Underground facility monitoring system and method based on optical fiber sensing technology

Abstract

The underground facility can be effectively monitored through the distributed optical fiber sensor technology, when the underground facility and the surrounding geological structure change, the principle that optical fibers transmit optical signals in a medium is adopted, and related information of a target object is obtained by detecting the optical signals. The optical fiber sensing technology is different from the traditional sensing technology, and the sensor of the optical fiber sensing technology can be very small, is easy to install and has very high precision and sensitivity. The optical fiber sensor can be applied to various occasions such as temperature, pressure, strain, humidity and the like, and can monitor each abnormal change information, so that the abnormity caused by deformation, geologic structure change and the like of the underground facility can be found, and effective data can be provided for urban management.

Description

Technical Field

[0001] A buried facility monitoring system and method based on optical fiber sensing technology is an algorithm and method for measuring external strain using optical information and medium transmission. Background Art

[0002] With the development of urbanization, modern urban construction requires multiple types of underground infrastructure, such as water pipelines, natural gas pipelines, energy pipelines, groundwater pipelines, underground lines, and other types of urban underground infrastructure. However, with the development of the city, the management of each pipeline belongs to different departments, and the natural geological structure is likely to produce slow displacement. It is difficult to grasp the precise location after a long time, resulting in many accidents during the repair process. Summary of the invention

[0003] A buried facility monitoring system and method based on optical fiber sensing technology can solve the problem of effective monitoring of buried facilities through distributed optical fiber sensor technology. When the buried facilities and the surrounding geological structures change, the vibration, temperature and other information of each abnormal change can be monitored, thereby discovering the abnormalities caused by the deformation of the buried facilities and the changes in the geological structure, and providing effective data for urban management.

[0004] Install and deploy relevant types of optical fibers on the surface of underground facilities, such as laying long-distance optical fiber facilities outside the pipeline corridor or directly using optical fiber lines in underground communication lines, and ensure the integrity of optical fiber facilities. Optical fibers need to be protected in special outdoor underground environments.

[0005] The fiber optic sensor collection device is deployed at the end of the optical fiber, and a laser pulse is sent to the other end of the fiber optic sensor. The sensor can receive the vibration mode control signal in the optical fiber to generate vibration sound waves. The fiber optic sensor can receive real-time vibration information from multiple vibration sound sources in the buried facilities contacted by the optical fiber and multiple vibration sound sources in the surrounding geological structure, analyze the sound wave vibration at the desired location, and analyze the signal returned by the scattered light signal after a delay corresponding to the distance to resolve the sound wave of abnormal location information.

[0006] The monitoring content of the fiber optic sensor acquisition equipment includes the laser pulse generator and the abnormal vibration point positioning system found in the buried facilities.

[0007] The laser pulse generator is used to monitor the optical signal laser pulse from one end of the optical fiber sensor to the other end; the buried facility detects abnormal vibration point positioning system, so that the vibration mode control signal is transmitted to multiple vibration sound sources in real time and orderly. At the same time, the laser pulse is monitored by analyzing the optical signal scattered back from the optical fiber sensor to obtain the time delay from the vibration wave of the vibration sound source to the scattering point of the optical fiber sensor.

[0008] Vibration waves are generated by a laser pulse generator, and the abnormal vibration point positioning system is used to detect laser pulses and analyze the returned scattered light signals in the buried facilities, and the vibration waves of each section of the optical fiber sensor are monitored.

[0009] By linking the abnormal vibration point positioning system found in the buried facilities, the arrival delay time information of the vibration wave reaching each section of the optical fiber sensor is used to calculate the distance to the abnormal point monitored.

[0010] The arrival delay time information is used to calculate the distance between the installation point of the vibration source and its scattering point, and the distance information calculated according to the vibration source is integrated to calculate the two-dimensional or three-dimensional position of the buried facility.

[0011] The abnormal vibration point positioning system for underground facilities also includes a display device for displaying analysis data or underground buried object location information, an input unit for users to input setting values ​​or data, and a network connection module for remotely controlling the device or transmitting measurement data to other computers or servers. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of a system for locating abnormal vibration points in underground facilities according to the present invention; Figure 2 The schematic diagram of the abnormal vibration point location system for underground facilities according to the present invention; Figure 3 A structural diagram of a system for locating abnormal vibration points of underground facilities according to the present invention; Figure 4 A flow chart of a system for locating abnormal vibration points in underground facilities according to the present invention; Figure 5 This is a data analysis diagram of the abnormal vibration point positioning system for underground facilities based on the present invention. DETAILED DESCRIPTION

[0013] like Figure 1 As shown, according to the underground facility location monitoring embodiment of the present invention, when detecting the location of the underground facility 103, a side of the optical fiber sensor (104) connected to the underground facility location detection system (101) and a vibration wave generated on the surface near the underground facility include a sound source (102).

[0014] In order to detect the situation of the buried facility (103), the data collected by the optical fiber (104) is used to analyze the vibration source situation of the buried facility (103). At this time, the host (101) of the buried facility detection system and the vibration source (102) are connected by wired or wireless communication means. The buried facility detection host (101) transmits a command to the controller in the vibration wave, that is, the laser pulse generates a signal in the optical fiber and returns to receive the scattered light signal, and the sensor performs a delay analysis on the light information. By calculating the delay information from the vibration source (102) and the speed of the vibration wave with the medium, the distance from the vibration source (102) to each section of the optical fiber sensor (104) can be known for positioning. At this time, the shorter the time interval of analyzing the scattered light signal, the shorter the distance calculation of each point from the vibration source (102), that is, the interval of each section of the optical fiber sensor (104), which is the resolution.

[0015] If the vibration source (102) is moved to the surface and the work of 0014 is repeated, the three-dimensional relative coordinates of the optical fiber sensor (104) can be calculated based on the coordinates of the vibration source. The optical fiber sensor (104) can also be used to accurately analyze the three-dimensional coordinates of abnormal changes in buried facilities.

[0016] like Figure 2 As shown in the figure, the principle diagram of the abnormal vibration point positioning system using buried facilities to find abnormal changes in buried facilities is shown. In three-dimensional space, knowing the abnormal vibration point positioning system with any buried facilities Figure 4 By knowing the distance to a place (coordinates), you can know the location (coordinates) of a place.

[0017] To calculate the coordinates of a point (La) of the optical fiber sensor (202), l1a, l2a, l3a, and l4a can be obtained from the four vibration sources P1, P2, P3, and P4. Figure 1 As described above, the positions of different locations (Lb) can also be obtained from the four vibration sources (203) P1, P2, P3, P4 angles. That is, the three-dimensional coordinates of any point of the buried facility can be calculated.

[0018] As described in 0017, the more vibration sources (203) are added, the more equations are used in the calculation, which can reduce the errors caused by the homogeneity of the medium and the velocity value. If the vibration sources are increased from four to five or more, the fuzzy three-dimensional coordinates will become more and more clear. Displaying such a process on the screen with a three-dimensional image will enable more accurate analysis of the abnormal detection data of the buried facility.

[0019] .like Figure 3As shown, it is a structural diagram of the abnormal vibration point positioning system for buried facilities. First, the buried facility abnormal vibration point positioning system (301) receives external power input and generates a power supply component (312) for generating necessary power for each component, a vibration source (308) generates a vibration mode generator (307) for transmitting the vibration mode through wired and wireless communication means, a laser pulse generator (311) for generating pulse emission from the laser to the optical fiber sensor, and then the laser pulse generator (311) sends the laser pulse generator (311) signal through the optical fiber sensor, and the received signal is transmitted to the optical fiber sensor (314) in the direction of the receiving part, an optical filter (313) for separating the required band signal from the new scattered light signal, an optical information collector (310) for changing the signal before amplifying the separated optical signal, and then converting the optical signal converted from the above optical information collector (310) into an electrical signal to a digital A / D converter (309), and calculating the average value of the data measured multiple times to reduce the error frequency of the digital signal. A DSP (305) controls each of the above parts and receives and displays the operation data from the user for display or sending to the network. It is composed of a CPU (306), a network component (302) associated with the above control part, a display component (303) and an input component (304).

[0020] There may be one or more vibration sources (308) connected to the buried facility abnormal vibration point location system (301) via wired or wireless communication means.

[0021] The laser pulse generator (311) does not generate high-power pulses, but randomly encodes and detects low-power optical signals diffused in a broadband, and by receiving the scattered optical signals and back-diffusing them into the same random signals, it can obtain an effect similar to detecting high-power laser pulses and receiving scattered optical signals, thereby eliminating the need to use a high-power laser light generator.

[0022] like Figure 4 The figure shows a flow chart of the abnormal vibration point positioning system for underground facilities. First, it is assumed that the vibration source (308) is set at four different places on the surface (P1, P2, P3, P4), and measurements are taken in sequence starting from P1. A vibration wave (401) is generated in P1, a laser pulse is generated in the optical fiber sensor (402), and then the scattered light signal (402) returned by the optical fiber sensor is analyzed to calculate the distance from P1 to each section of the optical fiber sensor (402). Similarly, the vibration wave generation (403, 405, 407) process and the scattered light signal analysis (404, 406, 408) process are repeated for the positions of P2, P3, and P4. The result of such analysis and calculation, that is, the three-dimensional information (409) of the optical fiber sensor is calculated based on the distance information from P1, P2, P3 and P4 to each section of the optical fiber sensor. The result of such calculation can be displayed in the host computer of the underground facility detection system. Figure 3 The display component (303) is visually displayed, or by Figure 3 The network component (302) transmits it to a server on the network.

[0023] like Figure 5 As shown in the figure, it is a data analysis diagram of the abnormal vibration point positioning system found in underground facilities. It is drawn by the delay (tD1, tD2, tD3, tD4) of the sound waves generated by P1, P2, P3 and P4 reaching any point of the optical fiber sensor. That is, the vibration wave starting from the vibration source P1 propagates along the underground medium, and there is a time delay of tD1 at any point La of the optical fiber sensor. Then, if the vibration wave is generated in the vibration source P2, the same point La of the optical fiber sensor has a different delay tD2. Using the same method, the vibration sources P3 and P4 also have different delays tD3 and tD4 respectively. The three-dimensional coordinates of the position of the vibration wave sensed on the optical fiber sensor based on the coordinates of the above four vibration sources and the four delay information can be calculated. Repeating the above steps, the three-dimensional position of all intervals of the optical fiber sensor can be calculated.

[0024] In order to reduce errors and transmit stronger light wave signals, a pulse signal modulated by a specific frequency can be used instead of a simple pulse on the vibration source (sound source), and the receiving party can find the abnormal modulation frequency and analyze it. In order to distinguish the vibration waves generated by multiple vibration sources, the analysis of the vibration wave pattern uses a pseudo-noise sequence, and the correlation (Correlation) and despreading (Despreading) operations of the same code are used in the abnormal vibration point positioning system of the buried facility to identify the vibration wave pattern.

Claims

1. A buried facility monitoring system and method based on optical fiber sensing technology, characterized in that: Step 1: Install and deploy relevant types of optical fibers on the surface of underground facilities, such as laying out long-distance optical fiber facilities outside the pipeline corridor or directly using lines with optical fibers in underground communication lines, and ensure the integrity of optical fiber facilities. Optical fibers need to be protected in special outdoor underground environments; Step 2: Deploy optical fiber sensor acquisition equipment at the end of the optical fiber. The sensor can receive vibration mode control signals in the optical fiber to generate vibration sound waves. The optical fiber sensor can receive real-time vibration information transmitted back through multiple vibration sound sources in the underground facilities contacted by the optical fiber and multiple vibration sound sources in the surrounding geological structures; Step 3: The monitoring content of the optical fiber sensor acquisition equipment includes a laser pulse generator and a positioning system for abnormal vibration points found in underground facilities. The laser pulse generator is used to monitor the optical signal laser pulse from one end of the optical fiber sensor to the other end; the buried facility detects abnormal vibration point positioning system, so that the vibration mode control signal is transmitted to multiple vibration sound sources in real time and orderly, and at the same time, the monitoring laser pulse is analyzed by analyzing the optical signal scattered and returned from the optical fiber sensor to obtain the arrival delay time from the vibration wave of the vibration sound source to the scattering point of the optical fiber sensor; step four, using the arrival delay time information to calculate the distance between the installation point of the vibration source and its scattering point, comprehensively based on the distance information calculated according to the vibration source, and calculate the two-dimensional or three-dimensional position of the buried facility.

2. According to step 2 of claim 1, the optical fiber sensor acquisition device body transmits the vibration mode control signal to the abnormal vibration point positioning system of multiple vibration source buried facilities through wireless communication.

3. According to step 2 of claim 1, the optical fiber sensor acquisition device body transmits the vibration mode control signal to the abnormal vibration point positioning system of multiple vibration source buried facilities through wireless communication.

4. According to claim 3, the monitoring of abnormal positions of the abnormal vibration point positioning system of the buried facility is carried out by distinguishing the vibration waves generated by multiple vibration sources and the surrounding vibration frequencies during detection based on the unique vibration frequency.

5. According to claim 3, the monitoring of abnormal position of the abnormal vibration point positioning system of the buried facility is carried out by distinguishing the vibration waves generated by multiple vibration sources and the surrounding vibration frequencies during detection based on the unique vibration frequency.

6. According to claims 4 and 5, in order to distinguish the vibration waves generated by multiple vibration sources, a pseudo-noise sequence is used to analyze the vibration wave pattern, and the correlation (Correlation) and despreading (Despreading) operations of the same code are used in the abnormal vibration point positioning system of the buried facility to identify the vibration wave pattern.

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