CN207164242U - A kind of calibration system of middle infrared differential absorption lidar - Google Patents
A kind of calibration system of middle infrared differential absorption lidar Download PDFInfo
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- CN207164242U CN207164242U CN201721154207.XU CN201721154207U CN207164242U CN 207164242 U CN207164242 U CN 207164242U CN 201721154207 U CN201721154207 U CN 201721154207U CN 207164242 U CN207164242 U CN 207164242U
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- power meter
- gas
- absorption cell
- infrared differential
- middle infrared
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Abstract
The utility model discloses a kind of calibration system of middle infrared differential absorption lidar, including middle infrared differential absorption lidar, beam splitter, absorption cell, the first power meter, the second power meter, computer, balloon, gas pouch, atmosphere pollution detection instrument；During inflation, the outlet side of the gas pouch connects absorption cell and balloon respectively；The middle infrared differential absorption lidar transmitting laser is divided into two-way by beam splitter, enters the first power meter after absorption cell all the way, another way is directly entered the second power meter, and the first power meter and the second power meter connect computer respectively；The atmosphere pollution detection instrument is connected with balloon.The utility model is demarcated by existing atmosphere pollution detection instrument centering infrared differential absorption lidar, it is possible to increase the measurement accuracy of middle infrared differential absorption lidar, while higher sensitivity, farther detection range can be obtained.
Description
Technical field
The utility model is more particularly to a kind of middle infrared differential absorption lidar of pollutant measure
Calibration system.
Background technology
Laser radar is a kind of active contemporary optics remote sensing equipment, combines conventional radar technology and Modern Laser skill
Art, it is the product that traditional radio or microwave radar extend to optics frequency range.Laser radar spatial and temporal resolution is high, detection blind area
It is small, conventional detection instrument can be relatively well made up not with dusty gas particulate optical characteristic Characteristics of Vertical Distribution in atmospheric sounding
Foot.These particular advantages of laser radar, make it the effective means of detection study atmosphere pollution.In recent decades, greatly
The research and development of gas pollutant is quickly, it has also become an important branch of environmental monitoring.With Modern Laser radar system and technology
Development, laser radar detection atmosphere pollution technology, atmospheric environment, Atmospheric Chemistry, atmospheric radiation monitoring with analysis and
The fields such as climatic prediction are just playing very important effect.
Normal atmospheric pollutant monitoring mode mainly has electric chemical formula, catalytic combustion type, semiconductor-type and infrared-type, base
Single in the instrument probe gas species of these modes, distance is near, short life.Laser gas monitoring technology is to develop in recent years
Come new gas Detection Techniques, feature be it is non-contact without sampling, high sensitivity, the response time soon, can long-haul telemetry.Mesh
Before, the most frequently used spectral technique has the differential optical absorption spectrum of ultraviolet/visible waveband in domestic and international laser radar system
(DOAS), Fourier trasform spectroscopy (FTIR), the tunable semiconductor laser of DIAL (DIAL), infrared band
Absorption spectrum (TDLAS) etc..Prior art uses ultraviolet, near-infrared fixed wave length laser more, and gas absorption is weaker in this wave band,
Laser limited transmission distance in an atmosphere.Many toxic and harmful gas have strong absworption peak (than visible in middle infrared band
Light and near infrared band absorb high several orders of magnitude), infrared band can obtain higher sensitivity, farther detection in utilization
Distance.
Therefore, on the basis of existing instrument, centering infrared differential absorption lidar is surveyed data accuracy and demarcated
It is most important to follow-up practical application.
The content of the invention
The purpose of this utility model is to solve defect present in prior art, there is provided a kind of centering infrared differential is inhaled
Receive calibration system of the laser radar to atmosphere pollution measurement data.
In order to achieve the above object, the utility model provides a kind of demarcation system of middle infrared differential absorption lidar
System, including middle infrared differential absorption lidar, beam splitter, absorption cell, the first power meter, the second power meter, computer, balloon,
Gas pouch, atmosphere pollution detection instrument；During inflation, the outlet side of the gas pouch connects absorption cell and balloon respectively；It is described
Middle infrared differential absorption lidar transmitting laser is divided into two-way by beam splitter, enters the first power after absorption cell all the way
Meter, another way are directly entered the second power meter, and the first power meter and the second power meter connect computer respectively；The atmosphere pollution
Detection instrument is connected with balloon.
Wherein, atmosphere pollution detection instrument uses high sensitivity thermoelectrometry apparatus or portable nitrogen oxides.
High sensitivity thermoelectrometry apparatus Measurement Resolution is 0.01ppm, the degree of accuracy is full scale ± 2%.
Absorption cell is short light path gas absorption cell, and optical path length is 500 millimeters, 157 milliliters of volume, and window diameter 12.7 is in the least
Rice.
The utility model has advantages below compared with prior art：
Demarcated by existing atmosphere pollution detection instrument centering infrared differential absorption lidar, it is possible to increase in
The measurement accuracy of infrared differential absorption lidar, while higher sensitivity, farther detection range can be obtained.
Brief description of the drawings
Fig. 1 is the system structure diagram of the utility model absorption cell demarcation；
Fig. 2 is the system structure diagram of the utility model opening demarcation.
In figure, infrared differential absorption lidar in 1-, 2- absorption cells, the power meters of 3- first, the power meters of 4- second, 5- electricity
Brain, 6- atmosphere pollution detection instruments, 6A- high sensitivity thermoelectrometry apparatuses, the portable nitrogen oxides detectors of 6B-, 7- balloons, 8- gas
Body bag, the hard targets of 9-, 10- beam splitters.
Embodiment
The utility model provide one kind can the sensitivity of centering infrared differential absorption lidar systematic survey, accuracy enter
The calibration system of row calibration, as shown in figure 1, including middle infrared differential absorption lidar 1, beam splitter 10, absorption cell 2, first
Power meter 3, the second power meter 4, computer 5, balloon 7, gas pouch 8, atmosphere pollution detection instrument 6；During specific demarcation, with measurement
The thermoelectrometry apparatus 6A that resolving power is 0.01ppm, the degree of accuracy is full scale ± 2% and portable nitrogen oxides detector 6B measurement knot
Fruit is as reference, and calibration precision is high, relative error is small.
In order to better illustrate the scaling method that the utility model is related to, divide two parts combination accompanying drawing below to this practicality
It is new to be described in detail.Part I is absorption cell internal standard concentration calibration, red in being measured under known gas concentration levels
Outer DIAL measures with existing atmosphere pollution detection instrument (thermoelectrometry apparatus, portable nitrogen oxides detector)
As a result coefficient correlation, laid the foundation for the demarcation of follow-up measurement capability；Part II is demarcated for opening, is divided into release titanium dioxide
Nitrogen is not with discharging nitrogen dioxide gas, infrared differential absorption lidar measurement accuracy and sensitivity, centering in confirmation
Infrared differential absorption lidar measurement accuracy is demarcated.
Introduce specific steps and respective algorithms in two sub-sections below：
(1) absorption cell internal standard concentration calibration：
Step：
(1) intend before testing, carry out preparation before each unit test of instrument in advance according to instrument use demand respectively,
(high sensitivity thermoelectrometry apparatus 6A, portable nitrogen oxides detector 6B and middle infrared differential absorb and swashed each instrument in this calibrating method
Optical radar 1) by placement as shown in Figure 1.Air in absorption cell 2 is emptied using vavuum pump, absorption cell 2 is placed in figure middle position
Put.Each instrument be in can working condition, after system mode is stable, use wavemeter measurement optical maser wavelength, it is ensured that optical maser wavelength is steady
It is fixed；It is two-way that wherein middle infrared differential absorption lidar 1, which launches laser by beam splitter 10, laggard by absorption cell 2 all the way
Enter the first power meter 3, another way is directly entered the second power meter 4, and the first power meter 3 and the second power meter 4 connect computer respectively
5, into data collecting system；
(2) is under balanced air pressure, state of temperature, and instrument show value when survey absorption cell, balloon 7 are not filled with dusty gas is more
Secondary measurement is averaged as the zero point error x in follow-up measurement process01With y01；
(3) be filled with by the gas pouch 8 equipped with nitrogen dioxide gas into absorption cell 2, balloon 7 be filled with respectively it is different dense
The standard solid gas of degree, concentration value change from low to high, are initially filled with concentration value close to calibration instrument high sensitivity thermoelectrometry apparatus
Measurement Resolution value smaller value in 6A, portable nitrogen oxides detector 6B, and be filled with gas concentration and changed directly using dichotomy
Concentration value and high sensitivity thermoelectrometry apparatus 6A, portable nitrogen oxides detector 6B are surveyed to middle infrared differential absorption lidar 1
Close, thus, repeatedly measurement takes minimum value as infrared differential absorption lidar measurement sensitivity S in confirming1；
(4) records mutually descend high sensitivity thermoelectrometry apparatus 6A, portable nitrogen oxides detector 6B concentration values and absorption in the same time
The first power meter 3 and the second power meter 4 are worth before and after pond, and it is dense to calculate the corresponding gas of transmitance mean value calculation in absorption cell 5 minutes
Angle value and optical maser wavelength, whole process will ensure pressure, temperature close to pressure when not being filled with dusty gas in absorption cell, temperature
Degree；
(5) is fitted to measurement concentration and actual concentrations, draws middle infrared differential absorption lidar 1 and height respectively
Sensitivity thermoelectrometry apparatus 6A, portable nitrogen oxides detector 6B linearly dependent coefficient two-by-two, analysis system measurement result accuracy.
Algorithm：
(1) described in steps as measured above, by measuring respective power P 1, P2 of two light paths after the light splitting of radar emission light path,
Calculate transmitance of the standard gas adsorption pond on, off wavelength
τ0=exp (σOn, off·Nmε L) × 100%
Wherein σOn, offFor gas molecules sorb section, NLFor Loschimite constants 2.687 × 1019For in unit volume
Gas molecule Particle density, ε are total gas volume percentage shared by dusty gas, and L is absorption cell optical length.P (R) is environment pressure
By force, T (R) is environment temperature.
(2) optical path splitting ratio is calculated
(3) actual measurement air body absorption cell transmitance is calculated
(4) actual measurement charge air conditioning absorption cell transmitance is calculated
(5) actual measurement gas cell concentration x is calculated
According to formula in (1) formula, τ is made0=τ2, calculate Nm, i.e. the Particle density of gas, according to molecular weight and Avobenzene gal moral
The Particle density conversion of gas is unit mg/m by sieve constant3Concentration value x.
(6) linear regression formula is utilized, infrared differential absorption lidar and thermoelectrometry apparatus, portable nitrogen oxides in calculating
Detector measurement concentration linearly dependent coefficient r.
Xi=x-x01Yi=y-y01
Wherein, x, y are that middle infrared differential absorption lidar and thermoelectrometry apparatus (or portable detector) measure nitrogen dioxide
Concentration show value；
xi、yiFor measured value after two instrument background amendments；
x0To be filled with dusty gas concentration in absorption cell；
x01And y01Respectively middle infrared differential absorption lidar and thermoelectrometry apparatus (or portable detector) sample-out count
Value；
N is pendulous frequency.
(2) opening is demarcated：
Step：
(1), selection more opening can be easy to place system, dispose calibration instrument as shown in Figure 2 as calibration place
Device.Distance is 30 meters between setting the hard target 9 of target, such as campus basketball court, and can carry out at night and calibrate, can avoid idler couple
Interference caused by experiment；
(2) in advance disposes middle infrared differential absorption lidar system and measuring instrument according to each instrument requirement
In measuring environment, beaten in middle infrared differential absorption lidar 1 to being equidistantly positioned other two kinds measurements on the hard target direction of target 9
Instrument 6 (high sensitivity thermoelectrometry apparatus or portable nitrogen oxides detector) settlement, three instrument can be just opened after being all connected with properly
Device, and calibration and usage instrument is calibrated respectively, and swashed by infrared differential absorption lidar horizontal emission in the guarantee of hard target 9
Light；
(3) ensures three instruments under measurable state, and hard targets are moved with 30 meters of intervals, in thermoelectrometry apparatus, portable
Detector lay down location discharges nitrogen dioxide gas, and measuring condition is not by discharging dusty gas, gas low concentration to gas high concentration
Discharge successively, and various concentrations gas is discharged behind each hard target shift position, three kinds of instruments measure 10 minutes gas concentrations
Value, to cause the wealthy line Long-term change trend of concentration to tend to measured value, will finally measure average value as measured value；
(4) for after in view of coefficient correlation between zero point error and instrument, being drawn using spot measurement concentration value has distance
The concentration profile of resolution ratio, the result of three kinds of measuring instruments is contrasted, analysis system measurement accuracy, sensitivity and dusty gas exist
The time and space regularity of distribution in air, draw measurement result linearly dependent coefficient between instrument.
Algorithm：
(1) when DIAL is in measuring route concentration, radar equation can be expressed as：
Wherein, PtIt is peak power, c is the light velocity, and τ is laser radar system transmitance, and A looks in the distance mirror area, η reception systems
Efficiency, β (R) atmospheric backscatter coefficient, α (R) atmospheric extinction coefficient, C are under test gas concentration, and L is that gas absorbs light path,
γOn, offFor gas molecules sorb coefficient, R is detection range.Generally regard CL as a variable, turn into concentration light path product, also may be used
C is referred to as gas mean concentration under the light path.
(2) after infrared differential absorption lidar measures on and off pulse accumulation echo-signals among, first to returning
Ripple signal is pre-processed：
1. selection distant location signal (2~3km) is deducted point by point as background signal；
2. denoising smooth is carried out to signal using slipping smoothness, Wavelet Denoising Method scheduling algorithm；
(3) is accumulated to the signal by pretreatment using the mean concentration or concentration light path of ratio method inverting gas, and formula is such as
Under：
Wherein, C represents gas path mean concentration, and CL accumulates for concentration light path, and Δ γ is the Difference Absorption system of gas molecule
Number, PonAnd PoffFor two wavelength echo powers.T items are atmospheric extinction error term.
(4) is using gas path mean concentration C as measurement concentration value x, using linear regression formula, Infrared Difference in calculating
Divide absorption lidar and thermoelectrometry apparatus (portable detector) measurement concentration linearly dependent coefficient r.
Xi=x-x01Yi=y-y01
Wherein, x, y are that middle infrared differential absorption lidar and thermoelectrometry apparatus (portable detector) measurement nitrogen dioxide are dense
Spend show value；
xi、yiFor measured value after two instrument background amendments；
x0To be filled with dusty gas concentration in absorption cell；
x01And y01Respectively middle infrared differential absorption lidar and thermoelectrometry apparatus (portable detector) sample-out count value；
N is pendulous frequency.
Claims (3)
- A kind of 1. calibration system of middle infrared differential absorption lidar, it is characterised in that：The calibration system is infrared in including DIAL, beam splitter, absorption cell, the first power meter, the second power meter, computer, balloon, gas pouch, air are dirty Contaminate thing detection instrument；During inflation, the outlet side of the gas pouch connects absorption cell and balloon respectively；The middle infrared differential absorbs Laser radar transmitting laser is divided into two-way by beam splitter, enters the first power meter after absorption cell all the way, another way is direct Into the second power meter, the first power meter and the second power meter connect computer respectively；The atmosphere pollution detection instrument and gas Ball is connected.
- 2. calibration system according to claim 1, it is characterised in that：The atmosphere pollution detection instrument is using highly sensitive Spend thermoelectrometry apparatus or portable nitrogen oxides.
- 3. calibration system according to claim 2, it is characterised in that：The absorption cell is short light path gas absorption cell, light Cheng Changdu is 500 millimeters, 157 milliliters of volume, 12.7 millimeters of window diameter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721154207.XU CN207164242U (en) | 2017-09-11 | 2017-09-11 | A kind of calibration system of middle infrared differential absorption lidar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721154207.XU CN207164242U (en) | 2017-09-11 | 2017-09-11 | A kind of calibration system of middle infrared differential absorption lidar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207164242U true CN207164242U (en) | 2018-03-30 |
Family
ID=61721142
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721154207.XU Expired - Fee Related CN207164242U (en) | 2017-09-11 | 2017-09-11 | A kind of calibration system of middle infrared differential absorption lidar |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207164242U (en) |
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2017
- 2017-09-11 CN CN201721154207.XU patent/CN207164242U/en not_active Expired - Fee Related
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Granted publication date: 20180330 Termination date: 20190911 |