Subway tunnel foreign matter invasion identification and positioning system and method

Abstract

The invention relates to the technical field of subway safe operation monitoring, and discloses a subway tunnel foreign matter invasion identification and positioning system and method, and the system comprises a detection unit, a photoelectric conversion module, a processor, and a transmission optical fiber. The subway tunnel internally comprises at least one running track, two columns of detection units are arranged above each track in the track direction, each column of detection units is provided with a plurality of infrasonic wave sensors, and all the infrasonic wave sensors are located at the same horizontal height. The infrasonic wave sensors in each column of detection units are distributed at equal intervals, and the infrasonic wave sensors in the two columns of detection units are distributed in a staggered manner; the infrasonic wave sensors on each column of detection units are connected in series through transmission optical fibers; the infrasonic wave sensors on each column of detection units are connected to a photoelectric conversion module through a transmission optical fiber; the photoelectric conversion module is connected with the processor. On the basis of ensuring high detection sensitivity and high accuracy, the equipment and the detection method are simplified, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of subway safe operation monitoring, and in particular to a subway tunnel foreign body intrusion identification and positioning system and method. Background Art

[0002] At present, the main security monitoring methods used for subway tracks in the world include video monitoring, thermal imaging, mobile laser detection, etc., and they are mainly used for monitoring personnel intrusion, falling objects in tunnels, etc., and many commercial products have been formed. However, ground construction activities may cause damage to existing tracks or subway systems. There are few existing research results, and technical means are still relatively lacking. The subway is a major traffic artery in a city. Once invaded, it is very easy to cause major safety accidents, which may cause the subway to stop operating at the least, or economic losses or even casualties at the worst. The existing subway security mainly relies on civil defense, and the subway mileage ranges from tens of kilometers to hundreds of kilometers. Relying entirely on civil defense requires a lot of human resources, and there is a window period. Therefore, effective technical means are needed to achieve real-time, full-range, and online monitoring of subway tracks.

[0003] The existing patent document CN 111341049 A discloses a method and device for identifying and locating foreign body intrusion in a tunnel. The intrusion source is identified based on a morphological image processing method and a wavelet packet transform method. The location of the intrusion source is determined by calculating the propagation of the acoustic vibration excited by the intrusion source in the tunnel axial direction and the propagation law of the acoustic energy excited on the tunnel cross section. The method for identifying and locating foreign body intrusion in a tunnel is complex in calculation, high in cost, low in efficiency, and does not have wide adaptability. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention aims to provide a subway tunnel foreign body intrusion monitoring system and method, which can simplify the equipment and detection method and reduce the cost on the basis of ensuring high detection sensitivity and high accuracy.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A subway tunnel foreign body intrusion identification and positioning system, comprising a detection unit, a photoelectric conversion module, a processor and a transmission optical fiber;

[0007] Two rows of detection units are arranged above the track in the tunnel along the tunnel direction, each row of detection units is provided with a plurality of infrasonic wave sensors, and all the infrasonic wave sensors are located at the same horizontal height;

[0008] The infrasonic sensors in each column of detection units are evenly distributed, and the infrasonic sensors in two columns of detection units are staggered, that is, an infrasonic sensor in another column of detection units is distributed on the midline of every two infrasonic sensors in one column of detection units;

[0009] The infrasound wave sensors on each column of detection units are connected in series to the photoelectric conversion module via one of the transmission optical fibers;

[0010] The photoelectric conversion module is connected to the processor.

[0011] Furthermore, the infrasonic wave sensor comprises a diaphragm-type optical fiber external cavity Fabry-Perot interferometer infrasonic wave sensor.

[0012] Furthermore, the infrasonic wave sensor comprises a mounting box, a fiber coil, an infrasonic wave probe and an amplifier.

[0013] The fiber coil, infrasonic wave probe and amplifier are all located in the installation box;

[0014] The fiber coiling tray is located above the amplifier and in contact with the amplifier, a fiber coiling path is provided on the fiber coiling tray, and the transmission optical fiber is placed in the fiber coiling path;

[0015] The upper end of the amplifier is provided with a groove, and the infrasonic wave probe is located in the groove.

[0016] Furthermore, the photoelectric conversion module includes a light source transmitter, a pulse modulator, a coupler and a conversion unit.

[0017] The light source transmitter is connected to the input end of the pulse modulator, the output end of the pulse modulator is connected to the input end of the coupler, and the output end of the coupler is connected to the multi-channel conversion unit.

[0018] The conversion unit includes a circulator, a detector and a mediation device,

[0019] The first end of the circulator is connected to the output end of the coupler, the second end of the circulator is connected to the infrasound sensor, the third end of the circulator is connected to the input end of the detector, and the output end of the detector is connected to the input end of the mediation device.

[0020] The output end of the mediation device is connected to the processor.

[0021] A method for identifying and locating foreign body intrusion in a subway tunnel comprises the following steps:

[0022] S01. Arrange infrasound sensors in the tunnel:

[0023] Two rows of detection units are arranged above the track in the tunnel and along the tunnel direction, each row of detection units is provided with a plurality of infrasonic wave sensors, and all the infrasonic wave sensors are located at the same horizontal height,

[0024] The infrasonic sensors in each column of detection units are evenly distributed, and the infrasonic sensors in two columns of detection units are staggered, that is, an infrasonic sensor in another column of detection units is distributed on the midline of every two infrasonic sensors in one column of detection units;

[0025] S02, connecting the infrasonic wave sensors of each column of detection units in series through transmission optical fibers and connecting them to a photoelectric conversion module, and connecting the photoelectric conversion module to a processor;

[0026] S03, the infrasound sensor receives the sound wave signal in the tunnel, and the sound wave signal is transmitted to the processor via the photoelectric conversion module;

[0027] S04, the processor identifies the sensing data corresponding to each infrasonic wave sensor, determines whether the sensing data falls within a set range, and records the position of the infrasonic wave sensor corresponding to the sensing data falling within the set range;

[0028] S05. Selecting three infrasonic wave sensor positions with the largest signal amplitude and the closest distance from the infrasonic wave sensors falling within the set range;

[0029] S06. Calculate the location of the foreign object by a three-point positioning method according to the positions of the three infrasonic wave sensors.

[0030] Furthermore, the processor identifies the sensing data corresponding to each infrasonic wave sensor in the following steps:

[0031] S1. Space division multiplexing: Through space division multiplexing technology, multiple transmission optical fibers can be monitored simultaneously;

[0032] S2. Time division multiplexing: Through time division multiplexing technology, multiple infrasound sensors can be monitored simultaneously on a single transmission optical fiber;

[0033] S3, transmission and processing: combining the signals of multiple transmission optical fibers and multiple infrasound sensors on the transmission optical fibers and transmitting them to a processor, where a space division multiplexer and a time division multiplexer are used to demultiplex the transmitted composite signal and separate the sensing data of each infrasound sensor;

[0034] S4. Identification: After demultiplexing, the sensing data of the infrasound sensor corresponding to each time segment is identified through the timestamp.

[0035] Furthermore, the calculation formula for calculating the location of the foreign body by the three-point positioning method based on the positions of the three infrasonic wave sensors is:

[0036] (x-x1) 2 +(z-z1) 2 =(t1v′+l′) 2

[0037] (x-x2) 2 +(z-z2) 2 =(t2v′+l′) 2

[0038] (x-x3) 2 +(z-z3) 2 =(t3v′+l′) 2

[0039] t1, t2, t3 are the times when the sensing data of the three infrasonic sensors arrive at the processor, l′ is the height of the three infrasonic sensors from the ground, v′ is the propagation speed of sound waves, the plane coordinates of the three infrasonic sensors are (X1, Z1), (X2, Z2) and (X3, Z3), and the plane coordinates of the location of the foreign body are (X, Z);

[0040] The spatial coordinates of the location of the foreign body can be solved by the above formula as (X, Z, l′).

[0041] The beneficial effects of the present invention are:

[0042] 1. The setting of the detection unit of the present invention can realize real-time, long-distance, high-precision, high-resolution sensing measurement, and the equipment line layout is simple, the layout cost is low and the layout efficiency is high;

[0043] 2. The present invention provides a subway tunnel foreign body intrusion identification and positioning system and method, which is based on a highly sensitive fiber interferometric infrasonic sensor array technology and utilizes a method combining space division multiplexing and time division multiplexing to achieve real-time and high-precision monitoring of foreign body intrusion in subway tunnels;

[0044] 3. The structural setting of the infrasonic sensor of the present invention can enhance the induction intensity between the infrasonic probe and the transmission optical fiber, and improve the sensitivity of the infrasonic sensor.

[0045] 4. The tunnel foreign body intrusion identification and positioning method of the present invention is simple in calculation, has low equipment operation difficulty, high efficiency, and has wide adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0047] Figure 1 This is a schematic diagram of the structure of a subway tunnel foreign body intrusion identification and positioning system of the present invention;

[0048] Figure 2 This is a schematic diagram of the deployment scheme of the infrasound sensor of the present invention in a tunnel;

[0049] Figure 3 It is a schematic diagram of the structure of the infrasound sensor of the present invention;

[0050] Figure 4 The figure is a schematic diagram of the principle of a method for identifying and locating foreign body intrusion in a subway tunnel according to the present invention.

[0051] Reference numerals:

[0052] 1. Detection unit; 2. Photoelectric conversion module; 3. Infrasonic sensor; 21. Light source transmitter; 22. Pulse modulator; 23. Coupler; 24. Circulator; 25. Detector; 9. Transmission optical fiber; 10. Subway machine room; 11. Subway up line; 12. Subway down line; 31. Installation box; 32. Amplifier; 33. Infrasonic probe; 34. Fiber reel. DETAILED DESCRIPTION

[0053] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0054] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] like Figure 1As shown, a subway tunnel foreign body intrusion identification and positioning system includes a detection unit 1, a photoelectric conversion module 2, a processor and a transmission optical fiber 9. The transmission optical fiber 9 can effectively measure physical quantities such as temperature, stress, pressure, vibration, etc. The detection unit 1 is used to detect vibration signals generated by foreign body intrusion inside the subway tunnel or by mechanical equipment construction above the tunnel. Two rows of detection units 1 are arranged above the track in the tunnel and along the direction of the tunnel, each row of detection units 1 is provided with a plurality of infrasonic sensors 3, and all infrasonic sensors 3 are located at the same horizontal height; the infrasonic sensors 3 in each row of detection units 1 are evenly distributed, and the infrasonic sensors 3 in the two rows of detection units 1 are staggered, that is, an infrasonic sensor 3 of the other row of detection units 1 is distributed on the midline of two adjacent infrasonic sensors 3 in one row of detection units 1; the infrasonic sensors 3 are connected to the transmission optical fiber 9 through a coupler 23 to ensure crosstalk-free synchronous reception of signals of multiple infrasonic sensors 3 connected in series on a single transmission optical fiber 9; the infrasonic sensors 3 on each row of detection units 1 are connected in series through the transmission optical fiber 9; the infrasonic sensors 3 on each row of detection units 1 are connected to the photoelectric conversion module 2 through a transmission optical fiber 9; the photoelectric conversion module 2 is connected to the processor.

[0057] like Figure 2 As shown, as a preferred embodiment of the present invention, the layout distance between two adjacent infrasonic wave sensors 3 in one row of detection units 1 is 60 m, and the layout distance between two adjacent infrasonic wave sensors 3 in one row of detection units 1 and another row of detection units is 30 m.

[0058] As a preferred embodiment of the present invention, the infrasonic wave sensor 3 is a high-sensitivity fiber-optic interferometric infrasonic wave sensor, which includes but is not limited to a diaphragm-type fiber-optic external cavity Fabry-Perot interferometer infrasonic wave sensor.

[0059] The detection unit of this embodiment is cheap to manufacture and can realize real-time, long-distance, high-precision, and high-resolution sensing measurement. In addition, the equipment line layout is simple, the layout cost is low, and the layout efficiency is high.

[0060] like Figure 3 As shown, the infrasonic sensor 3 includes an installation box 31, a fiber coiling plate 34, an infrasonic probe 33 and an amplifier 32. The fiber coiling plate 34, the infrasonic probe 33 and the amplifier 32 are all located in the installation box 31; the fiber coiling plate 34 is located above the amplifier 32 and is in contact with the amplifier 32, a fiber coiling path is provided on the fiber coiling plate 34, and the transmission optical fiber 9 is placed in the fiber coiling path; a groove is provided at the upper end of the amplifier 32, and the infrasonic probe 33 is located in the groove.

[0061] The structural arrangement of the infrasonic wave sensor 3 of this embodiment can enhance the induction intensity between the infrasonic wave probe 33 and the transmission optical fiber 9 , thereby improving the sensitivity of the infrasonic wave sensor 3 .

[0062] The photoelectric conversion module 2 includes a light source transmitter 21, a pulse modulator 22, a coupler 23 and a conversion unit.

[0063] The light source refers to a narrow-linewidth laser light source in the communication band, and the light source transmitter 21 outputs continuous light; the pulse modulator 22 can modulate the continuous light output by the light source into an optical pulse signal, including but not limited to an electro-optic modulator and an acousto-optic modulator; the function of the coupler 23 is to convert one optical pulse signal into multiple optical pulse signal outputs; the conversion unit includes a circulator 24 and a detector 25; the circulator 24 is used to control and guide the transmission of the optical signal in the optical fiber network. The detector 25 is used to receive, measure and process the optical signal.

[0064] The light source transmitter 21 is connected to the input end of the pulse modulator 22, the output end of the pulse modulator 22 is connected to the input end of the coupler 23, the output end of the coupler 23 is connected to the multiplexer unit, the conversion unit includes a circulator 24, a detector 25 and a mediation device, the first end of the circulator 24 is connected to the output end of the coupler 23, the second end of the circulator 24 is connected to the infrasound sensor 3, the third end of the circulator 24 is connected to the input end of the detector 25, the output end of the detector 25 is connected to the input end of the mediation device, and the output end of the mediation device is connected to the processor.

[0065] The continuous light output by the light source transmitter 21 is output as an optical pulse signal through the pulse modulator 22 and the coupler 23. The optical pulse signal is input from the first end of the circulator 24 and output from the second end of the circulator 24. The vibration signal sensed by the infrasonic sensor 3 modulates the optical pulse signal, causing the intensity or phase of the optical pulse signal to change. The modulated optical pulse signal is reflected and input from the second end of the circulator 24, and output from the third end of the circulator 24 to the detector 25. The detector 25 outputs the modulated reflected optical pulse signal, which is processed into an electrical signal by the modulation device. The electrical signal is the sensing data of the infrasonic sensor 3. Finally, the processor analyzes the sensing data to identify whether there is a foreign object and obtains the specific location of the foreign object using the positioning algorithm.

[0066] The processor realizes real-time and accurate monitoring of foreign body intrusion signals by combining the signal data output by the regulating device with the positioning algorithm.

[0067] like Figure 1 As shown, a method for identifying and locating foreign body intrusion in a subway tunnel comprises the following steps:

[0068] S01. Arrange infrasound sensor 3 in the tunnel:

[0069] like Figure 2As shown, the subway tunnel includes at least one running track, two rows of detection units 1 are arranged above each track and along the track direction, each row of detection units 1 is provided with a plurality of infrasonic sensors 3, and all infrasonic sensors 3 are located at the same horizontal height, the infrasonic sensors 3 in each row of detection units 1 are evenly distributed, and the infrasonic sensors 3 in the two rows of detection units 1 are staggered, that is, an infrasonic sensor 3 of the other row of detection units 1 is distributed on the midline of every two infrasonic sensors 3 in one row of detection units 1;

[0070] S02, connecting the infrasound wave sensors 3 of each column of detection units 1 in series to the photoelectric conversion module 2 through the transmission optical fiber 9, and connecting the photoelectric conversion module 2 to the processor;

[0071] S03, the infrasound sensor 3 receives the vibration signal in the tunnel and outputs the sensing data, which is transmitted to the processor via the photoelectric conversion module 2. The specific implementation process is as follows:

[0072] The continuous light output by the light source transmitter 21 is output as an optical pulse signal through the pulse modulator 22 and the coupler 23. The optical pulse signal is input from the first end of the circulator 24 and output from the second end of the circulator 24. The vibration signal sensed by the infrasonic sensor 3 modulates the optical pulse signal, causing the intensity or phase of the optical pulse signal to change. The modulated optical pulse signal is reflected and input from the second end of the circulator 24, and output from the third end of the circulator 24 to the detector 25. The detector 25 outputs the modulated reflected optical pulse signal, which is processed into an electrical signal by the modulation device. The electrical signal is the sensing data of the infrasonic sensor 3. The sensing data is finally transmitted to the processor, which identifies whether there is a foreign object by analyzing the sensing data and obtains the specific location of the foreign object using the positioning algorithm.

[0073] S04, the processor identifies the sensing data corresponding to each infrasonic wave sensor 3, determines whether the sensing data falls within a set range, and records the position of the infrasonic wave sensor 3 corresponding to the sensing data falling within the set range;

[0074] The method by which the processor identifies the sensing data corresponding to each infrasonic wave sensor 3 is:

[0075] Space division multiplexing: Through space division multiplexing technology, multiple transmission optical fibers 9 can be monitored simultaneously;

[0076] Time division multiplexing: Through time division multiplexing technology, multiple infrasound sensors 3 on a single transmission optical fiber 9 can be monitored simultaneously;

[0077] Transmission and processing: The signals of the multiple transmission optical fibers 9 and the multiple infrasound sensors 3 on the transmission optical fibers 9 are combined and transmitted to the processor. In the processor, the transmitted composite signal is demultiplexed using a space division multiplexer and a time division multiplexer to separate the sensing data of each infrasound sensor 3;

[0078] Identification: After demultiplexing, the sensing data of the infrasound sensor 3 corresponding to each time segment can be identified through the timestamp.

[0079] S05. Select the positions of three infrasonic wave sensors 3 with the largest signal amplitude and the closest distance from each other from the infrasonic wave sensors 3 that fall within the set range;

[0080] S06. Calculate the location of the foreign object by a three-point positioning method based on the positions of the three infrasonic wave sensors 3.

[0081] The three-point positioning method uses the distance from the three infrasonic wave sensors to the location of the foreign object sound source for positioning. The location of the foreign object sound source is determined by the intersection of three circles with each infrasonic wave sensor as the center and the distance from each infrasonic wave sensor to the target as the radius. The positioning geometry is as follows: Figure 4 shown.

[0082] The calculation formula of the three-point positioning method is:

[0083] (x-x1) 2 +(z-z1) 2 =(t1v′+l′) 2

[0084] (x-x2) 2 +(z-z2) 2 =(t2v′+l′) 2

[0085] (x-x3) 2 +(z-z3) 2 =(t3v′+l′) 2

[0086] t1, t2, and t3 are the times when the sensing data of the three sensors arrive at the processor, l′ is the height of the three sensors from the ground, the plane coordinates of the three infrasonic sensors are (x1, z1), (x2, z2), and (x3, z3), and the sound wave propagation speed is v′.

[0087] The three-dimensional coordinates of the unique foreign body sound source point can be obtained through the above equation as (x, z, l′), and the sound source point position is the foreign body position.

[0088] The specific solution process of the above equation is as follows:

[0089] The calculation formula of the three-point positioning method is:

[0090] (x-x1) 2 +(z-z1) 2 =(t1v′+l′) 2

[0091] (x-x2) 2 +(z-z2) 2 =(t2v′+l′) 2

[0092] (x-x3) 2 +(z-z3) 2 =(t3v′+l′) 2 (1)

[0093] Rearranging (1) we can get

[0094]

[0095] Among them, R1, R2, and R3 are Figure 4 The radii of the three circles.

[0096] Eliminating R in equation (2) yields two independent equations.

[0097]

[0098] The plane coordinates (x, z) of the foreign object sound source point can be obtained from formula (3). Since l′ is the height of the three sensors from the ground and is known, the three-dimensional coordinates (x, z, l′) of the object sound source point can be directly obtained.

[0099] The tunnel foreign body intrusion identification and positioning method of the present invention has simple calculation, low equipment operation difficulty, high efficiency and wide adaptability.

[0100] The invention discloses a subway tunnel foreign body intrusion identification and positioning system. The system is based on the arrangement of a high-sensitivity optical fiber interference infrasound wave sensor, a transmission optical fiber, and a photoelectric conversion module. The optical fiber sensor has the advantages of light weight, small size, high temperature resistance, corrosion resistance, and electromagnetic interference resistance. It can still work normally even in some special environments. It can be well applied to external intrusion detection under complex conditions such as tunnels, elevated sections, and mountain sections in the urban rail transit industry, forming an external intrusion optical fiber detection and early warning technology with high precision, strong sensitivity, and high accuracy. Through the system and detection method of the invention, the disadvantages and problems of traditional detection technology in application scenarios of the urban rail transit industry such as narrow space, complex noise in subway tunnels, low-frequency and weak infrasound wave detection, etc. can be overcome, and long-distance, large-range, and all-weather real-time monitoring can be achieved.

[0101] This example is only an example of the use of the present invention. The probe for detecting infrasound waves is not limited to the case of using a reflective optical fiber probe with a diaphragm. The subsequent processing of the signal is not limited to specific programming hardware, and the working band is not limited to the traditional communication band. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0102] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A subway tunnel foreign body intrusion identification and positioning system, It is characterized in that It comprises a detection unit (1), a photoelectric conversion module (2), a processor and a transmission optical fiber (9); Two rows of detection units (1) are arranged above the track in the tunnel along the tunnel direction, each row of detection units (1) is provided with a plurality of infrasound wave sensors (3), and all the infrasound wave sensors (3) are located at the same horizontal height; The infrasonic wave sensors (3) in each column of detection units (1) are evenly spaced, and the infrasonic wave sensors (3) in two columns of detection units (1) are staggered, that is, an infrasonic wave sensor (3) in another column of detection units (1) is distributed on the midline of every two infrasonic wave sensors (3) in one column of detection units (1); The infrasound wave sensors (3) on each column of detection units (1) are connected in series to the photoelectric conversion module (2) via one transmission optical fiber (9); The photoelectric conversion module (2) is connected to the processor.

2. According to claim 1, a subway tunnel foreign body intrusion identification and positioning system, It is characterized in that The infrasonic wave sensor (3) comprises a diaphragm-type optical fiber external cavity Fabry-Perot interferometer infrasonic wave sensor.

3. According to claim 1, a subway tunnel foreign body intrusion identification and positioning system, It is characterized in that The infrasonic wave sensor (3) comprises a mounting box (31), a fiber coil (34), an infrasonic wave probe (33) and an amplifier (32). The fiber coil (34), the infrasonic wave probe (33) and the amplifier (32) are all located in the installation box (31); The fiber coiling plate (34) is located above the amplifier (32) and in contact with the amplifier (32); a fiber coiling path is provided on the fiber coiling plate (34), and the transmission optical fiber (9) is placed in the fiber coiling path; The upper end of the amplifier (32) is provided with a groove, and the infrasonic wave probe (33) is located in the groove.

4. According to claim 1, a subway tunnel foreign body intrusion identification and positioning system, It is characterized in that The photoelectric conversion module (2) comprises a light source transmitter (21), a pulse modulator (22), a coupler (23) and a conversion unit. The light source transmitter (21) is connected to the input end of the pulse modulator (22), the output end of the pulse modulator (22) is connected to the input end of the coupler (23), and the output end of the coupler (23) is connected to the multi-channel conversion unit. The conversion unit comprises a circulator (24), a detector (25) and a mediation device, The first end of the circulator (24) is connected to the output end of the coupler (23), the second end of the circulator (24) is connected to the infrasound sensor (3), the third end of the circulator (24) is connected to the input end of the detector (25), and the output end of the detector (25) is connected to the input end of the mediation device. The output end of the mediation device is connected to the processor.

5. A method for identifying and locating foreign body intrusion in subway tunnels, The following steps are involved: S01. Arrange infrasound sensors in the tunnel (3): Two rows of detection units (1) are arranged above the track in the tunnel and along the tunnel direction, each row of detection units (1) is provided with a plurality of infrasound wave sensors (3), and all the infrasound wave sensors (3) are located at the same horizontal height. The infrasonic wave sensors (3) in each column of detection units (1) are evenly spaced, and the infrasonic wave sensors (3) in two columns of detection units (1) are staggered, that is, an infrasonic wave sensor (3) in another column of detection units (1) is distributed on the midline of every two infrasonic wave sensors (3) in one column of detection units (1); S02, connecting the infrasound wave sensors (3) of each column of detection units (1) in series through a transmission optical fiber (9) and connecting the sensors to a photoelectric conversion module (2), and connecting the photoelectric conversion module (2) to a processor; S03, the infrasound sensor (3) receives the sound wave signal in the tunnel, and the sound wave signal is transmitted to the processor via the photoelectric conversion module (2); S04, the processor identifies the sensing data corresponding to each infrasonic wave sensor (3), determines whether the sensing data falls within a set range, and records the position of the infrasonic wave sensor (3) corresponding to the sensing data falling within the set range; S05. From the infrasonic wave sensors (3) falling within the set range, select the positions of the three infrasonic wave sensors (3) with the largest signal amplitude and the closest distance; S06. Calculate the location of the foreign object by a three-point positioning method based on the positions of the three infrasonic wave sensors (3).

6. A method for identifying and locating foreign body intrusion in a subway tunnel according to claim 5, It is characterized in that The processor identifies the sensing data corresponding to each infrasonic wave sensor (3) in the following steps: S1. Space division multiplexing: Through space division multiplexing technology, multiple transmission optical fibers (9) can be monitored simultaneously; S2. Time division multiplexing: using time division multiplexing technology, a plurality of infrasound sensors (3) on a single transmission optical fiber (9) can be monitored simultaneously; S3, transmission and processing: combining the signals of the plurality of transmission optical fibers (9) and the plurality of infrasound sensors (3) on the transmission optical fibers (9) and transmitting them to a processor, and in the processor, using a space division multiplexer and a time division multiplexer to demultiplex the transmitted composite signal, and separating the sensing data of each infrasound sensor (3); S4, identification: After demultiplexing, the sensing data of the infrasound sensor (3) corresponding to each time segment is identified through the time stamp.

7. According to claim 5, a method for identifying and locating foreign body intrusion in a subway tunnel, Features: The calculation formula for calculating the location of the foreign body by the three-point positioning method based on the positions of the three infrasonic wave sensors (3) is: t 1 ,t 2 ,t 3 is the time when the sensing data of the three infrasonic sensors (3) arrive at the processor, l′ is the height of the three infrasonic sensors (3) from the ground, v′ is the propagation speed of the sound wave, and the plane coordinates of the three infrasonic sensors (3) are (X 1 ,Z 1 )、(X 2 ,Z 2 ) and (X 3 ,Z 3 ), the plane coordinates of the location of the foreign body are (X, Z); The spatial coordinates of the location of the foreign body can be solved by the above formula as (X, Z, l′).

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