CN104730039B - An Indoor Visibility Meter Calibration System - Google Patents

Abstract

The invention relates to an indoor visibility meter calibration system. An aerosol generator located in an equipment room is arranged outside the atmospheric environment simulation cabin. The aerosol generator is transported and connected to the interior of the atmospheric environment simulation cabin through underground pipelines. One end of the air supply system is installed with the air supply circulation system in the air supply system installation room, and the other end of the atmospheric environment simulation cabin is equipped with an ultra-clean room and an air shower room, and a calibration system is installed in the atmospheric environment simulation cabin. The display system, the control system, the atmospheric simulation environment cabin is provided with an air inlet at one end and an air inlet at the other end. This indoor visibility meter calibration system realizes the approximate real simulation based on the atmospheric environment, and tests the error of the visibility meter under test by measuring and comparing the transmittance of multiple points of the equipment to be tested under different visibility conditions.

Description

An Indoor Visibility Meter Calibration System

technical field

The invention relates to a visibility detection device, in particular to an indoor visibility meter calibration system.

Background technique

Visibility is one of the important meteorological factors to ensure flight safety, and it is an important basis for judging the opening or closing of airports, the take-off or landing of aircraft, and the use of visual flight or instrument flight. The accurate measurement of visibility has important practical value and research significance.

At present, almost all the large and medium-sized airports in my country use the MITRAS atmospheric transmissometer and FD12P forward scatterometer produced by the Finnish company VAISALA. The purchase price of the equipment is very expensive. Since the equipment does not have its own intellectual property rights, the maintenance and Repairs and upgrades are even more expensive. Even so, my country has a vast territory and many airports, and the atmospheric environment and atmospheric composition are very different. Different atmospheric components have a huge impact on the extinction coefficient or atmospheric transmittance. The difference in extinction coefficient or atmospheric transmittance directly affects the accuracy of visibility measuring instruments. However, the algorithms and software related to extinction coefficient inversion visibility are mastered abroad, resulting in large differences in the accuracy and reliability of the existing foreign instruments we purchased, which brought great difficulties to the actual business application of civil aviation.

The accuracy and measurement error of the visibility meter are important indicators of the visibility measurement instrument. The true visibility of the atmosphere is affected by the optical characteristics of the target, the background characteristics of the target, the uniformity of the atmosphere, and the human visual physiology. Visibility measuring instruments will be affected by different degrees of mirror pollution, temperature drift of photodetectors, discreteness of circuit parameters, stability of light source, monochromaticity of light source, length of system working time, aging of devices, etc. Influence, the accuracy and reliability of the measurement cannot meet the requirements of actual use. At present, the manufacturers of visibility instruments all over the world use their own relative reference benchmarks to evaluate the accuracy of their own products, and there is no unified inspection benchmark. Domestic civil aviation airports lack laboratory calibration equipment for regular calibration and calibration of visibility measuring instruments.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide an indoor visibility meter calibration system, which can realize the approximate real simulation based on the atmospheric environment. Compare and test the error of the visibility meter under test.

The present invention solves its technical problem and realizes through the following technical solutions:

An indoor visibility meter calibration system is characterized in that: it mainly consists of an atmospheric environment simulation cabin, an equipment room, an aerosol generation system, an air supply circulation system, an air supply system installation room, an ultra-clean room, an air shower, a calibration system, an external It consists of a display system and a control system. An aerosol generator located in the equipment room is set outside the atmospheric environment simulation cabin. The aerosol generator is connected to the interior of the atmospheric environment simulation cabin through underground pipelines, and is installed at one end of the atmospheric environment simulation cabin. The air supply circulation system located in the air supply system installation room, the ultra-clean room and the air shower room are installed at the other end of the atmospheric environment simulation cabin, the calibration system is installed in the atmospheric environment simulation cabin, and the external display system and control system are installed in the ultra-clean room. The atmospheric simulation environment cabin is provided with an air inlet at one end and an air outlet at the other end.

Moreover, the calibration system is a mobile variable baseline calibration system. The mobile variable baseline calibration system is composed of a sliding track, a laser emission unit, a sliding platform, a platform drive mechanism, a receiving end mounting plate and a control box. Install the laser emitting unit and sliding platform on the track, install the receiving end mounting plate and control box on the sliding platform, install the platform drive mechanism on the sliding platform, install the power box and PLC control unit in the control box, and install the visibility meter on the receiving end mounting plate The photoelectric receiving probe is connected to the PLC control unit through a signal transmission line, and the PLC control unit includes a wireless communication module.

Moreover, the platform driving mechanism is composed of a servo motor, a transmission mechanism and a coupling, the servo motor is installed on the upper surface of the sliding platform, and the output shaft of the servo motor extends into the lower part of the sliding platform and is controlled by the transmission mechanism and the coupling The rollers at the bottom of the sliding platform move, and this servo motor is powered by the power box inside the control box.

Moreover, the servo motor is connected and installed with a rotary encoder, the rotary encoder is connected with the PLC control unit, a group of induction sheets are installed on the sliding track at intervals, and a sensor is installed on the sliding platform.

Moreover, the atmospheric environment simulation cabin is a cabin with a square section, the section height is 1-1.5m, the width is 1.5-2m, and the length is 55-65m. It is composed of tempered glass, the installation frame is composed of columns and beams, and the side wall of the atmospheric environment simulation cabin is made of laminated tempered glass.

Moreover, a background light meter is installed in the cabin.

Moreover, a group of fans is installed in the cabin.

The advantages and beneficial effects of the present invention are:

1. This indoor visibility meter calibration system can simulate the real atmospheric environment, measure the transmittance in real time, measure the visibility corresponding to the transmittance, display the brightness of the background light, and is equipped with a data interface, which can transmit the measured data to the The external computer can display the data comparison between the calibration system and the instrument to be tested, and the measurement results obtained by the control system can be transmitted to the external display system interface for display.

2. The calibration system of the indoor visibility meter is a mobile variable baseline calibration system. The fixed-point method is used to measure the received light energy at multiple points from 0m to 50m without a distance of 1m, and the visibility value can be calculated. The measurement and calibration are carried out in the way of averaging the length of the point baseline. The more scattered the sampling points averaged according to the mathematical principle, the more accurate the value obtained, thereby improving the accuracy of the visibility measurement.

3. The indoor visibility meter calibration system realizes the approximate real simulation based on the atmospheric environment, and tests the error of the measured visibility meter by measuring and comparing the transmittance of multiple points of the equipment to be tested under different visibility conditions.

Description of drawings

Fig. 1 is the structural representation (perspective view) of the present invention;

Fig. 2 is the structural representation of the present invention;

3 is a schematic cross-sectional view of FIG. 1;

Fig. 4 is the structural representation (perspective view) of the mobile variable baseline calibration system of the present invention;

5 is a schematic structural diagram of a mobile variable baseline calibration system of the present invention;

6 is a schematic structural diagram of a sliding track of the present invention;

FIG. 7 is a block diagram of the control system of the present invention.

Description of reference numbers:

1- Air supply system installation room, 2- Equipment room, 3- Atmospheric environment simulation cabin, 4- Air shower room, 5- Ultra-clean room, 6- Air filter device, 7- Air inlet, 8- Gas mixing room, 9-Aerosol spray outlet, 10-Spoiler fan, 11-Air outlet, 12-Air filter device, 13-Sliding track, 14-Control box, 15-Photoelectric receiving probe, 16-Receiver mounting plate, 17-Sliding platform, 18-first servo motor, 19-horizontal moving seat, 20-roller, 21-coupling, 22-second servo motor, 23-induction sheet, 24-sensor.

Detailed ways

The present invention will be further described in detail below through specific embodiments, the following embodiments are only exemplary and descriptive descriptions, not restrictive words, and cannot limit the protection scope of the present invention.

An indoor visibility meter calibration system, which mainly consists of an atmospheric environment simulation cabin 3, an equipment room 2, an aerosol generation system, an air supply circulation system, an air supply system installation room 1, an ultra-clean room 5, an air shower room 4, and a calibration system. , The external display system and the control system are composed of an aerosol generator located in the equipment room outside the atmospheric environment simulation cabin. The aerosol generator is connected to the interior of the atmospheric environment simulation cabin through underground pipeline transportation. The air supply circulation system is installed in the air supply system installation room, the ultra-clean room and the air shower room are installed at the other end of the atmospheric environment simulation cabin, the calibration system is installed in the atmospheric environment simulation cabin, and the external display system is installed in the ultra-clean room. , control system, the atmospheric simulation environment cabin is provided with an air inlet at one end and an air outlet at the other end. Smoke generators can also be installed in the equipment room.

The atmospheric environment simulation cabin is a cabin with a square section, the section height is 1-1.5m, the width is 1.5-2m, and the length is 55-65m. The atmospheric environment simulation cabin is a frame structure, which is composed of a mounting frame and tempered glass. The installation frame is composed of uprights and beams, and the side walls of the atmospheric environment simulation cabin are made of laminated tempered glass. The surface is fluorocarbon sprayed (blue), the side wall is made of laminated tempered glass (thickness 6+6mm), the total area is 239.6m2, it can transmit visible and near-infrared bands, the visible band transmittance is more than 90%, and the infrared band (780nm～ 1000nm) is greater than 70%. Use fixed anchors to connect. A background light meter is installed in the cabin. A row of fans is installed at the top of the cabin.

A total of three 0.8-meter-wide openable access doors are set in the atmospheric environment simulation cabin, which are located at 3m, 38.2m, and 52.76m in the simulation cabin, and are used to enter the cabin for debugging equipment. The door frame and door lock are made of aluminum alloy, the door body is made of laminated tempered glass (thickness 6+6mm), and three door functions can be opened. The simulated cabin has a certain strength and resists a certain impact force, preventing it from being damaged by objects, strong wind damage or earthquake damage. Basic wind pressure: 0.50KN/㎡, basic snow pressure: 0.40KN/㎡.

The air inlet 7 of the atmospheric environment simulation cabin is provided with a high-efficiency air filter device 6 and an air outlet 11 is provided with a high-efficiency air filter device 12 .

The two sides of the cabin of the atmospheric environment simulation cabin are provided with air intake pipes of the air supply circulation system at intervals, and aerosol spray ports 9 are arranged on the ground and the two sides of the air intake pipes alternately inside the cabin, and the aerosol spray ports are installed with Aerosol control valve, an intake control valve is installed on the intake pipe. The aerosol inflow uses an air compressor device to mix the gas generated by the aerosol generating equipment through the gas mixing chamber 8 and then input it to the middle of the atmospheric environment simulation cabin through an underground pipeline.

10 spoiler fans 10 are installed inside the simulation cabin for continuous purging to ensure that the aerosols in the cabin air are mixed as evenly as possible. The preparation time for uniform mixing of the air flow inside the cabin is less than 30 minutes (the dust meter is tested at the front, middle and back of the simulated warehouse, and the reading difference is less than 5μg/m3 as the cut-off). The working parameters of the air compressor equipment are 3m ³ /min, and the air inlet is equipped with rain-proof louvers and medium and high-efficiency filters. The three-dimensional compressed gas nozzle uses a variable diameter bell mouth, which is connected to DN32 galvanized steel pipe, and the working parameter of the nozzle device is 0.1m3/min. Internal compressed air pipes use DN50 galvanized steel pipes and DN30 galvanized light pipes, coated with anti-rust paint. All air flow pipes are controlled by solenoid valves, which can be opened and closed remotely, which is convenient to realize various cycle work modes.

On the premise of ensuring the uniform mixing of aerosols in the cabin, the controllable range of the wind speed in the cabin is 0-5m/s, and the wind speed of 5m/s is used to remove the internal air and air-dry after water spraying inside the cabin. The exhaust port is equipped with rain-proof louvers, high-efficiency filters and electric regulating air valves.

The side end of the atmospheric simulation cabin is tightly connected with an ultra-clean room 5 . Install the external display system and control system in the clean room. The ultra-clean room adopts a fixed structure with a length of 6m, a width of 4m and a height of 3m. The air shower is 1.4m long, 1m wide and 2.1m high. Purification efficiency ≥0.3μm dust, outlet wind speed ≥25m/s, circulating air volume 2500m3/h, N=0.75kw. The monitoring room is equipped with an air-conditioning system.

The monitoring room is used to place the control PLC, industrial control PC, and system status display of the entire system. The overall working status of the system can be monitored in the monitoring room. Please refer to the drawings for the placement and wiring layout of the equipment in the monitoring room.

A camera is placed in the equipment room to monitor the working status of the aerosol equipment; one is placed outside the atmospheric simulation cabin, with the lens facing the cabin, to monitor the cabin environment, working status, and working environment.

The movement of the trolley is driven by a servo motor, and the motor is controlled by a PLC. After calculation, it is found that the transmittance of the 532nm laser per meter is about 0.14% under the condition of 2km visibility. The rate of change is in the order of one thousandth. If you want to measure the distance more precisely, it will cause a large measurement error. Therefore, an interval of 1 meter is initially planned to be measured once. The precise positioning of the trolley is realized by means of sensors and induction sheets.

The calibration system is a mobile variable baseline calibration system, which consists of a sliding track 13, a laser emission unit (omitted in the figure), a sliding platform 17, a platform drive mechanism, a receiving end mounting plate 16 and a control box 14. The structure is as follows: install the laser emitting unit and the sliding platform on the sliding track, install the receiving end mounting plate and the control box on the sliding platform, install the platform driving mechanism on the sliding platform, install the power supply box and the PLC control unit in the control box, and install the board on the receiving end. The photoelectric receiving probe 15 of the visibility meter is installed on it, and the photoelectric receiving probe is connected to the PLC control unit through a signal transmission line. The PLC control unit includes a wireless communication module.

The platform driving mechanism is composed of a longitudinal first servo motor 18, a transmission mechanism and a coupling 21. The first servo motor is installed on the upper surface of the sliding platform, and the output shaft of the first servo motor extends into the lower part of the sliding platform and passes through the transmission mechanism. And the coupling controls the movement of the roller 20 at the bottom of the sliding platform, and the first servo motor is powered by the power supply box in the control box. The first servo motor is connected and installed with a rotary encoder, and the rotary encoder is connected with the PLC control unit, so as to realize the movement accuracy along the direction of the sliding track. The receiving end mounting plate is mounted on the sliding platform through a horizontal moving seat 19, and the horizontal moving seat is driven by a horizontally mounted second servo motor 22 through a screw drive system to achieve horizontal fine adjustment. The second servo motor installed horizontally is connected with a rotary encoder, and the rotary encoder is connected with the PLC control unit. In order to achieve precise adjustment of the horizontal position of the receiving end mounting plate.

A rotary encoder is connected to the first servo motor, and the rotary encoder is connected to the PLC control unit. A group of induction sheets 23 are installed on the sliding track at intervals, and a sensor 24 is installed on the sliding platform. The induction piece adopts permanent magnet material induction piece, and the sensor adopts the proximity magnetic sensor.

A communication system is set up on the trolley to ensure stable and effective signal transmission, which can meet the transmission requirements of the trolley's measurement data. The walking distance of 50 meters is long, and it also needs to have high-precision invariance of up, down, left and right, so the communication on the car is wireless, and the power of each device is realized by battery. In wireless communication, select the wireless network card to connect to the fanless computer to realize the connection between the experimental data and the computer in the operating room. The specific method used is a small fanless computer to control the lock-in amplifier, chopper, motion control of the car, wireless network connection and data transmission, data processing and application operation, etc. The wireless network card uses TP-LINK,

The whole system adopts PLC as the main control mode and industrial PC as the auxiliary control method.

The control system and its display are placed in the clean room, and the control system can perform the following functions:

Control the occurrence, mixing and emission of aerosols, and can accurately control the type, amount and speed of aerosol emission. Control the trolley to move freely on the slide rail, and the moving distance can be precisely controlled.

Control and clean the drainage system to clean the system.

The display of the control software includes:

The visibility and RVR of the instrument to be tested, and the transmittance given by the manufacturer of the instrument to be tested.

The calibration system measures the visibility and RVR, and the transmittance of the measurement point of the calibration system.

Compare the RVR, visibility, and transmittance errors of the instrument under test and the calibration system, and integrate the measurement curves of various visibility.

The type of aerosol injected into the current cabin, the amount and speed of injected aerosol, and the uniformity of injected aerosol.

It can measure the transmittance in real time, measure the visibility corresponding to the transmittance, display the brightness of the background light, and is equipped with a data interface, which can transmit the measured data to an external computer. It can display the data comparison between the calibration system and the instrument under test. The measurement results obtained by the control system can be transmitted to the external display system interface for display.

The working principle and method of the indoor visibility meter calibration system are as follows:

1. Consistency calibration

(1) Place the three calibration instruments in the cabin, and mark them as the instrument to be tested 1, the instrument to be tested 2, and the instrument to be tested 3, and aerosols are injected into the cabin. Since the calibrated visibility is the low visibility condition below 1000m, the visibility is divided into 6 parts: 0m～100m, 100m～250m, 250m～400m, 400m～650m, 650m～800m, 800m～1000m;

(2) Turn on the instrument under test 1, when the visibility of the instrument under test 1 is displayed as 800m-1000m, stop injecting gas, and measure the visibility display value of the instrument under test 1 at this time as V ₁ ;

(3) Close the instrument under test 1, open the instrument under test 2, and measure the visibility display value of the instrument under test 2 at this time as V ₂ ;

(4) Turn off the instrument under test 2, open the instrument under test 3, and measure the visibility display value of the instrument under test 3 at this time as V ₃ ;

⑸ According to the consistency measurement formula, obtain:

ΔV ₁ =V ₁ -V _m (2)

ΔV ₂ =V ₂ -V _m (3)

ΔV ₃ =V ₃ -V _m (4)

According to the requirements of ICAO for visibility error, ΔV ₁ ′, ΔV ₂ ′, ΔV ₃ ′ need to be less than 10%.

2. Accuracy calibration

Option One:

(1) Put the calibrated instrument in the cabin, and inject aerosol into the cabin. Since the calibrated visibility is the low visibility condition below 1000m, the visibility is divided into 6 parts: 0m～100m, 100m～250m, 250m～400m, 400m～650m, 650m～800m, 800m～1000m.

(2) When the visibility of the instrument to be calibrated is displayed as 800m ~ 1000m, stop injecting gas. At this time, the MOR value measured by the instrument manufacturer through the visibility instrument to be calibrated is deduced. 24m, 26m, 29m, 32m, 35m, 39m, 43m, Optical transmittance T at 48m and 53m (see Table 1). The measured MOR values were averaged over 1 min as a standard.

(3) Turn off the instrument to be tested, use the 532nm LD light source transmitter as the emission source, and measure the optical transmission at 24m, 26m, 29m, 32m, 35m, 39m, 43m, 48m, 53m with an accurate light intensity measuring device through the sliding track rate T′, according to the standard specified by the experimental platform, compare the push-down value of the instrument manufacturer with the experimental measurement value, and all points are required to satisfy the formula

Among them, T' represents the accurately calibrated transmittance value, and T represents the transmittance reversely deduced by the instrument under test.

⑷Inject gas into the cabin until the concentration is 650m～800m, repeat the process of 1～3, and so on, to obtain multiple atmospheric visibility (0m～100m, 100m～250m, 250m～400m, 400m～650m, 650m～ 800m, 800m～1000m) The comparison results of the visibility of the instrument to be tested and the calibration device are shown in Table 2.

Table 1 Transmittance result table of the instrument to be tested

24m 26m 29m 32m 35m 39m 43m 48m 53m 0m～100m 100m～250m 250m～400m 400m～650m 650m～800m 800m～1000m

The T in Table 1 has a total of 54 points, corresponding to the 54 points of T'. When all of them satisfy the formula 8, the visibility meter meets the requirements of the calibration test.

Option 2: Visibility calibration of sliding track of atmospheric simulation cabin

(1) Put the calibrated instrument in the cabin, and inject aerosol into the cabin. Since the calibrated visibility is the low visibility condition below 1000m, the visibility is divided into 6 parts: 0m～100m, 100m～250m, 250m～400m, 400m～650m, 650m～800m, 800m～1000m.

(2) When the visibility of the instrument to be calibrated is displayed as 800m~1000m, read the visibility value V' of the instrument to be calibrated, use the 532nm LD light source transmitter as the emission source, and use an accurate light intensity measuring device to measure the distance L ₁ through the slidable track ,L ₂ ,..., _{L i} ,..., _{L N (} wherein L _{1 ≤L 2 ≤} ... The extinction coefficient σ _i is calculated from the excess rate:

Weighted average of multiple extinction coefficients to calculate the most accurate extinction coefficient

Finally, the visibility value of the calibration system is calculated:

(3) Inject gas into the cabin until the concentration is 650m~800m, repeat the process of 1~2, and so on, to obtain multiple atmospheric visibility (0m~100m, 100m~250m, 250m~400m, 400m~650m, 650m~ 800m, 800m～1000m) The comparison results of the visibility between the instrument to be tested and the calibration device are shown in Table 2.

Table 2 Visibility comparison table between the instrument to be tested and the calibration device

0m～100m 100m～250m 250m～400m 400m～650m Instrument to be tested Calibration system 650m～800m 800m～1000m Instrument to be tested Calibration system

It is required that the error must be less than 10% under each condition.

third solution:

(1) Put the calibrated instrument in the cabin, and inject aerosol into the cabin. Since the calibrated visibility is the low visibility condition below 1000m, the visibility is divided into 6 parts: 0m～100m, 100m～250m, 250m～400m, 400m～650m, 650m～800m, 800m～1000m.

(2) When the visibility of the instrument to be calibrated is displayed as 800m~1000m, read the visibility value V' of the instrument to be calibrated, use the 532nm LD light source transmitter as the emission source, and use an accurate light intensity measuring device to measure the distance L ₁ through the slidable track ,L ₂ ,..., _{L i} ,..., _{L N (} wherein L _{1 ≤L 2 ≤} ... The extinction coefficient σ _i is calculated from the excess rate:

Then calculate N visibility values:

Calculate the N relative error values of multiple visibility between the instrument under test and the calibration system under this visibility:

(3) Inject gas into the cabin until the concentration is 650m~800m, repeat the process of 1~2, and so on, to obtain multiple atmospheric visibility (0m~100m, 100m~250m, 250m~400m, 400m~650m, 650m~ 800m, 800m～1000m) The comparison results of the visibility between the instrument to be tested and the calibration device are shown in Table 3.

Table 3 Visibility comparison table between the instrument to be tested and the calibration device

In Table 3, it is required that 60% of each row (calculated by taking the atmospheric projector 30m baseline as the standard) have values less than 10%.

Option 4: Fixed point projector calibration

Install a fixed throw rate calibration device next to the sliding track to calculate the visibility value.

(1) Place the calibrated instrument in the cabin, and inject aerosol into the cabin. Since the calibrated visibility is the low visibility condition below 1000m, the visibility is divided into 6 parts: 0m～100m, 100m～250m, 250m～400m, 400m～650m, 650m～800m, 800m～1000m.

(2) When the visibility of the instrument to be calibrated is displayed as 800m ~ 1000m, read the visibility value V' of the instrument to be calibrated, use the 532nm LD light source transmitter as the emission source, and measure the transmittance of the calibration system at 30m from the fixed point. The transmittance directly calculates the visibility V of the calibration system, and the calculation represents the error Δ between the calibration visibility meter and the calibration system.

(3) Inject gas into the cabin until the concentration is 650m~800m, repeat the process of 1~2, and so on, to obtain multiple atmospheric visibility (0m~100m, 100m~250m, 250m~400m, 400m~650m, 650m~ 800m, 800m～1000m) The comparison results of the visibility between the instrument to be tested and the calibration device are shown in Table 4.

Table 4 Visibility comparison table between the instrument to be tested and the calibration device

visibility level Δ 0m～100m 100m～250m 250m～400m 400m～650m 650m～800 800m～1000m

Each Δ is required to be less than 10%.

Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims (7)

1. an indoor visibility meter calibration system, it is characterized in that: by atmospheric environment simulation cabin, equipment room, aerosol generation system, air supply circulation system, air supply system installation room, ultra-clean room, calibration system, external display system and The control system consists of an aerosol generator located in the equipment room outside the atmospheric environment simulation cabin. The aerosol generator is connected to the interior of the atmospheric environment simulation cabin through underground pipelines, and is installed at one end of the atmospheric environment simulation cabin. The air supply circulation system in the system installation room, the ultra-clean room is installed at the other end of the atmospheric environment simulation cabin, the calibration system is installed in the atmospheric environment simulation cabin, the external display system and control system are installed in the ultra-clean room, and one end of the atmospheric simulation environment cabin is installed is provided with an air inlet and the other end is provided with an air outlet; The calibration system is a mobile variable baseline calibration system, which is composed of a sliding track, a laser emission unit, a sliding platform, a platform drive mechanism, a receiving end mounting plate and a control box. Install the laser emitting unit and the sliding platform, install the receiving end mounting plate and the control box on the sliding platform, install the platform drive mechanism on the sliding platform, install the power box and PLC control unit in the control box, and install the photoelectricity of the visibility meter on the receiving end mounting plate. A receiving probe, the photoelectric receiving probe is connected to a PLC control unit through a signal transmission line, and the PLC control unit includes a wireless communication module. 2 . The indoor visibility meter calibration system according to claim 1 , wherein 2-4 air showers are arranged at intervals in the atmospheric environment simulation cabin, and an air shower is arranged in the ultra-clean room. 3 . 3. The indoor visibility meter calibration system according to claim 1, wherein the platform drive mechanism is composed of a first servo motor, a transmission mechanism and a coupling, and the first servo motor is installed on the upper surface of the sliding platform, The output shaft of the first servo motor extends into the lower part of the sliding platform and controls the movement of the rollers at the bottom of the sliding platform through the transmission mechanism and the coupling. The first servo motor is powered by the power box in the control box. 4. The indoor visibility meter calibration system according to claim 3, characterized in that: the first servo motor is connected to install a rotary encoder, the rotary encoder is connected with the PLC control unit, and a sliding track is also installed at intervals. A group of induction sheets is installed with sensors on the sliding platform. 5. The indoor visibility meter calibration system according to claim 1, wherein the atmospheric environment simulation cabin is a cabin with a square section, the section height is 1-1.5m, the width is 1.5-2m, and the length is 1-1.5m. It is 55-65m long. The atmospheric environment simulation cabin is a frame structure, which is composed of installation frame and tempered glass. The installation frame is composed of columns and beams. The side wall of the atmospheric environment simulation cabin is made of laminated tempered glass. 6 . The indoor visibility meter calibration system according to claim 5 , wherein a background light meter is installed in the cabin. 7 . 7 . The indoor visibility meter calibration system according to claim 5 , wherein a group of fans is installed in the cabin. 8 .

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