CN112730342A - Transmission-type visibility standard ware measurement system - Google Patents

Transmission-type visibility standard ware measurement system Download PDF

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Publication number
CN112730342A
CN112730342A CN202011525467.XA CN202011525467A CN112730342A CN 112730342 A CN112730342 A CN 112730342A CN 202011525467 A CN202011525467 A CN 202011525467A CN 112730342 A CN112730342 A CN 112730342A
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laser
power meter
microcontroller
power
receiving end
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CN112730342B (en
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朱海博
郝云霞
陈静
李金凤
王喜宝
马剑哲
曹志鹏
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Zhonghuan Tig Tianjin Meteorological Instruments Co ltd
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Zhonghuan Tig Tianjin Meteorological Instruments Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
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Abstract

The invention discloses a transmission-type visibility standard measuring system. The standard device measuring system comprises a transmitting end, a receiving end, a testing end and a PC; the transmitting end comprises a laser, a spectroscope, a first power meter, a beam expander, a first control circuit and a cooperative reflecting surface. The receiving end comprises a converging mirror, a second power meter, a distance meter and a second control circuit. The test end comprises a calibration power meter and an attenuation piece black box. In order to solve the problem of visibility measuring equipment traceability, the attenuation sheet is introduced into a calibration system, and the attenuation sheet-transmittance-visibility corresponding relation is established. Therefore, the invention can provide a high-precision tracing basis for scattering visibility equipment in the meteorological field and solve the problem that the relevant visibility equipment assessment standards in China are not uniform.

Description

Transmission-type visibility standard ware measurement system
Technical Field
The invention relates to a scattering type/transmission type visibility measuring instrument used at home and abroad, in particular to a transmission type visibility standard instrument measuring system.
Background
The equipment for weather and airport visibility measurement mainly comprises transmission type and scattering type visibility equipment. The transmission type visibility equipment derives the visibility by measuring the air transmission rate with fixed length. The scattering type visibility equipment inverts the visibility by measuring an extinction coefficient of a local sampling space, and the scattering type visibility equipment calculates the visibility value and establishes the visibility value on the premise of three assumptions: (1) the atmosphere is assumed to be homogeneous; (2) the scattering, absorption and internal interaction optical effects of the molecules are assumed to be 0; (3) the scattered light intensity is assumed to be proportional to the scattering coefficient. The scattering type visibility equipment is small in size and convenient to install, but is greatly influenced by particles such as sunlight noise, sand and dust, the accuracy and the consistency among different products are poor, as shown in fig. 1, the observation values of the scattering type visibility equipment produced by different manufacturers in the same atmospheric environment are different, and the fundamental reason is that the observation values of the visibility equipment of different models are greatly different due to the fact that no unified traceability standard exists. There is a need for a high-precision visibility device to calibrate these scattering visibility devices with observation differences, so as to determine the applicability of different scattering visibility devices in different atmospheric environments.
Transmission-type visibility equipment is the visibility measuring equipment of earlier utility model, though bulky, but more stable and accurate than scattering-type visibility equipment, is used widely in the automatic observation system's of visibility RVR measurement in airport. Although the transmission type visibility equipment has better observation performance than the scattering type visibility equipment, in practical application, the transmission type visibility equipment also has the problem of observation difference of different models caused by non-uniform traceability standards. In addition, the transmission-type visibility equipment in the market at present is generally a long baseline of 30 meters, 50 meters or even 100 meters, and the long baseline is easy to increase errors in the observation process, reduces the measurement accuracy of the transmission-type visibility equipment, and cannot reach the high-accuracy measurement standard of traceability calibration.
Disclosure of Invention
Aiming at the prior art situation, the invention designs a transmission-type visibility standard device measuring system, namely, a visibility transmission device with a short baseline and high-precision measurement is designed to solve the problem of the difference of observed values of scattering-type/transmission-type visibility devices caused by inconsistent calibration standards of different manufacturers; the applicability problem of scattering type/transmission type visibility equipment is solved under different determined atmospheric environments.
The technical scheme adopted by the invention is as follows: a transmissive visibility standard measurement system, characterized by: the system comprises a transmitting end, a receiving end, a testing end and a PC; the transmitting end comprises a laser, a spectroscope, a first power meter, a beam expander, a first control circuit and a cooperative reflecting surface; wherein the first control circuit is respectively connected with the laser and the first power meter and used for emitting laser power PtMeasuring, wherein a first control circuit is connected to a PC through a serial port UART1T for transmitting end data communication; laser emitted by the laser is divided into two paths by the spectroscope and respectively enters the first power meter and the beam expander, so that the laser power P emitted by the emitting end is realizedtMeasuring; the receiving end comprises a converging lens, a second power meter, a distance meter and a second control circuit; wherein the second control circuit is respectively connected with the distance meter and the second power meter and is respectively used for measuring the length of the base line of the standard device and the incident laser power P of the receiving endrMeasuring, wherein the second control circuit is connected to a PC through a serial port UART1R for receiving end data communication; the converging mirror converges the received laser to the second power meter, so as to realize the incident laser power P of the receiving endrMeasuring; the receiving end is fixed on a three-dimensional adjusting frame and used for accurately adjusting the posture of the receiving end and aligning the view fields of the transmitting end and the receiving end; the base length of the etalon is 10cm and 10 m.
When the power meter is calibrated, the testing end of the standard is positioned between the beam expanding lens at the transmitting end of the standard and the converging lens at the receiving end of the standard, wherein a calibration power meter is arranged at the testing end and is connected to a PC (personal computer) to realize the calibration of the power meter at the transmitting end and the receiving end and the transmittance measurement of an optical system; the length of the base line of the standard is adjusted to 10 cm.
When the transmissivity is calibrated, the testing end of the standard device is arranged between the emission end of the standard device and the receiving end of the standard device, wherein the testing end is provided with an attenuation sheet black box; the end surface of the attenuation piece black box is provided with an attenuation piece hole site, and the left side and the right side are respectively provided with a light inlet and a light outlet; the optical axes of the light inlet and the light outlet of the black box of the attenuation sheet, the beam expanding lens at the transmitting end of the standard device and the converging lens at the receiving end of the standard device are on the same horizontal plane; the base length of the system was adjusted to 10 cm.
When the visibility tracing is carried out, the testing end of the standard device is arranged between the beam expander at the transmitting end of the standard device and the converging lens at the receiving end of the standard device, wherein aerosol with different transmittances is injected into the testing end; the base length of the system was adjusted to 10 m.
The first control circuit comprises a thermistor RT1, a thermistor RT2, a first operational amplifier, a first analog-digital converter, a first microcontroller, a first square wave driving unit and a first power supply circuit; the thermistor RT1 and the thermistor RT2 are respectively connected with the first operational amplifier and are used for converting the detected laser temperature and the emission end environment temperature into voltage; the first operational amplifier is connected with the first analog-digital converter and used for converting the voltage into digital codes; the first analog-digital converter is connected with the first microcontroller and is used for sending the digital codes into the first microcontroller; the first microcontroller is connected with the PC through a serial port UART1T, receives a control command of the PC, and respectively forwards the control command to the laser and the first power meter through serial ports UART2T and UART 3T; the first microcontroller receives the query results of the laser and the first power meter through the serial port UART2T and the serial port UART3T respectively and forwards the query results to the PC through the serial port UART 1T; the first microcontroller is connected with the external fan through a first square wave driving unit, and the first square wave driving unit is a power amplification circuit and is used for receiving a square wave signal input by the first microcontroller and amplifying the power of the square wave signal to drive the external fan so as to cool the system.
The second control circuit comprises a thermistor RT3, a thermistor RT4, a second operational amplifier, a second analog-digital converter, a second microcontroller, a second square wave driving unit and a second power supply circuit; the thermistor RT3 and the thermistor RT4 are respectively connected with the second operational amplifier and are used for converting the detected temperature of the convergent lens and the ambient temperature of the receiving end into voltage; the second operational amplifier is connected with the second analog-digital converter and used for converting the voltage into digital codes; the second analog-digital converter is connected with the second microcontroller and is used for sending the digital codes into the second microcontroller; the second microcontroller is connected with the PC through a serial port UART1R, receives a control command of the PC, and forwards the control command to the distance meter and the second power meter through serial ports UART2R and UART3R respectively; the second microcontroller receives the query results of the distance meter and the second power meter through the serial port UART2R and the serial port UART3R respectively and forwards the query results to the PC through the serial port UART 1R; the second microcontroller is connected with the external fan through a second square wave driving unit, and the second square wave driving unit is a power amplification circuit and is used for receiving a square wave signal input by the second microcontroller and amplifying the power of the square wave signal to drive the external fan so as to cool the system.
The invention has the following beneficial effects: the invention introduces the attenuation sheet into a calibration system, establishes the attenuation sheet-transmissivity-visibility corresponding relation, provides a transmission type visibility measurement system based on attenuation sheet traceability, and effectively solves the problem that visibility measurement equipment cannot be traceable. The device has the advantages of high precision, good stability, long-time continuous measurement, convenience in calibration and the like.
Drawings
FIG. 1 is a schematic diagram showing differences in observed values of scattering type visibility devices from different manufacturers;
FIG. 2 is a schematic diagram of the system of the present invention;
FIG. 3 is a schematic diagram of an internal structure of the first control circuit shown in FIG. 2;
FIG. 4 is a schematic diagram of an internal structure of the second control circuit shown in FIG. 2;
FIG. 5 is a schematic diagram of the black box structure of the attenuation sheet of the present invention;
FIG. 6 is a schematic diagram of the power meter calibration principle of the present invention;
FIG. 7 is a schematic diagram of the transmittance calibration principle of the present invention;
fig. 8 is a schematic diagram illustrating visibility traceability principle of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
As shown in fig. 1, the observation values of scattering type visibility devices produced by different manufacturers in the same atmospheric environment are different. This is because the measurement principle of a scattering visibility device is: the visibility is inverted by measuring the extinction coefficient of a local sampling space, and the principle is established under the following assumptions: (1) the atmosphere is assumed to be homogeneous; (2) the scattering, absorption and internal interaction optical effects of the molecules are assumed to be 0; (3) the scattered light intensity is assumed to be proportional to the scattering coefficient. This results in scattering-type visibility equipment that is greatly affected by particulate matter such as sun noise, sand and dust, and the accuracy and consistency between different products are poor.
As shown in fig. 2, the etalon measuring system includes a transmitting terminal, a receiving terminal, a testing terminal and a PC; the transmitting end comprises a laser, a spectroscope, a first power meter, a beam expander, a first control circuit and a cooperative reflecting surface; wherein the first control circuit is respectively connected with the laser and the first power meter and used for emitting laser power PtMeasuring, wherein a first control circuit is connected to a PC through a serial port UART1T for transmitting end data communication; laser emitted by the laser is divided into two paths by the spectroscope and respectively enters the first power meter and the beam expander, so that the laser power P emitted by the emitting end is realizedtMeasuring; the receiving end comprises a converging lens, a second power meter, a distance meter and a second control circuit; wherein the second control circuit is respectively connected with the distance meter and the second power meter and is respectively used for measuring the length of the base line of the standard device and the incident laser power P of the receiving endrMeasuring, wherein the second control circuit is connected to a PC through a serial port UART1R for receiving end data communication; the converging mirror converges the received laser to the second power meter, so as to realize the incident laser power P of the receiving endrMeasuring; the receiving end is fixed on a three-dimensional adjusting frame and used for accurately adjusting the posture of the receiving end and aligning the view fields of the transmitting end and the receiving end; base line length adjustment of the etalon10cm and 10 m.
As shown in fig. 3, the first control circuit includes a thermistor RT1 and a thermistor RT2, a first operational amplifier, a first analog-to-digital converter, a first microcontroller, a first square wave driving unit, and a first power supply circuit; the thermistor RT1 and the thermistor RT2 are respectively connected with the first operational amplifier and are used for converting the detected laser temperature and the emission end environment temperature into voltage; the first operational amplifier is connected with the first analog-digital converter and used for converting the voltage into digital codes; the first analog-digital converter is connected with the first microcontroller and is used for sending the digital codes into the first microcontroller; the first microcontroller is connected with the PC through a serial port UART1T, receives a control command of the PC, and respectively forwards the control command to the laser and the first power meter through serial ports UART2T and UART 3T; the first microcontroller receives the query results of the laser and the first power meter through the serial port UART2T and the serial port UART3T respectively and forwards the query results to the PC through the serial port UART 1T; the first microcontroller is connected with the external fan through a first square wave driving unit, and the first square wave driving unit is a power amplification circuit and is used for receiving a square wave signal input by the first microcontroller and amplifying the power of the square wave signal to drive the external fan so as to cool the system.
As shown in fig. 4, the second control circuit includes a thermistor RT3 and a thermistor RT4, a second operational amplifier, a second analog-digital converter, a second microcontroller, a second square wave driving unit, and a second power supply circuit; the thermistor RT3 and the thermistor RT4 are respectively connected with the second operational amplifier and are used for converting the detected temperature of the convergent lens and the ambient temperature of the receiving end into voltage; the second operational amplifier is connected with the second analog-digital converter and used for converting the voltage into digital codes; the second analog-digital converter is connected with the second microcontroller and is used for sending the digital codes into the second microcontroller; the second microcontroller is connected with the PC through a serial port UART1R, receives a control command of the PC, and forwards the control command to the distance meter and the second power meter through serial ports UART2R and UART3R respectively; the second microcontroller receives the query results of the distance meter and the second power meter through the serial port UART2R and the serial port UART3R respectively and forwards the query results to the PC through the serial port UART 1R; the second microcontroller is connected with the external fan through a second square wave driving unit, and the second square wave driving unit is a power amplification circuit and is used for receiving a square wave signal input by the second microcontroller and amplifying the power of the square wave signal to drive the external fan so as to cool the system.
As shown in fig. 6, during calibration of the power meter, the testing end of the etalon is located between the beam expander at the transmitting end of the etalon and the converging lens at the receiving end of the etalon, wherein a calibration power meter is placed at the testing end, and the calibration power meter is connected to the PC to realize calibration of the power meter at the transmitting end and the receiving end and measurement of transmittance of the optical system; the length of the base line of the standard is adjusted to 10 cm.
As shown in fig. 5 and 7, when the transmittance calibration is performed, the testing end of the etalon is arranged between the emission end of the etalon and the receiving end of the etalon, wherein the testing end is provided with an attenuation plate black box; the end surface of the attenuation piece black box is provided with an attenuation piece hole site 1, and the left side and the right side are respectively provided with a light inlet 2 and a light outlet 3; the optical axes of the light inlet and the light outlet of the black box of the attenuation sheet, the beam expanding lens at the transmitting end of the standard device and the converging lens at the receiving end of the standard device are on the same horizontal plane; the base length of the system was adjusted to 10 cm.
As shown in fig. 8, when visibility tracing is performed, the testing end of the etalon is located between the beam expander at the transmitting end of the etalon and the converging lens at the receiving end of the etalon, wherein aerosol with different transmittances is injected into the testing end; the base length of the system was adjusted to 10 m.
The design principle and the function of the standard device are as follows:
1. transmitting terminal of standard device
As shown in fig. 2, the transmitting end of the etalon is divided into two parts, namely an optical path and an electric circuit.
The work flow of the optical path part is as follows:
the laser is a system light source, the working wavelength is 532nm, the line width is less than 1nm, and continuous laser can be emitted. The 532nm laser enters the spectroscope and is divided into two parts by the spectroscope. Because the splitting ratio of the spectroscope is 1 to tau0The power ratio of the 532nm laser is
Figure BDA0002850653050000051
The laser enters a first power meter at the transmitting end of the standard device, and the first power meter gives a measured value P of the laser power of the parttm. The first power meter is an average power meter for measuring continuous laser, can detect 532nm laser, has a maximum power measurement value of more than or equal to 100mW, and is manufactured by company of Ophir, NewPort, Coherent and the like. Another part of the power is in proportion
Figure BDA0002850653050000052
The laser enters the beam expander, and the laser emergent power of the emitting end which is emitted to the air after passing through the beam expander is Pt. The beam expander is used for compressing the part of the laser visual field into parallel light with the diameter less than or equal to 1 mrad. Due to the transmittance tau of the beam expandertLess than 1, it is necessary to measure the beam expander transmittance τ using a calibrated power metertThe exact numerical value of (c).
If the laser is a pulse laser, all power meters in the standard device adopt pulse function meters, and the related power measurement result is the energy test result of the pulse laser.
The function of the cooperative reflecting surface of the transmitting end of the standard is as follows: 1) reflecting ranging laser emitted by a range finder at the receiving end of the standard device to assist the range finder in measuring the accurate baseline length; 2) when the base length is 10m, it serves as a reference for rough alignment of the transmission and reception optical axes.
The partial working flow of the transmitting end circuit is as follows:
the PC machine sends a control command to the first control circuit through the serial port UART1T, the first control circuit identifies whether the command belongs to the laser or the first power meter, and forwards the command to the laser through the serial port UART2T and forwards the command to the first power meter through the serial port UART 3T; after the laser or the first power meter identifies the control command, the execution result is sent to the first control circuit through the serial port UART2T or the serial port UART3T, and the first control circuit forwards the query result to the PC through the serial port UART 1T. The PC sends a query command to the first control circuit through the serial port UART1T, and the first control circuit identification command is forwarded to the first power meter through the serial port UART 3T; after the first power meter identifies the query command, the query result is sent to the first control circuit through the serial port UART3T, and the first control circuit forwards the query result to the PC through the serial port UART 1T.
2. Receiving end of standard device
As shown in fig. 2, the receiving end of the etalon is divided into three parts, namely an optical path, a circuit and a structure.
The work flow of the optical path part is as follows:
laser power PtA transmittance through the film of taumAerosol or transmission rate tauaAfter the attenuation sheet, the power is reduced and becomes P before reaching the receiving end and the converging lensr，PrThe laser power is incident to the receiving end. PrA transmittance through the film of taurThe convergent lens is measured by a second power meter at the receiving end to obtain a power measurement value Prm. The distance meter emits 633nm sine wave laser which irradiates on the cooperative reflection surface of the emitting end, the cooperative reflection surface reflects the sine wave laser, and the reflected sine wave laser enters the inside of the distance meter again. The distance measuring instrument completes the measurement of the flight time of the sine wave laser and calculates the accurate length values of the base lines of the transmitting end and the receiving end of the system.
The circuit part work flow is as follows:
the PC machine sends a control command to the second control circuit through the serial port UART1R, the second control circuit identifies whether the command belongs to the laser or the power meter, and forwards the command to the distance meter through the UART2R and forwards the command to the second power meter through the serial port UART 3R; after the range finder or the second power meter identifies the control command, the execution result is sent to the second control circuit through the serial port UART2R or the serial port UART3R, and the second control circuit forwards the query result to the PC through the serial port UART 1R. The PC sends a query command to the second control circuit through the serial port UART1R, the second control circuit identifies whether the command belongs to the range finder or the power meter, the command is forwarded to the range finder through the serial port UART2R, and the command is forwarded to the second power meter through the serial port UART 3R; after the distance measuring instrument or the second power meter identifies the query command, the query result is sent to the second control circuit through the serial port UART2R or the serial port UART3R, and the second control circuit forwards the query result to the PC through the serial port UART 1R.
The workflow of the structural part is as follows:
when the length of the system base line is 10cm or 10m, the three-dimensional adjusting frame is adjusted, so that the optical axis of the transmitting end and the optical axis of the receiving end can be accurately aligned, and the numerical value displayed by the second power meter of the receiving end is the largest.
3. Calibrating a power meter
As shown in fig. 6, the etalon calibrates the power meters of the transmitting end and the receiving end using the calibration power meters. The testing end is arranged between the beam expanding lens of the transmitting end of the standard device and the converging lens of the receiving end of the standard device, a calibration power meter is arranged at the testing end at the moment, and the laser power P emitted by the transmitting end in the graph 6 is measuredt1And Pt2. The PC sends a control command to the calibration power meter through a serial port UART 4; the calibration power meter receives the control command and configures the parameters of the calibration power meter. The PC sends a query command to the calibration power meter through the serial port UART 4; after receiving the query command, the calibration power meter sends the query result to the PC through the serial port UART 4.
4. Control circuit
As shown in fig. 3 and 4, the first and second control circuits are substantially the same. A thermistor RT1 of the first control circuit is attached to the laser meter body and used for detecting the temperature of the laser; a thermistor RT2 is attached to the structural member body for detecting the system operating environment temperature. A thermistor RT3 of the second control circuit is attached in the receiving end convergent lens and used for detecting the temperature of the convergent lens; a thermistor RT4 is attached to the structural member body for detecting the system operating environment temperature. The thermistor RT1, the thermistor RT2, the thermistor RT3 and the thermistor RT4 are required to meet the requirements that the precision is less than or equal to 0.5 ℃ and the application range is-45 ℃ to +85 ℃.
The microcontroller has two functions: serial port communication and temperature detection, and the model is STM32F103RCT 6.
1) The microcontroller is connected and communicated with the outside through the serial port UART1, the serial port UART2 and the serial port UART3 to forward related information.
2) The microcontroller receives the data of the analog-digital converter and respectively calculates the temperatures of the thermistor RT1, the thermistor RT2, the thermistor RT3 and the thermistor RT 4. If heat-sensitive electricityWhen the temperature of the laser at the transmitting end of the resistor RT1 exceeds a specified threshold value, the fan is started through the first square wave driving unit to dissipate heat of the laser. The temperature data of the thermistor RT3 on the collecting lens input by the second analog-digital converter is reported to the PC through the serial port UART 1R. After receiving the temperature data, the PC compensates the transmittance tau of the convergent lens at the receiving end due to the temperature changerThe influence of (c). If the system working environment temperatures of the transmitting end and the receiving end on the thermistor RT2 and the thermistor RT4 exceed the specified value, the user is reminded to start the air conditioner and adjust the system working temperature. The square wave driving unit is a power amplifying circuit. The micro-controller receives a square wave signal input by the micro-controller, and amplifies the power of the square wave signal to drive an external fan to cool the system.
The power supply circuit receives 12V power supply input from the outside, and converts the 12V power supply into 5V power supply and 3.3V power supply for each chip of the control circuit.
5. Attenuation sheet
The attenuation sheet is placed in the attenuation sheet placing hole 1 in fig. 5. The testing end is arranged between the beam expander at the transmitting end of the standard device and the converging lens at the receiving end of the standard device, and the black box of the attenuation sheet is arranged at the testing end, as shown in fig. 7. When emitting light P from the emitting endt3After entering the black box of the attenuation sheet through the light inlet, the laser beam passes through the attenuation sheet, the power drop is reduced, the laser beam is output through the light outlet 3 and finally reaches the front of the receiving end convergent lens in the figure 7, and the incident laser power P of the receiving endr3. When the attenuation sheet is delivered from a factory, the manufacturer measures its transmittance tauaIn the invention, tau is usedaAs a true value. Putting attenuators with different transmittances into the black box of the attenuator to establish a true value tau of the transmittanceaAnd the system transmittance measurement τ of FIG. 7mThe corresponding relationship of (1).
6. Aerosol and method of making
When the etalon normally works, the testing end is between the beam expander at the transmitting end of the etalon and the converging lens at the receiving end of the etalon, wherein aerosol with different transmittances is injected into the testing end, as shown in fig. 8. By measuring the transmittance tau of the aerosolmThe visibility of the aerosol can be deduced, thereby establishing a true value τ of the transmittanceaTransmittance of aerosolMeasured value τmAnd aerosol visibility RVThe plastic source relationship of (1).
7. PC machine
The PC sends a control command and an inquiry command to the transmitting terminal through a serial port UART 1T; sending a control command and a query command to a receiving end through UART 1R; control commands and inquiry commands are sent to the calibration power meter through UART 4. The PC calculates corresponding transmittance according to the measurement results of the power meters of the receiving transmitting end and the receiving end, and calculates visibility R according to a formula (1)V。
The etalon use method is as follows:
when the following using method is implemented, the PC is placed outside the aerosol bin, so that a user can conveniently operate and observe a measurement result; the remainder of the standard, is located inside the aerosol chamber.
(1) Power meter calibration
The standard is calibrated and calibrated before each operation because different power meters of the same model have certain inherent errors. Thus, if two power meters are aligned with the same power meter, as shown in FIG. 6, the errors inherent in their measurement of the same beam of light are eliminated.
During calibration, the baseline is firstly adjusted to be 10cm, the optical axes of the transmitting end and the receiving end are aligned, the testing environment is ensured to be dark, and the visibility in the aerosol bin is more than 10 km. When the laser in FIG. 6 is transmitted within a 10cm baseline, the transmittance may be approximately 1, and thus Pr1＝Pt1，Pr2＝Pt2。
And placing the calibration power meter in front of the transmitting end beam expanding lens of the testing end, and setting a laser to transmit two lasers with different powers. Multiple recording of measured values P of a calibrated dynamometert1And Pt2Measured value P of the transmitting-end power metertm1And Ptm2. Suppose PtAnd PtmIs a first order linear relationship, using the point coordinates as (P)tm1，Pt1) And point coordinates of (P)tm2，Pt2) The first order linear equation can be solved. The parameters of the equations comprise tau in FIGS. 2, 5, 6 and 70And τtSimultaneously eliminateInherent error between the transmitting end power meter and the calibration power meter is accounted for.
And removing the calibration power meter of the transmitting end, and enabling the laser emitted by the transmitting end to directly enter the converging lens of the receiving end. Since the baseline is 10cm at this time, the transmittance can be regarded as 1, Pt1＝Pr1，Pt2＝Pr2. The laser emits the same two lasers with different powers to obtain the measurement value P of the power meter at the receiving endrm1And Prm2. Using the point coordinates of (P)rm1，Pr1) And point coordinates of (P)rm2，Pr2) Can find PrAnd PrmA first order linear equation of (a). The parameters of the equations comprise tau in FIGS. 2, 5, 6 and 7rMeanwhile, the inherent error between the transmitting end power meter and the calibration power meter is eliminated.
(2) Transmittance calibration
The calibrated power meter at the test end was replaced with an attenuator black box, the base line was held constant at 10cm as shown in FIG. 7, and the attenuator was placed in the attenuator placement hole site 1 shown in FIG. 5. Setting the laser to emit laser light of a third power, and Ptm1＜Ptm3＜Ptm2. By measuring Ptm3And Prm3Can obtain Pt3And Pr3，τm＝Pr3/Pt3。
Changing the attenuation sheet in the black box to change the transmittance tau of the attenuation sheetaThe standard device obtains different transmittance measured values tau by measuring the transmittance of the attenuation sheetm. Thus, τ is establishedaAnd τmThe corresponding relationship of (1).
(3) Visibility tracing source
First, the base line length is positioned to about 10m, the attenuation sheet black box and the attenuation sheet are removed, the optical axes of the transmitting end and the receiving end are aligned, and the base line accurate values L of the transmitting end and the receiving end are measured by the distance meter, as shown in fig. 8.
Second, an aerosol is produced in the visibility cabin, changing the aerosol concentration. By measuring the transmittance tau of the aerosolmA true value of the transmittance τ is establishedaIn relation to (2), settingτm＝k*τa. Aerosol transmission measurement τmAnd aerosol visibility RVThe calculated relationship of (c) is shown in formula (1). Thus, the system traces to the true value tau of transmittanceaTransmittance of aerosol τmAnd aerosol visibility RVThe corresponding relation of the three.
Figure BDA0002850653050000081

Claims (6)

1. A transmissive visibility standard measurement system, characterized by: the system comprises a transmitting end, a receiving end, a testing end and a PC; the transmitting end comprises a laser, a spectroscope, a first power meter, a beam expander, a first control circuit and a cooperative reflecting surface; wherein the first control circuit is respectively connected with the laser and the first power meter and used for emitting laser power PtMeasuring, wherein a first control circuit is connected to a PC through a serial port UART1T for transmitting end data communication; laser emitted by the laser is divided into two paths by the spectroscope and respectively enters the first power meter and the beam expander, so that the laser power P emitted by the emitting end is realizedtMeasuring; the receiving end comprises a converging lens, a second power meter, a distance meter and a second control circuit; wherein the second control circuit is respectively connected with the distance meter and the second power meter and is respectively used for measuring the length of the base line of the standard device and the incident laser power P of the receiving endrMeasuring, wherein the second control circuit is connected to a PC through a serial port UART1R for receiving end data communication; the converging mirror converges the received laser to the second power meter, so as to realize the incident laser power P of the receiving endrMeasuring; the receiving end is fixed on a three-dimensional adjusting frame and used for accurately adjusting the posture of the receiving end and aligning the view fields of the transmitting end and the receiving end; the base length of the etalon is 10cm and 10 m.
2. A transmissive visibility standard measurement system as claimed in claim 1 wherein: when the power meter is calibrated, the testing end of the standard is positioned between the beam expanding lens of the transmitting end of the standard and the converging lens of the receiving end of the standard, wherein a calibration power meter is arranged at the testing end and is connected to a PC (personal computer) to realize power meter calibration and optical system transmittance measurement of the transmitting end and the receiving end; the length of the base line of the standard is adjusted to 10 cm.
3. A transmissive visibility standard measurement system as claimed in claim 1 wherein: when the transmissivity is calibrated, the testing end of the standard device is arranged between the emission end of the standard device and the receiving end of the standard device, wherein an attenuation sheet black box is arranged at the testing end; the end surface of the attenuation piece black box is provided with an attenuation piece hole site, and the left side and the right side are respectively provided with a light inlet and a light outlet; the optical axes of the light inlet and the light outlet of the black box of the attenuation sheet, the beam expanding lens at the transmitting end of the standard device and the converging lens at the receiving end of the standard device are on the same horizontal plane; the base length of the system was adjusted to 10 cm.
4. A transmissive visibility standard measurement system as claimed in claim 1 wherein: when visibility tracing is carried out, the testing end of the standard device is arranged between a beam expanding lens at the transmitting end of the standard device and a converging lens at the receiving end of the standard device, wherein aerosol with different transmittances is injected into the testing end; the base length of the system was adjusted to 10 m.
5. A transmissive visibility standard measurement system as claimed in claim 1 wherein: the first control circuit comprises a thermistor RT1, a thermistor RT2, a first operational amplifier, a first analog-digital converter, a first microcontroller, a first square wave driving unit and a first power supply circuit; the thermistor RT1 and the thermistor RT2 are respectively connected with the first operational amplifier and are used for converting the detected laser temperature and the emission end environment temperature into voltage; the first operational amplifier is connected with the first analog-digital converter and used for converting the voltage into digital codes; the first analog-digital converter is connected with the first microcontroller and is used for sending the digital codes into the first microcontroller; the first microcontroller is connected with the PC through a serial port UART1T, receives a control command of the PC, and respectively forwards the control command to the laser and the first power meter through serial ports UART2T and UART 3T; the first microcontroller receives the query results of the laser and the first power meter through the serial port UART2T and the serial port UART3T respectively and forwards the query results to the PC through the serial port UART 1T; the first microcontroller is connected with the external fan through a first square wave driving unit, and the first square wave driving unit is a power amplification circuit and is used for receiving a square wave signal input by the first microcontroller and amplifying the power of the square wave signal to drive the external fan so as to cool the system.
6. A transmissive visibility standard measurement system as claimed in claim 1 wherein: the second control circuit comprises a thermistor RT3, a thermistor RT4, a second operational amplifier, a second analog-digital converter, a second microcontroller, a second square wave driving unit and a second power supply circuit; the thermistor RT3 and the thermistor RT4 are respectively connected with the second operational amplifier and are used for converting the detected temperature of the convergent lens and the ambient temperature of the receiving end into voltage; the second operational amplifier is connected with the second analog-digital converter and used for converting the voltage into digital codes; the second analog-digital converter is connected with the second microcontroller and is used for sending the digital codes into the second microcontroller; the second microcontroller is connected with the PC through a serial port UART1R, receives a control command of the PC, and forwards the control command to the distance meter and the second power meter through serial ports UART2R and UART3R respectively; the second microcontroller receives the query results of the distance meter and the second power meter through the serial port UART2R and the serial port UART3R respectively and forwards the query results to the PC through the serial port UART 1R; the second microcontroller is connected with the external fan through a second square wave driving unit, and the second square wave driving unit is a power amplification circuit and is used for receiving a square wave signal input by the second microcontroller and amplifying the power of the square wave signal to drive the external fan so as to cool the system.
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