Reflectivity coded fiber bragg grating sensing system and measuring method

Abstract

The invention provides a reflectivity coding fiber bragg grating sensing system and a measuring method. The system comprises a broadband light source, a circulator, a fiber bragg grating array, a fiber bragg grating demodulation module and a data processor, the fiber bragg grating array comprises a plurality of fiber bragg grating sensors which are connected in series on one optical fiber; the number of the fiber grating sensors on the same optical fiber is smaller than or equal to two times of the demodulation bandwidth of the broadband light source divided by the bandwidth range used by each fiber grating sensor; the fiber grating sensors positioned on the same optical fiber are sequentially arranged according to the size of wavelengths and are arranged at intervals according to the high-low rule of reflectivity; and the data processor performs binary coding on the light intensity, positions the light intensity to the corresponding fiber grating sensor by analyzing the code, and converts the physical quantity to be measured. According to the method, the peak hopping phenomenon caused by excessive arrangement of the sensors in the fiber grating array and too dense wavelength intervals can be identified, and adjacent sensors can share part of bandwidth, so that the capacity expansion of the number of the fiber sensors is realized.

Description

Technical Field

[0001] The invention belongs to the field of optical fiber sensing and long-distance measurement applications, and in particular relates to a reflectivity-coded optical fiber grating sensing system and a measurement method. Background Art

[0002] Multi-point high temperature or large strain monitoring systems have important application prospects in the field of large-scale structural safety. For example, in the field of large-scale civil engineering safety, during the construction process, concrete is affected by temperature and load, and is prone to cracking, threatening the overall safety of the project. Multi-point strain monitoring can timely detect the strain conditions of various key parts and predict the health and life of the structure. For example, in the fields of oil tanks, tunnels, and pipe galleries, fire monitoring and fire source location also require a large number of high-temperature sensor points.

[0003] Traditional strain and temperature measurement methods use fiber grating arrays to prepare multiple fiber grating temperature sensors on one optical fiber, so that multi-point long-distance temperature and strain measurement can be achieved on one optical fiber. This multiplexing method is often determined by the different central wavelengths of the reflection spectrum of the fiber grating sensor at different positions on the optical fiber. Since the bandwidth of the demodulator used to monitor the movement of the fiber grating reflection peak is limited, each grating sensor needs to occupy a certain instrument bandwidth. Therefore, the number of sensors that can be connected in series on one optical fiber can only be the total bandwidth of the instrument divided by the bandwidth that each sensor needs to occupy. In the field of high temperature or large strain monitoring, the bandwidth that each grating sensor needs to occupy is very large, which leads to a limit on the number of sensors that can be connected in series to the system, which cannot meet the needs of high-density monitoring. How to effectively increase the number of sensors that the system can accommodate while maintaining the hardware bandwidth of the demodulator unchanged is a core technical issue.

[0004] In traditional demodulation systems, each grating sensor must occupy a certain bandwidth because its reflectivity is consistent. In the demodulation spectrum, the reflection spectrum of each grating has the same peak shape. When the reflection peak spectrum of a grating moves too much and exceeds the reflection peak of the grating next to it (called the "peak jumping" phenomenon), the system will not be able to identify the "misalignment" of the two peaks, and will save the data of the adjacent peak as the original peak, which will cause data recording errors. Therefore, in actual engineering, when designing a fiber optic sensing system, the center wavelength difference between the two gratings that may jump peaks is often increased to reserve sufficient bandwidth to ensure that the peak jumping phenomenon does not occur. Although this eliminates the possibility of error, it will significantly reduce the number of gratings multiplexed on a single optical fiber.

[0005] Therefore, the above-mentioned "peak jumping" phenomenon results in a limited number of sensors that can be accommodated under a certain bandwidth, making it difficult for the fiber Bragg grating system to be used on a large scale in actual engineering. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a reflectivity-coded fiber Bragg grating sensing system and a measuring method, which can identify the peak-hopping phenomenon and reduce the bandwidth used by a single fiber Bragg grating sensor, thereby achieving the expansion of the number of fiber optic sensors. The technical solution adopted by the present invention to solve the above technical problems is: a reflectivity-encoded fiber Bragg grating sensing system, comprising a broadband light source, a circulator, a fiber Bragg grating array, a fiber Bragg grating demodulation module and a data processor; wherein, The fiber grating array comprises a plurality of fiber grating sensors connected in series on an optical fiber, which are laid in a long-distance object to be measured, and each fiber grating sensor is used to sense the physical quantity to be measured at the location; the number of fiber grating sensors on the same optical fiber is less than or equal to twice the demodulation bandwidth of the broadband light source divided by the bandwidth range used by each fiber grating sensor; the central wavelengths of the fiber grating sensors on the same optical fiber are different and are arranged in order of wavelength size; The light beam emitted by the broadband light source enters the fiber grating array through the circulator, each fiber grating sensor in the fiber grating array returns a reflection spectrum with a different central wavelength, the fiber grating array demodulation module converts the optical signal into an electrical signal according to the reflection spectrum, the data processor performs binary encoding on the electrical signal, locates the corresponding fiber grating sensor by analyzing the encoding, and then converts the physical quantity to be measured; The fiber grating sensors are arranged on the optical fiber at regular intervals according to their respective reflectivity, and the data processor encodes the electrical signal according to corresponding rules.

[0007] According to the above scheme, the certain sorting rule is specifically: the fiber Bragg grating sensors are divided into two types: high reflection type and low reflection type according to reflectivity, and the two types of fiber Bragg grating sensors are staggered on the same optical fiber; A certain light intensity threshold is set according to the two types of fiber grating sensors, so that the highest light intensity at the center of the reflection spectrum returned by the high-reflection fiber grating sensor is higher than the light intensity threshold, and the highest light intensity at the center of the reflection spectrum returned by the low-reflection fiber grating sensor is lower than the light intensity threshold; The data processor sets corresponding rules to encode the electrical signal specifically as follows: the electrical signal includes wavelength and light intensity, when the received light intensity is higher than the light intensity threshold, it is encoded as 1; when the received light intensity is lower than the light intensity threshold, it is encoded as 0; binary code is formed according to the light intensity of the reflected spectrum returned by all fiber grating sensors; Under normal conditions, the number of bits of the initial binary code is the same as the number of the fiber Bragg grating sensors, and the value of the binary code corresponds one-to-one to the position sequence of the fiber Bragg grating sensors.

[0008] According to the above scheme, the data processor is specifically used for: Obtain the wavelength and light intensity of each grating from the fiber grating string spectrum measured by the fiber grating demodulation module; The binary code is obtained according to the light intensity, and the binary code state change is compared in real time, and the position of the fiber grating sensor where the physical quantity to be measured changes occurs is determined by analyzing the binary code value change; The corresponding physical quantity to be measured is calculated according to the grating peak jump state and the spectrum center wavelength offset.

[0009] According to the above scheme, the real-time comparison of binary code state changes and determination of the fiber grating sensor position where the measured physical quantity changes through binary code value change analysis are specifically: Setting a register for storing a binary subtraction difference between the current binary code and the initial binary code; When the difference is 0, the peak jump state is no peak jump, and the physical quantity to be measured of each fiber grating sensor is determined by the wavelength drift of each fiber grating sensor; When a certain bit in the difference is 1, the peak jumping state of the fiber grating sensor corresponding to the bit is judged as peak jumping, the number of the fiber grating sensor where the peak jump occurs is exchanged with the number of the fiber grating sensor that is skipped, the wavelength drift amount is recalculated, and then the physical quantity to be measured of each fiber grating sensor is determined.

[0010] According to the above solution, the physical quantity to be measured is obtained by dividing the wavelength offset of each fiber grating sensor by the sensitivity of the corresponding fiber grating sensor.

[0011] According to the above scheme, the physical quantity to be measured is the temperature of the long-distance measured object at each fiber grating sensor; the long-distance measured object is an oil tank, a tunnel or a pipe gallery.

[0012] According to the above scheme, the physical quantity to be measured is the strain of the long-distance object to be measured at each fiber grating sensor; the long-distance object to be measured is a bridge or a building.

[0013] As a second aspect of the present invention, the present invention also provides a measurement method of the fiber Bragg grating sensing system based on the reflectivity coding, the method comprising: Binary encoding is performed according to the light intensity of the reflected spectrum of the fiber Bragg grating sensor; By analyzing the code, the corresponding fiber grating sensor is located; Convert the physical quantity to be measured at each fiber grating sensor.

[0014] According to the above method, the initial binary code is obtained under normal conditions; Monitor the received light intensity in real time to obtain the current binary code; By analyzing the difference between the current binary code and the initial binary code, it is determined whether each fiber grating sensor has a peak jump, thereby locating the fiber grating sensor for the received wavelength, and then converting the physical quantity to be measured at each fiber grating sensor.

[0015] As a third aspect of the present invention, the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the measurement method when executing the computer program.

[0016] The beneficial effects of the present invention are as follows: by arranging the fiber grating sensors according to certain rules according to the reflectivity, and formulating coding rules according to the above rules, the corresponding code is obtained according to the coding rules when the light intensity is received, and the peak jumping phenomenon caused by too many sensors arranged in the fiber grating array and too dense wavelength intervals is identified through the code change value, so that the fiber grating sensor can be accurately located even when there is a peak jump, and then when setting the fiber grating array, adjacent sensors can share part of the bandwidth, thereby realizing the expansion of the number of fiber optic sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the system structure of an embodiment of the present invention.

[0018] Figure 2 This is a spectrum diagram of the fiber grating sensor received under normal conditions according to an embodiment of the present invention.

[0019] Figure 3 This is a spectrum change diagram of a fiber grating sensor according to an embodiment of the present invention when high temperature / large strain occurs.

[0020] Figure 4 This is a binary code change diagram of a fiber grating sensor according to an embodiment of the present invention when high temperature occurs.

[0021] Figure 5 It is a method logic diagram of an embodiment of the present invention.

[0022] In the figure: 1- broadband light source, 2- circulator, 3- fiber grating array, 4- fiber grating demodulator, 5- data processor. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The present invention provides a reflectivity-coded fiber Bragg grating sensing system and a measurement method, which can identify the peak jumping phenomenon caused by too many sensors arranged in a fiber Bragg grating array and too dense wavelength spacing, so that adjacent sensors can share part of the bandwidth, thereby achieving the expansion of the number of fiber optic sensors. The fiber Bragg grating sensing system is mainly used to measure the physical quantity to be measured of long-distance objects, such as: the temperature of oil tanks, tunnels or pipe galleries. When the temperature changes greatly, it indicates that there is a risk of explosion; the strain of bridges or buildings. When the strain changes greatly, it indicates that the structure is at risk of collapse.

[0025] As a first aspect of the present invention, the present invention provides a reflectivity-coded fiber Bragg grating sensing system, such as Figure 1 As shown, it includes a broadband light source 1, a circulator 2, a fiber grating array 3, a fiber grating demodulation module 4 and a data processor 5.

[0026] The fiber grating array includes a plurality of fiber grating sensors connected in series on an optical fiber, which are laid in a long-distance object to be measured, and each fiber grating sensor is used to sense the physical quantity to be measured at the location. The number of fiber grating sensors on the same optical fiber is less than or equal to twice the demodulation bandwidth of the broadband light source divided by the bandwidth range used by each fiber grating sensor; the center wavelengths of the fiber grating sensors on the same optical fiber are different and are arranged in order of the size of the center wavelength, for example, in order from small to large, or from large to small. The peak jump phenomenon of a single fiber grating sensor will only occur once, and the maximum center wavelength offset will not exceed the second peak, so the interval between the center wavelengths of adjacent fiber grating sensors usually does not need to be constrained, and is based on actual conditions, and usually does not exceed 3nm.

[0027] The light beam emitted by the broadband light source passes through the circulator and enters the fiber grating array. Each fiber grating sensor in the fiber grating array returns a different central wavelength. The fiber grating array demodulation module converts the optical signal into an electrical signal according to the reflection spectrum. The data processor encodes the electrical signal, locates the corresponding fiber grating sensor by analyzing the code, and then converts the physical quantity to be measured.

[0028] The fiber grating sensors are arranged on the optical fiber according to their respective reflectivity in a certain ordering rule, and the data processor encodes the electrical signal according to the corresponding rule.

[0029] In this embodiment, the certain sorting rules are specifically as follows: the fiber Bragg grating sensors are divided into two types according to reflectivity: high-reflection type and low-reflection type, and the two types of fiber Bragg grating sensors are set alternately on the same optical fiber. Due to the different reflectivities, the intensity of the reflected light is also different. A certain light intensity threshold is set according to the two types of fiber Bragg grating sensors, so that the highest light intensity at the center of the reflection spectrum returned by the high-reflection fiber Bragg grating sensor is higher than the light intensity threshold, and the highest light intensity at the center of the reflection spectrum returned by the low-reflection fiber Bragg grating sensor is lower than the light intensity threshold; The data processor sets corresponding rules to encode the electrical signal specifically as follows: the electrical signal includes wavelength and light intensity. When the received light intensity is higher than the light intensity threshold, it is encoded as 1; when the received light intensity is lower than the light intensity threshold, it is encoded as 0; and a binary code is formed based on the light intensity of the reflected spectrum returned by all fiber grating sensors.

[0030] In this way, under normal conditions, the number of bits of the initial binary code is the same as the number of fiber Bragg grating sensors, and the value of the binary code corresponds one-to-one to the position order of the fiber Bragg grating sensors. The normal state refers to: the physical quantity to be measured is in a normal state without major changes, the reflection spectrum of the fiber Bragg grating sensor does not move much, and there is no peak jump phenomenon. For example: the temperature or strain is the temperature or strain of the long-distance object to be measured under normal conditions. When the temperature of the long-distance object to be measured changes drastically (which may cause an explosion) or the strain exceeds a certain threshold (which may cause structural instability), it is an abnormal state.

[0031] The data processor is specifically used for: The wavelength and light intensity of each grating are obtained from the fiber grating string spectrum measured by the fiber grating demodulation module.

[0032] The binary code is obtained according to the light intensity, and the binary code state changes are compared in real time. The position of the fiber grating sensor where the measured physical quantity changes is determined by analyzing the binary code value changes. Specifically, a register can be set to store the binary subtraction difference between the current binary code and the initial binary code.

[0033] The corresponding physical quantity to be measured is converted according to the grating peak jumping state and the center wavelength offset of the spectrum. Specifically, when the difference is 0, the peak jumping state is no peak jumping, and the physical quantity to be measured of each fiber grating sensor is determined by the wavelength drift of each fiber grating sensor. When a certain bit in the difference is 1, the peak jumping state of the fiber grating sensor corresponding to the bit is judged as peak jumping, and the number of the fiber grating sensor where the peak jumping occurs is exchanged with the number of the fiber grating sensor that is skipped, and the wavelength drift is recalculated, and then the physical quantity to be measured of each fiber grating sensor is determined.

[0034] Furthermore, the physical quantity to be measured is obtained by dividing the wavelength offset of each fiber grating sensor by the sensitivity of the corresponding fiber grating sensor.

[0035] There needs to be a certain interval between the central wavelengths of adjacent fiber grating sensors located on the same optical fiber.

[0036] As a second aspect of the present invention, the present invention also provides a measurement method of the fiber Bragg grating sensing system based on the reflectivity coding, the method comprising: S1. Encoding according to the light intensity of the fiber grating sensor. For the convenience of calculation, the encoding is preferably binary encoding.

[0037] S2. Locate the corresponding fiber Bragg grating sensor by analyzing the code. Under normal conditions, obtain the initial binary code; monitor the received light intensity in real time to obtain the current binary code. By analyzing the difference between the current binary code and the initial binary code, determine whether each fiber Bragg grating sensor has a peak jump, and thus locate the fiber Bragg grating sensor for the received wavelength.

[0038] S3. Convert the physical quantity to be measured at each fiber grating sensor.

[0039] The present invention is further described below by taking 12 fiber Bragg grating sensors as an example. In actual situations, the number of fiber Bragg grating sensors can be much greater than 12.

[0040] Continue to refer to Figure 1 , the fiber grating array 3 includes 12 fiber grating sensors connected in series on an optical fiber, the reflectivity of the odd-numbered fiber grating sensors is 90%, and the reflectivity of the even-numbered fiber grating sensors is 40%. Because the reflectivity of the fiber grating string is set from left to right, one high and one low, the reflected spectrum intensity is arranged from left to right, one high and one low. The fiber grating demodulator converts the spectrum quantization into discrete voltage values, and the data processor encodes the collected high voltage as 1 and the low voltage as 0. Therefore, the binary code of the fiber grating string at room temperature is 101010101010. Here, it is necessary to record the fiber grating reflection spectrum and binary at room temperature to use as the initial state to identify the jump peak.

[0041] The following is an explanation of the temperature measurement and positioning of a single-point high-temperature heat source.

[0042] Assume that the characteristic of fiber Bragg grating is that the central wavelength drifts 1pm to the right for every 1℃ increase in temperature. At room temperature, the central wavelength of each fiber Bragg grating differs by 3nm from its adjacent one. Figure 2 Assume that the fiber grating sensor No. x is stimulated by a high temperature heat source. Figure 3 This is the spectrum change diagram of the high temperature heat source appearing in the xth sensor of this fiber grating string. Figure 3It can be seen that within the entire temperature variation range, the center wavelength of the xth fiber Bragg grating will drift to the center wavelength position of the x+2th fiber Bragg grating at most, so the binary code value only needs to consider 3 bits, the xth bit, the x+1th bit, and the x+2th bit. Figure 4 This is the binary code change diagram of the high temperature heat source appearing in the xth sensor of the fiber grating string. According to the specific temperature change and the parity of x, different spectrum diagrams and different binary code values ​​correspond. When the temperature of the high temperature heat source measured by the xth sensor is at room temperature, the code value corresponding to the odd number is 101, and the code value corresponding to the even number is 010. When the temperature of the high temperature heat source measured is between 0-300℃, the reflection spectrum of the xth fiber grating will shift to The code value corresponding to the odd number is 101, and the code value corresponding to the even number is 010, which remains unchanged. When the temperature is 300℃, the reflection spectrum will shift to The code value for odd numbers is 11, and the code value for even numbers is 10. The reason for the missing bit is that the center wavelength of the reflection spectrum of sensor x coincides with the center wavelength of the reflection spectrum of sensor x+1, and the data processor encodes the voltage value corresponding to the coincident spectrum as 1. When the temperature is between 300-600 degrees Celsius, the reflection spectrum will shift to The code value corresponding to an odd number is 011, and the code value corresponding to an even number is 100.

[0043] Make the initial state binary value m 0 and the binary code value m after the change 1 The absolute value of the difference is recorded as the absolute state change value m c As follows: |m 0- m 1 | = m c Record the central wavelength value of the spectral grating reflection at each position, and compare them with the central wavelength value of the reflection grating at room temperature one by one. The fiber grating with a change in central wavelength is the position where the high-temperature heat source appears. The wavelength offset can be obtained by subtracting the central wavelength value after the change from the central wavelength value at room temperature, and then the measured temperature can be converted. This method is recorded as the wavelength-by-wavelength comparison method. When the temperature of the x-th sensor is in the range of 0-300℃, the absolute state change value obtained by the register is 000, which is a non-peak jump state. Therefore, it is necessary to further perform the wavelength-by-wavelength comparison method to obtain the measured temperature. When the temperature of the x-th sensor is in the range of 300-600℃, when x is less than 12, the absolute state change value obtained by the register is 010, which is a peak jump state. Because there are a total of 12 binary bits, the remaining nine bits are 0. Therefore, the position of the high-temperature heat source can be determined by the 1 appearing at the position of the 12-bit binary. If a high-temperature heat source appears in the x-th sensor, 1 appears in the binary x+1 position. After that, perform the wavelength comparison method one by one, and add 300℃ to the converted temperature value to get the measured temperature. In the case where x is equal to 12, directly perform the wavelength comparison method one by one. When the temperature of the x-th sensor is above 300℃, the two center wavelengths of the spectrum will be superimposed, and the resulting 12-bit binary code value will be reduced to 11 bits, and the corresponding peaks will coincide. In this case, calculate the center wavelength value of each position. When x is greater than 1, the center wavelength of the x-th fiber grating sensor reflection spectrum will differ by 6nm from the x+1th position. Therefore, as long as the difference between adjacent wavelengths is determined to be 6nm, the high-temperature heat source can be located. Based on the above analysis, the software logic diagram is as follows: Figure 5 shown.

[0044] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the measurement method when executing the computer program. The electronic device may be a smart phone, a tablet computer, a laptop computer, a desktop computer, a rack server, a blade server, a tower server, or a cabinet server (including an independent server or a server cluster composed of multiple servers) that can execute the program.

[0045] The present invention provides a method and system for expanding a fiber grating array for high temperature / large strain measurement with binary reflectivity coding, so as to achieve the purpose of doubling the number of fiber grating sensors accommodated on one optical fiber without reducing the measurement range, and effectively improve the system utilization rate by solving the recording error problem caused by peak jumping.

[0046] It should be noted that there is no standard for the bandwidth of a fiber Bragg grating sensor, and the bandwidth can be selected according to the actual situation. The purpose of the present invention is to double the usage of the fiber Bragg grating sensor without changing the original bandwidth.

[0047] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A reflectivity-coded fiber Bragg grating sensing system, characterized in that: It includes a broadband light source, a circulator, a fiber grating array, a fiber grating demodulation module and a data processor; wherein, The fiber grating array comprises a plurality of fiber grating sensors connected in series on an optical fiber, which are laid in a long-distance object to be measured, and each fiber grating sensor is used to sense the physical quantity to be measured at the location; the number of fiber grating sensors on the same optical fiber is less than or equal to twice the demodulation bandwidth of the broadband light source divided by the bandwidth range used by each fiber grating sensor; the central wavelengths of the fiber grating sensors on the same optical fiber are different and are arranged in order of wavelength size; The light beam emitted by the broadband light source enters the fiber grating array through the circulator, each fiber grating sensor in the fiber grating array returns a reflection spectrum with a different central wavelength, the fiber grating array demodulation module converts the optical signal into an electrical signal according to the reflection spectrum, the data processor performs binary encoding on the electrical signal, locates the corresponding fiber grating sensor by analyzing the encoding, and then converts the physical quantity to be measured; The fiber grating sensors are arranged on the optical fiber at regular intervals according to their respective reflectivity, and the data processor sets corresponding rules to encode the electrical signal.

2. The reflectivity-coded fiber Bragg grating sensing system according to claim 1, characterized in that: The fiber Bragg grating sensors are divided into two types according to reflectivity: high-reflection type and low-reflection type. The two types of fiber Bragg grating sensors are staggered on the same optical fiber. A certain light intensity threshold is set according to the two types of fiber grating sensors, so that the highest light intensity at the center of the reflection spectrum returned by the high-reflection fiber grating sensor is higher than the light intensity threshold, and the highest light intensity at the center of the reflection spectrum returned by the low-reflection fiber grating sensor is lower than the light intensity threshold; The data processor sets corresponding rules to encode the electrical signal specifically as follows: the electrical signal includes wavelength and light intensity, when the received light intensity is higher than the light intensity threshold, it is encoded as 1; when the received light intensity is lower than the light intensity threshold, it is encoded as 0; binary code is formed according to the light intensity of the reflected spectrum returned by all fiber grating sensors; Under normal conditions, the number of bits of the initial binary code is the same as the number of the fiber Bragg grating sensors, and the value of the binary code corresponds one-to-one to the position sequence of the fiber Bragg grating sensors.

3. The reflectivity-coded fiber Bragg grating sensing system according to claim 2, characterized in that: The data processor is specifically used for: Obtain the wavelength and light intensity of each grating from the fiber grating string spectrum measured by the fiber grating demodulation module; The binary code is obtained according to the light intensity, and the binary code state change is compared in real time, and the position of the fiber grating sensor where the physical quantity to be measured changes occurs is determined by analyzing the binary code value change; The corresponding physical quantity to be measured is calculated according to the grating peak jump state and the spectrum center wavelength offset.

4. The reflectivity-coded fiber Bragg grating sensing system according to claim 3, characterized in that: The real-time comparison of binary code state changes and determination of the fiber grating sensor position where the measured physical quantity changes through binary code value change analysis are specifically: Setting a register for storing a binary subtraction difference between the current binary code and the initial binary code; When the difference is 0, the peak jump state is no peak jump, and the physical quantity to be measured of each fiber grating sensor is determined by the wavelength drift of each fiber grating sensor; When a certain bit in the difference is 1, the peak jumping state of the fiber grating sensor corresponding to the bit is judged as peak jumping, the number of the fiber grating sensor where the peak jump occurs is exchanged with the number of the fiber grating sensor that is skipped, the wavelength drift amount is recalculated, and then the physical quantity to be measured of each fiber grating sensor is determined.

5. The reflectivity-coded fiber Bragg grating sensing system according to claim 1, characterized in that: The physical quantity to be measured is obtained by dividing the wavelength offset of each fiber grating sensor by the sensitivity of the corresponding fiber grating sensor.

6. The reflectivity-coded fiber Bragg grating sensing system according to any one of claims 1 to 5, characterized in that: The physical quantity to be measured is the temperature of the long-distance measured object at each fiber optic grating sensor; the long-distance measured object is an oil tank, a tunnel or a pipe gallery.

7. The reflectivity-coded fiber Bragg grating sensing system according to any one of claims 1 to 5, characterized in that: The physical quantity to be measured is the strain of the long-distance measured object at each fiber grating sensor; the long-distance measured object is a bridge or a building.

8. A method for measuring a reflectivity-coded fiber Bragg grating sensing system according to any one of claims 1 to 7, characterized in that: The method includes: Binary encoding is performed according to the light intensity of the reflected spectrum of the fiber Bragg grating sensor; By analyzing the code, the corresponding fiber grating sensor is located; Convert the physical quantity to be measured at each fiber grating sensor.

9. The measuring method according to claim 8, characterized in that: Get the initial binary code under normal conditions; Monitor the received light intensity in real time to obtain the current binary code; By analyzing the difference between the current binary code and the initial binary code, it is determined whether each fiber grating sensor has a peak jump, thereby locating the fiber grating sensor for the received wavelength, and then converting the physical quantity to be measured at each fiber grating sensor.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the measurement method according to any one of claims 8 or 9 are implemented.

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