CN108955733A - A method of it is encoded based on assembled pulse and improves BOTDA system signal noise ratio - Google Patents
A method of it is encoded based on assembled pulse and improves BOTDA system signal noise ratio Download PDFInfo
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- CN108955733A CN108955733A CN201810468864.4A CN201810468864A CN108955733A CN 108955733 A CN108955733 A CN 108955733A CN 201810468864 A CN201810468864 A CN 201810468864A CN 108955733 A CN108955733 A CN 108955733A
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- 238000005259 measurement Methods 0.000 claims abstract description 8
- 230000003287 optical effect Effects 0.000 claims description 16
- 239000011159 matrix material Substances 0.000 claims description 13
- 238000001514 detection method Methods 0.000 claims description 8
- 230000000295 complement effect Effects 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 2
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 239000013307 optical fiber Substances 0.000 abstract description 11
- 230000004044 response Effects 0.000 description 12
- 230000000875 corresponding effect Effects 0.000 description 6
- 239000000523 sample Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 238000005314 correlation function Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000005311 autocorrelation function Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 230000008859 change Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
- G01D5/35354—Sensor working in reflection
- G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
- G01D5/35364—Sensor working in reflection using backscattering to detect the measured quantity using inelastic backscattering to detect the measured quantity, e.g. using Brillouin or Raman backscattering
Abstract
The invention discloses a kind of methods of raising BOTDA system signal noise ratio based on CCPONS and Walsh assembled pulse coding, belong to distributing optical fiber sensing field.It is made of laser, coupler, electrooptic modulator, microwave signal source, DC power supply, EDFA Erbium-Doped Fiber Amplifier, isolator, electrooptic modulator, EDFA Erbium-Doped Fiber Amplifier, pulse signal generator, circulator, sensor fibre, photodetector, data collecting card and computer.By using the mode that CCPONS coding and Walsh coding techniques combine, system signal noise ratio is greatly improved under limited code length, to improve measurement accuracy.
Description
Technical field
The invention belongs to distributing optical fiber sensing fields, and in particular to a kind of to be compiled using CCPONS and Walsh assembled pulse
The method for the raising BOTDA system signal noise ratio that code combines.
Background technique
Strain measurement system based on Brillouin optical time domain analysis (BOTDA) technology is because its reception signal is strong, measurement accuracy
The advantages that high and dynamic range is big, is widely applied in the temperature of petroleum pipeline, power cable etc. and strain monitoring field.
In BOTDA system, pulse pump light is injected from one end of optical fiber, and continuous probe light is injected from the other end of optical fiber, two beam phases
Excited Brillouin (SBS) effect is occurred by sound wave in a fiber to the optical signal of transmission, when light beam falls in another light beam
When in Brillouin scattering spectral limit, the transfer of energy occurs between two-beam.The frequency difference of two-beam is equal to when energy transfer maximum
The Brillouin shift of optical fiber, continuous probe optical power change is maximum at this time.By detecting continuous optical power under different frequency differences
Brillouin spectrum can be obtained in variation, so that it is determined that the Brillouin shift of optical fiber, then utilizes Brillouin shift and temperature or strain
Relationship, realize along fiber optic temperature or the measurement of strain.But spatial resolution, pulse width, signal-to-noise ratio etc. measure systematicness
The important indicator of energy mutually restricts each other, and pulse width determines resolution ratio, and pulse is narrower, and resolution ratio is higher, but cloth simultaneously
In deep gain it is weaker, signal-to-noise ratio is lower.
System letter can be improved under the premise of not changing light source pulse width, intensity and system stacking fold using coding
It makes an uproar ratio.But it is limited to the increase rate of system signal noise ratio to be single use a kind of pulse coding technique, is unable to satisfy system to height
The requirement of signal-to-noise ratio.Therefore, the present invention proposes a kind of technology for combining CCPONS and Walsh pulse code, and is answered
For BOTDA system, to further increase the signal-to-noise ratio of system.
Summary of the invention
The object of the present invention is to provide a kind of raising BOTDA systems combined using CCPONS and Walsh pulse code
The method of signal-to-noise ratio.
The structure of BOTDA strain measurement system used in the present invention is as shown in Figure 1, by laser, coupler, electric light tune
Device 1 processed, microwave signal source, DC power supply, EDFA Erbium-Doped Fiber Amplifier 1, isolator, electrooptic modulator 2, EDFA Erbium-Doped Fiber Amplifier 2,
Pulse signal generator, circulator, sensor fibre, photodetector, data collecting card and computer composition.
The continuous light that laser issues is divided into two through coupler, and optical signal enters through microwave signal source and direct current all the way
The electrooptic modulator (Electro-optic Modulator, EOM) 1 of source driving generates shift frequency optical signal, this signal is by er-doped light
Enter sensor fibre as detection light after fiber amplifier (Erbium Doped Fiber Amplifier, EDFA) amplification；It is another
The electrooptic modulator 2 of the encoded pulsed drive of road optical signal generates pump light, is amplified by erbium-doped fiber amplifier belt
Device (Circulator).The detection light for carrying SBS information enters photoelectric detector through circulator, is finally adopted by data collecting card
Collection is responded by the pulse of decoding program recovery system.The reverse transfers generated due to various reasons in optical path in order to prevent
Isolator (Optical Isolator, OI) is added in detection optical path in the adverse effect that light generates light source and light path system.
BOTDA system detection end continuous probe light variation delta ICWRelationship with time t, optical frequency difference Δ υ is
The formula
It is denoted as pulse response r (t) of system, ICWLFor detection luminous intensity incident at optical fiber connector (z=L), α is fibre loss system
Number, L is fiber lengths, υgFor group velocity, Δ z is the spatial resolution determined by pulse width, gB(ξ, Δ υ) and IP(ξ, Δ υ)
Brillouin gain and pulse pump luminous intensity respectively at fiber position.
For BOTDA system, Brillouin shift resolution ratioIt is by signal-to-noise ratio (Signal to Noise
Ratio, SNR) determine, it is represented byIn formula, Δ υBIt is Brillouin linewidth.
Brillouin shift resolution ratio directly influences the temperature and strain resolution of BOTDA system, and is represented by
In formula, δ T, δ ε respectively indicate temperature
And strain resolution, CυT、CυsRespectively indicate the temperature and the coefficient of strain of Brillouin shift.
As can be seen that the variation delta I of continuous probe lightCWIt is mainly related with spatial resolution and pulse pump luminous intensity.
When improving System spatial resolution, Δ ICWReduce, SNR reduces, so that Brillouin shift resolution ratio can be reduced.Pulse code
BOTDA system is by restoring pulse response with data processor in receiving end, can overcome to optical fiber injected pulse sequence
Contradiction between spatial resolution and signal-to-noise ratio increases system signal noise ratio in the case where spatial resolution is constant, improves temperature
With strain resolution.But it is limited to the increase rate of system signal noise ratio to be single use a kind of pulse coding technique, is unable to satisfy
Requirement of the system to high s/n ratio.Therefore, the present invention proposes a kind of technology for combining CCPONS and Walsh pulse code,
And it is applied to BOTDA system, to further increase the signal-to-noise ratio of system.
Two rows, two column matrix that CCPONS code is made of a pair of of complementary series starts, by additional 2 obtained of ranksm×
2mRank (m is positive integer) matrix.A pair of of complementary series is formed therewith and all there is another row in every a line of matrix.It is produced by orthogonal matrix
Raw complementary dependent quadrature sequence are as follows:
cm(K)=Ak, Bk, Ck, Dk
={ a(m-1)K, b(m-1)K, { a(m-1)K,-b(m-1)K, b (M-1)K, a(m-1)K, {-b(m-1)K, a(m-1)K}
In formula, the value of K is 1,2,3 ..., 2m-2。
The quasi- orthogonal correlated series A of biddingk, Bk, Ck, DkLength be n, then their the sum of cross-correlation function beIn formula, " ★ " indicates related operation.
Since CCPONS code is a kind of bipolar code, original four groups of bipolaritys CCPONS code need to be divided into eight groups by biasing
Unipolar pulse sequence.Four groups of unipolar codes are obtained by the following method:
In formula, A0、B0、C0、D0It indicates "+1 ".
Its corresponding four groups of mutual-complementing code obtains in the following ways:
Eight groups of unipolarity CCPONS codes are in BOTDA system, the light pulse for generating identical pattern to enter sensor fibre, so
Detect eight groups of corresponding response signals respectively afterwards
To it
It is decoded, obtains the final response of system:
In formula, " " indicates convolution algorithm, CiIt (t) is brewed pump signal, n is code length.
By calculate CCPONS code BOTDA system coding gain i.e. signal-to-noise ratio improvement amount are as follows:
Walsh code can be mapped by the row or column of Hadamard matrix to be constituted, and the type of code is equal to the length of code.
Single order Hadamard matrix are as follows:
H1=(1)
Second order Hadamard matrix are as follows:
N rank Hadamard matrix can be made of following recurrence formula:
Wherein, N=2m, m=1,2,3 ...
Walsh sequence 0, the i.e. the first row of Hadamard matrix are indicated with W (0), and W (k) indicates that Walsh sequence k is
+ 1 row of kth of Hadamard matrix.N rank Walsh function (N=2n, n=0,1,2 ...) corresponds to Walsh sequence W (0), W
(1) ..., W (N-1), the length of each Walsh sequence is N.
Walsh code has ideal orthogonality, i.e. auto-correlation function Ra(0)=1, cross-correlation function Rc(0)=1.
It is similar with CCPONS code since Walsh code is a kind of bipolar code, it need to be logical by original four groups of bipolaritys Walsh code
It crosses biasing and is divided into eight groups of unipolar pulse sequences.Eight groups of unipolarity Walsh codes are for generating identical pattern in BOTDA system
Light pulse enters sensor fibre, then detects eight groups of corresponding response signals respectively, carries out to it similar with CCPONS code
Decoding operate.
Coding gain, that is, signal-to-noise ratio improvement amount of Walsh code BOTDA system is
Example with CCPONS and Walsh assembled pulse coded modulation pump light is as shown in Figure 2.By the every of 4 Walsh codes
Each element multiplication of a element and 4 CCPONS codes, the multiplication generate 16 codings by two coded combinations.
Decoding process of the assembly coding in BOTDA system is as shown in Figure 3.The 16 road signals detected are divided into 4 groups, often
4 tunnel echo-signals are 1 group.CCPONS decoding first is carried out to every group of signal respectively, obtains 1 group of output response, then decoding is obtained
4 groups of response signals by Walsh decode after obtain final output response R (t).
If the noise jamming mean-square value being subject in every road optical signal injection tested optical fiber is σ2, signal is after CCPONS is decoded
System noise is reduced to σ2/GC 2, then after Walsh is decoded system noise is reduced to σ2/(GCGW)2.By calculating to obtain CCPONS code
Coding gain, that is, signal-to-noise ratio improvement amount of rear BOTDA system is combined with Walsh code are as follows:
The beneficial effects of the present invention are: CCPONS and Walsh assembled pulse coding is introduced into BOTDA system, it can be
System signal noise ratio is greatly improved under limited code length, to improve distance sensing.
Detailed description of the invention
Fig. 1 is BOTDA strain measurement system schematic diagram；
Fig. 2 is the example with CCPONS and Walsh assembled pulse coded modulation pump light；
Fig. 3 is CCPONS and Walsh assembled pulse decoding process schematic diagram；
Fig. 4 is the system response curve under pulse working method；
Fig. 5 corresponding system response curve when being individually using 4 rank CCPONS coding；
Fig. 6 corresponding system response curve when being individually using 4 rank Walsh coding；
Fig. 7 corresponding system response curve when being using 4 rank CCPONS and 4 rank Walsh assembly coding.
Specific embodiment
Embodiment 1:
The TSL-510 tunable laser of Santec company is selected to make carrier wave light source, the wave-length coverage of laser is 1510nm-
1630nm sets wavelength as 1550nm；Modulator 1, modulator 2 are the MXAN-LN-40 of Photline company, and bandwidth is
32GHz；Dc bias is 9V；Amplifier be Co., Ltd of ZTE Corporation erbium-doped fiber amplifier, wave-length coverage be 1530~
1565nm, amplification factor are greater than 35 times；Microwave signal source is the 8257D of agilent company；The pulse pattern of agilent company is believed
Number generator, model 81134A, frequency range are 15MHz~3.35GHz；Photodetector is the SD-48 of Imtech, band
Width is 35GHz；Sensor fibre is the optical fiber of Yangtze Optical Fiber and Cable Company Ltd, and excited Brillouin gain line width is 40MHz, in cloth
Deep frequency shift amount, length are 300 meters；The isolation of optoisolator is greater than 40dB；Data collecting card is the PCI-5114 number of NI company
According to capture card, sample frequency 100MSPS.
Claims (7)
1. a kind of encode the method for improving BOTDA system signal noise ratio based on assembled pulse, it is characterised in that: by laser, coupling
Device, electrooptic modulator (1), microwave signal source, DC power supply, EDFA Erbium-Doped Fiber Amplifier (1), isolator, electrooptic modulator (2),
EDFA Erbium-Doped Fiber Amplifier (2), pulse signal generator, circulator, sensor fibre, photodetector, data collecting card and calculating
Machine composition；The continuous light that laser issues is divided into two through coupler, and optical signal enters through microwave signal source and direct current all the way
Source driving electrooptic modulator (1) generate shift frequency optical signal, this signal amplified by erbium-doped fiber amplifier after as detection light into
Enter sensor fibre；The electrooptic modulator (2) of the encoded pulsed drive of another way optical signal generates pump light, by Erbium-doped fiber amplifier
Device is amplified into circulator；The detection light for carrying SBS information enters photoelectric detector through circulator, finally by data collecting card
Acquisition is responded by the pulse of decoding program recovery system, and isolator is added in detection optical path.
2. a kind of method for encoding raising BOTDA system signal noise ratio based on assembled pulse as described in claim 1, feature exist
In laser wave-length coverage be 1510nm-1630nm.
3. a kind of method for encoding raising BOTDA system signal noise ratio based on assembled pulse as described in claim 1, feature exist
In modulator (1), modulator (2) bandwidth be 32GHz.
4. a kind of method for encoding raising BOTDA system signal noise ratio based on assembled pulse as described in claim 1, feature exist
In: it combines by using CCPONS coding and Walsh coding techniques and to improve the signal-to-noise ratio of BOTDA system, and then improve and survey
Accuracy of measurement.
5. a kind of method for encoding raising BOTDA system signal noise ratio based on assembled pulse as described in claim 1, feature exist
Two rows, two column matrix being made of in: CCPONS code a pair of of complementary series, by additional 2 obtained of ranksm×2mRank square
Battle array, m are positive integer, and every a line of matrix all has another row and forms a pair of of complementary series therewith.
6. a kind of method for encoding raising BOTDA system signal noise ratio based on assembled pulse as described in claim 1, feature exist
In: Walsh code can be mapped by the row or column of Hadamard matrix to be constituted, and the type of code is equal to the length of code.
7. being encoded based on assembled pulse such as claim 1,5 or a kind of 6 as described in any one and to improve BOTDA system signal noise ratio
Method, it is characterised in that: pulse volume is carried out to pump light after combining by using the CCPONS code and Walsh code of appropriate code length
Code, is then combined decoding in the collected data in data processing end, to improve the signal-to-noise ratio of system and then improve survey
Accuracy of measurement.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109781154A (en) * | 2019-02-14 | 2019-05-21 | 哈尔滨工业大学 | Brillouin's domain of dependence analysis system of high spatial resolution based on intensity modulated |
| CN111323678A (en) * | 2020-03-09 | 2020-06-23 | 浙江日新电气有限公司 | Power cable abnormality detection method and system and distributed optical fiber temperature measurement host |
| CN113049014A (en) * | 2021-03-10 | 2021-06-29 | 太原理工大学 | Time-frequency multiplexing BOTDA system based on pumping light frequency sweep and sensing method |
| CN116015462A (en) * | 2023-02-27 | 2023-04-25 | 中国科学院国家授时中心 | EDFA optical gain setting method applied to optical fiber time transmission |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101476948A (en) * | 2008-12-19 | 2009-07-08 | 南京大学 | Long-distance optical fiber sensing method based on Hadamard matrix self-correlated characteristic |
| CN103245370A (en) * | 2013-04-10 | 2013-08-14 | 南京大学 | BOTDA (Brillouin Optical Time-Domain Analysis) system based on pulse coding and coherent detection |
| US20130230077A1 (en) * | 2008-05-13 | 2013-09-05 | Metropolitan Area Networks, Inc. | Communication system, apparatus and methods |
| CN103314276A (en) * | 2010-12-22 | 2013-09-18 | 奥姆尼森股份公司 | A brillouin optoelectronic measurement method and apparatus |
| CN104048684A (en) * | 2014-02-13 | 2014-09-17 | 上海温光自动化技术有限公司 | OTDR device and method based on coded pulse optical signals |
| CN105675031A (en) * | 2016-01-23 | 2016-06-15 | 中国人民解放军国防科学技术大学 | Pre-pumped pulse and Gray code based BOTDA (Brillouin Optical Time Domain Analysis) instrument |
-
2018
- 2018-05-16 CN CN201810468864.4A patent/CN108955733A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130230077A1 (en) * | 2008-05-13 | 2013-09-05 | Metropolitan Area Networks, Inc. | Communication system, apparatus and methods |
| CN101476948A (en) * | 2008-12-19 | 2009-07-08 | 南京大学 | Long-distance optical fiber sensing method based on Hadamard matrix self-correlated characteristic |
| CN103314276A (en) * | 2010-12-22 | 2013-09-18 | 奥姆尼森股份公司 | A brillouin optoelectronic measurement method and apparatus |
| CN103245370A (en) * | 2013-04-10 | 2013-08-14 | 南京大学 | BOTDA (Brillouin Optical Time-Domain Analysis) system based on pulse coding and coherent detection |
| CN104048684A (en) * | 2014-02-13 | 2014-09-17 | 上海温光自动化技术有限公司 | OTDR device and method based on coded pulse optical signals |
| CN105675031A (en) * | 2016-01-23 | 2016-06-15 | 中国人民解放军国防科学技术大学 | Pre-pumped pulse and Gray code based BOTDA (Brillouin Optical Time Domain Analysis) instrument |
Non-Patent Citations (1)
| Title |
|---|
| MOHD SAIFUL DZULKEFLY ZAN, AHMAD ASHRIF A.BAKAR AND TSUNEO HORI: "Improvement of Signal-to-Noise-Ratio by combining Walsh and Golay codes in modulating the pump light of phase-shift pulse BOTDA fiber sensor", 《IEEE XPLORE》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109781154A (en) * | 2019-02-14 | 2019-05-21 | 哈尔滨工业大学 | Brillouin's domain of dependence analysis system of high spatial resolution based on intensity modulated |
| CN111323678A (en) * | 2020-03-09 | 2020-06-23 | 浙江日新电气有限公司 | Power cable abnormality detection method and system and distributed optical fiber temperature measurement host |
| CN113049014A (en) * | 2021-03-10 | 2021-06-29 | 太原理工大学 | Time-frequency multiplexing BOTDA system based on pumping light frequency sweep and sensing method |
| CN116015462A (en) * | 2023-02-27 | 2023-04-25 | 中国科学院国家授时中心 | EDFA optical gain setting method applied to optical fiber time transmission |
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