阅读说明：本技术 一种基于多源光纤传感的军用车辆入侵识别装置 (Military vehicle intrusion recognition device based on multi-source optical fiber sensing ) 是由 丁凯 郑守军 王宇 徐跃林 马诗洋 陈宇 高妍 靳宝全 于 2020-06-29 设计创作，主要内容包括：本发明提供一种基于多源光纤传感的军用车辆入侵识别装置,可识别军用车辆入侵行为产生的磁场变化、应变变化和声音变化,将三种信号检测手段进行融合,形成多源光纤传感技术,并利用磁致伸缩薄片、金属应变增敏薄片和声音增敏薄片提升光纤光栅和光纤环检测性能。为防止外力对机械装置进行破坏,采用了顶部保护层、中间弹簧缓冲层、底部保护层、及120°对称设置的三组机械臂上保护层和机械臂下保护层对整套装置进行防护。为提升装置埋设稳定性,采用了三组抓地装置构成三足式埋地结构以保护光纤光栅和光纤环传感器件,利于战场条件下的迅速布置,具有体积小巧、便于携带、操作简单、灵敏度高的优点。(The invention provides a military vehicle intrusion identification device based on multi-source optical fiber sensing, which can identify magnetic field change, strain change and sound change generated by military vehicle intrusion behaviors, integrates three signal detection means to form a multi-source optical fiber sensing technology, and improves the detection performances of an optical fiber grating and an optical fiber ring by utilizing a magnetostrictive thin sheet, a metal strain sensitization thin sheet and a sound sensitization thin sheet. In order to prevent the mechanical device from being damaged by external force, a top protective layer, a middle spring buffer layer, a bottom protective layer, three groups of mechanical arm upper protective layers and mechanical arm lower protective layers which are symmetrically arranged at 120 degrees are adopted to protect the whole device. In order to improve the embedding stability of the device, three groups of ground grabbing devices are adopted to form a three-legged embedded structure so as to protect the fiber bragg grating and the fiber ring sensing device, the rapid arrangement under the battlefield condition is facilitated, and the three-legged embedded structure has the advantages of small volume, convenience in carrying, simplicity in operation and high sensitivity.)

1. The utility model provides a military vehicle intrusion recognition device based on multisource optical fiber sensing which characterized in that: comprises a mechanical structure and a demodulation system; the mechanical structure is arranged at a designated position on the ground and is connected to a demodulation system arranged at a far end through a buried optical cable; the mechanical structure comprises a top protective layer (1), a middle spring buffer layer (2), a bottom protective layer (3), a connecting optical fiber in-out device (4), a first mechanical arm, a first ground gripping device (7), an optical fiber ring sound sensor (8), a sound sensitization sheet (9), a second mechanical arm, a second ground gripping device (12), an optical fiber grating magnetic field sensor (13), a magnetostrictive sheet (14), a third mechanical arm, a third ground gripping device (17), an optical fiber grating strain sensor (18) and a metal strain sensitization sheet (19); the demodulation system comprises a first broadband light source (23), a second broadband light source (24), an optical isolator (25), a circulator (26), a wavelength division multiplexer (27), a first optical fiber coupler (28), a second optical fiber coupler (29), a third optical fiber coupler (30), a Fabry-Perot tunable filter (31), a spectrometer (32), a first photoelectric detector (33), a second photoelectric detector (34), a two-way high-speed analog-to-digital conversion module (35), a Gaussian filter module (36), a high-speed digital-to-analog conversion module (37), a low-pass filter module (38), a peak searching module (39), a digital frequency synthesizer module (40) and a microcontroller (41);

wherein, the top protective layer (1) of the mechanical structure is a cylinder, the bottom protective layer (3) is a round box-shaped body, a middle spring buffer layer (2) is arranged between the top protective layer (1) and the bottom protective layer (3), the diameters of the top protective layer (1), the middle spring buffer layer (2) and the bottom protective layer (3) are the same, a round hole is arranged at the center of the bottom protective layer (3) and is communicated with a connecting optical fiber access device (4), a mechanical arm is arranged at the periphery of the bottom protective layer (3) at intervals of 120 degrees, a first ground gripping device (7) is arranged at the outer end part of a first mechanical arm downwards, a second ground gripping device (12) is arranged at the outer end part of a second mechanical arm downwards, a third ground gripping device (17) is arranged at the outer end part of the third mechanical arm downwards, a sound sensitization slice (9) is, the optical fiber ring sound sensor (8) and the sound sensitization slice (9) are placed in a clinging mode, the magnetostrictive slice (14) is attached to the bottom of the second mechanical arm, the optical fiber grating magnetic field sensor (13) and the magnetostrictive slice (14) are placed in a clinging mode, the metal strain sensitization slice (19) is attached to the bottom of the third mechanical arm, and the optical fiber grating strain sensor (18) and the metal strain sensitization slice (19) are placed in a clinging mode; the connection optical fibers of the optical fiber ring sound sensor (8), the optical fiber grating magnetic field sensor (13) and the optical fiber grating strain sensor (18) are connected to a demodulation system;

in the demodulation system, a first broadband light source (23) is connected with an a port of an optical isolator (25), a second broadband light source (24) is connected with a b port of the optical isolator (25), a c port of the optical isolator (25) is connected with an a port of a circulator (26), a b port of the circulator (25) is connected with an a port of a wavelength division multiplexer (27), a b port of the wavelength division multiplexer (27) is connected with an a port of a first optical fiber coupler (28), a b port of the first optical fiber coupler (28) is connected with an optical fiber grating magnetic field sensor (13), a c port of the first optical fiber coupler (28) is connected with an optical fiber grating strain sensor (18), a c port of the wavelength division multiplexer (27) is connected with an a port of a second optical fiber coupler (29), and b and c ports of the second optical fiber coupler (29) are respectively connected with an a port, a port and a port of an optical fiber ring sound sensor (8), The port b is connected, the port c of the circulator (26) is connected with the port a of the third optical fiber coupler (30), the port c of the third optical fiber coupler (30) is connected with the spectrometer (32), the port b of the third optical fiber coupler (30) is connected with the port a of the Fabry-Perot tunable filter (31), the port b of the Fabry-Perot tunable filter (31) is connected with the input end of the second photoelectric detector (34), the output end of the second photoelectric detector (34) is connected with the port a of the two-way high-speed analog-to-digital conversion module (35), the port c of the two-way high-speed analog-to-digital conversion module (35) is connected with the input end of the Gaussian filter module (36), the output end of the Gaussian filter module (36) is connected with the input end of the peak searching module (39), and the output end of the peak searching module (39) is connected with the port b of the microcontroller (41), the d port of the second optical fiber coupler (29) is connected with the first photoelectric detector (33), the first photoelectric detector (33) is connected with the b port of the two-way high-speed analog-to-digital conversion module (35), the d port of the two-way high-speed analog-to-digital conversion module (35) is connected with the low-pass filter module (38), the low-pass filter module (38) is connected with the a port of the microcontroller (41), the c port of the microcontroller (41) is connected with the input end of the digital frequency synthesizer module (40), the output end of the digital frequency synthesizer module (40) is connected with the input end of the high-speed digital-to-analog conversion module (37), and the output end of the high-speed digital-to-analog conversion module (37) is connected with the c port of the Fabry-Perot tunable filter (.

2. The military vehicle intrusion identification device based on multi-source optical fiber sensing according to claim 1, wherein: the first mechanical arm comprises a first mechanical arm upper protection layer (5) and a first mechanical arm lower protection layer (6); the second mechanical arm comprises a second mechanical arm upper protective layer (10) and a second mechanical arm lower protective layer (11); the third mechanical arm comprises a third mechanical arm upper protective layer (15) and a third mechanical arm lower protective layer (16); the upper and lower protective layers of the three layers are fixedly arranged in a laminating way.

3. The military vehicle intrusion identification device based on multi-source optical fiber sensing according to claim 2, wherein: the first ground grabbing device (7), the second ground grabbing device (12) and the third ground grabbing device (17) are all arranged to be triangular prisms with sections being regular triangles, the side length of the sections of the triangular prisms is far larger than the height of the triangular prisms, and the first mechanical arm lower protection layer (6), the second mechanical arm lower protection layer (11) and the third mechanical arm lower protection layer (16) are fixedly connected with the three through one side edge correspondingly, so that the whole device grabs stably.

4. The military vehicle intrusion identification device based on multi-source optical fiber sensing according to claim 2, wherein: the bottom of the bottom protective layer (3) is provided with an optical fiber ring wire hole (20), a first optical fiber grating wire hole (21) and a second optical fiber grating wire hole (22), and connecting optical fibers of the optical fiber ring sound sensor (8) penetrate into the bottom protective layer (3) through the optical fiber ring wire hole (20); the connecting optical fiber of the fiber bragg grating magnetic field sensor (13) penetrates into the bottom protective layer (3) through the first fiber bragg grating wire hole (21); connecting optical fibers of the fiber bragg grating strain sensor (18) are connected into the bottom protective layer (3) through fiber bragg grating wire holes (22); the three-way connection optical fiber is led out from the connection optical fiber access device (4) at the bottom protective layer (3) and is connected to the demodulation system.

Technical Field

The invention relates to the technical field of optical fiber sensing, in particular to a military vehicle intrusion identification device based on multi-source optical fiber sensing.

Background

In modern war, military vehicles undertake battle, transportation, traction and other battle tasks, and generally have the characteristics of large volume, high weight, hidden path and the like, so that the intrusion of the military vehicles is accurately identified, and the method has important significance for preferentially occupying the dominant right on a battlefield. Military vehicles are generally provided with protective armor made of metal and a forward track due to battlefield defense, the weight of the military vehicles can reach even tens of tons, huge pressure can be generated on the ground during the forward process, and meanwhile, distinct roaring sound can be generated by an engine. For the intrusion identification of military vehicles, the intrusion identification can be generally realized by using electric sensors such as electromagnetic sensors, sound sensors, image sensors and the like.

However, with the development of the battlefield countercheck technology, the strong electromagnetic interference technology can make various electric sensors blind and fail to work normally. Therefore, the optical fiber sensing technology can effectively supplement the original electric sensor due to the advantages of no electric sensing, electromagnetic interference resistance and flexible arrangement. Wherein, the metal material of the military vehicle can cause the change of the environment geomagnetic field, and can be detected by a fiber bragg grating magnetic field sensor; the strain change of the surface soil layer caused by the marching and rolling of the military vehicle can be detected by using a fiber bragg grating strain sensor; the military vehicle engine works to cause the change of an environmental sound field, and the change can be detected by using the optical fiber ring sound sensor. The three detection means are mutually fused to form a multi-source optical fiber sensing technology, and the efficiency and the accuracy of military vehicle intrusion identification are improved through the three-legged buried structure.

Disclosure of Invention

The invention aims to provide a military vehicle intrusion recognition device based on multi-source optical fiber sensing, which aims to adopt a wavelength division multiplexing technology to inject lasers with three central frequencies into an optical fiber grating magnetic field sensor, an optical fiber grating strain sensor and an optical fiber ring sound sensor respectively, utilize a magnetostrictive sheet, a metal strain sensitization sheet and a sound sensitization sheet to improve the detection performance of the optical fiber grating and the optical fiber ring, recognize multi-source signals such as magnetic field, strain and sound generated by the military vehicle respectively, and adopt a three-legged buried structure to protect the optical fiber grating and the optical fiber ring sensing device, thereby being beneficial to rapid arrangement under battlefield conditions and having the advantages of small volume, portability and simple operation.

The technical scheme adopted by the invention for solving the technical problems is as follows: constructing a military vehicle intrusion identification device based on multi-source optical fiber sensing, comprising: mechanical structures and demodulation systems; the mechanical structure is arranged at a designated position on the ground and is connected to a demodulation system arranged at a far end through a buried optical cable; the mechanical structure comprises a top protective layer, a middle spring buffer layer, a bottom protective layer, a connecting optical fiber in-out device, a first mechanical arm, a first ground gripping device, an optical fiber ring sound sensor, a sound sensitization sheet, a second mechanical arm, a second ground gripping device, an optical fiber grating magnetic field sensor, a magnetostrictive sheet, a third mechanical arm, a third ground gripping device, an optical fiber grating strain sensor and a metal strain sensitization sheet; the demodulation system comprises a first broadband light source, a second broadband light source, an optical isolator, a circulator, a wavelength division multiplexer, a first optical fiber coupler, a second optical fiber coupler, a third optical fiber coupler, a Fabry-Perot tunable filter, a spectrometer, a first photoelectric detector, a second photoelectric detector, a double-path high-speed analog-to-digital conversion module, a Gaussian filter module, a high-speed digital-to-analog conversion module, a low-pass filter module, a peak searching module, a digital frequency synthesizer module and a microcontroller;

wherein, the top protective layer of the mechanical structure is a cylinder, the bottom protective layer is a round box, a middle spring buffer layer is arranged between the top protective layer and the bottom protective layer, the diameters of the top protective layer, the middle spring buffer layer and the bottom protective layer are the same, a round hole is arranged at the center of the bottom protective layer and is communicated with a connecting optical fiber access device, a mechanical arm is arranged at the periphery of the bottom protective layer at intervals of 120 degrees, a first ground grabbing device is arranged at the outer end of the first mechanical arm downwards, a second ground grabbing device is arranged at the outer end of the second mechanical arm downwards, a third ground grabbing device is arranged at the outer end of the third mechanical arm downwards, a sound sensitization slice is attached to the bottom of the first mechanical arm, an optical fiber ring sound sensor is closely attached to the sound sensitization slice, a magnetostrictive slice is attached to the bottom of the second mechanical arm, and an optical fiber grating, a metal strain sensitization sheet is attached to the bottom of the third mechanical arm, and the fiber bragg grating strain sensor is placed in close contact with the metal strain sensitization sheet; the connection optical fibers of the optical fiber ring sound sensor, the optical fiber grating magnetic field sensor and the optical fiber grating strain sensor are connected to the demodulation system;

in the demodulation system, a first broadband light source is connected with an a port of an optical isolator, a second broadband light source is connected with a b port of the optical isolator, a c port of the optical isolator is connected with an a port of a circulator, a b port of the circulator is connected with an a port of a wavelength division multiplexer, a b port of the wavelength division multiplexer is connected with an a port of a first optical fiber coupler, a b port of the first optical fiber coupler is connected with an optical fiber grating magnetic field sensor, a c port of the first optical fiber coupler is connected with an optical fiber grating strain sensor, a c port of the wavelength division multiplexer is connected with an a port of a second optical fiber coupler, b and c ports of the second optical fiber coupler are respectively connected with a port and a port b port of an optical fiber ring sound sensor, a port of the circulator is connected with an a port of a third optical fiber coupler, a port of the third optical fiber coupler is connected with a spectrometer, and a b port of the third optical fiber coupler is connected with an a port of a Fabry-Perot tunable filter, the b port of the Fabry-Perot tunable filter is connected with the input end of a second photoelectric detector, the output end of the second photoelectric detector is connected with the a port of a double-path high-speed analog-to-digital conversion module, the c port of the double-path high-speed analog-to-digital conversion module is connected with the input end of a Gaussian filter module, the output end of the Gaussian filter module is connected with the input end of a peak searching module, the output end of the peak searching module is connected with the b port of a microcontroller, the d port of a second optical fiber coupler is connected with a first photoelectric detector, the first photoelectric detector is connected with the b port of the double-path high-speed analog-to-digital conversion module, the d port of the double-path high-speed analog-to-digital conversion module is connected with a low-pass filter module, the low-pass filter module is connected with the a port of the microcontroller, the c port of the microcontroller is connected with, the output end of the high-speed digital-to-analog conversion module is connected with the c port of the Fabry-Perot tunable filter.

The first mechanical arm comprises a first mechanical arm upper protection layer and a first mechanical arm lower protection layer; the second mechanical arm comprises a second mechanical arm upper protective layer and a second mechanical arm lower protective layer; the third mechanical arm comprises a third mechanical arm upper protective layer and a third mechanical arm lower protective layer; the upper and lower protective layers of the three layers are fixedly arranged in a laminating way.

The first ground grabbing device, the second ground grabbing device and the third ground grabbing device are all arranged to be triangular prisms with regular triangle-shaped cross sections, the side length of the cross section of each triangular prism is far larger than the height of each triangular prism, and the three devices are fixedly connected with the lower protection layer of the first mechanical arm, the lower protection layer of the second mechanical arm and the lower protection layer of the third mechanical arm correspondingly through one side edge of each triangular prism, so that the whole device is stably grabbed.

The bottom of the bottom protective layer is provided with an optical fiber ring wire hole, a first optical fiber grating wire hole and a second optical fiber grating wire hole, and a connecting optical fiber of the optical fiber ring sound sensor penetrates into the bottom protective layer through the optical fiber ring wire hole; the connecting optical fiber of the fiber bragg grating magnetic field sensor penetrates into the bottom protective layer through the first fiber bragg grating wire hole; connecting optical fibers of the fiber bragg grating strain sensor are connected into the bottom protective layer through fiber bragg grating wire holes; the three-way connection optical fiber is led out from the connection optical fiber access device at the bottom protective layer and is connected to the demodulation system.

Compared with the prior art, the military vehicle intrusion identification device based on the multi-source optical fiber sensing can identify sound change, magnetic field change and strain change generated by military vehicle intrusion behaviors, and integrates three signal detection means to form a multi-source optical fiber sensing technology; the detection performance of the fiber bragg grating and the fiber ring is improved by utilizing the magnetostrictive thin sheet, the metal strain sensitization thin sheet and the sound sensitization thin sheet; the three-legged buried structure is adopted to protect the fiber bragg grating and the fiber ring sensing device, rapid arrangement under battlefield conditions is facilitated, and the three-legged buried structure has the advantages of small size, convenience in carrying, simplicity in operation and the like.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic structural diagram of an intrusion identification device for military vehicles based on multi-source optical fiber sensing provided by the invention.

FIG. 2 is a schematic top view of the military vehicle intrusion identification device based on multi-source optical fiber sensing provided by the invention.

Fig. 3 is a schematic bottom view of the military vehicle intrusion identification device based on multi-source optical fiber sensing according to the present invention.

FIG. 4 is a schematic structural diagram of a demodulation system of the military vehicle intrusion identification device based on multi-source optical fiber sensing provided by the invention.

In the figure: 1. the device comprises a top protective layer 2, a middle spring buffer layer 3, a bottom protective layer 4, a connecting optical fiber in-out device 5, a first mechanical arm upper protective layer 6, a first mechanical arm lower protective layer 7, a first ground gripping device 8, an optical fiber ring sound sensor 9, a sound sensitization sheet 10, a second mechanical arm upper protective layer 11, a second mechanical arm lower protective layer 12, a second ground gripping device 13, an optical fiber grating magnetic field sensor 14, a magnetostrictive sheet 15, a third mechanical arm upper protective layer 16, a third mechanical arm lower protective layer 17, a third ground gripping device 18, an optical fiber grating strain sensor 19, a metal strain sensitization sheet 20, an optical fiber ring wire hole 21, a first optical fiber grating wire hole 22, a second optical fiber grating wire hole 23, a first broadband light source 24, a second broadband light source 25, an optical isolator 26, a light source and a light source, The device comprises a circulator 8, a fiber ring sound sensor 13, a fiber grating magnetic field sensor 18, a fiber grating strain sensor 27, a wavelength division multiplexer 28, a first fiber coupler 29, a second fiber coupler 30, a third fiber coupler 31, a Fabry-Perot tunable filter 32, a spectrometer 33, a first photoelectric detector 34, a second photoelectric detector 35, a two-way high-speed analog-to-digital conversion module 36, a Gaussian filter module 37, a high-speed digital-to-analog conversion module 38, a low-pass filter module 39, a peak searching module 40, a digital frequency synthesizer module 41 and a microcontroller.

Detailed Description

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Referring to fig. 1-3, the invention provides a military vehicle intrusion identification device based on multi-source optical fiber sensing, comprising: the mechanical system of the multisource optical fiber sensing military vehicle intrusion identification device comprises a top protective layer 1, a middle spring buffer layer 2, a bottom protective layer 3, a connecting optical fiber in-out device 4, a first mechanical arm upper protective layer 5, a first mechanical arm lower protective layer 6, a first ground gripping device 7, an optical fiber ring sound sensor 8, a sound sensitization sheet 9, a second mechanical arm upper protective layer 10, a second mechanical arm lower protective layer 11, a second ground gripping device 12, an optical fiber grating magnetic field sensor 13, a magnetostrictive sheet 14, a third mechanical arm upper protective layer 15, a third mechanical arm lower protective layer 16, a third ground gripping device 17, an optical fiber grating strain sensor 18, a metal strain sensitization sheet 19, an optical fiber ring wire hole 20, a first optical fiber grating wire hole 21 and a second optical fiber grating wire hole 22, and a first broadband light source 23, a second broadband light source 24, an optical isolator 25, a connecting optical fiber in-out device 4, The demodulation system of the multisource optical fiber sensing military vehicle intrusion identification device comprises a circulator 26, a wavelength division multiplexer 27, a first optical fiber coupler 28, a second optical fiber coupler 20, a third optical fiber coupler 30, a Fabry-Perot tunable filter 31, a spectrometer 32, a first photoelectric detector 33, a second photoelectric detector 34, a two-way high-speed analog-to-digital conversion module 35, a Gaussian filter module 36, a high-speed digital-to-analog conversion module 37, a low-pass filter module 38, a peak searching module 39, a digital frequency synthesizer module 40 and a microcontroller 41. FIG. 1 is a mechanical system diagram of the multi-source optical fiber sensing military vehicle intrusion identification device of the invention, and FIG. 2 is a demodulation system diagram of the multi-source optical fiber sensing military vehicle intrusion identification device of the invention.

When the mechanical device is laid on the spot, the mechanical device is buried on the ground where military vehicles frequently pass, the ground gripping depths of the first ground gripping device 7, the second ground gripping device 12 and the third ground gripping device 17 are kept consistent to ensure the horizontal laying of the mechanical device, the top protection layer 1 and the middle spring buffer layer 2 need to be laid above the ground, external pressure is buffered to protect the whole mechanical device, and the rest of the mechanical device is fully buried below the ground to realize the detection of sound, magnetic fields and strain signals.

The intrusion identification detection principle of the device in military vehicles and the working principle of the demodulation system of the device in the use process are further explained in the following with the attached figures 1 and 2.

As shown in the attached drawing 1, install middle spring buffer layer 2 between top protective layer 1 and bottom protective layer 3, and top protective layer 1 and middle spring buffer layer 2 need lay more than ground, so that protect the light path that the buffering protected bottom protective layer 3 department to the pressure that the external world applyed jointly, top protective layer 1, bottom protective layer 3 has the same diameter with middle spring buffer layer 2 and guarantees that the lifting surface area is enough big, reduce pressure, 3 bottom central point of bottom protective layer put to open there is the round hole and with connect optic fibre business turn over device 4 intercommunication, in addition 3 bottoms of bottom protective layer have still opened optic fibre ring wire guide 20, first optic fibre grating wire guide 21 and second optic fibre grating wire guide 22. The periphery of the bottom protective layer 3 is provided with one mechanical arm at intervals of 120 degrees, and three mechanical arms all adopt a double-layer protective structure to protect the fiber bragg grating and the fiber ring sensor below the mechanical arms from being damaged, wherein the first mechanical arm is formed by attaching a first mechanical arm upper protective layer 5 and a first mechanical arm lower protective layer 6 together, the outer end of the first mechanical arm lower protective layer 6 is provided with a first ground gripping device 7, the second mechanical arm is formed by attaching a second mechanical arm upper protective layer 10 and a second mechanical arm lower protective layer 11 together, the outer end of the second mechanical arm lower protective layer 11 is provided with a second ground gripping device 12, the third mechanical arm is formed by attaching a third mechanical arm upper protective layer 15 and a third mechanical arm lower protective layer 16 together, the outer end of the third mechanical arm lower protective layer 16 is provided with a third ground gripping device 17, the first ground gripping device 7, the second ground gripping device 12 and the third ground gripping device 17 form a three-foot type buried structure which is buried underground, and the ground grabbing depth of the three ground grabbing devices is kept consistent, and the horizontal burying of the whole mechanical device is ensured. The bottom of a first mechanical arm lower protective layer 6 is attached with a sound sensitization slice 9, a fiber ring sound sensor 8 and the sound sensitization slice 9 are placed in a close contact mode, so that the fiber ring sound sensor 8 is more sensitive to sound signals, a connecting optical fiber of the fiber ring sound sensor 8 penetrates into a bottom protective layer 3 through a fiber ring wire hole 20, a magnetostrictive slice 14 is attached to the bottom of a second mechanical arm lower protective layer 12, a fiber grating magnetic field sensor 13 and the magnetostrictive slice 14 are placed in a close contact mode, so that the fiber grating magnetic field sensor 13 is more sensitive to magnetic field signals, the connecting optical fiber of the fiber grating magnetic field sensor 13 penetrates into the bottom protective layer 3 through a first fiber grating wire hole 21, a metal strain sensitization slice 19 is attached to the bottom of a third mechanical arm lower protective layer 16, and a fiber grating strain sensor 18 and the metal strain sensitization slice 19 are placed in a close contact mode, the fiber grating strain sensor 18 is more sensitive to the detection of the strain signal, the connecting optical fiber of the fiber grating strain sensor 18 is connected to the bottom protective layer 3 through the second fiber grating wire hole 22, the optical fiber ring is connected to the bottom protective layer 3 through the optical fiber ring wire hole 20 and is led out from the connecting optical fiber in-out device 4 to be connected to the demodulation system, and the two paths of grating connecting optical fibers are led out from the connecting optical fiber in-out device 4 to be connected to the demodulation system after the intersection of the bottom protective layer 3. When a military vehicle passes through a mechanical device and is buried in the ground, the sound sensitization sheet 9, the magnetostrictive sheet 14 and the metal strain sensitization sheet 19 reinforce the sound, magnetic field and strain signals generated by the vehicle passing through, the sound, magnetic field and strain signals are respectively detected by the optical fiber ring sound sensor 8, the optical fiber grating magnetic field sensor 13 and the optical fiber grating strain sensor 18, and then the sensing optical signals are input into a demodulation system.

As shown in fig. 2, the first broadband light source 23 is connected to the port a of the optical isolator 25, the second broadband light source 24 is connected to the port b of the optical isolator 25, the port c of the optical isolator 25 is connected to the port a of the circulator 26, the port b of the circulator 26 is connected to the port a of the wavelength division multiplexer 27, the port b of the wavelength division multiplexer 27 is connected to the port a of the first optical fiber coupler 28, the port b of the first optical fiber coupler 28 is connected to the fiber grating magnetic field sensor 13, the port c of the first optical fiber coupler 28 is connected to the fiber grating strain sensor 18, the port c of the wavelength division multiplexer 27 is connected to the port a of the second optical fiber coupler 29, the port b of the second optical fiber coupler 29 is connected to the port a of the fiber ring acoustic sensor 8, the port c of the second optical fiber coupler 29 is connected to the port b of the fiber ring acoustic sensor 8, the port d of the second optical fiber coupler 29 is connected to the input terminal of the first photodetector 33, the port c of the circulator 26 is connected to the port a of the third optical fiber coupler 30, the port b of the third optical fiber coupler 30 is connected to the port a of the fabry-perot tunable filter 31, the port c of the third optical fiber coupler 30 is connected to the spectrometer 32, the port b of the fabry-perot tunable filter 31 is connected to the input end of the second photodetector 34, the output end of the second photodetector 34 is connected to the port a of the two-way high-speed analog-to-digital conversion module 35, the port b of the two-way high-speed analog-to-digital conversion module 35 is connected to the output end of the first photodetector 33, the port c of the two-way high-speed analog-to-digital conversion module 35 is connected to the input end of the gaussian two-way filter module 36, the port d of the high-speed analog-to-digital conversion module 35 is connected to the input end of the low-pass filter module 38, the output end, the output end of the peak searching module 39 is connected to the b port of the microcontroller 41, the output end of the low-pass filter module 38 is connected to the a port of the microcontroller 41, the c port of the microcontroller 41 is connected to the input end of the digital frequency synthesizer module 40, the output end of the digital frequency synthesizer module 40 is connected to the input end of the high-speed digital-to-analog conversion module 37, and the output end of the high-speed digital-to-analog conversion module 37 is connected to the c port of the fabry-perot tunable filter 31.

The first broadband light source 23 is a broadband light source with the central wavelength of 1550nm, the coverage waveband is 1528-1568 nm, the second broadband light source 24 is a broadband light source with the central wavelength of 1310nm, the coverage waveband is 1280-1340 nm, the first broadband light source 23 and the second broadband light source 24 respectively input optical signals from ports a and b of the optical isolator 25, then output the optical signals from port c of the optical isolator 25, input the optical signals from port a of the wavelength division multiplexer 27 through the circulator 26, output 1550nm broadband light from port b of the wavelength division multiplexer 27 and input the optical signals from port a of the first optical fiber coupler 28, and the first optical fiber coupler 28 divides 1550nm broadband light signals into 1: 1, two parts are respectively output from two ports b and c, an optical signal is input into an optical fiber grating magnetic field sensor 13 from a port b of a first optical fiber coupler 28, an optical signal is input into an optical fiber grating strain sensor 18 from a port c of the first optical fiber coupler 28, 1310nm broadband light is output from a port a of a second optical fiber coupler 29 by a port c of a wavelength division multiplexer 27, the optical signal is divided into two parts by an equal ratio by the second optical fiber coupler 29 and is output from ports b and c respectively, then the two parts are input along ports a and b of an optical fiber ring sound sensor 8 respectively, the optical fiber ring sound sensor 8 is an optical fiber ring which is formed by winding single-mode optical fibers and has the same diameter, and the optical fiber ring can be divided into a clockwise optical path with a port-optical fiber ring-b port and a counterclockwise optical path with a port b port-optical ring-a port; the reflection wavelength of the fiber grating is influenced by the refractive index of the fiber and the grating spacing, and when the fiber grating is subjected to an external magnetic field and a strain signal, the refractive index of the fiber and the grating spacing can generate different reflection wavelengths because the refractive index of the fiber and the grating spacing meet the different change rules; when the optical fiber loop sound sensor 8 is affected by an external sound signal, the clockwise laser light input from the port a and propagating in the clockwise direction and the counterclockwise laser light input from the port b and propagating in the counterclockwise direction form interference at the second optical fiber coupler 29 due to the sagnac effect, and the change rule of the interference light intensity is consistent with the change rule of the external sound intensity, so that the external sound signal can be detected.

When the optical fiber ring acoustic sensor 8 detects an acoustic change signal, it causes a change in interference light intensity at the second optical fiber coupler 29, the changed interference light signal is output to the first photoelectric detector 33 through the d port of the second optical fiber coupler 29, the optical power is converted into a voltage amplitude in an equal proportion, the first photoelectric detector 33 outputs a signal to the b port of the dual-path high-speed analog-to-digital conversion module 35, the analog signal is converted into a digital signal, the dual-path high-speed analog-to-digital conversion module 35 outputs the digital signal from the d port to the low-pass filter module 38, so as to filter low-frequency noise in the environment, the low-pass filter module 38 outputs the filtered signal to the a port of the microcontroller 41, and an interference optical time-domain signal of the optical fiber ring acoustic sensor 8 is obtained, thereby completing detection of an acoustic signal.

When the fiber grating magnetic field sensor 13 detects a magnetic field change signal, the grating selectively reflects the wavelength satisfying its bragg condition, the reflected light returns to the b port of the first fiber coupler 28 along the original path, and enters the b port of the wavelength division multiplexer 27 from the a port of the first fiber coupler 28, so that the reflected light enters the b port of the circulator 26 from the a port of the wavelength division multiplexer 27, and then enters the third fiber coupler 30 from the c port of the circulator 26, and the third fiber coupler 30 divides the reflected light signal into 10: 90, 10% of reflected light signals are input into the spectrometer 32 through a port c of the third optical fiber coupler 30, a reference value is obtained by analyzing a reflection spectrum of the optical fiber grating magnetic field sensor 13, 90% of reflected light signals are demodulated from a port a of the fabry-perot tunable filter 31 through a port b of the third optical fiber coupler 30, the fabry-perot tunable filter 31 outputs signals from the port b to the second photoelectric detector 34, optical power is converted into voltage amplitude in an equal proportion, output signals of the second photoelectric detector 34 are input through a port a of the high-speed analog-to-digital conversion module 35, analog signals are converted into digital signals, the digital signals are output to the gaussian filter module 36 through the port c of the high-speed analog-to-digital conversion module 35, the digital signals are input into the peak searching module 39 after being smoothed, peak value initial judgment is performed on filtered data, acquiring all sampling data between the starting point and the end point of the rising edge of the peak value edge of data which meets the requirement of a preset peak value, performing weighted average to obtain the accurate position of the peak value, storing the accurate position, inputting the output signal of the peak searching module 39 from the port b of the microcontroller 41, identifying and judging the signal to send a next step instruction, inputting the output signal of the microcontroller 41 from the port c to the digital frequency synthesizer module 40 to generate a digital signal for generating a triangular wave, converting the digital signal into a triangular wave analog signal through the high-speed digital-to-analog conversion module 37, inputting the triangular wave signal from the port c of the Fabry-Perot tunable filter 31 through the high-speed digital-to-analog conversion module 37, driving the Fabry-Perot tunable filter 31 to perform uninterrupted periodic scanning on the reflection spectrum of the fiber bragg grating to obtain the time domain distribution of the fiber grating reflection spectrum of the fiber grating magnetic field sensor, the demodulation of the magnetic field signal is completed.

When the fiber grating strain sensor 18 detects a strain change signal, the grating selectively reflects a wavelength satisfying its bragg condition, the reflected light returns to the c port of the first fiber coupler 28 along the original path, and enters the b port of the wavelength division multiplexer 27 from the a port of the first fiber coupler 28, so that the reflected light enters the b port of the circulator 26 from the a port of the wavelength division multiplexer 27, and then enters the third fiber coupler 30 from the c port of the circulator 26, and the third fiber coupler 30 divides the reflected light signal into 10: 90, 10% of reflected light signals are input into the spectrometer 32 through a port c of the third optical fiber coupler 30, a reference value is obtained by analyzing a reflection spectrum of the fiber bragg grating strain sensor 18, 90% of reflected light signals are demodulated from a port a of the fabry-perot tunable filter 31 through a port b of the third optical fiber coupler 30, the fabry-perot tunable filter 31 outputs signals from the port b to the second photoelectric detector 34, optical power is converted into voltage amplitude in an equal proportion mode, output signals of the second photoelectric detector 34 are input through a port a of the high-speed analog-to-digital conversion module 35, analog signals are converted into digital signals, the digital signals are output to the gaussian filter module 36 through the port c of the high-speed analog-to-digital conversion module 35, the digital signals are input into the peak searching module 39 after being subjected to smoothing processing, peak value initial judgment is performed on filtered data, acquiring all sampling data between the starting point and the end point of the rising edge of the peak value edge of data which meets the requirement of a preset peak value, performing weighted average to obtain the accurate position of the peak value, storing the accurate position, inputting the output signal of a peak searching module 39 from a port b of a microcontroller 41, identifying and judging the signal to send a next step instruction, inputting the output signal of the microcontroller 41 from a port c to a digital frequency synthesizer module 40 to generate a digital signal for generating a triangular wave, converting the digital signal into a triangular wave analog signal through a high-speed digital-to-analog conversion module 37, inputting the triangular wave signal from the port c of the Fabry-Perot tunable filter 31 through the high-speed digital-to-analog conversion module 37, driving the Fabry-Perot tunable filter 31 to perform uninterrupted periodic scanning on the reflection spectrum of the fiber bragg grating to obtain the time domain distribution of the fiber grating reflection spectrum of the fiber grating strain sensor 18, and completing the demodulation of the strain signal.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.