CN109084816A - A kind of anti-polarization decay alarm algorithm of Fibre Optical Sensor signal - Google Patents
A kind of anti-polarization decay alarm algorithm of Fibre Optical Sensor signal Download PDFInfo
- Publication number
- CN109084816A CN109084816A CN201810548215.5A CN201810548215A CN109084816A CN 109084816 A CN109084816 A CN 109084816A CN 201810548215 A CN201810548215 A CN 201810548215A CN 109084816 A CN109084816 A CN 109084816A
- Authority
- CN
- China
- Prior art keywords
- signal
- phase
- light intensity
- interference
- polarization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000835 fiber Substances 0.000 title claims abstract description 61
- 230000003287 optical effect Effects 0.000 title claims abstract description 17
- 230000010363 phase shift Effects 0.000 claims abstract description 46
- 230000010287 polarization Effects 0.000 claims abstract description 30
- 238000000034 method Methods 0.000 claims abstract description 26
- 108010076504 Protein Sorting Signals Proteins 0.000 claims abstract description 14
- 238000012545 processing Methods 0.000 claims description 23
- 238000003466 welding Methods 0.000 claims description 8
- 230000008859 change Effects 0.000 claims description 7
- 230000000694 effects Effects 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims 1
- 230000007613 environmental effect Effects 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 5
- 238000005070 sampling Methods 0.000 abstract description 3
- 230000002452 interceptive effect Effects 0.000 abstract description 2
- 238000012544 monitoring process Methods 0.000 abstract 1
- 239000013307 optical fiber Substances 0.000 description 8
- 238000012360 testing method Methods 0.000 description 5
- 230000009545 invasion Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 210000001367 artery Anatomy 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 210000003462 vein Anatomy 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- 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
- G01D5/35306—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 an interferometer arrangement
- G01D5/35322—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 an interferometer arrangement using interferometer with one loop with several directions of circulation of the light, e.g. Sagnac interferometer
Abstract
The invention discloses the anti-polarization decay methods and alarm algorithm of a kind of fiber grating sensing signal, the two adjacent reflected interference signals of fiber grating are received using three state polarization diversity receiver first, the uncertain interference signal of polarization state is divided into three tunnels, then is modulated by the signal generator of system and forms three groups of every road phase shift light intensity signal.Then the size for solving three tunnel phase shift light intensity signals and interfering contrast is compared to each other in one section of sampling time by three groups of phase shift light intensity signals on every road, it determines that contrast is best all the way in three tunnel phase shift light intensity signals, the phase demodulating of fibre optical sensor vibration is carried out in conjunction with three step Phase-shifting algorithms.Then it uses discrete differential algorithm process phase signal sequence and sets the threshold value of alarm, discrete differential signal judges whether to alarm more than the number of threshold value after counting difference.The method strong real-time of the judgement interference signal contrast, accuracy are high；Alarm algorithm monitoring Dynamic Signal changing capability is strong, precision is higher, environment resistant interference performance is strong.
Description
Technical field
The invention belongs to technical field of optical fiber sensing, and in particular to a kind of anti-polarization decay alarm calculation of Fibre Optical Sensor signal
Method.
Background technique
In China, with the deep implementation of policies of reform and opening to the outside world, wealth of society high speed increases, and compatriots are equally to the need of safety
Ask higher and higher, more and more extensively.State's inner perimeter security product recent years will keep fast-developing situation, and development potentiality is huge
Greatly.
It is compared with traditional electronic sensor, fiber-optic grating sensor fibre optical sensor has size small, light-weight, cost
Many advantages, such as cheap, electromagnetism interference, high sensitivity is securely and reliably, corrosion-resistant, can carry out distributed measurement, be easy to networking,
It has been widely used for temperature, vibration, the measurement of the parameters such as stress.
In actual operation, the signal that system is received from sensor fibre include invasion vibration signal, disturbing signal and
Noise signal.The three kind signal parsers common to the alarm decision of three kinds of signals are respectively as follows: statistic algorithm, comentropy algorithm
With fft analysis algorithm.
Statistic algorithm mainly from signal amplitude and invades signal and noise signal in terms of signal duration two to distinguish.When
External force is on sensor fibre, and the invasion signal amplitude that system receives has significant change, and the duration is relatively long, and
Noise signal amplitude is relatively small, and the amplitude duration is long.The algorithm key is that reasonable pulse lower threshold is arranged, if
Threshold value is reasonable, can effectively distinguish three kinds of signals.To obtain reasonable lower threshold, needs to carry out a large amount of field test, obtain
Proficiency data, and then analyze and obtain relatively reasonable threshold value；Comentropy is one that metric amount size is used in information theory
Concept, information content is bigger, and entropy is also bigger.Can be with comentropy come gauge signal, the semaphore of statistics gatherer is each
The distribution situation in section, and then the comentropy of the signal can be calculated, entropy is bigger, and signal information contained amount is also more.It is logical
The comentropy of signal is crossed, i.e. information content contained by the signal, as the foundation for determining invasion.Statistic algorithm and comentropy algorithm are all
It is to be analyzed in time domain, wherein statistic algorithm is more to be counted for the pulse shape of unlike signal, and comentropy is then
Be to be obtained according to the probability distribution in signal difference section, direct relation had no between sampled value, distinguish invasion signal and
Effect is more preferable in disturbing signal；FFT is fast discrete Fourier transformation, signal can be transformed from the time domain to frequency domain, work as signal
When time domain is difficult to differentiate its feature, transforms to and be then easy to distinguish on frequency domain.
Chinese patent " optical fiber grating sensing modulation-demo-demodulation method and device based on phase shift signal modulation "
(CN107290042A) in, when signal system demodulates light intensity phase, the interference light intensity that directly acquisition is spread out of from 3 port of circulator is believed
The solution for number carrying out three step phase-shifting methods, then obtains the phase information of interference signal after unpacking.In the process, by fiber grating
Group return interference light intensity signal polarization direction be it is uncertain, the feelings that will lead to difference in signal strength are directly received by detector
Condition, light intensity signal can not be acquired when serious influences subsequent demodulating process.
Summary of the invention
The purpose of the present invention is to provide a kind of anti-polarization decay alarm algorithms of Fibre Optical Sensor signal, solve data and adopt
Collection module receives the weak disadvantage of interference light intensity signal of circulator output, realizes and adopt to uncertain polarization state interference signal
Collection；Simplify and realize that strong real-time, environment resistant interference performance be strong, the higher alarm algorithm of accuracy.
The technical solution for realizing the aim of the invention is as follows: a kind of anti-polarization decay alarm algorithm of Fibre Optical Sensor signal,
Method and step is as follows:
Step 1 opens laser light source, and emergent light is made successively to pass through isolator, photoswitch and phase-modulator.Wherein, believe
Number generator is connect with photoswitch and phase-modulator respectively, is generated pulse signal effect in photoswitch by signal generator, is produced
Raw continuous light pulse, acts on phase-modulator, generates continuous phase impulse modulation.Form phase modulated laser pulse light
Beam；The 1st port for entering circulator by the laser pulse light beam of phase-modulation enters the optical fiber of welding by its 2nd port
Grating group.Fiber grating group can incude the vibration signal of environment, and when pulsed light beam is not through sharing the same light in fiber grating group
When fine grating, there is partial pulse light beam to return to circulator, the signal of adjacent two fiber gratings reflection generates dry in circulator
It relates to, then exports interference signal from the 3rd port of circulator.
Interference light intensity signal I (t) expression formula that step 2, two neighboring fiber grating generate is as follows:
Wherein, phase is closed For initial phase,For drift about phase,Indicate vibration signal phase,
A, B is constant.It is generated for phase-modulator0、Three road light intensity signals phase intervals, substitute intoIt obtains
Xin tri- road interference light intensity signal I (n) such as following formula:
That is:
The uncertain interference signal of polarization state being emitted from 3 port of circulator is received using three state polarization diversity receiver,
And it is divided into tri- road interference signal of Xin, it all include three groups of above-mentioned interference light intensity signals per interference signal all the way；Three tunnels are dry
It relates to signal and is converted to three tunnel light intensity electric signals, data collecting module collected light intensity electric signal by three photodetectors, and incite somebody to action
It is sent into data processing module；Data processing module is finally obtained by the delay of calibration phase modulated signal and reception signal
Two neighboring fiber grating generates three tunnels totally nine groups of phase shift light intensity signal I after interfering11、I12、I13、I21、I22、I23、I31、
I32、I33。
Step 3, three groups of phase shift light intensity signals for setting the first via are respectively I11, I12, I13, then | I11-I12| it is B1[cos(θ)
+ sin (θ)], | I11-I13| it is 2B1Sin (θ), | I12-I13| it is B1[cos(θ)-sin(θ)]；Will | I11-I12|, | I11-I13|, |
I12-I13| in maximal term be denoted as Imax1；The I on the second tunnel is found out in the same waymax2And the I on third roadmax3。
Under synchronization, Imax1、Imax2And Imax3Three is simultaneously Bi[cos(θ)+sin(θ)]、 2BiSin (θ) or Bi
In [cos (θ)-sin (θ)] a certain item (wherein i=1,2 or 3)；At a time, if Imax1、Imax2And Imax3Respectively B1
[cos(θ)+sin(θ)]、B2[cos(θ)+sin(θ)]、 B3[cos (θ)+sin (θ)], then compare Imax1、Imax2And Imax3It is big
Small you can get it B1、B2、B3Size；B under different moments can be compared in the same wayiThe size of value, by BiIt is worth maximum
Signal is determined as the maximum phase shift light intensity signal all the way of contrast all the way.
Step 4, the selection maximum light intensity signal of phase shift all the way of contrast are denoted as I1、I2、I3, then carry out three step phase-shifting methods
Phase signal is solved and unpacks to obtain, phase signal contains the information of phase in time domain, and phase signal carries out forward difference meter
Calculation obtains discrete differential signal, the discrete differential signal reaction change information of phase signal, wherein the signal segment changed greatly
Show that there are disturbing signals in environment；The discrete differential signal under various environment, which is calculated, by acquisition carries out signal threshold value Tmin's
Setting, statistics of the data discrete differential signal of progress beyond threshold point quantity that will acquire in a period of time, when passing through threshold
It alarms when the quantity overrate of value point.
Compared with prior art, the present invention its remarkable advantage is:
(1) the uncertain interference signal of polarization state exported from circulator is obtained using three state polarization diversity receiver, it is real
The reception to the interference signal is showed, has made receiving end that can receive the uncertain interference signal of polarization state.
(2) it is compared to each other in one section of sampling time using per three groups of phase shift light intensity signals all the way, by comparing identical multiply
The light intensity peak factor of the method factor has determined the strongest phase shift light intensity signal all the way of contrast in three road signals.Acquired phase shift
Light intensity signal be three road signals in subsequent calculating it is best all the way, and algorithm is easy, real-time is high, stability is strong.
(3) the discrete differential signal obtained through three step phase-shifting methods is handled by difference operator, obtains characterization phase signal
The fairly obvious data of change rate, to judge to provide to calculate with the presence or absence of alarm factors in environment above to count with visually obvious
According to.The timeliness of system can be met with discrete differential algorithm, quickly handle phase signal sequence.
(4) it is able to satisfy in use process according to the setting that the discrete differential signal acquired under different situations carries out threshold value to report
The accurate judgement of alert signal can exclude the influence of ambient noise again, ensure that the accuracy of system reduces rate of false alarm.
(5) passed through using threshold value count legally constituted authority meter discrete differential signal pass through the number of threshold value can be to avoid enumerative mixed
Confuse, number is passed through by the threshold value set in a period of time and carries out alarm decision, the method can pass through setting triggering alarm
The specified sensitivity passed through quantity and effectively control alarm.
Detailed description of the invention
Fig. 1 is a kind of system structure diagram of the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal of the invention.
Fig. 2 is the system flow chart of algorithm.
Fig. 3 be in the present invention three state polarization diversity receiver receive certain all the way in interference signal by signal generator tune
System three groups of phase intervals be0、Interference light intensity signal graph.
Fig. 4 is in the present invention by certain phase shift light intensity signal all the way | I11-I12|, | I11-I13|, | I12-I13| middle maximal term
It is denoted as Imax1, the I of other two-way is found out in the same waymax2And Imax3The comparison figure of latter three.
After Fig. 5 is judges the light intensity signal of phase shift all the way that contrast is best in three tunnel phase shift light intensity signals in the present invention,
Three step phase-shifting methods are used to restore the phase signal figure after phase information unpacks.
Fig. 6 is the discrete differential signal graph for preferably obtaining contrast after phase signal series processing all the way in the present invention.
Specific embodiment
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, right with reference to the accompanying drawings of the specification
A specific embodiment of the invention is described in detail.
The present invention is at Chinese patent " optical fiber grating sensing modulation-demo-demodulation method and device based on phase shift signal modulation "
(CN107290042A) it on the basis of, is connect before using three step phase-shifting method demodulation phase signals using three state polarization diversity receiver
The uncertain interference signal of polarization state is received, is divided into behind three tunnels by judging that phase shift contrast of the light signal intensity is optimal true all the way
Determine the best light intensity signal of phase shift all the way of signal strength and carries out subsequent demodulation work.The road phase shift light intensity signal is used into three steps
Forward difference processing is carried out again after phase-shifting method demodulation, the final discrete differential signal obtained in time domain, according to discrete differential
Signal given threshold simultaneously judges alert if.
Step 1, in conjunction with Fig. 1, a kind of system building of the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal is as follows:
The output end of laser light source is connected with the input terminal of isolator, the output end of isolator is then connected into photoswitch
Input terminal, the output end of photoswitch is connected with the input terminal of phase-modulator, then phase-modulator output end and annular
No. 1 port of device is connected.For circulator, by its No. 2 port welding optic fibre grating groups, by its No. 3 ports and three state polarization point
Collect the input terminal connection of receiver, three output ends of three state polarization diversity receiver are defeated with three photodetectors respectively
Enter end to be connected, the output end of three photodetectors is connect with the input terminal of data acquisition module jointly, finally acquires data
The output end of module and the input terminal of data processing module connect.Wherein the output end of signal generator respectively with photoswitch and phase
The control port of position modulator is connected, and regulates and controls the action time of the two.
Laser light source 1 is opened, the light that laser light source issues successively passes through isolator 2, photoswitch 3 and phase-modulator 4.Its
In, signal generator 7 is connect with photoswitch 3 and phase-modulator 4 respectively, by signal generator 7 generate pulse signal effect in
Photoswitch 3 generates continuous light pulse, acts on phase-modulator 4, generates continuous phase impulse modulation.It is formed phase modulated
Laser pulse light beam；The 1st port for entering circulator 5 by the laser pulse light beam of phase-modulation, by its 2nd port into
Enter the optical fiber of welding optic fibre grating group 6.When fiber grating 6 induction vibration of group, pulsed light beam is penetrated in fiber grating group 6 not
When with fiber grating, there is partial pulse light beam to return to circulator 5.The interference is received using three state polarization diversity receiver 8
Signal, and the interference signal that polarization state portion determines is divided by three tunnels by the three state polarization diversity receiver 8, it is formed altogether newly
Three road interference signals.Interference signal is converted to three tunnel light intensity electric signals by photodetector 9.The acquisition of data acquisition module 10 comes
From 9 light intensity electric signals, it is finally sent to data processing module 11.Fiber grating group can incude the vibration signal of environment, and
When pulsed light beam is through different fiber gratings in fiber grating group, there is partial pulse light beam to return to circulator, adjacent two
The signal of fiber grating reflection generates interference in circulator.
Each fiber grating interval holding in step 2, the fiber grating group of circulator welding is identical, according to data processing mould
Three tunnels that block generates every two adjacent fiber grating totally nine groups of phase shift light intensity signals, will be different by the data structure of setting
Phase shift light intensity signal is distinguish, it is ensured that is not mixed mutually between each signal, is not interfered with each other.What two neighboring fiber grating generated
Interference light intensity signal I (t) expression formula is as follows:
Wherein, phase is closed For initial phase,For drift about phase,Indicate vibration signal phase,
A, B is constant；It is generated for phase-modulator0、The phase intervals of three road light intensity signals substitute intoIt obtains new
Three road interference light intensity signal I (n) such as following formula:
That is:
I (n) is received using three state polarization diversity receiver, since the polarization state of interfering beam during this is uncertain, in
It is to receive the uncertain interference signal of polarization state being emitted from 3 port of circulator using three state polarization diversity receiver and be divided into three
Road then receives the uncertain interference letter of three groups of polarization states of three state polarization classification receiver output using three photodetectors
Number, ensure that three photodetectors at least 1 can receive the resolving that interference signal carries out next step in this way.
Collected interference signal is converted to three tunnel light intensity electric signals, data collecting module collected light intensity telecommunications by photodetector simultaneously
Number, finally it is sent to data processing module；Data processing module passes through calibration phase modulated signal and receives the delay of signal,
It obtains and generates three tunnels totally nine groups of phase shift light intensity signal I after two neighboring fiber grating interferes11、I12、I13、I21、I22、I23、
I31、I32、I33, wherein three groups of phase shift light intensity signals are as shown in Figure 3 in the first via.
The system flow chart of step 3, as shown in connection with fig. 2 algorithm, if the phase shift light intensity signal of the first via is respectively I11,
I12, I13, then | I11-I12| it is B1[cos (θ)+sin (θ)], | I11-I13| it is 2B1Sin (θ), | I12-I13| it is B1[cos(θ)-
sin(θ)].If the phase shift light intensity signal on the second tunnel is respectively I21, I22, I23, then | I21-I22| it is B2[cos (θ)+sin (θ)], |
I21-I23| it is 2B2Sin (θ), | I22-I23| it is B2[cos(θ)-sin(θ)].If the phase shift light intensity signal on third road is respectively I31,
I32, I33, then | I31-I32| it is B3[cos (θ)+sin (θ)], | I31-I33| it is 2S3Sin (θ), | I32-I33| it is B3[cos(θ)-
sin(θ)].Will | I11-I12|, | I11-I13|, | I12-I13| in maximal term be denoted as Imax1, will | I21-I22|, | I21-I23|, |
I22-I23| in maximal term be denoted as Imax2, will | I31-I32|, | I31-I33|, | I32-I33| in maximal term be denoted as Imax3.Same
It inscribes for the moment, Imax1、 Imax2And Imax3Three is simultaneously Bi[cos(θ)+sin(θ)]、2BiSin (θ) or Bi[cos(θ)-sin
(θ)] in a certain item (wherein i=1,2 or 3).Such as at a time, Imax1、Imax2And Imax3Respectively B1[cos(θ)+
sin(θ)]、B2[cos(θ)+sin/(θ)]、B3[cos (θ)+sin (θ)], then compare Imax1、Imax2And Imax3Size can obtain
B out1、B2、B3Size；B under different moments can be compared in the same wayiThe size of value, by BiIt is worth maximum signal all the way
It is determined as the maximum phase shift light intensity signal all the way of contrast.Wherein, certain two adjacent three tunnel phase shift light intensity signal of fiber grating compares
Process is as shown in Figure 4 according to above-mentioned steps.
Step 4, the selection maximum light intensity signal of phase shift all the way of contrast are denoted as I1、I2、I3, then carry out as described in following formula
The phase solution of three step phase-shifting methods:
The phase signal θ that will be obtained after the phase unwrapping acquired in time domain.Wherein, the phase signal θ such as Fig. 5 institute recovered
Show.The phase signal θ of a period of time acquisition sequence constituted is set as array { xn, define difference operator Δ: Δ xn=
xn+1-xnFor the forward difference at n, the phase signal sequence acquired is subjected to forward-difference operator processing and obtains discrete differential
Signal, a certain segment difference sub-signal are as shown in Figure 6.The signal reaction change information of phase signal sequence, wherein changing greatly
Signal segment show that there are disturbing signals in environment.The phase signal sequence under varying environment is acquired, phase signal sequence is poor
Discrete differential signal is obtained after dividing processing and sets suitable threshold value Tmin, exclude the influence of slight perturbations in environment, reduce system
Rate of false alarm counts the number that differential signal in a period of time exceeds threshold value after given threshold, when the number beyond threshold value is more
Triggering alarm.
Embodiment 1
In conjunction with Fig. 1 to Fig. 6, a kind of anti-polarization decay alarm algorithm of Fibre Optical Sensor signal, experiment tests certain optical fiber light
The vibration information of gate sensor, two grating fibers spacing are 24m, sampling time 22s, laser pulse period and phase-modulation arteries and veins
The frequency of punching is 1MHz, and the pulse width of phase-modulation is 160ns in a cycle, selects light intensity signal and alarm algorithm real
Existing step are as follows:
Step 1, in conjunction with Fig. 1, open laser light source 1 and simultaneously allow tester near the optical fiber of welding fiber grating group 6
It walks about, so that 6 induction vibration of fiber grating group, the light that laser light source 1 issues successively passes through isolator 2, photoswitch 3 and phase tune
Device 4 processed, signal generator 7 generate the high-speed pulse signal that frequency is 1MHz, act on photoswitch 3, generate continuous laser arteries and veins
Punching, while the phase-modulation of pi/2 being provided between providing to phase-modulator 4, phase modulated laser pulse light beam is formed, is passed through
The laser pulse light beam of phase-modulation enters the 1st port of circulator 5, and the light of welding optic fibre grating group 6 is entered by the 2nd port
Fibre generates interference signal after the reflection of fiber grating group 6 in circulator 5, and photoelectric converter 8 receives interference signal.Data
Acquisition module 9 acquires the light intensity electric signal generated by photoelectric converter 8, and is sent to data acquisition module 10, data acquisition
Module 10 transmits a signal to data processing module 11, and data processing module is by calibration phase modulated signal and receives signal
Delay, to obtain three tunnel phase shift light intensity signals.
Step 2 keeps each fiber grating interval holding in the fiber grating group of circulator welding identical and is 24m.It is dry
Relate to light intensity signal I (n) such as following formula:
That is:
I (n) is received using three state polarization diversity receiver, while photodetector is converted to collected interference signal
Three tunnel light intensity electric signals, the data collecting module collected light intensity electric signal, are finally sent to data processing module.Data processing
Module obtains after two neighboring fiber grating interferes by the delay of calibration phase modulated signal and reception signal and generates three
Lu Gongjiu group phase shift light intensity signal I11、I12、I13、I21、I22、I23、I31、 I32、I33。
Step 3, the phase shift light intensity signal I by the first via11, I12, I13It indicates, three groups of phase shift light intensity signals locally put
Big figure as shown in figure 3, in figure three kinds not synteny respectively represent three groups of phase shift light intensity signals that phase intervals are pi/2.It counts respectively
Calculate | I11-I12|、|I11-I13|、|I12-I13|.Next will find out | I11-I12|、|I11-I13|、||I12-I13| in maximum
Item is denoted as Imax1.The corresponding I in the second tunnel is found out in the same waymax2I corresponding with third roadmax3, three kinds of line styles in Fig. 4
The curve of drafting has respectively represented Imax1、Imax2、Imax3.As can be seen from the figure Imax3Representative phase shift light intensity signal all the way
Contrast is maximum, the I in this segment signalmax1、Imax2And Imax3Maximum value be respectively 37,78,183；Mean value is respectively
22.3684,46.9813,110.0440.According to the choosing method of phase shift light intensity signal in three tunnels described previously, I is selectedmax3It represents
The light intensity signal of phase shift all the way carry out subsequent phase resolving, data of the road the Gu Jiangci signal as later period resolving phase.
Step 4 chooses Imax3It is representative all the way in three groups of phase shift light intensity signals be denoted as I respectively1、I2、I3, this is comparison
Spend strongest phase shift light intensity signal all the way.The resolving of phase is carried out then according to three step Phase-shifting algorithms, three step phase-shifting method such as following formulas:
The phase signal that will be obtained after the phase unwrapping acquired in time domain.Wherein, the phase signal recovered such as Fig. 5 institute
Show.By a period of time, the phase signal sequence of acquisition is set as array { xn, define difference operator Δ: Δ xn=xn+1-xnFor at n
Forward difference, by the phase signal sequence acquired carry out forward-difference operator processing obtain discrete differential signal.The signal is anti-
The change information of phase signal sequence is answered, wherein the signal segment changed greatly shows that there are disturbing signals in environment.
The phase signal sequence under varying environment is acquired, suitable threshold value will be set after the processing of phase signal differential of sequence
Tmin, the setting of threshold value should exclude the influence of slight perturbations in environment, reduce system rate of false alarm.The number that will be acquired in a period of time
Exceed threshold point quantity statistics according to a signal is carried out, alarms when passing through the quantity overrate of threshold point.Fig. 6 institute
It is shown as phase signal sequence carrying out the discrete differential signal obtained after forward difference processing, is illustrated as sensor-based system someone nearby
The test signal walked about can acquire various ambient noise signals and defined alarm signal in actual samples, according to multiple groups
The threshold value of signal setting alarm is acquired, such as the low alarm setting threshold value in embodiment can be selected as ± 0.5, count difference later
Signal exceeds the number of threshold value, sets nominal threshold value according to ideal system sensitivity requirement and passes through quantity, when one section
Between statistics pass through quantity a little compared with load quantity, judge whether to alarm.
The present embodiment realizes the measurement to phase oscillation signal by a series of measure.The discrete differential finally acquired
Signal graph, fluctuation larger part be test man across optical fiber when generate, the amplitude of discrete differential signal and test man it is practical walk emotionally
Condition is coincide, and the vibration signal for reflecting that the fiber grating signal is chosen and alarm algorithm accurately detects in working range becomes
Change, shows that this method real-time height, strong operability, measurement accuracy is higher, environment resistant interference performance is strong.
Claims (7)
1. a kind of anti-polarization decay alarm algorithm of Fibre Optical Sensor signal, which is characterized in that method and step is as follows:
Step 1 opens laser light source, and emergent light is made successively to pass through isolator, photoswitch and phase-modulator；Wherein, signal is sent out
Raw device is connect with photoswitch and phase-modulator respectively, generates pulse signal effect in photoswitch, the company of generation by signal generator
Continuous light pulse, acts on phase-modulator, generates continuous phase impulse modulation；Phase modulated laser pulse light beam is formed,
The 1st port for entering circulator by the laser pulse light beam of phase-modulation enters the fiber grating of welding by its 2nd port
Group；Fiber grating group incudes the vibration signal of environment, and when pulsed light beam penetrates the different fiber gratings in fiber grating group,
There is partial pulse light beam to return to circulator, the signal of adjacent two fiber grating reflection generates interference in circulator, then from
The 3rd port of circulator exports interference signal；
Interference light intensity signal I (t) expression formula that step 2, two neighboring fiber grating generate is as follows:
Wherein, phase is closed For initial phase,For drift about phase,Indicate vibration signal phase, A, B are equal
For constant；It is generated for phase-modulator0、The phase intervals of three road light intensity signals substitute intoObtain tri- tunnel Xin
Interference light intensity signal I (n) such as following formula:
That is:
The uncertain interference signal of polarization state being emitted from 3 port of circulator is received using three state polarization diversity receiver, and will
It is divided into tri- road interference signal of Xin, all includes three groups of above-mentioned interference light intensity signals per interference signal all the way；Three tunnels interference letter
Number three tunnel light intensity electric signals, data collecting module collected light intensity electric signal are converted to by three photodetectors, and are sent
Enter data processing module；Data processing module is finally obtained adjacent by the delay of calibration phase modulated signal and reception signal
Two fiber gratings generate three tunnels totally nine groups of phase shift light intensity signal I after interfering11、I12、I13、I21、I22、I23、I31、I32、
I33；
Step 3, three groups of phase shift light intensity signals for setting the first via are respectively I11, I12, I13, then | I11-I12| it is B1[cos(θ)+sin
(θ)], | I11-I13| it is 2B1Sin (θ), | I12-I13| it is B1[cos(θ)-sin(θ)]；Will | I11-I12|, | I11-I13|, | I12-
I13| in maximal term be denoted as Imax1；The I on the second tunnel is found out in the same waymax2And the I on third roadmax3；
Under synchronization, Imax1、Imax2And Imax3Three is simultaneously Bi[cos(θ)+sin(θ)]、2BiSin (θ) or Bi[cos
(θ)+sin (θ)] in a certain item (wherein i=1,2 or 3)；At a time, if Imax1、Imax2And Imax3Respectively B1[cos
(θ)+sin(θ)]、B2[cos(θ)+sin(θ)]、B3[cos (θ)+sin (θ)], then compare Imax1、Imax2And Imax3Size
Obtain B1、B2、B3Size；B under different moments can be compared in the same wayiThe size of value, by BiIt is worth maximum true all the way
It is set to the maximum phase shift light intensity signal all the way of contrast；
Step 4, the selection maximum light intensity signal of phase shift all the way of contrast are denoted as I1、I2、I3, then carry out the solution of three step phase-shifting methods
And unpack and obtain phase signal, phase signal contains the information of phase in time domain, and phase signal carries out forward difference and calculates
To discrete differential signal, the discrete differential signal reaction change information of phase signal, wherein the signal segment changed greatly shows
There are disturbing signals in environment；The discrete differential signal under various environment, which is calculated, by acquisition carries out signal threshold value TminSetting,
Statistics of the data discrete differential signal of progress beyond threshold point quantity that will acquire in a period of time, when passing through threshold point
It alarms when quantity overrate.
2. the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal according to claim 1, it is characterised in that: the step
In 2, the interference signal in the different polarization direction come out by 3 port transmission of circulator is received using three state polarization diversity receiver,
It is divided into three tunnels again, receiver at least 1 of three polarization directions in three state polarization diversity receiver is made to can ensure that reception
The resolving of next step is carried out to interference signal.
3. the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal according to claim 1, it is characterised in that: the step
In 2, the interval holding of each fiber grating is identical, three tunnels for being generated every two adjacent fiber grating according to data processing module
Different phase shift light intensity signals are distinguish, it is ensured that between each signal by totally nine groups of phase shift light intensity signals by the data structure of setting
Do not mix mutually, interfere with each other.
4. the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal according to claim 1, it is characterised in that: the step
In 4, according to three step Phase-shifting algorithms, phase signal θ is solved:
Wherein, three groups of phase shift light intensity signals in the maximum signal all the way of contrast are followed successively by I1、I2、I3。
5. the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal according to claim 1, it is characterised in that: the step
In 4, the phase signal θ of a period of time acquisition sequence constituted is set as array { xn, define difference operator Δ: Δ xn=xn+1-
xnFor the forward difference at n, phase signal sequence is subjected to forward-difference operator processing and obtains discrete differential signal, according to adopting
Phase signal sequence under the different situations collected is judged, alarm threshold value is finally set.
6. the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal according to claim 5, it is characterised in that: acquisition is different
Phase signal sequence under environment will set suitable threshold value T after the processing of phase signal differential of sequencemin, exclude slight in environment
The influence of disturbance reduces system rate of false alarm, and the number that discrete differential signal in a period of time exceeds threshold value is counted after given threshold,
The triggering alarm when the number beyond threshold value is more.
7. the anti-polarization decay alarm algorithm of Fibre Optical Sensor signal according to claim 6, it is characterised in that: exceed threshold value
Number refer to differential data exceeded threshold TminThe quantity of point, the specified quantity that surmounts for reaching alarm is according to environmental condition
Setting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810548215.5A CN109084816B (en) | 2018-05-31 | 2018-05-31 | Anti-polarization-fading alarm algorithm for optical fiber sensing signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810548215.5A CN109084816B (en) | 2018-05-31 | 2018-05-31 | Anti-polarization-fading alarm algorithm for optical fiber sensing signal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109084816A true CN109084816A (en) | 2018-12-25 |
| CN109084816B CN109084816B (en) | 2020-09-18 |
Family
ID=64839209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810548215.5A Active CN109084816B (en) | 2018-05-31 | 2018-05-31 | Anti-polarization-fading alarm algorithm for optical fiber sensing signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109084816B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022181935A1 (en) * | 2021-02-26 | 2022-09-01 | 주식회사 피피아이 | Reflected optical wavelength scanning device provided with silicon photonic interrogator |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9009003B1 (en) * | 2012-05-03 | 2015-04-14 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Apparatus and method for elimination of polarization-induced fading in fiber-optic sensor system |
| CN106323478A (en) * | 2016-10-09 | 2017-01-11 | 中国船舶重工集团公司第七〇五研究所 | Phase generation and carrier modulation and demodulation system of optical fiber interferometric sensor with polarization fading resistance |
| CN107179097A (en) * | 2016-03-10 | 2017-09-19 | 南京理工大学 | The optical fiber interference type sensing modulation-demo-demodulation method and device modulated based on phase shift signal |
| CN107290042A (en) * | 2016-04-05 | 2017-10-24 | 南京理工大学 | The optical fiber grating sensing modulation-demo-demodulation method and device modulated based on phase shift signal |
-
2018
- 2018-05-31 CN CN201810548215.5A patent/CN109084816B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9009003B1 (en) * | 2012-05-03 | 2015-04-14 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Apparatus and method for elimination of polarization-induced fading in fiber-optic sensor system |
| CN107179097A (en) * | 2016-03-10 | 2017-09-19 | 南京理工大学 | The optical fiber interference type sensing modulation-demo-demodulation method and device modulated based on phase shift signal |
| CN107290042A (en) * | 2016-04-05 | 2017-10-24 | 南京理工大学 | The optical fiber grating sensing modulation-demo-demodulation method and device modulated based on phase shift signal |
| CN106323478A (en) * | 2016-10-09 | 2017-01-11 | 中国船舶重工集团公司第七〇五研究所 | Phase generation and carrier modulation and demodulation system of optical fiber interferometric sensor with polarization fading resistance |
Non-Patent Citations (2)
| Title |
|---|
| 张文华 等: "基于外差解调的偏振分集接收技术的研究", 《光纤与电缆及其应用技术》 * |
| 王潇 等: "干涉型光纤传感系统偏振分集接收实验研究", 《光学学报》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022181935A1 (en) * | 2021-02-26 | 2022-09-01 | 주식회사 피피아이 | Reflected optical wavelength scanning device provided with silicon photonic interrogator |
| KR20220122331A (en) * | 2021-02-26 | 2022-09-02 | 주식회사 피피아이 | Reflected light wavelength scanning device including silicon photonics interrogator |
| KR102522885B1 (en) * | 2021-02-26 | 2023-04-18 | 주식회사 피피아이 | Reflected light wavelength scanning device including silicon photonics interrogator |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109084816B (en) | 2020-09-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Wu et al. | Feature extraction and identification in distributed optical-fiber vibration sensing system for oil pipeline safety monitoring | |
| CN105806465B (en) | A kind of novel Φ-OTDR detection device and its detection method based on fixation reflex point | |
| CN102360519B (en) | Intrusion detecting and positioning method for distributed optical fiber fence | |
| CN200979076Y (en) | Distributed optical fiber oil gas pipeline alarming and sensor device | |
| CN104990620A (en) | Fiber bragg grating array-based phase-sensitive optical time domain reflection device and method | |
| CN111222743B (en) | Method for judging vertical offset distance and threat level of optical fiber sensing event | |
| CN105067104A (en) | Composite optical fiber sensing system and sensing method | |
| CN107782438A (en) | Optical fiber raster vibration measuring system based on pulse code and edge filter demodulation method | |
| CN103196465A (en) | Phase sensitive optical time-domain reflectometer (phi-OTDR) sensing signal noise separation and signal extraction method | |
| CN105651373B (en) | A method of based on measurement two o'clock once per revolution vibration in polarized light time domain reflection technology | |
| CN104376306A (en) | Optical fiber sensing system invasion identification and classification method and classifier based on filter bank | |
| CN106254064A (en) | A kind of receiving terminal local oscillator light method for safety monitoring being applicable to continuous variable quantum key distribution | |
| CN109084816A (en) | A kind of anti-polarization decay alarm algorithm of Fibre Optical Sensor signal | |
| CN107730798A (en) | A kind of early warning system and method | |
| CN107290042A (en) | The optical fiber grating sensing modulation-demo-demodulation method and device modulated based on phase shift signal | |
| CN113721287A (en) | Monitoring method and device based on sensing optical fiber | |
| CN104833378B (en) | Method for identifying interference signal of optical fiber perimeter system | |
| CN105675501B (en) | A kind of fluid composition analysis instrument and its detection channels method for arranging | |
| CN110987151A (en) | Communication optical cable state real-time monitoring system | |
| CN114362830B (en) | Shock detection method based on TF-QKD network and TF-QKD network | |
| CN109781156A (en) | BOTDA system and its method for sensing based on brillouin gain spectrum modulation | |
| CN112179475B (en) | Separation method of multi-source aliasing distributed optical fiber vibration sensing signals | |
| CN112532337B (en) | Distributed high-precision optical fiber vibration invasion and online monitoring detector | |
| CN115165071A (en) | Method and system for realizing accurate vibration positioning based on machine learning and phase segmentation difference | |
| CN207515900U (en) | Optical fiber raster vibration measuring system based on pulse code and edge filter demodulation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |