CN108226819A - A kind of ground magnetic field monitoring system and method based on fiber grating - Google Patents

Abstract

The embodiment provides a kind of ground magnetic fields based on fiber grating to monitor system and method, and system includes sequentially connected pulsed light generating unit, optical fiber grating sensing unit and optical signal processing unit；Pulsed light generating unit is used to generate pulsed light, and the pulsed light is transmitted to optical fiber grating sensing unit；Optical fiber grating sensing unit is embedded under the surface layer of ground, and reflects multiple optical signals in different location for the pulsed light according to reception, and multiple optical signals are transmitted to optical signal processing unit；Optical signal processing unit for the optical signal of reception to be converted into electric signal, and is monitored ground magnetic field according to electric signal.The present invention improves the accuracy and reliability for monitoring and judging to ground magnetic field, effectively reduces ground magnetic field vibrations wrong report, realizes the advanced warning to ground changes of magnetic field.

Description

A fiber grating-based ground magnetic field monitoring system and method

technical field

The invention relates to the technical field of ground magnetic field monitoring, in particular to a ground magnetic field monitoring system and method based on an optical fiber grating.

Background technique

Fiber optic cables are widely used in various industries due to their light transmission characteristics. In addition to being used in communications, they are also used as sensing devices to sense changes in external physical quantities, such as changes in temperature, stress, vibration, and stress; and in cities , the optical fiber cable is used as a sensing device for detecting ground vibration, that is, the ground vibration is obtained through the change of the ground magnetic field, so as to give an early warning of pipeline damage and other behaviors.

At present, the main technical way to sense ground vibration through optical fiber sensing technology is to collect ground vibration signals through optical fibers, and to judge the ground vibration source through vibration signals. However, this method cannot perceive the actual size of the vibration intensity of the vibration source, that is, the optical fiber with a source with a larger vibration at a longer distance and a source with a smaller vibration at a closer distance feels similar to the vibration intensity, which leads to false alarms .

Contents of the invention

Aiming at the defects in the prior art, the present invention provides a ground magnetic field monitoring system and method based on fiber bragg grating, which can accurately judge the vibration intensity of the vibration source on the ground through vibration signals at different positions, thereby improving the monitoring and judgment of the ground magnetic field. Accuracy and reliability, effectively reducing false alarms of ground magnetic field vibrations, and realizing early warning of ground magnetic field changes.

In order to solve the above technical problems, the present invention provides the following technical solutions:

On the one hand, the present invention provides a ground magnetic field monitoring system based on an optical fiber grating, the system comprising: a pulsed light generating unit, an optical fiber grating sensing unit, and an optical signal processing unit connected in sequence;

The pulsed light generating unit is used to generate pulsed light and transmit the pulsed light to the fiber grating sensing unit;

The fiber grating sensing unit is buried under the ground surface, and is used to reflect multiple optical signals at different positions according to the received pulsed light, and transmit the multiple optical signals to the optical signal processing unit;

The optical signal processing unit is used to convert the received optical signal into an electrical signal, and monitor the ground magnetic field according to the electrical signal.

Further, the fiber grating sensing unit includes: a sensing fiber buried under the surface of the ground, and a plurality of fiber grating sensors separately arranged within the sensing range of the sensing fiber, and each fiber grating sensor is connected to the The distances between the pulse light generating units are all different;

The sensing optical fiber is used to receive the pulsed light transmitted by the pulsed light generating unit;

The fiber grating sensors are configured to reflect light signals when the sensing fiber receives pulsed light, and each of the fiber grating sensors respectively transmits light signals to the light signal processing unit.

Further, the end of the sensing fiber away from the pulsed light generating unit is provided with a specular reflection device;

The specular reflection device is used for the sensing optical fiber to mirror the pulsed light after receiving the pulsed light transmitted by the pulsed light generating unit to obtain a reflected light signal, and send the reflected light signal to The optical signal processing unit.

Further, the optical signal processing unit includes: an optical fiber detector, a signal acquisition card and a signal processor connected in sequence;

The optical fiber detector is used to receive the optical signal reflected by the fiber grating sensing unit, convert the optical signal into an electrical signal, and send the electrical signal to a signal acquisition card;

The signal acquisition card is configured to send the received electrical signal to the signal processor;

The signal processor is configured to monitor the ground magnetic field according to the received electrical signal, and determine the scene that causes the current magnetic field change.

Further, the pulsed light generating unit includes: interconnected broadband lasers and optical fiber amplifiers;

The wide-line-broadband laser is used to generate long-pulse light, and transmit the long-pulse light to the fiber amplifier;

The fiber amplifier is used to amplify the received long pulse light and transmit the amplified pulse light to the fiber grating sensing unit.

Further, the system also includes:

The circulator is used to transmit the pulsed light emitted by the pulsed light generating unit to the fiber grating sensing unit, and transmit the light signal reflected by the fiber grating sensing unit to the optical signal processing unit.

On the other hand, the present invention also provides a method for monitoring the ground magnetic field based on an optical fiber grating, the method comprising:

Generate pulsed light within the target magnetic field monitoring range, and transmit the pulsed light to the sensing optical fiber buried under the surface of the ground;

When the sensing optical fiber receives the optical signal, collect multiple optical signals at different positions;

Convert multiple collected optical signals into electrical signals;

And, monitor the ground magnetic field within the current target magnetic field monitoring range according to the plurality of electrical signals.

Further, the pulsed light is generated within the target magnetic field monitoring range, and the pulsed light is transmitted to the sensing optical fiber buried under the surface of the ground, including:

Generate pulsed light within the target magnetic field monitoring range;

Optical signal amplification is performed on the pulsed light, and the amplified pulsed light is transmitted to the sensing optical fiber buried under the ground surface.

Further, the monitoring of the ground magnetic field within the current target magnetic field monitoring range according to the plurality of electrical signals also includes:

The optical signal transmitted into the sensing fiber is specularly reflected, and the reflected optical signal is converted into an electrical signal.

Further, the monitoring of the ground magnetic field within the current target magnetic field monitoring range according to the plurality of electrical signals includes:

According to the electrical signals corresponding to different time points, determine the change of the magnetic field intensity within the current target magnetic field monitoring range;

If it is determined that the current change in magnetic field strength exceeds a preset strength threshold, then obtain a change frequency value of the change in magnetic field strength;

And, determine the scene that causes the current magnetic field change in the preset frequency scene table according to the change frequency value;

Wherein, the frequency scene table is used to store the corresponding relationship between the change frequency value and each scene.

It can be seen from the above-mentioned technical scheme that a kind of ground magnetic field monitoring system and method based on fiber Bragg grating according to the present invention, the system connects successively through the pulsed light generation unit, the fiber grating sensing unit and the optical signal processing unit; the pulsed light generation unit uses To generate pulsed light, and transmit the pulsed light to the fiber grating sensing unit; the fiber grating sensing unit is buried under the ground surface, and is used to reflect multiple optical signals at different positions according to the received pulsed light, and transmit multiple The optical signals are all transmitted to the optical signal processing unit; the optical signal processing unit is used to convert the received optical signal into an electrical signal, and monitor the ground magnetic field according to the electrical signal, which improves the accuracy and reliability of the ground magnetic field monitoring and judgment It effectively reduces the false alarm of the ground magnetic field vibration and realizes the early warning of the ground magnetic field change; and the system is simple in structure, low in cost, high in precision, more convenient in installation, use and maintenance, and can be used in harsh environments reliably for a long time It has the advantages of corrosion resistance and anti-interference, and has a very wide range of application scenarios.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are For some embodiments of the present invention, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the structural representation of a kind of concrete implementation of a kind of ground magnetic field monitoring system based on fiber Bragg grating in embodiment one of the present invention;

FIG. 2 is a schematic structural diagram of the pulsed light generating unit 10 in Embodiment 2 of the present invention;

FIG. 3 is a schematic structural diagram of a fiber grating sensing unit 20 in Embodiment 3 of the present invention;

Fig. 4 is the structural representation of the sensing optical fiber 21 in the ground magnetic field monitoring system in the present invention;

FIG. 5 is a schematic structural diagram of an optical signal processing unit 30 in Embodiment 4 of the present invention;

Fig. 6 is a schematic structural view of another embodiment of a fiber grating-based ground magnetic field monitoring system in Embodiment 5 of the present invention;

Fig. 7 is a schematic structural view of a fiber grating-based ground magnetic field monitoring system in a specific application example of the present invention;

FIG. 8 is a schematic flow chart of a specific implementation of a fiber grating-based ground magnetic field monitoring method in Embodiment 6 of the present invention;

FIG. 9 is a schematic flowchart of a specific implementation of step 100 in the above monitoring method in Embodiment 7 of the present invention;

FIG. 10 is a schematic flowchart of a specific implementation of the above-mentioned monitoring method including step A00 in Embodiment 8 of the present invention;

FIG. 11 is a schematic flowchart of a specific implementation of step 400 in the above monitoring method in Embodiment 9 of the present invention;

Fig. 12 is a schematic structural diagram of a fiber grating-based ground magnetic field monitoring device in Embodiment 10 of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Embodiment 1 of the present invention provides a ground magnetic field monitoring system based on an optical fiber grating. Referring to Figure 1, the monitoring system specifically includes the following contents:

The pulsed light generating unit 10 , the fiber grating sensing unit 20 and the optical signal processing unit 30 are connected in sequence.

The pulsed light generating unit 10 is used to generate pulsed light and transmit the pulsed light to the fiber grating sensing unit 20 .

In this unit, the pulsed light generating unit 10 is connected with the fiber grating sensing unit 20, and the pulsed light generating unit 10 periodically generates long pulsed light according to a preset frequency value, and transmits the pulsed light to the The fiber grating sensing unit 20.

The fiber grating sensing unit 20 is arranged at the surface of the ground, and is used for reflecting multiple optical signals at different positions according to the received pulsed light, and transmitting the multiple optical signals to the optical signal processing unit 30 .

In this unit, the fiber grating sensing unit 20 is set at the surface of the ground, can be buried under the ground close to the ground, or can be set close to the ground, and receives the pulsed light sent by the pulsed light generating unit 10, and according to the pulse The light reflects a plurality of optical signals, and transmits the plurality of optical signals to the optical signal processing unit 30, wherein, since the reflection positions are different, that is, the distance between each position and the pulsed light generating unit 10 is also different, Therefore, the time point of the reflected light signal is also different, that is to say, the closer the position from the pulsed light generating unit 10, the shorter the time used for the reflected light signal, and the farther the position from the pulsed light generating unit 10, the shorter the time used for the reflected light signal. the longer the time.

The optical signal processing unit 30 is configured to convert the received optical signal into an electrical signal, and monitor the ground magnetic field according to the electrical signal.

In this unit, the optical signal processing unit 30 converts the received optical signal into an electrical signal, and the number of the converted electrical signal is the same as the received optical signal, and monitors the ground magnetic field according to the electrical signal, and judges Work scenarios that cause changes in the magnetic field.

It can be seen from the above description that the embodiment of the present invention realizes the collection of vibration signals at different positions on the ground through optical fibers through the sequentially connected pulsed light generating unit, fiber grating sensing unit and optical signal processing unit, and judges the vibration signal based on the vibration signals at different positions The vibration intensity of the vibration source on the ground improves the accuracy and reliability of the monitoring and judgment of the ground magnetic field, and realizes the early warning of the change of the ground magnetic field.

Embodiment 2 of the present invention provides a specific implementation manner of the pulse light generating unit 10 in the above monitoring system. Referring to Fig. 2, the pulsed light generating unit 10 specifically includes the following contents:

A wide line and wide frequency laser 11 and a fiber amplifier 12 are connected to each other.

The wide-line-broadband laser 11 is used to generate long pulsed light and transmit the long pulsed light to the fiber amplifier 12 .

The fiber amplifier 12 is used to amplify the received long pulse light and transmit the amplified pulse light to the fiber grating sensing unit 20 .

It can be seen from the above description that the embodiments of the present invention can periodically generate pulsed light, so that the fiber grating sensing unit 20 can acquire pulsed light in real time, ensuring the timeliness of acquiring ground magnetic field changes.

Embodiment 3 of the present invention provides a specific implementation manner of the fiber grating sensing unit 20 in the above monitoring system. Referring to Fig. 3, the fiber grating sensing unit 20 specifically includes the following contents:

The sensing optical fiber 21 buried under the surface of the ground, and a plurality of fiber grating sensors 22 separately located in the sensing range of the sensing optical fiber 21, and the distance between each fiber grating sensor 22 and the pulsed light generating unit 10 All are different.

The sensing optical fiber 21 is used to receive the pulsed light transmitted by the pulsed light generating unit 10. In practical applications, the sensing optical fiber 21 can be buried in a designated position in the monitoring range area according to the actual situation, or can directly use the pre-embedded Sensing optical fiber 21 under the ground.

The fiber grating sensors 22 are configured to reflect light signals when the sensing fiber 21 receives pulsed light, and each of the fiber grating sensors 22 transmits light signals to the light signal processing unit 10 respectively.

It can be seen from the above description that the embodiments of the present invention provide an optical signal that can be reflected at different time points at different locations, enabling the optical signal processing unit to accurately obtain ground magnetic field changes and vibration sources based on the optical signals at different time points. , using a fiber grating magnetic field sensor, not a vibration sensor in the traditional sense. The principle of system operation is to realize accurate investigation and early warning of construction and man-made equipment damage around the optical fiber by detecting the change of the magnetic field near the optical fiber. In order to realize the early warning maintenance of the pipeline network from another angle.

In a specific implementation manner, the present invention provides a specific implementation manner of the above-mentioned sensing optical fiber 21 . Referring to Fig. 4, the sensing optical fiber 21 specifically includes the following contents:

The end of the sensing fiber 21 away from the pulse light generating unit 10 is provided with a specular reflection device 211 .

The mirror reflection device 211 is used for the sensing optical fiber 21 to mirror the pulse light after receiving the pulse light transmitted by the pulse light generating unit 10 to obtain a reflected light signal, and to transmit the reflected light The signal is sent to the optical signal processing unit 30 .

It can be known from the above description that the specific embodiment of the present invention provides another device capable of reflecting optical signals, which enables the optical signal processing unit to accurately troubleshoot interference items based on the reflected optical signals, and infer construction conditions near the optical fiber.

Embodiment 4 of the present invention provides a specific implementation manner of the optical signal processing unit 30 in the above monitoring system. Referring to FIG. 5, the optical signal processing unit 30 specifically includes the following contents:

Optical fiber detector 31, signal acquisition card 32 and signal processor 33 connected in sequence;

The optical fiber detector 31 is used for receiving the optical signal reflected by the FBG sensing unit 20 , converting the optical signal into an electrical signal, and sending the electrical signal to the signal acquisition card 32 .

The signal acquisition card 32 is configured to send the received electrical signal to the signal processor 33 .

The signal processor 33 is configured to monitor the ground magnetic field according to the received electrical signal, and determine the scene that causes the current magnetic field change.

It can be seen from the above description that the embodiments of the present invention can accurately check the interference items and infer the construction conditions near the optical fiber according to the optical signals and reflected optical signals at different time points, and obtain the ground magnetic field changes and vibration sources.

Embodiment 5 of the present invention provides another specific implementation manner of the above monitoring system. Referring to Figure 6, the monitoring system also includes the following:

The circulator 40 is used for optical signal transmission between the pulsed light generating unit 10 , the fiber grating sensing unit 20 and the optical signal processing unit 30 .

The circulator 40 is used to transmit the pulsed light emitted by the pulsed light generating unit to the FBG sensing unit, and to transmit the optical signal reflected by the FBG sensing unit to the optical signal processing unit.

It can be seen from the above description that the embodiment of the present invention provides a transmission device for optical signal transmission between the pulsed light generating unit, the fiber grating sensing unit and the optical signal processing unit, and the device is characterized by one-way transmission , so that the transmission accuracy and reliability are high.

In order to further illustrate this solution, the present invention also provides a specific application example of a ground magnetic field monitoring system based on a fiber Bragg grating. Referring to Figure 7, the monitoring system specifically includes the following contents:

It consists of a wide linewidth laser 11 , a fiber amplifier 12 , a circulator 40 , a fiber grating sensor 22 , a fiber detector 31 , a signal acquisition card 32 and a signal processor 33 .

The analysis software is installed on the signal processor 33 , and the position of the change of the magnetic field B can be judged by analyzing the reflected light signal s.

The long pulsed light generated by the wide-linewidth laser 11 is amplified by the fiber amplifier 12 and enters the No. 1 port of the circulator 40, and enters the sensing fiber 21 from the No. 2 port of the circulator 40. One fiber grating sensor 22 is placed, and N pieces are placed in total. Therefore, when the long pulse light enters the sensing fiber 21, each fiber grating sensor 22 will return a reflected light signal sn, where n=1, 2, 3, . . . , N.

Since the position Dn of each fiber grating sensor 22 is different from the wide linewidth laser 11, the reflected light becomes a continuous pulsed light, and the reflected continuous pulsed light enters the 3rd port of the circulator 40 through the No. 2 port of the circulator 40 port, thereby entering the optical fiber detector 31, the main function of the optical fiber detector 31 is to convert the optical signal sn into an electrical signal Sn, and then send the electrical signal to the signal acquisition card 32, and the software installed on the signal processor 33 passes the program Read the returned electrical signal Sn data on the signal acquisition card 32 .

The optical signal analysis process includes: the software on the signal processor 33 collects all returned optical signals Sn, t1 and the signal Sn, t2 of the previous time point for comparative analysis, when the intensity of the signal Sn, t1 and the signal Sn, t2 The intensity change ΔSn exceeds a certain ratio τ (the ratio is determined by the working characteristics of different construction devices), namely:

ΔSn=|Sn,t1-Sn,t2|/Sn,t1>τ,

According to ΔSn, the amount of change ΔB generated by the magnetic field B at this place can be judged. When there is a large-scale construction machine under construction above the sensing optical fiber 21, the change ΔB of the magnetic field will form a specific change frequency Δf according to the different construction machines. By analyzing again For different frequency of change Δf, compare ΔB and Δf with the pre-identified work scene confirmation table, see Table 1, which is the magnetic field change and change frequency caused by different scenes such as pre-identified construction machinery construction or vehicle passing, so that Determine the working scene that causes the magnetic field change, such as whether there is real construction machinery construction or the passing of vehicles.

Table 1 The magnetic field change amount and change frequency corresponding to the scene

Magnetic field variation ΔB Frequency of change Δf work scene ΔB _w Δf _w excavator ΔB _D Δf _D Pipe jacking machine ΔB _c Δf _c car passing by

Since the position information Dn of each fiber grating sensor 22 is known, the position information Dn of the optical fiber corresponding to the magnetic field change ΔB can be determined.

The port at the end of the sensing fiber 21 is provided with a mirror, which can reflect the pulsed light entering the sensing fiber 21 as a mirror, and the fiber detector 31 detects the reflected light signal sr in the sensing fiber 21 instead of the scattered light signal ss.

The reflected continuous pulsed light produces a corresponding change Δsr after being affected by the external magnetic field change ΔB, and after being collected by the fiber optic detector 31 (if 8 fiber gratings are used, 8 fiber optic detectors 31 are required), the signal acquisition card 32 ( The A/D acquisition card has 8 channels, and each channel detects one optical fiber) converts the optical signal into an electrical signal Sr to generate a special and recognizable waveform, and then analyzes and checks the interference items through the signal processor 33 software to infer the construction situation near the optical fiber .

It can be seen from the above description that the specific application example of the present invention uses a fiber grating to detect magnetic field changes on the sensing fiber. When the magnetic field around the sensing fiber changes, the system collects the reflected light to determine the position where the magnetic field changes. The system has simple structure, low cost, high precision, more convenient installation, use and maintenance, and can be used for long-term and reliable work in harsh environments. It has the advantages of corrosion resistance and anti-interference, and has a very wide range of application scenarios; The optical fiber vibration sensing system has a simple structure, low cost, high precision, and is very convenient for installation, use and maintenance. It can be used for long-term and reliable work in harsh environments, and has a very wide range of application scenarios.

Embodiment 6 of the present invention provides a specific implementation manner of a ground magnetic field monitoring method based on an optical fiber grating. Referring to Figure 8, the monitoring method includes the following:

Step 100: Generate pulsed light within the target magnetic field monitoring range, and transmit the pulsed light to the sensing optical fiber buried under the surface of the ground.

Step 200: Collect multiple optical signals at different positions when the optical signal is received by the sensing fiber.

Step 300: Convert the collected multiple optical signals into electrical signals.

Step 400: Monitor the ground magnetic field within the current target magnetic field monitoring range according to the multiple electrical signals.

It can be seen from the above description that the embodiments of the present invention realize the collection of vibration signals at different locations on the ground through optical fibers, and judge the vibration intensity of the vibration source on the ground through the vibration signals at different locations, thereby improving the accuracy of monitoring and judging the ground magnetic field and reliability; by detecting changes in the magnetic field near the optical fiber, accurate investigation and early warning of construction and man-made equipment damage around the optical fiber can be realized, and then the early warning and maintenance of the pipe network can be completed from another perspective.

Embodiment 7 of the present invention provides a specific implementation manner of step 100 in the above monitoring method. Referring to Fig. 9, this step 100 includes the following contents:

Step 101: Generate pulsed light within the target magnetic field monitoring range.

Step 102: performing optical signal amplification on the pulsed light, and transmitting the amplified pulsed light to the sensing optical fiber buried under the surface of the ground.

It can be seen from the above description that the embodiments of the present invention can generate pulsed light periodically, and the pulsed light acquired in real time ensures the timeliness of acquiring changes in the ground magnetic field.

Embodiment 8 of the present invention provides a specific implementation manner in which step A00 is also included before step 300 in the above monitoring method. Referring to Fig. 10, this step A00 includes the following contents:

Step A00: performing specular reflection on the optical signal transmitted to the sensing optical fiber, and converting the reflected optical signal into an electrical signal.

It can be seen from the above description that the embodiments of the present invention provide another implementation method capable of reflecting optical signals, which realizes accurate troubleshooting of interference items based on the reflected optical signals, and infers the construction conditions near the optical fiber.

Embodiment 9 of the present invention provides a specific implementation manner of step 400 in the above monitoring method. Referring to Fig. 11, this step 400 includes the following contents:

Step 401: Determine the change of the magnetic field intensity within the current target magnetic field monitoring range according to the electrical signals corresponding to different time points.

Step 402: If it is determined that the current change in magnetic field strength exceeds a preset strength threshold, obtain a change frequency value of the change in magnetic field strength.

Step 403: Determine the scene that causes the current magnetic field change in the preset frequency scene table according to the change frequency value.

Wherein, the frequency scene table is used to store the corresponding relationship between the change frequency value and each scene.

It can be seen from the above description that the embodiments of the present invention can accurately check the interference items and infer the construction conditions near the optical fiber according to the optical signals and reflected optical signals at different time points, and obtain the ground magnetic field changes and vibration sources.

Embodiment 10 of the present invention provides a ground magnetic field monitoring device based on an optical fiber grating, as shown in FIG. 12. The details of the device are as follows:

Processor (processor) 801, memory (memory) 802, communication interface (CommunicationsInterface) 803 and bus 804;

in,

The processor 801, the memory 802, and the communication interface 803 complete mutual communication through the bus 804;

The communication interface 803 is used for information transmission between the automatic release device and the communication device of the billing system;

The processor 801 is used to call the program instructions in the memory 802 to execute the methods provided by the above method embodiments, for example, including: generating pulsed light within the target magnetic field monitoring range, and transmitting the pulsed light to the buried The sensing optical fiber under the surface of the ground; when the sensing optical fiber receives the optical signal, collects a plurality of optical signals at different positions; converts the collected optical signals into electrical signals; according to the plurality of electrical signals The ground magnetic field within the current target magnetic field monitoring range is monitored.

Embodiment 11 of the present invention provides a computer program product. This embodiment discloses a computer program product. The computer program product includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes Program instructions, when the program instructions are executed by the computer, the computer can execute the methods provided by the above method embodiments, see Figure 8, for example, including: generating pulsed light within the target magnetic field monitoring range, and transmitting the pulsed light to Sensing optical fiber buried under the surface of the ground; when the sensing optical fiber receives the optical signal, collect multiple optical signals at different positions; convert the collected multiple optical signals into electrical signals; according to the multiple electrical signals Monitor the ground magnetic field within the current target magnetic field monitoring range.

Embodiment 12 of the present invention provides a non-transitory computer-readable storage medium, where the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the methods provided in the foregoing method embodiments. The method includes, for example: generating pulsed light within the target magnetic field monitoring range, and transmitting the pulsed light to a sensing optical fiber buried under the surface of the ground; when the sensing optical fiber receives an optical signal, collecting multiple Optical signal; converting multiple collected optical signals into electrical signals; monitoring the ground magnetic field within the current target magnetic field monitoring range according to the multiple electrical signals.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

The above-described embodiments such as the ground magnetic field monitoring equipment based on fiber gratings are only illustrative, and the units described as separate components may or may not be physically separated, and the components displayed as units may be or are also It may not be a physical unit, that is, it may be located in one place, or it may be distributed to multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without any creative efforts.

Through the above description of the implementations, those skilled in the art can clearly understand that each implementation can be implemented by means of software plus a necessary general hardware platform, and of course also by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the prior art can be embodied in the form of software products, and the computer software products can be stored in computer-readable storage media, such as ROM/RAM, magnetic discs, optical discs, etc., including several instructions to make a computer device (which may be a personal computer, server, or network device, etc.) execute the methods described in various embodiments or some parts of the embodiments.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, not to limit them; although the embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art The skilled person should understand that: it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the present invention The scope of the technical solutions of each embodiment.

Claims (10)

1. A ground magnetic field monitoring system based on an optical fiber grating, characterized in that the system comprises: a pulsed light generating unit, an optical fiber grating sensing unit and an optical signal processing unit connected in sequence; The pulsed light generating unit is used to generate pulsed light and transmit the pulsed light to the fiber grating sensing unit; The fiber grating sensing unit is buried under the ground surface, and is used to reflect multiple optical signals at different positions according to the received pulsed light, and transmit the multiple optical signals to the optical signal processing unit; The optical signal processing unit is used to convert the received optical signal into an electrical signal, and monitor the ground magnetic field according to the electrical signal. 2. The system according to claim 1, wherein the fiber grating sensing unit comprises: a sensing optical fiber buried under the surface of the ground, and a plurality of optical fibers separately arranged in the sensing range of the sensing optical fiber A fiber grating sensor, and the distance between each fiber grating sensor and the pulsed light generating unit is different; The sensing optical fiber is used to receive the pulsed light transmitted by the pulsed light generating unit; The fiber grating sensors are configured to reflect light signals when the sensing fiber receives pulsed light, and each of the fiber grating sensors respectively transmits light signals to the light signal processing unit. 3. The system according to claim 2, wherein a specular reflection device is provided at the end of the sensing fiber away from the pulsed light generating unit; The specular reflection device is used for the sensing optical fiber to mirror the pulsed light after receiving the pulsed light transmitted by the pulsed light generating unit to obtain a reflected light signal, and send the reflected light signal to The optical signal processing unit. 4. The system according to claim 1, wherein the optical signal processing unit comprises: an optical fiber detector, a signal acquisition card and a signal processor connected in sequence; The optical fiber detector is used to receive the optical signal reflected by the fiber grating sensing unit, convert the optical signal into an electrical signal, and send the electrical signal to a signal acquisition card; The signal acquisition card is configured to send the received electrical signal to the signal processor; The signal processor is configured to monitor the ground magnetic field according to the received electrical signal, and determine the scene that causes the current magnetic field change. 5. The system according to claim 1, wherein the pulsed light generating unit comprises: interconnected broadband lasers and optical fiber amplifiers; The wide-line-broadband laser is used to generate long-pulse light, and transmit the long-pulse light to the fiber amplifier; The fiber amplifier is used to amplify the received long pulse light and transmit the amplified pulse light to the fiber grating sensing unit. 6. The system according to any one of claims 1 to 5, wherein the system further comprises: The circulator is used to transmit the pulsed light emitted by the pulsed light generating unit to the fiber grating sensing unit, and transmit the light signal reflected by the fiber grating sensing unit to the optical signal processing unit. 7. A ground magnetic field monitoring method based on an optical fiber grating, characterized in that the method comprises: Generate pulsed light within the target magnetic field monitoring range, and transmit the pulsed light to the sensing optical fiber buried under the surface of the ground; When the sensing optical fiber receives the optical signal, collect multiple optical signals at different positions; Convert multiple collected optical signals into electrical signals; And, monitor the ground magnetic field within the current target magnetic field monitoring range according to the plurality of electrical signals. 8. The method according to claim 7, wherein the pulsed light is generated within the target magnetic field monitoring range, and the pulsed light is transmitted to the sensing optical fiber buried under the surface of the ground, comprising: Generate pulsed light within the target magnetic field monitoring range; Optical signal amplification is performed on the pulsed light, and the amplified pulsed light is transmitted to the sensing optical fiber buried under the ground surface. 9. The method according to claim 7, characterized in that, the ground magnetic field within the current target magnetic field monitoring range is monitored according to a plurality of said electrical signals, and also includes before: The optical signal transmitted into the sensing fiber is specularly reflected, and the reflected optical signal is converted into an electrical signal. 10. The method according to claim 9, wherein said monitoring the ground magnetic field within the current target magnetic field monitoring range according to a plurality of said electrical signals comprises: According to the electrical signals corresponding to different time points, determine the change of the magnetic field intensity within the current target magnetic field monitoring range; If it is determined that the current change in magnetic field strength exceeds a preset strength threshold, then obtain a change frequency value of the change in magnetic field strength; And, determine the scene that causes the current magnetic field change in the preset frequency scene table according to the change frequency value; Wherein, the frequency scene table is used to store the corresponding relationship between the change frequency value and each scene.