CN102280001B - Distributed optical fiber fence intrusion detection and location method based on phi-OTDR (Optical Time Domain Reflectometer) - Google Patents
Distributed optical fiber fence intrusion detection and location method based on phi-OTDR (Optical Time Domain Reflectometer) Download PDFInfo
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- CN102280001B CN102280001B CN 201110214678 CN201110214678A CN102280001B CN 102280001 B CN102280001 B CN 102280001B CN 201110214678 CN201110214678 CN 201110214678 CN 201110214678 A CN201110214678 A CN 201110214678A CN 102280001 B CN102280001 B CN 102280001B
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Abstract
The invention discloses a distributed optical fiber fence intrusion detection and location method based on a phi-OTDR (Optical Time Domain Reflectometer), and the method comprises the following steps of: firstly, subtracting an acquired ith signal by an acquired (i-1)th signal to obtain a preprocessing monitoring signal; secondly, carrying out at least four-layer wavelet decomposition on the preprocessing monitoring signal by adopting a plurality of wavelet functions; thirdly, judging whether actual intrusion exists according to the consistency of distribution positions of maximum-wavelet mode maximums in all scale signals; fourthly, judging that the actual intrusion exists if the distribution positions of the maximum-wavelet mode maximums in at least three scale signals are consistent; fifthly, corresponding multiplying the scale signals in which the intrusion exists and the distribution positions of the maximum-wavelet mode maximums are consistent to obtain a composite signal of which pseudo maximums are inhibited and mode maximums at a catastrophe point are enhanced, using a position corresponding to the maximum-mode maximum in the composite signal as a position of the determined intrusion point, determining the intrusion generation and the intrusion position by combining various composite signal judgment results of wavelet multi-scale analysis according to the majority voting criterion.
Description
Technical field
The present invention relates to circumference security protection and distributing optical fiber sensing signal process field, be specifically related to a kind of distributed optical fiber fence intrusion detection based on Φ-OTDR and the method for location.
Background technology
(Φ-OTDR) is a kind of new distribution type optical fiber sensing technology to the phase-sensitive optical time domain reflectometer.Identical with conventional optical time domain reflectometer (OTDR) is that light pulse is injected from an end of optical fiber, surveys backward Rayleigh scattering light by detector and judges disturbance and abort situation; Different is, what Φ-OTDR system was injected is strong coherent light, and surveying what obtain is the result of backward Rayleigh scattering light interference in the pulse width range, judges the position of noise spot by measuring input pulse and the time delay of the interference signal that receives.
In actual applications, although the distributed optical fiber fence system for monitoring intrusion has many outstanding advantages with respect to other system, but because monitoring distance is long, environmental interference is responsive to external world, and optical system is subject to external environment and temperature effect is unstable, the monitor signal signal to noise ratio (S/N ratio) is lower, and self fluctuates and cause greatly intrusion detection difficulty, and the simultaneity factor rate of false alarm is higher.How accurately to detect invasion and accurately determine invasion point position under strong noise background, effectively reducing the misreport of system rate is the subject matter that long-distance distributed optical fiber fence system for monitoring intrusion faces, directly the application prospect of decision systems.
Summary of the invention
For above-mentioned prior art, the technical problem to be solved in the present invention provides a kind of based on Φ-OTDR(phase-sensitive optical time domain reflectometer) the distributed optical fiber fence intrusion detection and the method for location, it can effectively extract invasion signal real features, detect and locate, noise effect be can also avoid, distributed optical fiber fence invasion information and accurate location accurately detected.
In order to solve the problems of the technologies described above, the present invention adopts following technical scheme: a kind of based on the distributed optical fiber fence intrusion detection of Φ-OTDR and the method for location, may further comprise the steps:
The i time signal and the i-1 time collection signal of collecting are subtracted each other, obtain pretreated monitor signal;
Adopt at least three kinds of wavelet functions that preprocessed signal is carried out wavelet decomposition;
For every kind of wavelet function the pre-service monitor signal is carried out at least four layers of wavelet decomposition;
For every kind of wavelet decomposition, judge according to Wavelet Modulus Maxima distributing position consistance maximum in its all magnitude signals whether true invasion exists; Wherein, the maximum wavelet modulus maximum distributing position in the three scales signal thinks then that unanimously true invasion exists at least;
There are invasion and the consistent magnitude signal correspondence of maximum wavelet modulus maximum distributing position to multiply each other judgement, obtain all suppressed composite signals that is enhanced with catastrophe point place modulus maximum of a pseudo-maximum value, the corresponding position of maximum norm maximum value is the position of definite invasion point in the composite signal;
The composite signal judged result of last comprehensive multiple wavelet multi-scale analysis, according to majority ballot criterion, final generation and the invasion position thereof of determining invasion.
Further, described wavelet function is haar, db6, four kinds of coif5 and sym5.
Further, through haar, db6, after four kinds of wavelet functions of coif5 and sym5 decompose, four kinds of wavelet multi-scale analysis results are carried out comprehensively again, if two or more wavelet decomposition has obtained identical or consistent judged result, think that then true invasion exists; When confirming that the invasion point exists, the composite signal under each wavelet decomposition that judged result is consistent multiplies each other and obtains the more specific location information of final catastrophe point.
Further, each wavelet function carries out six layers of wavelet decomposition with monitor signal, comprises ground floor detail coefficients d1, second layer detail coefficients d2, the 3rd layer of detail coefficients d3, the 4th layer of detail coefficients d4, layer 5 detail coefficients d5, layer 6 detail coefficients d6 and layer 6 approximate signal a6.
The present invention is according to Φ-OTDR distributed optical fiber fence system intrusion detection principle, fibre circuit is subject to extraneous the invasion when invasion occurs, the corresponding position optical fibre refractivity changes, cause this place's coherent light phase differential to change and cause that its backward Rayleigh scattering light interference fringe changes, can obtain namely invading information along the light intensity change information of whole optical fiber space distribution through twice continuous acquisition signal subtraction.Signal essence during invasion is with the signal of sudden change, namely undergos mutation in a certain position of signal amplitude, causes the discontinuous of signal, and its catastrophe point belongs to the first type discontinuous point.The sudden change that intrusion detection is actually non-stationary signal detects, because sudden change has short, wide band characteristics of duration, therefore adopts this powerful of wavelet transformation to detect.
Compared with prior art, the present invention has following beneficial effect: based on phase-sensitive optical time domain reflectometer (the distributed optical fiber fence system for monitoring intrusion of technology of Φ-OTDR), utilize the optical fiber disturbance of optical cable self that online real-time detection, warning and location are carried out in the threat security incidents such as circumference invasion, realize intrusion detection and the defence in important area circumference or national defence border.System has good concealment, monitoring sensitivity is high, the monitoring distance range is wide in, long outstanding features such as bearing accuracy are high, system cost is lower.In addition, the maximum characteristics of this system are to need not special sensing optic cable, utilize the circuit of common communications optical cable own as sensing unit, realize on-line monitoring and Realtime Alerts, can greatly save system cost and other people power, material resources, financial resources, realize simultaneously detection alarm and location dual-use function, high for long distance and extra long distance periphery intrusion preventing monitoring cost performance.
Description of drawings
Fig. 1 is the intruding detection system schematic diagram of the embodiment of the invention;
Fig. 2 is intrusion detection and the location algorithm flow process of the embodiment of the invention;
Signal carried out haar wavelet decomposition result when Fig. 3 was the embodiment of the invention without invasion;
Fig. 4 has the invasion signal to carry out haar wavelet decomposition result when being embodiment of the invention high s/n ratio;
Fig. 5 has the signal of invasion to carry out haar wavelet decomposition result when being embodiment of the invention low signal-to-noise ratio;
The comprehensive judged result of a plurality of wavelet decomposition when Fig. 6 is the high s/n ratio of the embodiment of the invention;
The comprehensive judged result of a plurality of wavelet decomposition when Fig. 7 is the low signal-to-noise ratio of the embodiment of the invention.
Embodiment
The invention will be further described below in conjunction with the drawings and the specific embodiments.
As shown in Figure 1, a kind of distributed optical fiber fence intrusion detection and positioning system based on Φ-OTDR comprise:
Optical cable is used for the invasion in the perception external world, and it is neighbouring or underground to be embedded in the circumference that need to carry out intrusion detection;
Laser instrument is for generation of strong coherent light;
Modulator is used for receiving the strong coherent light that laser instrument transmits, and modulates burst pulse light;
Coupling mechanism is for an end of rear injection fibre that burst pulse light is coupled;
Photodetector is used for surveying the rear generation that changes and judge whether invasion to the Rayleigh scattering light result of interference of the burst pulse light that transmits at optical fiber;
Signals collecting and treating apparatus, it is alarm host machine, be used for measuring input optical pulse and judge the position of invading point with the time delay of the interference variable signal that receives, send CPU (central processing unit) to by the high-speed data acquisition card image data in the present embodiment and process.
In optical fibre channel, can require to select some fiber amplifier equipment according to monitoring distance, such as Erbium-Doped Fiber Amplifier (EDFA), raman amplifier etc.The course of work of said system is as follows: send strong coherent light by narrow band laser and go out burst pulse light through modulators modulate, light pulse is injected through the end of coupling mechanism from optical fiber, the Rayleigh scattering that occurs during through Optical Fiber Transmission, survey backward Rayleigh scattering light result of interference by detector and change the generation of judging invasion, judge the position of noise spot by measuring input pulse and the time delay of the interference variable signal that receives.
Based on distributed optical fiber fence intrusion detection and the location algorithm flow process of Φ-OTDR, as shown in Figure 2, by the signal processing host, with the i time collection signal and front once namely the i-1 time collection signal subtract each other, obtain pretreated monitor signal; The parallel haar that adopts, db6, four kinds of wavelet functions of coif5 and sym5 carry out multi-level Wavelet Transform to the pre-service monitor signal respectively and decompose.As preferably, utilize each wavelet function that monitor signal is carried out 6 layers of wavelet decomposition, be divided into ground floor detail coefficients d1, second layer detail coefficients d2, the 3rd layer of detail coefficients d3, the 4th layer of detail coefficients d4, layer 5 detail coefficients d5, layer 6 detail coefficients d6 and layer 6 approximate signal a6; Based on basically identical these characteristics in the invasion sign mutation point position that the modulus maximum horizontal ordinate is corresponding under different scale, judge according to maximum wavelet modulus maximum (absolute value) distributing position in all magnitude signals (asterisk among Fig. 3,4,5,6,7 " * " number expression) consistance whether true invasion exists, as judgment threshold, the maximum wavelet modulus maximum distributing position at least 3 magnitude signals thinks then that unanimously true invasion exists to position consistency with the spatial resolution of system location.Fig. 3, Fig. 4, Fig. 5 be respectively unlike signal carry out 6 layers of decomposition result: Fig. 3 of haar small echo for without when invasion signal carry out haar wavelet decomposition result, its ground floor detail coefficients d1 maximum wavelet modulus maximum distributing position on layer 6 detail coefficients d6 and each magnitude signal of layer 6 approximate signal a6 is stochastic distribution, therefore be judged as without invasion, need not to carry out next step location; Fig. 4 is that the invasion signal carries out haar wavelet decomposition result in the high s/n ratio situation, the maximum wavelet modulus maximum is basically identical at ground floor detail coefficients d1 distributing position on layer 6 detail coefficients d6 and the layer 6 approximate signal a6 on its each magnitude signal, and invasion is arranged in the decision signal; Fig. 5 is that the invasion signal carries out haar wavelet decomposition result in the low signal-to-noise ratio situation, because noise effect, maximum wavelet modulus maximum position has inconsistent individually on its each magnitude signal, show the 4th layer of detail coefficients d4, on layer 6 detail coefficients d6 and the layer 6 approximate signal a6, but at ground floor detail coefficients d1, second layer detail coefficients d2, the 3rd layer of detail coefficients d3, distributing position is all consistent on four magnitude signals of layer 5 detail coefficients d5, still in the talkative clear signal invasion is arranged.
Judge when invasion is arranged, also need to carry out catastrophe point and namely invade a little accurate location, concrete invasion independent positioning method: have invasion and the consistent magnitude signal correspondence of maximum wavelet modulus maximum distributing position to multiply each other above-mentioned judgement, obtain a composite signal, such as the composition(composite signal among Fig. 4 and Fig. 5) shown in the signal, through behind the product, when pseudo-maximum value is inhibited, the modulus maximum at catastrophe point place has obtained enhancing, the corresponding position of maximum norm maximum value is the position of definite invasion point in the composite signal, such as Fig. 4, shown in the asterisk among Fig. 5 in the composition signal " * " number.Other wavelet functions db6, the wavelet-decomposing method of coif5 and sym5 and the judgement of catastrophe point information and localization method are identical with wavelet function haar's.
Through haar, db6, after four kinds of wavelet functions of coif5 and sym5 decompose, four kinds of wavelet multi-scale analysis results are carried out comprehensively again, the most ballot of utilization criterions are invaded judgement and location a little, obtain the final result of decision: if two or more wavelet-decomposing method has obtained identical or consistent judged result, namely judging simultaneously has invasion, and the invasion position consistency of determining in the composite signal separately thinks that then true invasion exists; Otherwise think that true invasion does not exist.When confirming that the invasion point exists, each wavelet decomposition result of invasion point will be determined to exist, be that composite signal under each wavelet decomposition multiplies each other and obtains the more specific location information of final catastrophe point, the alarming result that final acquisition needs, be recorded in the alarm log, convenience is put on record to alert event and is inquired about; Such as Fig. 6, shown in Figure 7, be respectively the comprehensive judged result in two kinds of situations of high s/n ratio and low signal-to-noise ratio.By the judged result under Fig. 7 low signal-to-noise ratio as can be known, when a certain wavelet decomposition result judges that invasion information is inaccurate, because other wavelet decomposition are consistance as a result, comprehensive judged result remains correct, this inventive method can effectively reduce the generation of system's false-alarm or wrong report, has greatly improved the level of confidence of Distributed intrusion detection system intrusion detection and location.
The distributed optical fiber fence system for monitoring intrusion specific implementation method of the Φ-OTDR technology that is based on of enumerating in the embodiment of the invention, the haar that adopts in this inventive method, db6, four kinds of wavelet functions of coif5 and sym5; But can substitute with other various wavelet functions fully, the catastrophe point that proposes judges that also can be applied to other relevant various jump signals fully with localization method detects in the application.
Claims (4)
1. one kind based on the distributed optical fiber fence intrusion detection of Φ-OTDR and the method for location, it is characterized in that, may further comprise the steps:
The i time signal and the i-1 time collection signal of collecting are subtracted each other, obtain the pre-service monitor signal;
Adopt at least three kinds of wavelet functions that preprocessed signal is carried out wavelet decomposition;
For every kind of wavelet function the pre-service monitor signal is carried out at least four layers of wavelet decomposition;
For every kind of wavelet decomposition, judge according to Wavelet Modulus Maxima distributing position consistance maximum in its all magnitude signals whether true invasion exists; Wherein, the maximum wavelet modulus maximum distributing position in the three scales signal thinks then that unanimously true invasion exists at least;
There are invasion and the consistent magnitude signal correspondence of maximum wavelet modulus maximum distributing position to multiply each other judgement, obtain all suppressed composite signals that is enhanced with catastrophe point place modulus maximum of a pseudo-maximum value, the corresponding position of maximum norm maximum value is the position of definite invasion point in the composite signal;
The composite signal judged result of last comprehensive multiple wavelet multi-scale analysis, according to majority ballot criterion, final generation and the invasion position thereof of determining invasion.
2. according to claim 1 based on the distributed optical fiber fence intrusion detection of Φ-OTDR and the method for location, it is characterized in that: described wavelet function is haar, db6, four kinds of coif5 and sym5.
3. according to claim 2 based on the distributed optical fiber fence intrusion detection of Φ-OTDR and the method for location, it is characterized in that: through haar, db6, after four kinds of wavelet functions of coif5 and sym5 decompose, four kinds of wavelet multi-scale analysis results are carried out comprehensively again, if having obtained identical or consistent judged result, two or more wavelet decomposition judge simultaneously that namely invasion is arranged, and the invasion position consistency of determining in the composite signal separately, think that then true invasion exists; Otherwise think that true invasion does not exist; When confirming that the invasion point exists, will determine to exist each wavelet decomposition result of invasion point, namely the composite signal under each wavelet decomposition multiplies each other and obtains the more specific location information of final catastrophe point.
4. according to claim 1 and 2 or 3 described based on the distributed optical fiber fence intrusion detection of Φ-OTDR and the method for location, it is characterized in that: each wavelet function carries out six layers of wavelet decomposition with monitor signal, comprise ground floor detail coefficients (d1), second layer detail coefficients (d2), the 3rd layer of detail coefficients (d3), the 4th layer of detail coefficients (d4), layer 5 detail coefficients (d5), layer 6 detail coefficients (d6) and layer 6 approximate signal (a6).
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| CN107667489A (en) * | 2015-05-28 | 2018-02-06 | 瑞典爱立信有限公司 | Apparatus and method for monitoring fiber link |
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