CN113295259A - Distributed optical fiber sensing system - Google Patents
Distributed optical fiber sensing system Download PDFInfo
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- CN113295259A CN113295259A CN202110573380.8A CN202110573380A CN113295259A CN 113295259 A CN113295259 A CN 113295259A CN 202110573380 A CN202110573380 A CN 202110573380A CN 113295259 A CN113295259 A CN 113295259A
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- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
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Abstract
The invention discloses a distributed optical fiber sensing system, which comprises an optical fiber sensing module, a first data processing module, a first data storage module, a first display module and a first communication module, wherein the optical fiber sensing module is used for sensing optical fiber; the invention provides a distributed optical fiber sensing system, which realizes intelligent monitoring and intelligent control on a target to be monitored, is not only applied to the safety monitoring field of monitoring targets such as intelligent security and protection field, road safety monitoring and the like, but also applied to the safety monitoring field of monitoring the targets, such as pipeline safety monitoring, railway safety monitoring and the like, and provides a new technical idea for intelligent monitoring.
Description
Technical Field
The invention relates to the technical field of intelligent monitoring, in particular to a distributed optical fiber sensing system.
Background
The intelligent monitoring is to utilize a sensor to collect and record monitoring target information in real time, and can grasp the existing condition of the monitoring target and predict the change condition of the monitoring target by intelligently analyzing the target information, thereby realizing the intelligent management of the monitoring target.
The intelligent monitoring has higher requirement to the sensor, and more current sensors are the sensor that sets up above ground, not only receive external environment's influence, and the disguise is not strong moreover, is destroyed easily.
In the telecommunications industry, there is an optical time domain reflectometer, a technique for analyzing optical fibers and other optical components that can detect high attenuation points in the optical fiber, such as breaks and splice losses; also included is a correlation technique using coherent optical pulses in a single mode fiber. This coherence causes the components of the backscattered light to interfere with each other and produce intensity variations at the photodetector. The magnitude of this light intensity variation depends on the intensity of the light backscattered at the backscatter point and on the phase of the light. In an optical fiber, the amplitude and phase of the backscatter varies depending on the position of the length of the fiber. This variation results from the inherent small variations in the glass fibers. The presence of external influences or disturbances (such as temperature and pressure) or acoustic waves can cause changes in the refractive index of the fiber. These changes in the refractive index cause the velocity of the light pulses and the backscattered light to change along the fiber. The phase of the backscattered light received by the photodetector will then vary with these external influences. Therefore, the intensity of the backscattered light also changes under these external influences. Based on the technical characteristics, the optical fiber or the optical fiber sensor is laid in the target area of the target to be monitored, the monitoring purpose of the target to be monitored can be realized by collecting the change of the optical fiber transmission signal in the target area, and therefore, an optical fiber sensing system is urgently needed to meet the technical requirement of intelligent monitoring.
Disclosure of Invention
The invention aims to provide a distributed optical fiber sensing system, which comprises:
the optical fiber sensing module is used for collecting position information and motion information of a target to be monitored, wherein the motion information at least comprises a motion speed and a motion direction;
the first data processing module is used for acquiring first data of the target to be monitored according to the position information and the motion information, wherein the first data is used for representing the motion track of the target to be monitored or the stress condition of the target to be monitored, which is subjected to an external force;
the first data storage module is respectively connected with the optical fiber sensing module and the data processing module;
the first display module is connected with the data storage module and used for displaying the first data;
and the first communication module is connected with the first data storage module and is used for data interaction between the system and other systems.
Preferably, the optical fiber sensing module is composed of a plurality of optical fiber sensors, wherein each optical fiber sensor at least comprises a sensor optical fiber, a light source, a photoelectric detector and an analysis unit;
the sensor optical fiber is respectively connected with the light source and the photoelectric detector;
the light source is used for providing light pulses for the sensor optical fiber;
the photoelectric detector is used for obtaining a time speckle pattern of the sensor optical fiber, wherein the time speckle pattern is used for representing an image obtained by backscattering the optical pulse by the sensor optical fiber;
the analysis unit is used for obtaining position information and motion information according to the time speckle pattern.
Preferably, the sensor fiber comprises a first polarization eigenmode, a second polarization eigenmode;
the first polarization eigenmode is used for obtaining a first image;
the second polarization eigenmode is used for obtaining a second image;
the photodetector is configured to obtain a temporal speckle pattern based on the first image and the second image.
Preferably, the time speckle pattern comprises several speckle patterns;
the analysis unit is used for comparing the adjacent speckle patterns to obtain a plurality of first characteristic patterns, and then comparing the adjacent first characteristic patterns to obtain position information and motion information.
Preferably, the position information at least comprises a stressed position of the target to be monitored and a distance position of the target to be monitored relative to a reference target, wherein the reference target is used for representing a monitoring station or a monitoring point for monitoring the target to be monitored and a reference for measuring the position of the target to be monitored.
Preferably, the first data processing module at least comprises a data analysis unit and an early warning unit;
the data analysis unit is used for obtaining first data;
the early warning unit is used for obtaining a first instruction according to the first data, wherein the first instruction is used for representing a first safety degree of the target to be monitored, and the first safety degree is used for representing a first safety condition of the target to be monitored in the existing state.
Preferably, the system further comprises an early warning module;
the early warning unit is respectively connected with the early warning module and the first display module;
the early warning module is used for converting the first instruction into voice or early warning sound;
the first display module is also used for displaying a first instruction on the current interface.
Preferably, the system further comprises a first system for application in a mobile device, comprising,
the second display module is used for displaying the first instruction and the first data;
the second data storage module is used for storing the first data and the first instruction;
and the second communication module is used for the data interaction between the first system and the system.
Preferably, the system further comprises a second system applied in the cloud server, comprising,
the third data storage module is used for storing second data of a second system, wherein the second data at least comprises first data, a first instruction and a second instruction obtained by the second system according to the first data;
the second data processing module is used for obtaining situation data of the target to be monitored according to the first data, predicting a second safety degree of the target to be monitored according to the situation data and obtaining a second instruction, wherein the second safety degree is used for representing a second safety situation of the target to be monitored after the target to be monitored continues to be in the existing state;
the third communication module is used for the second system to respectively carry out data interaction with the first system and the system;
the first display module and the second display module are also used for displaying a second instruction.
Preferably, the system further comprises a third system for application in the object to be monitored, comprising,
the fourth communication module is used for the data interaction between the third system and the system and between the third system and the second system respectively;
the fourth storage module is used for storing the first instruction and the second instruction;
and the control module is used for controlling the target to be monitored according to the first instruction or the second instruction.
The invention discloses the following technical effects:
the invention provides a distributed optical fiber sensing system, which realizes intelligent monitoring and intelligent control on a target to be monitored, is not only applied to the safety monitoring field of monitoring targets such as the intelligent security field and road safety monitoring, but also applied to the safety monitoring field of monitoring the targets per se such as pipeline safety monitoring and railway safety monitoring, and provides a new technical idea for intelligent monitoring.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a system according to the present invention;
fig. 2 is a schematic structural diagram of an optical fiber sensing module according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1-2, the present invention provides
A distributed fiber optic sensing system comprising:
the optical fiber sensing module is used for collecting position information and motion information of a target to be monitored, wherein the motion information at least comprises a motion speed and a motion direction;
the first data processing module is used for acquiring first data of the target to be monitored according to the position information and the motion information, wherein the first data is used for representing the motion track of the target to be monitored or the stress condition of the target to be monitored, which is subjected to an external force;
the first data storage module is respectively connected with the optical fiber sensing module and the data processing module;
the first display module is connected with the data storage module and used for displaying the first data;
and the first communication module is connected with the first data storage module and is used for data interaction between the system and other systems.
The optical fiber sensing module consists of a plurality of optical fiber sensors, wherein each optical fiber sensor at least comprises a sensor optical fiber, a light source, a photoelectric detector and an analysis unit; the sensor optical fiber is respectively connected with the light source and the photoelectric detector; the light source is used for providing light pulses for the sensor optical fiber; the photoelectric detector is used for obtaining a time speckle pattern of the sensor optical fiber, wherein the time speckle pattern is used for representing an image obtained by backscattering the optical pulse by the sensor optical fiber; the analysis unit is used for obtaining position information and motion information according to the time speckle pattern.
The sensor fiber comprises a first polarization eigenmode and a second polarization eigenmode; the first polarization eigenmode is used for obtaining a first image; the second polarization eigenmode is used for obtaining a second image; the photodetector is configured to obtain a temporal speckle pattern based on the first image and the second image.
The time speckle pattern comprises a plurality of speckle patterns; the analysis unit is used for comparing the adjacent speckle patterns to obtain a plurality of first characteristic patterns, and then comparing the adjacent first characteristic patterns to obtain position information and motion information.
The position information at least comprises the stress position of the target to be monitored and the distance position of the target to be monitored relative to a reference target, wherein the reference target is used for representing a monitoring station or a monitoring point for monitoring the target to be monitored and a reference for measuring the position of the target to be monitored.
The first data processing module at least comprises a data analysis unit and an early warning unit; the data analysis unit is used for obtaining first data; the early warning unit is used for obtaining a first instruction according to the first data, wherein the first instruction is used for representing a first safety degree of the target to be monitored, and the first safety degree is used for representing a first safety condition of the target to be monitored in the existing state.
The system also comprises an early warning module; the early warning unit is respectively connected with the early warning module and the first display module; the early warning module is used for converting the first instruction into voice or early warning sound; the first display module is also used for displaying a first instruction on the current interface.
The system also comprises a first system applied in the mobile equipment, and the first system comprises a second display module and a first display module, wherein the second display module is used for displaying the first instruction and the first data; the second data storage module is used for storing the first data and the first instruction; and the second communication module is used for the data interaction between the first system and the system.
The system also comprises a second system applied in the cloud server, wherein the second system comprises a third data storage module used for storing second data of the second system, and the second data at least comprises first data, a first instruction and a second instruction obtained by the second system according to the first data; the second data processing module is used for obtaining situation data of the target to be monitored according to the first data, predicting a second safety degree of the target to be monitored according to the situation data and obtaining a second instruction, wherein the second safety degree is used for representing a second safety situation of the target to be monitored after the target to be monitored continues to be in the existing state; the third communication module is used for the second system to respectively carry out data interaction with the first system and the system; the first display module and the second display module are also used for displaying a second instruction.
The system also comprises a third system applied to the target to be monitored, and the third system comprises a fourth communication module used for data interaction between the third system and the system and between the third system and the second system respectively; the fourth storage module is used for storing the first instruction and the second instruction; and the control module is used for controlling the target to be monitored according to the first instruction or the second instruction.
The invention also provides a fibre optic sensing method for determining location and direction information of a disturbance of cure in a sensor fibre optic environment, the method comprising: emitting a light pulse into at least one polarization eigenmode of a polarization maintaining fiber as a sensor fiber; detecting a time-speckle pattern of light backscattered from at least one polarization eigenmode of the optical fiber; the time speckle patterns are compared to determine location and direction information of the disturbance in the sensor fiber environment. The position information corresponds to a distance along the optical fiber, and the direction information corresponds to a direction radial from an axis of the optical fiber. The perturbation is determined by the variation of the time speckle pattern. The time-speckle pattern is a self-perturbing backscatter mode that results in a time-varying intensity of the detected signal. The measure of the time variation gives the position along the fibre of the perturbation which causes an exchange of refractive index in the fibre at that point, and the variation over a particular local time range gives a measure of the magnitude and radial direction of the perturbation with respect to time. By fiber environment we mean the region around the fiber where pressure waves or temperature changes affect the refractive index of the fiber. The optical pulses are partially coherent pulses and therefore self-perturbing, but not fully coherent, so that the power in the optical pulses is not limited to a large extent by brillouin scattering.
The location information of the perturbations may be determined in accordance with the relative timing of the time speckle pattern variation range. The change in the time speckle pattern is caused by a perturbation-induced change in the refractive index of the fiber along its length. Such disturbances may be or may generate pressure waves, such as sound waves or temperature changes.
The directional information may be determined by comparing one or more time speckle patterns detected from each polarization eigenmode.
The directional information can be determined by comparing the time speckle patterns of the two polarization eigenmodes over a particular time range. The range-specific timing corresponds to a specific location along the fiber.
The injecting step includes launching the light pulses into two polarization eigenmodes of a length of polarization maintaining fiber; and the detecting step comprises detecting a time-speckle pattern of backscattered light from both eigenmodes. To obtain the best position and orientation information, a pulse is launched into both eigenmodes and backscatter is detected from both eigenmodes. The detecting step may include separating the backscattered light into polarized eigenmodes and detecting the intensity of the backscattered light in each eigenmode. While photodetectors typically detect intensity, the amplitude is preferably used to calculate position and orientation information.
The light pulses may be linearly polarized. The light pulse may be launched at substantially 45 ° to the polarization eigenmode of the polarization maintaining fiber so that the amplitudes injected into the two eigenmodes are substantially equal. Alternatively, different pulses may be launched into both eigenmodes, or pulses may be launched into only one eigenmode and, after the return pulse is detected, a pulse launched into the other eigenmode.
The comparing step may comprise comparing the time speckle pattern of the backscattered light from the first eigenmode component of the first pulse with the time speckle pattern of the backscattered light from the first eigenmode component of the second pulse to determine a first change in the refractive index of the optical fibre at a location along the length of the optical fibre. The comparing step may further comprise comparing the time-speckle pattern of the backscattered light from the second eigenmode component of the first pulse with the time-speckle pattern of the backscattered light from the second eigenmode component of the second pulse to determine a second change in refractive index at a location along the optical fiber. The radial direction of the perturbation is determined by the comparison of each eigenmode.
The comparing step may further comprise comparing the time-speckle pattern of the backscattered light from the second eigenmode component of the first pulse with the time-speckle pattern of the backscattered light from the second eigenmode component of the second pulse to determine a second change in refractive index at a location along the optical fiber. By comparing each eigenmode, the radial direction of the perturbation is determined.
The method may also include calibrating the relationship between the change in the speckle pattern of the polarization eigenmode and the position and orientation information. The method may also include calculating the location and direction of the disturbance around the optical fiber using the relationship determined in the calibration step.
The calibration step may include inducing perturbations at known locations in the sensor fiber environment, and the detection step may include detecting a temporal speckle pattern of backscattered light from the polarization eigenmodes, and may further include determining a relationship between the known locations and variations in the detected temporal speckle pattern.
The invention can determine the direction (within 180 °) in which the disturbance occurs. This can be achieved by using a polarization maintaining fiber and separately detecting the interference signals from the two polarization birefringent eigenmodes. The ratio of the amplitudes of the two perturbations provides a change in the angular orientation of the perturbations relative to the birefringent axes.
The direction of the birefringent axes in space can be determined by using, for example, the D-fiber and corresponding markers on the containing cable.
The above examples may be applied to many different scenarios to detect different kinds of disturbances. For example, it can be used as an intrusion detection system, where optical fibers are laid on the ground around an exclusion zone. Footstep sounds in the vicinity of the fiber produce acoustic vibrations that can be detected by the time-varying refractive index of the fiber, indicating the presence of an intruder. In another example, the fibers may be inserted into a pipe carrying a fluid, such as water, oil, or gas. When a crack or object in the pipe impacts the pipe, it can be detected by the sound wave generated by the crack or impact. Both of these examples have the problem that although the position of the disturbance along the length of the fibre can be determined, there is no information as to which direction the disturbance has occurred from. In the first example, an intruder detection system, the direction of the footstep sound may be particularly important because it may not indicate that an intruder is about to cross the perimeter and enter the exclusion zone, but rather indicate security personnel walking inside the perimeter.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus once an item is defined in one figure, it need not be further defined and explained in subsequent figures, and moreover, the terms "first", "second", "third", etc. are used merely to distinguish one description from another and are not to be construed as indicating or implying relative importance.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the present invention in its spirit and scope. Are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A distributed fiber optic sensing system, comprising:
the optical fiber sensing module is used for collecting position information and motion information of a target to be monitored, wherein the motion information at least comprises a motion speed and a motion direction;
the first data processing module is used for acquiring first data of the target to be monitored according to the position information and the motion information, wherein the first data is used for representing the motion track of the target to be monitored or the stress condition of the target to be monitored under the action of an external force;
the first data storage module is respectively connected with the optical fiber sensing module and the data processing module;
the first display module is connected with the data storage module and used for displaying the first data;
and the first communication module is connected with the first data storage module and is used for the data interaction between the system and other systems.
2. A distributed optical fiber sensing system according to claim 1,
the optical fiber sensing module consists of a plurality of optical fiber sensors, wherein each optical fiber sensor at least comprises a sensor optical fiber, a light source, a photoelectric detector and an analysis unit;
the sensor optical fiber is respectively connected with the light source and the photoelectric detector;
the light source is used for providing light pulses for the sensor optical fiber;
the photoelectric detector is used for obtaining a time speckle pattern of the sensor optical fiber, wherein the time speckle pattern is used for representing an image obtained by backscattering the light pulse by the sensor optical fiber;
the analysis unit is used for obtaining the position information and the motion information according to the time speckle pattern.
3. A distributed fibre optic sensing system according to claim 2,
the sensor fiber comprises a first polarization eigenmode and a second polarization eigenmode;
the first polarization eigenmode is used for obtaining a first image;
the second polarization eigenmode is used for obtaining a second image;
the photodetector is configured to obtain the temporal speckle pattern based on the first image and the second image.
4. A distributed fibre optic sensing system according to claim 3,
the time speckle pattern comprises a plurality of speckle patterns;
the analysis unit is used for comparing the adjacent speckle patterns to obtain a plurality of first characteristic patterns, and then comparing the adjacent first characteristic patterns to obtain the position information and the motion information.
5. A distributed fibre optic sensing system according to claim 4,
the position information at least comprises a stress position of the target to be monitored and a distance position of the target to be monitored relative to a reference target, wherein the reference target is used for representing a monitoring station or a monitoring point for monitoring the target to be monitored and a reference for measuring the position of the target to be monitored.
6. A distributed fibre optic sensing system according to claim 5,
the first data processing module at least comprises a data analysis unit and an early warning unit;
the data analysis unit is used for obtaining the first data;
the early warning unit is used for obtaining a first instruction according to the first data, wherein the first instruction is used for representing a first safety degree of the target to be monitored, and the first safety degree is used for representing a first safety condition of the target to be monitored in the existing state.
7. A distributed fibre optic sensing system according to claim 6,
the system also comprises an early warning module;
the early warning unit is respectively connected with the early warning module and the first display module;
the early warning module is used for converting the first instruction into voice or early warning sound;
the first display module is further used for displaying the first instruction on a current interface.
8. A distributed fibre optic sensing system according to claim 7 further comprising a first system for use in a mobile device, comprising,
the second display module is used for displaying the first instruction and the first data;
the second data storage module is used for storing the first data and the first instruction;
and the second communication module is used for the data interaction between the first system and the system.
9. A distributed fibre optic sensing system according to claim 8 further comprising a second system for use in a cloud server, comprising,
a third data storage module, configured to store second data of the second system, where the second data at least includes the first data, the first instruction, and a second instruction obtained by the second system according to the first data;
the second data processing module is used for obtaining situation data of the target to be monitored according to the first data, predicting a second safety degree of the target to be monitored according to the situation data, and obtaining the second instruction, wherein the second safety degree is used for representing a second safety situation of the target to be monitored after the existing state continues;
the third communication module is used for the second system to respectively perform data interaction with the first system and the system;
the first display module and the second display module are further used for displaying the second instruction.
10. A distributed fibre optic sensing system according to claim 9 further including a third system for use in said object to be monitored, comprising,
the fourth communication module is used for the third system to respectively carry out data interaction with the system and the second system;
the fourth storage module is used for storing the first instruction and the second instruction;
and the control module is used for controlling the target to be monitored according to the first instruction or the second instruction.
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| CN202110573380.8A CN113295259A (en) | 2021-05-25 | 2021-05-25 | Distributed optical fiber sensing system |
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