Greenhouse gas detector with multi-collinearity noise suppression

Abstract

The utility model discloses a multi-collinearity noise suppression greenhouse gas detector, which belongs to the technical field of gas detection and comprises a laser emission component, an optical resonant cavity, an information acquisition and processing component, a noise suppression device and an environment control component. According to the greenhouse gas detector, by arranging the phase-locked amplifier as well as the self-adaptive filter and the self-adaptive wave trap which are connected in parallel, extraction and phase-locked amplification of same-frequency and same-phase signals of laser modulation frequencies are realized, weak signals are extracted from noise, and the filtering characteristic of the detector is automatically adjusted according to the change of input signals under complex environmental noise; the self-adaptive wave trap recognizes the frequency characteristic with the specific dominant frequency coherent noise in the input signal and adjusts the filtering characteristic of the input signal, effective signals can be extracted from the complex environment noise, the coherent noise can be restrained, and therefore the detection precision of an instrument in the complex environment is improved.

Description

Technical Field

[0001] This utility model relates to the field of gas detection technology, specifically a greenhouse gas detector with multicollinearity noise suppression. Background Technology

[0002] The detection of atmospheric greenhouse gases requires long-term, continuous observation, and the validity of the data during the monitoring process places stringent demands on the detection instruments. To achieve long-term, high-precision, and highly stable observations, it is essential to address instrument noise and drift issues caused by environmental noise, human activity noise, and multicollinearity during the detection process. This is not only a technical challenge but also crucial for achieving accurate monitoring of atmospheric greenhouse gas concentrations.

[0003] In practical applications, signals are often interfered with by various types of noise, which may originate from the equipment itself, external environmental interference, or losses during signal transmission. This noise mixes with the signal, making the identification of weak signals extremely difficult. Furthermore, coherent noise, as an interference wave with a specific dominant frequency, may alias with the original signal during signal processing and transmission due to errors and interference. Therefore, extracting effective signals and suppressing coherent noise in complex environments is crucial to improving the detection accuracy of instruments in such conditions. Utility Model Content

[0004] This invention provides a greenhouse gas detector with multicollinearity noise suppression, aiming to solve the problem in the background art of how to extract effective signals and suppress coherent noise in complex environmental noise.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a greenhouse gas detector with multicollinearity noise suppression, comprising a laser emitting component, an optical resonant cavity connected to the output end of the laser emitting component, an information acquisition and processing component connected to the output end of the optical resonant cavity, a noise suppression device connected to the output end of the information acquisition and processing component, and an environmental control component; the laser emitting component includes a laser, a laser controller connected to the input end of the laser, and a signal generator connected to the input end of the laser controller; the environmental control component includes a microcontroller, a temperature sensor fixedly installed on one side of the cavity of the optical resonant cavity and electrically connected to the input end of the microcontroller, and a differential pressure control system bidirectionally connected to the microcontroller. The input terminal of the microcontroller is electrically connected to the output terminal of the information acquisition and processing component; the optical resonant cavity includes the cavity body, a front high-reflection mirror fixedly installed at the front end of the cavity body, a rear high-reflection mirror fixedly installed at the rear end of the cavity body, and an air inlet and an air outlet disposed on one side surface of the cavity body; the information acquisition and processing component includes a focusing lens, a photodetector disposed at the focal point of the focusing lens, and the terminal, the terminal being connected to the input terminal of the laser controller; the noise suppression device includes a lock-in amplifier connected to the output terminal of the photodetector and connected to the input terminal of the signal generator, an adaptive filter and an adaptive notch filter connected in parallel with the output terminal of the signal generator, the output terminals of the adaptive filter and the adaptive notch filter being electrically connected to the input terminal of the signal generator.

[0006] When the aforementioned greenhouse gas detector starts working, the laser controller adjusts the laser's operating temperature and current. The laser reflects the light off the front high-reflection mirror at the front end of the optical resonant cavity, injecting the reflected light into the cavity at an off-axis angle. The laser then reflects back and forth between the front and rear high-reflection mirrors multiple times, converging and superimposing the transmitted light from each reflection. Finally, a strong beam with consistent propagation direction, frequency, and phase is output. A focusing lens focuses the transmitted signal output from the optical resonant cavity. A photodetector converts the focused transmitted signal into an electrical signal and outputs it to the terminal. The terminal collects and processes the electrical signal output from the photodetector and outputs a digital signal to the noise suppression device. By setting up a lock-in amplifier and using phase-sensitive detection technology, the laser modulation frequency is synchronized. Signal extraction and phase-locked amplification effectively extract weak signals from noise, thereby improving the system's detection sensitivity. Parallel adaptive filters and adaptive notch filters are introduced. The adaptive filter automatically adjusts its filtering characteristics according to changes in the input signal under complex environmental noise, achieving effective signal extraction and noise suppression. For coherent noise with a specific dominant frequency, the adaptive notch filter identifies the frequency characteristics of the coherent noise in the input signal and automatically adjusts its filtering characteristics, effectively suppressing the coherent noise. By incorporating temperature sensors and a differential pressure control system to provide feedback on environmental factors, the microcontroller controls the differential pressure control system to regulate the internal pressure of the cavity at suitable temperatures. Through this precise environmental control, the interference of these factors on the measurement results can be minimized.

[0007] Preferably, the differential pressure control system includes an air pump fixedly connected to the air inlet, a mass flow controller fixedly connected to the air outlet, and a pressure sensor fixedly installed on one side of the cavity. The input terminals of the air pump and the mass flow controller are both electrically connected to the output terminal of the microcontroller, and the output terminal of the pressure sensor is electrically connected to the input terminal of the microcontroller.

[0008] Preferably, the temperature sensor is a TPB430-SUB optical thermometer.

[0009] Preferably, the mass flow controller is an ACU20FD-L high-precision mass flow controller, and the pressure sensor is a PTJ410 gas pressure sensor.

[0010] Preferably, the base material of both the front and rear high-reflectivity mirrors is zinc selenide, the lens thickness is 5mm, the diameter is 30mm, and the concave surface curvature radius is 1000mm. The concave surfaces of both the front and rear high-reflectivity mirrors are coated with a high-reflectivity dielectric film, and the flat surfaces are coated with an anti-reflection film.

[0011] Preferably, the distance between the front high-reflection mirror and the rear high-reflection mirror is 160mm.

[0012] This greenhouse gas detector with multicollinearity noise suppression is simple in structure and easy to use. By incorporating a lock-in amplifier and utilizing phase-sensitive detection technology, it extracts and amplifies signals with the same frequency and phase as the laser modulation frequency, effectively extracting weak signals from noise and thus improving the system's detection sensitivity. Parallel adaptive filters and adaptive notch filters are introduced. The adaptive filter automatically adjusts its filtering characteristics according to changes in the input signal under complex environmental noise, thereby achieving effective signal extraction and noise suppression. For coherent noise with a specific dominant frequency, the adaptive notch filter identifies the frequency characteristics of the coherent noise in the input signal and automatically adjusts its filtering characteristics, effectively suppressing the coherent noise. By incorporating a temperature sensor and a differential pressure control system to provide feedback on environmental factors, the microcontroller controls the differential pressure control system to control the internal pressure of the cavity at a suitable temperature. Through this precise environmental control, the interference of these factors on the measurement results can be minimized. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a greenhouse gas detector designed to suppress multicollinear noise.

[0014] In the picture:

[0015] 1. Laser emitting assembly; 101. Laser; 102. Laser controller; 103. Signal generator;

[0016] 2. Environmental control components; 201. Microcontroller; 202. Temperature sensor; 203. Differential pressure control system; 2031. Air pump; 2032. Mass flow controller; 2033. Pressure sensor;

[0017] 3. Optical resonant cavity; 301. Cavity body; 302. Front high-reflection mirror; 303. Rear high-reflection mirror; 304. Air inlet; 305. Air outlet;

[0018] 4. Information acquisition and processing components; 401. Focusing lens; 402. Photodetector; 403. Terminal;

[0019] 5. Noise suppression device; 501. Lock-in amplifier; 502. Adaptive filter; 503. Adaptive notch filter. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] This embodiment provides a greenhouse gas detector with multicollinearity noise suppression, such as Figure 1 As shown, the greenhouse gas detector with multicollinearity noise suppression includes a laser emitting component 1, an optical resonant cavity 3 connected to the output end of the laser emitting component 1, an information acquisition and processing component 4 connected to the output end of the optical resonant cavity 3, a noise suppression device 5 connected to the output end of the information acquisition and processing component 4, and an environmental control component 2. The laser emitting component 1 includes a laser 101, a laser controller 102 connected to the input end of the laser 101, and a signal generator 103 connected to the input end of the laser controller 102. The environmental control component 2 includes a microcontroller 201, a temperature sensor 202 fixedly installed on one side of the cavity 301 of the optical resonant cavity 3 and electrically connected to the input end of the microcontroller 201, and a differential pressure control system 203 bidirectionally connected to the microcontroller 201. The input end of the microcontroller 201 is electrically connected to the output end of the terminal 403 of the information acquisition and processing component 4. The optical resonant cavity 3 includes a cavity body 301, a front high-reflection mirror 302 fixedly installed at the front end of the cavity body 301, a rear high-reflection mirror 303 fixedly installed at the rear end of the cavity body 301, and an air inlet 304 and an air outlet 305 disposed on one side surface of the cavity body 301; the information acquisition and processing component 4 includes a focusing lens 401, a photodetector 402 disposed at the focal position of the focusing lens 401, and a terminal 403, the terminal 403 being connected to the input end of the laser controller 102; the noise suppression device 5 includes a lock-in amplifier 501 connected to the output end of the photodetector 402 and connected to the input end of the signal generator 103, an adaptive filter 502 and an adaptive notch filter 503 connected in parallel with the output end of the signal generator 103, the output ends of the adaptive filter 502 and the adaptive notch filter 503 being electrically connected to the input end of the signal generator 103.

[0022] When the aforementioned greenhouse gas detector starts working, the operating temperature and current of the laser 101 are adjusted by the laser controller 102. The laser 101 reflects the laser light onto the plane of the front high-reflection mirror 302 at the front end of the optical resonant cavity 3, thereby injecting the reflected light into the optical resonant cavity 3 at an off-axis angle. Then, the laser light is reflected back and forth multiple times between the front high-reflection mirror 302 and the rear high-reflection mirror 303. The transmitted light from each time is then converged and superimposed, and finally, a strong beam with the same propagation direction, frequency, and phase is output. The focusing lens 401 is used to focus the transmitted signal output by the optical resonant cavity 3. The photodetector 402 is used to convert the focused transmitted signal into an electrical signal and output it to the terminal 403. The terminal 403 is used to collect and process the electrical signal output by the photodetector 402 and output a digital signal to the noise suppression device 5. By setting a lock-in amplifier 501, phase-sensitive detection technology is used to achieve laser modulation frequency. Extracting and amplifying the in-phase signal at the same frequency can effectively extract weak signals from noise, thereby improving the system's detection sensitivity. Introducing a parallel adaptive filter 502 and an adaptive notch filter 503 allows the adaptive filter 502 to automatically adjust its filtering characteristics according to changes in the input signal under complex environmental noise, thus achieving effective signal extraction and noise suppression. For coherent noise with a specific dominant frequency, the adaptive notch filter 503 identifies the frequency characteristics of the coherent noise in the input signal and automatically adjusts its filtering characteristics, effectively suppressing the coherent noise. By setting up a temperature sensor 202 and a differential pressure control system 203 to provide feedback on environmental factors, at a suitable temperature, the microcontroller 201 controls the differential pressure control system 203 to control the internal pressure of the cavity 301. Through this precise environmental control, the interference of these factors on the measurement results can be minimized.

[0023] In one embodiment, the differential pressure control system 203 includes an air pump 2031 fixedly connected to the air inlet 304, a mass flow controller 2032 fixedly connected to the air outlet 305, and a pressure sensor 2033 fixedly installed on one side of the cavity 301. The input terminals of the air pump 2031 and the mass flow controller 2032 are both electrically connected to the output terminal of the microcontroller 201, and the output terminal of the pressure sensor 2033 is electrically connected to the input terminal of the microcontroller 201.

[0024] In this embodiment, refer to Figure 1 The air pump 2031 controls the air intake and exhaust inside the cavity 301, the mass flow controller 6 controls the internal pressure to ensure that the internal pressure is constant, and the pressure sensor 2033 transmits the pressure data inside the cavity 301 to the microcontroller 201.

[0025] In one embodiment, the temperature sensor 202 is a TPB430-SUB optical thermometer.

[0026] In this embodiment, refer to Figure 1 The temperature sensor 202 uses a TPB430-SUB optical thermometer, which has a rated temperature range of 0 to 50 degrees Celsius and features fast response time and a wide temperature measurement range.

[0027] In one embodiment, the mass flow controller 2032 is an ACU20FD-L high-precision mass flow controller, and the pressure sensor 2033 is a PTJ410 gas pressure sensor.

[0028] In this embodiment, refer to Figure 1 The ACU20FD-L high-precision mass flow controller can accurately control the pressure inside the cavity 301. The pressure sensor 2033 adopts the PTJ410 gas pressure sensor, which has good moisture resistance and excellent media compatibility, and has the advantages of good stability and long service life.

[0029] In one embodiment, the base material of both the front high-reflection mirror 302 and the rear high-reflection mirror 303 is zinc selenide, the lens thickness is 5mm, the diameter is 30mm, and the concave surface curvature radius is 1000mm. The concave surfaces of both the front high-reflection mirror 302 and the rear high-reflection mirror 303 are coated with a high-reflection dielectric film, and the flat surfaces are coated with an anti-reflection film.

[0030] In this embodiment, refer to Figure 1 The concave surfaces of the front high-reflectivity mirror 302 and the rear high-reflectivity mirror 303 are coated with a high-reflectivity dielectric film with a reflectivity >99.98%, which helps to enhance the reflectivity. The flat surfaces are coated with an anti-reflection film to reduce reflected light.

[0031] In one embodiment, the distance between the front high-reflection mirror 302 and the rear high-reflection mirror 303 is 160 mm.

[0032] In this embodiment, refer to Figure 1 The distance between the two lenses satisfies the condition for a stable resonant cavity, allowing light to travel back and forth multiple times within cavity 301 without the light spot spreading.

[0033] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A greenhouse gas detector with multicollinear noise suppression, comprising a laser emitting component (1), an optical resonant cavity (3) connected to the output end of the laser emitting component (1), an information acquisition and processing component (4) connected to the output end of the optical resonant cavity (3), a noise suppression device (5) connected to the output end of the information acquisition and processing component (4), and an environmental control component (2). Its features are: The laser emitting assembly (1) includes a laser (101), a laser controller (102) connected to the input terminal of the laser (101), and a signal generator (103) connected to the input terminal of the laser controller (102). The environmental control component (2) includes a microcontroller (201), a temperature sensor (202) fixedly installed on one side of the cavity (301) of the optical resonant cavity (3) and electrically connected to the input terminal of the microcontroller (201), and a differential pressure control system (203) bidirectionally connected to the microcontroller (201). The input terminal of the microcontroller (201) is electrically connected to the output terminal of the terminal (403) of the information acquisition and processing component (4). The optical resonant cavity (3) includes the cavity body (301), a front high-reflection mirror (302) fixedly installed at the front end of the cavity body (301), a rear high-reflection mirror (303) fixedly installed at the rear end of the cavity body (301), and an air inlet (304) and an air outlet (305) disposed on one side surface of the cavity body (301). The information acquisition and processing component (4) includes a focusing lens (401), a photodetector (402) disposed at the focal point of the focusing lens (401), and a terminal (403), wherein the terminal (403) is connected to the input end of the laser controller (102); The noise suppression device (5) includes a lock-in amplifier (501) connected to the output terminal of the photodetector (402) and the input terminal of the signal generator (103), an adaptive filter (502) and an adaptive notch filter (503) connected in parallel with the output terminal of the signal generator (103), and the output terminals of the adaptive filter (502) and the adaptive notch filter (503) are both electrically connected to the input terminal of the signal generator (103).

2. The greenhouse gas detector with multicollinearity noise suppression according to claim 1, characterized in that: The differential pressure control system (203) includes an air pump (2031) fixedly connected to the air inlet (304), a mass flow controller (2032) fixedly connected to the air outlet (305), and a pressure sensor (2033) fixedly installed on one side of the cavity (301). The input terminals of the air pump (2031) and the mass flow controller (2032) are electrically connected to the output terminal of the microcontroller (201), and the output terminal of the pressure sensor (2033) is electrically connected to the input terminal of the microcontroller (201).

3. The greenhouse gas detector with multicollinearity noise suppression according to claim 1, characterized in that: The temperature sensor (202) is a TPB430-SUB optical thermometer.

4. The greenhouse gas detector with multicollinearity noise suppression according to claim 2, characterized in that: The mass flow controller (2032) is an ACU20FD-L high-precision mass flow controller, and the pressure sensor (2033) is a PTJ410 gas pressure sensor.

5. The greenhouse gas detector with multicollinearity noise suppression according to claim 1, characterized in that: The base material of both the front high-reflection mirror (302) and the rear high-reflection mirror (303) is zinc selenide. The lens thickness is 5mm, the diameter is 30mm, and the concave surface curvature radius is 1000mm. The concave surface of both the front high-reflection mirror (302) and the rear high-reflection mirror (303) is coated with a high-reflection dielectric film, and the flat surface is coated with an anti-reflection film.

6. The greenhouse gas detector with multicollinearity noise suppression according to claim 1, characterized in that: The distance between the front high-reflection mirror (302) and the rear high-reflection mirror (303) is 160 mm.

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