 to 75,000 PPM, the direct method of the first wavelength is measured for 74,999 to 300 PPM, and the harmonic method of the first wavelength is measured for 299 to 50.

[0038] To ensure the lower measurement limit, a gas band with a high water vapor absorption rate, 1392.5 nm, is selected. At low and conventional concentrations, the direct method and harmonic method are switched to process the acquired signals. (1) During direct method measurement, the output drive current is scanned within a relatively wide range corresponding to the current value at the absorption peak. Once a scan is completed, the corresponding light intensity signal can be obtained. By fitting several points far from the absorption peak and unaffected by absorption, an original curve without the influence of the gas to be measured is generated. By subtracting the original curve from the actual curve, the corresponding absorption curve can be obtained, and after further calibration, the concentration measurement can be achieved. The direct method removes the optical power interference through wavelength scanning, improving the measurement accuracy of the sensor in the air. (2) During harmonic method measurement, a second harmonic detection scheme is adopted. The detector output signal is combined with technologies such as band-pass filtering, digital phase-locked amplification, and low-pass filtering (corresponding to the modulation part of the measurement circuit in the system structure block diagram) to achieve the functions of weak signal extraction and signal noise reduction. The concentration of the gas to be measured is obtained after processing the ratio of the second harmonic to the first harmonic amplitude. The harmonic method also uses wavelength scanning. The drive current is scanned near the center wavelength of the absorption peak. The difference is that the drive current consists of a reference working current, a low-frequency triangular wave, and a high-frequency sine wave. The reference working current corresponds to the center wavelength of the DFB laser. The low-frequency triangular wave enables a large range of laser wavelength output, and the high-frequency sine wave enables laser wavelength modulation. Among them, the digital phase-locked amplifier has a simple structure, no DC amplifier, avoiding interference such as temperature drift; it has a highly stable clock source, reducing the error caused by unstable reference signals; it has high-performance quadrature demodulation technology, which can improve the detection accuracy of weak signals. To ensure the upper measurement limit and prevent the absorption peak from being truncated and unable to be measured at high concentrations, the output wavelength of the laser is regulated through temperature control or current control, so that the laser output wavelength selects a band with a lower absorption rate in the band close to the high absorption peak, that is, the second wavelength direct method measurement is used to achieve dual-wavelength large-range measurement.

[0039] The air relative humidity measurement system for meteorological monitoring provided in this embodiment uses a distributed feedback laser with a center wavelength of 1392.5 nm, combined with a dual-wavelength measurement method, to achieve large-range air humidity measurement and improve the measurement accuracy of air relative humidity.

[0040] On the basis of the above embodiment, to further improve the measurement accuracy, in the air relative humidity measurement system for meteorological monitoring provided in this embodiment, the temperature sensor 205 is a platinum resistance temperature sensor.

[0041] Specifically, a platinum resistance temperature sensing element is used. The resistance value of this element is 100 Ω at 0 °C, and its resistance value increases approximately uniformly as the temperature rises. However, the relationship between temperature and resistance value is not a simple proportional relationship. The calculation formula for the change of platinum resistance value with temperature:

[0042] -200 < t < 0 °C, R t = R0[1 + At + Bt 2 + C(t - 100)t 3 ............(1)

[0043] 0 ≤ t < 850 °C, R t = R0(1 + At + Bt 2 ).........................(2)

[0044] Wherein, Rt is the resistance value at t °C, and R0 is the resistance value at 0 °C. The coefficients A, B, and C in the formula can be determined by experiments.

[0045] According to the quadratic formula, the temperature conversion formula when the resistance value is greater than or equal to 100 Ω is:

[0046]

[0047] The platinum resistance temperature sensor is a resistive temperature sensor made of platinum metal (Pt), belonging to a positive temperature coefficient device. The resistance value of this device at 0 °C is 100 Ω, simply referred to as Pt100. By sampling Pt100, the resistance value at the current temperature is obtained, and the current temperature value is calculated through calculation. Applying a high-precision temperature sensing element (1 / 3B or 1 / 5B) in cooperation with a four-wire measurement circuit can achieve a maximum error within ±0.1 °C, which helps to improve the measurement accuracy of the relative humidity of the air.

[0048] Please refer to Figure 2 , in some alternative embodiments, the barometric pressure sensor 204 in the air relative humidity measurement system for meteorological monitoring can adopt a silicon resonant barometric pressure sensor. The silicon resonant barometric pressure sensing element is a new type of structural pressure sensor, which has higher resolution, sensitivity, accuracy, and stability compared with the traditional silicon piezoresistive pressure sensing element. The basic principle is to use a silicon resonator and a frequency-selective amplifier to form a positive feedback oscillation system. When this system is subjected to pressure, its inherent oscillation frequency changes. Therefore, the magnitude of the pressure can be measured according to the change in its frequency. Its structure mainly consists of four parts: a sensitive diaphragm layer, a resonant layer, a capacitance layer, and a glass substrate layer.

[0049] Based on any of the above embodiments, in order to meet the long-term reliable measurement in various environments and prevent the problem of inability to measure due to the slight deviation of the light beam by the high-reflection mirror, a diffuse reflection weak signal detection method is adopted to design a diffuse reflection optical path. The sensor collects weak reflection signals and cooperates with a low-noise photoelectric automatic gain adjustment circuit module to achieve highly reliable gas measurement, extend the maintenance cycle, and meet the application requirements of various environments. In the air relative humidity measurement system for meteorological monitoring provided in this embodiment, a reflection-type gas chamber is adopted, and a diffuse reflection lens is provided in the gas chamber 202. The reflection-type gas chamber can be composed of a lens and one or more reflectors, and the absorption optical path is increased by changing the number of reflections of the laser in the gas chamber, which is more complex in structure than the transmission-type gas chamber. The structure of the reflection-type gas chamber in this embodiment is as shown in Figure 3 (a) in the figure, mainly including a diffuse reflection mirror fixed end 2021, a gas chamber 202, and a detector collimator installation end 2022, so as to increase the detection optical path, improve the detection lower limit, achieve accurate measurement at a low concentration of 50 PPM, and ensure the measurement of a large range in the meteorological field. A diffuse reflection mirror is fixed at the diffuse reflection mirror fixed end 2021. In this application, a single diffuse reflection lens is used for single reflection, which can increase the optical path compared with the transmission type. The diffuse reflection optical path is as shown in Figure 3 (b) in the figure. The air relative humidity measurement system for meteorological monitoring provided in this embodiment uses a diffuse reflection lens instead of a high-precision reflector, which not only expands the measurement range, but also reduces the cost and has stronger environmental adaptability.

[0050] In summary, the air relative humidity measurement system for meteorological monitoring provided in this application realizes the measurement of a large range of air humidity by switching between the direct method, the harmonic method, and the dual-wavelength detection method under different air concentrations, and cooperating with a gas cell with a diffuse reflection lens to increase the absorption optical path; through the built-in high-precision temperature and pressure sensing module, cooperating with the absolute humidity measured by TDLAS, and the meteorological humidity different unit conversion algorithm, high-precision relative humidity measurement is realized; the reflection lens uses a diffuse reflection lens instead of a high-precision reflector, which not only expands the measurement range, but also reduces the cost and has stronger environmental adaptability. This measurement system has the characteristics of a large range, high precision, and strong weather resistance.

[0051] Each embodiment in this disclosure is described in a progressive manner. The same or similar parts between each embodiment can be referred to each other, and the key points of each embodiment are the differences from other embodiments.

[0052] The protection scope of this disclosure is not limited to the above embodiments. Obviously, those skilled in the art can make various changes and deformations to this disclosure without departing from the scope and spirit of this disclosure. If these changes and deformations belong to the scope of the claims of this disclosure and their equivalent technologies, the intention of this disclosure also includes these changes and deformations.

Claims

1. An air relative humidity measurement system for meteorological monitoring, characterized in that, Comprising: A power supply unit, a measurement unit, a processing unit and a communication unit. The power supply unit is used to supply power to the measurement system, and the communication unit is used for communication between the measurement system and the host computer; The processing unit includes a power supply circuit, a laser driver control circuit, a measurement circuit, a temperature compensation circuit and a processor. The input end of the power supply circuit is connected to the power supply unit, and the output end of the power supply circuit is respectively connected to the laser driver control circuit, the measurement circuit, the temperature compensation circuit and the processor. The power supply circuit is used to convert the electric energy provided by the power supply unit into the electric energy required by each load; The measurement unit includes a laser, a gas cell, a detector, a barometric pressure sensor and a temperature sensor. The laser is connected to the laser driver control circuit. The gas cell is respectively connected to the laser and the detector. The laser driver control circuit drives the laser to provide near-infrared laser. The near-infrared laser emitted by the laser is transmitted to the gas cell through an optical fiber. The gas cell converts the near-infrared laser transmitted by the optical fiber into spatial light, irradiates the gas to be measured in the gas cell, and couples it to the detector; The input end of the measurement circuit is respectively connected to the detector, the barometric pressure sensor and the temperature sensor. The output end of the measurement circuit is connected to the input end of the temperature compensation circuit. The output end of the temperature compensation circuit is connected to the processor. The processor is connected to the communication unit.

2. The measurement system according to claim 1, wherein The laser is a distributed feedback laser with a central wavelength of 1392.5 nm.

3. The measurement system according to claim 1, characterized in that, The gas cell is provided with a diffuse reflection lens.

4. The measurement system according to claim 1, wherein The detector uses a PIN photodiode.

5. The measurement system according to claim 1, wherein, The measurement circuit includes an acquisition circuit, an amplification and modulation circuit and an A / D conversion circuit connected in sequence.

6. The measurement system according to claim 1, wherein The temperature compensation circuit uses a thermistor as a temperature compensation component.

7. The measurement system according to claim 1, characterized in that, The barometric pressure sensor uses a silicon resonant barometric pressure sensor.

8. The measurement system according to claim 1, characterized in that, The temperature sensor is a platinum resistance temperature sensor.

9. The measurement system according to claim 1, wherein The communication unit is connected using an RS-232 interface.

10. The measurement system according to claim 1, characterized in that, The power supply unit uses a 9V-15V DC power supply.

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