CN112857612B - Distributed optical fiber temperature measurement calculation method - Google Patents
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Abstract
The invention provides a distributed optical fiber temperature measurement calculation method, which solves the problems that the existing temperature measurement method is insufficient in light intensity ratio data compensation of anti-Stokes Raman and Stokes Raman, and calibration of a constant temperature bath is complex. The method comprises the following steps: 1) ObtainOriginal waveforms data _ as and data _ s of the anti-stokes Raman light and the stokes Raman light are obtained; the temperature B of the environment of the case where the optical fiber is located; 2) Acquiring the ratio data _ X of the data _ as to the data _ s; 3) Selecting effective waveforms data _ AS and data _ S of the data _ AS and the data _ S; 4) Selecting data _ AS and S data sampling points before data _ S for fitting to obtain an attenuation coefficient alpha a 、α s And a maximum amplitude I a 、I s (ii) a 5) Selecting a data _ X effective waveform to obtain a data _ Y group; 6) Dividing the array data _ Y into equal parts by length L, and taking the rest array as data _ r; bisector array data _ Y q And the compensation array data _ r carries out loss compensation and outputs an integral compensation array data _ Z; 7) Calculating the measured temperature T of the distributed optical fiber: t = kX (data _ Z-I) a /I s )+B。
Description
Technical Field
The invention belongs to the field of optical fiber temperature measurement, relates to an optical fiber temperature measurement method, and particularly relates to a distributed optical fiber temperature measurement calculation method.
Background
The cables in the power system are far away, and the joints are more and scattered, so that the overhaul is difficult (such as the cables in a cable trench); in the long-term use process, the insulating sheath of the cable also can age and other conditions, and the aged insulating sheath can be punctured even when the cable is locally overheated, so that major accidents are caused. If the weak link of the cable can be monitored and early warned continuously for 24 hours, the aging degree of the cable is found in advance, so that the service life of the cable can be prolonged, and accidents are avoided. The distributed optical fiber temperature measurement technology can continuously measure the temperature field of optical fiber distribution in real time, and can effectively solve the problem of monitoring and early warning of the power cable.
The distributed optical fiber temperature measurement is based on a Raman scattering principle, raman scattering light is divided into anti-Stokes Raman light and Stokes Raman light, the common distributed temperature measurement method is that the light intensity of the anti-Stokes Raman light and the Stokes Raman light is directly used as a ratio, then data is compared for corresponding compensation, and then the temperature can be obtained through calibration of a constant temperature tank. The traditional compensation method is whole-section compensation, the optical fiber loss is larger and larger along with the increase of the length of the optical fiber, so that the ratio compensation of the tail part of the optical fiber is insufficient, the condition that the difference between the temperature measurement value and the actual value is larger easily occurs, and the measured temperature precision is poorer.
Disclosure of Invention
The invention provides a distributed optical fiber temperature measurement calculation method, aiming at solving the technical problems that the existing distributed temperature measurement method is insufficient in light intensity ratio data compensation of anti-Stokes Raman and Stokes Raman, a thermostatic bath is complicated to calibrate, the temperature measurement value is larger in difference with the actual value, and the use is complicated.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a distributed optical fiber temperature measurement calculation method is characterized by comprising the following steps:
1) Obtaining original waveform and reference optical fiber segment temperature
Enabling pulse light to enter an optical fiber through a coupler, generating Raman scattering in the optical fiber, dividing the generated Raman scattering light into Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes through a wavelength division multiplexer, then enabling the Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes to enter a photoelectric conversion module, and sampling to obtain Anti-Stokes Raman light Anti-Stokes original waveform data _ as and Stokes Raman light Stokes original waveform data _ s;
the optical fiber comprises a reference optical fiber section which is positioned in the case and connected with the coupler and a sensing optical fiber section which is positioned outside the case and connected with the reference optical fiber section; the data _ as and the data _ s are both one-dimensional arrays, the sizes of the arrays are both M, and M is an integer larger than 0;
meanwhile, obtaining the temperature B of the environment of the chassis where the reference optical fiber section is located;
2) Obtaining the original waveform ratio
The ratio data _ X of the Anti-Stokes raman light Anti-Stokes original waveform data _ as to the Stokes raman light Stokes original waveform data _ s is expressed as follows:
3) Selecting valid waveforms
Selecting effective waveforms of Anti-Stokes Raman light Anti-Stokes original waveform data _ AS and Stokes Raman light Stokes original waveform data _ S, and respectively representing the effective waveforms AS effective waveform data _ AS and effective waveform data _ S;
the data _ AS and the data _ S are both one-dimensional arrays, the size of the array is N, and N is smaller than M;
4) Calculating the attenuation coefficient alpha a 、α s And maximum amplitude I a 、I s
Selecting the first s data sampling points of the effective waveform data _ AS reference optical fiber section for fitting to obtain the attenuation coefficient alpha of Anti-Stokes Raman light Anti-Stokes a And maximum amplitude I of data _ AS a S is an integer greater than 80;
the fitting model of the data _ AS is AS follows:
in the formula: I.C. A ax Representing data _ AS specific amplitude, x =0,1, \8230; s-1;
and selecting the first S data sampling points of the effective waveform data _ S reference optical fiber section for fitting to obtain the attenuation coefficient alpha of Stokes Raman light s And the maximum amplitude I of data _ S s ；
Wherein, the fitting model of the data _ S is as follows:
in the formula: i is sx Representing the specific data _ S amplitude;
5) Get array data _ Y
Selecting an effective waveform of the data _ X to obtain an array data _ Y;
wherein, the data _ Y is a one-dimensional array, and the size of the array is N;
6) Segment compensation
6.1 Equally dividing the array data _ Y into lengths L, wherein 10 & ltl & lt 30 > the rest array is data _ r with the length of epsilon, wherein 0< epsilon < L;
6.2 ) the array data _ Y is equally divided into arrays denoted as data _ Y q Array, Q =1,2, \8230, Q is the number of the equal parts of the array data _ Y, data _ Y q Is a one-dimensional array with an array size of L, and is a peer-to-peer fractional group data _ Y q Loss compensation is carried out, and the data _ Z is expressed after compensation q ：
Wherein x =0,1,2, \8230; (L-1);
6.3 Loss compensation is performed on the compensation array data _ R, and the loss compensation is expressed as data _ R:
wherein y =0,1,2, \8230; (ε -1); 6.4 Output the global compensation array data _ Z from the data _ Z 1 、data_Z 2 、data_Z 3 、…data_Z Q The data _ R are connected in sequence;
7) Analytic temperature
The measured temperature T of the distributed fiber is calculated as follows:
T＝k×(data_Z-I a /I s )+B
in the formula: and k is the correlation coefficient of the Anti-Stokes/Stokes ratio and the temperature.
Further, in step 7), k =210.984.
Further, in step 1), the length ω of the reference fiber segment is less than 150m;
in the step 4), s is 100 to 150.
Further, in step 1), obtaining the temperature B of the enclosure environment where the reference optical fiber segment is located is achieved by a digital temperature sensor disposed on the reference optical fiber segment.
Meanwhile, the invention provides another distributed optical fiber temperature measurement calculation method which is characterized by comprising the following steps:
1) Obtaining original waveform and reference optical fiber segment temperature
Enabling pulse light to enter an optical fiber through a coupler, generating Raman scattering in the optical fiber, dividing the generated Raman scattering light into Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes through a wavelength division multiplexer, then enabling the Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes to enter a photoelectric conversion module, and sampling to obtain Anti-Stokes Raman light Anti-Stokes original waveform data _ as and Stokes Raman light Stokes original waveform data _ s;
the optical fiber comprises a reference optical fiber section which is positioned in the case and connected with the coupler and a sensing optical fiber section which is positioned outside the case and connected with the reference optical fiber section; the data _ as and the data _ s are both one-dimensional arrays, the sizes of the arrays are both M, and M is an integer larger than 0;
meanwhile, obtaining the temperature B of the environment of the chassis where the reference optical fiber section is located;
2) Obtaining the original waveform ratio
The ratio data _ X of the Anti-Stokes raman light Anti-Stokes original waveform data _ as to the Stokes raman light Stokes original waveform data _ s is expressed as follows:
3) Get array data _ Y
Selecting an effective waveform of the data _ X to obtain an array data _ Y;
wherein, the data _ Y is a one-dimensional array, and the size of the array is N;
4) Selecting valid waveforms
Selecting effective waveforms of Anti-Stokes Raman light Anti-Stokes original waveform data _ AS and Stokes Raman light Stokes original waveform data _ S, and respectively representing the effective waveforms AS effective waveform data _ AS and effective waveform data _ S;
the data _ AS and the data _ S are both one-dimensional arrays, the size of the array is N, and N is smaller than M;
5) Calculating the attenuation coefficient alpha a 、α s And maximum amplitude I a 、I s
Selecting the first s data sampling points of the effective waveform data _ AS reference optical fiber section for fitting to obtain the attenuation coefficient alpha of Anti-Stokes Raman light Anti-Stokes a And maximum amplitude I of data _ AS a S is an integer greater than 80;
wherein, the fitting model of the data _ AS is AS follows:
in the formula: I.C. A ax Representing data _ AS specific amplitude, x =0,1, \8230; s-1;
and selecting the first S data sampling points of the effective waveform data _ S reference optical fiber section for fitting to obtain the attenuation coefficient alpha of Stokes Raman light s And maximum amplitude I of data _ S s ；
Wherein, the fitting model of the data _ S is as follows:
in the formula: i is sx Representing the specific amplitude of the data _ S;
6) Segment compensation
6.1 Equally dividing the array data _ Y into lengths L, wherein 10 & ltl & lt 30 > the remaining array is data _ r, length is ε, where 0< ε < L;
6.2 ) the array after data _ Y is equally divided is represented as data _ Y q Array, Q =1,2, \ 8230, Q, Q being an aliquot of the array data _ Y, data _ Y q Is a one-dimensional array with an array size of L, and is equal to the data _ Y q Loss compensation is carried out, and the data _ Z is expressed after compensation q ：
Wherein x =0,1,2, \ 8230; (L-1);
6.3 Compensation array data _ R, expressed as data _ R:
wherein y =0,1,2, \ 8230; (ε -1);
6.4 Output the global compensation array data _ Z composed of data _ Z 1 、data_Z 2 、data_Z 3 、…data_Z Q The data _ R are connected in sequence;
7) Analytic temperature
The measured temperature T of the distributed fiber is calculated as follows:
T＝k×(data_Z-I a /I s )+B
in the formula: and k is the correlation coefficient of the Anti-Stokes/Stokes ratio and the temperature.
Further, in step 7), k =210.984.
Further, in step 1), the length ω of the reference fiber segment is less than 150m;
in step 5), s is 100 to 150.
Further, in step 1), obtaining the temperature B of the enclosure environment where the reference optical fiber segment is located is achieved by a digital temperature sensor disposed on the reference optical fiber segment.
In addition, the invention also provides a distributed optical fiber temperature measurement system which is characterized in that: the system comprises an optical fiber, a case, a light source, a coupler, a wavelength division multiplexer, a photoelectric conversion module, a control module, a digital temperature sensor, a data acquisition card and a data processing unit, wherein the light source, the coupler, the wavelength division multiplexer, the photoelectric conversion module, the control module, the digital temperature sensor, the data acquisition card and the data processing unit are positioned in the case;
the optical fiber comprises a reference optical fiber section which is positioned in the case and connected with the coupler and a sensing optical fiber section which is positioned outside the case and connected with the reference optical fiber section;
the digital temperature sensor is arranged in the case and used for measuring the temperature of the environment of the case where the reference optical fiber section is located;
the control module is used for controlling the synchronous action of the light source and the data acquisition card and transmitting the temperature measured by the digital temperature sensor to the data acquisition card;
the coupler is used for coupling pulsed light emitted by the light source into the optical fiber and transmitting Raman scattered light transmitted back through the optical fiber to the wavelength division multiplexer;
the wavelength division multiplexer is used for separating Anti-Stokes Raman light Anti-Stokes and Stokes of Raman scattering light and transmitting the Anti-Stokes Raman light Anti-Stokes and Stokes to the photoelectric conversion module;
the photoelectric conversion module is used for performing photoelectric conversion on Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes;
the data acquisition card acquires electric signals of Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes converted by the photoelectric conversion module, and acquires an Anti-Stokes Raman light Anti-Stokes original waveform data _ as and a Stokes Raman light Stokes original waveform data _ s;
and the data processing unit processes the Anti-Stokes Raman light Anti-Stokes original waveform data _ as, the Stokes Raman light Stokes original waveform data _ s and the temperature of the chassis environment where the reference optical fiber section is located, so as to obtain the measured temperature of the optical fiber.
Further, the digital temperature sensor is arranged on the reference optical fiber section.
Compared with the prior art, the invention has the advantages that:
1. the optical fiber temperature measurement calculation method adopts a sectional compensation mode, can effectively eliminate the insufficient compensation, and avoids the problem that the analytic temperature value is far lower than the actual temperature value along with the increase of the length of the optical fiber, thereby improving the precision of the demodulation temperature.
2. The optical fiber comprises a reference optical fiber section and a sensing optical fiber section, the temperature of the cabinet environment where the reference optical fiber section is located is obtained through the digital temperature sensor, the attenuation coefficients of Anti-Stokes and Stokes are conveniently and directly calculated, the Anti-Stokes/Stokes ratio of the reference optical fiber section and the actual temperature value of the reference optical fiber are obtained, the calibration of an existing thermostatic bath can be eliminated, and the use convenience is improved.
Drawings
FIG. 1 is a schematic structural diagram of a distributed optical fiber temperature measurement system according to the present invention;
FIG. 2 is a flowchart of a distributed optical fiber temperature measurement calculation method according to a first embodiment of the present invention;
FIG. 3 is a flow chart of step 6) sectional compensation in the distributed optical fiber temperature measurement calculation method of the present invention;
FIG. 4 is a data _ Y waveform of the present invention;
FIG. 5 is a schematic diagram of the sectional compensation equal division effect of the present invention;
FIG. 6 is a schematic diagram of an Anti-Stokes/Stokes ratio waveform after compensation according to the present invention;
FIG. 7 is a schematic diagram of an analytic temperature curve according to the present invention;
wherein the reference numbers are as follows:
1-optical fiber, 11-reference optical fiber section, 12-sensing optical fiber section, 2-cabinet, 3-light source, 4-coupler, 5-wavelength division multiplexer, 6-photoelectric conversion module, 7-control module, 8-digital temperature sensor, 9-data acquisition card, 10-data processing unit.
Detailed Description
The invention is described in further detail below with reference to the figures and specific embodiments.
Example one
As shown in fig. 1, the distributed optical fiber temperature measurement system of the present invention includes an optical fiber 1, a case 2, a light source 3, a coupler 4, a wavelength division multiplexer 5, a photoelectric conversion module 6, a control module 7, a digital temperature sensor 8, a data acquisition card 9, and a data processing unit 10, which are located in the case 2.
The optical fiber 1 comprises a reference optical fiber section 11 which is positioned in the case 2 and connected with the coupler 4 and a sensing optical fiber section 12 which is positioned outside the case 2 and connected with the reference optical fiber section 11; the digital temperature sensor 8 is arranged on the reference optical fiber section 11 and used for measuring the temperature of the environment of the case 2 where the reference optical fiber section 11 is located; the control module 7 is used for controlling the synchronous action of the light source 3 and the data acquisition card 9 and transmitting the temperature measured by the digital temperature sensor 8 to the data acquisition card 9; the coupler 4 is used for coupling the pulse light emitted by the light source 3 into the optical fiber 1 and transmitting the Raman scattering light transmitted back through the optical fiber 1 to the wavelength division multiplexer 5; the wavelength division multiplexer 5 is used for separating Anti-Stokes raman light Anti-Stokes from Stokes raman light Stokes of the raman scattering light and transmitting the Anti-Stokes raman light Anti-Stokes and Stokes raman light to the photoelectric conversion module 6; the photoelectric conversion module 6 is used for performing photoelectric conversion on the Anti-Stokes Raman light Anti-Stokes and the Stokes Raman light Stokes; the data acquisition card 9 acquires the Anti-Stokes Raman light Anti-Stokes and Stokes converted by the photoelectric conversion module 6, and acquires an Anti-Stokes original waveform data _ as and a Stokes original waveform data _ s; the data processing unit 10 processes the Anti-Stokes raman light Anti-Stokes original waveform data _ as, the Stokes raman light Stokes original waveform data _ s and the temperature of the environment of the chassis 2 where the reference optical fiber section 11 is located, so as to obtain the temperature measured by the optical fiber 1.
As shown in fig. 2, based on the distributed optical fiber temperature measurement system, the invention provides a distributed optical fiber temperature measurement calculation method, which includes the following steps:
1) Obtaining the original waveform and the reference fiber segment 11 temperature
The control module 7 controls the light source 3 and the data acquisition card 9 to work synchronously, the light source 3 emits pulsed light, the light enters the optical fiber 1 through the coupler 4, raman scattering occurs in the optical fiber 1 to generate Raman scattered light, the wavelength division multiplexer 5 divides the Raman scattered light into Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes, then the Raman scattered light enters the photoelectric conversion module 6, the Raman scattered light is converted into analog quantity through the photoelectric conversion module 6, and the analog quantity is converted into digital quantity through the data acquisition card 9, namely the Anti-Stokes Raman light Anti-Stokes original waveform data _ as and the Stokes Raman light Stokes original waveform data _ s are obtained through sampling;
the sampling rate of the data acquisition card 9 is 100Mbps, and the data resolution of the sampling optical fiber 1 is 1m through calculation;
the optical fiber 1 comprises a reference optical fiber section 11 which is positioned in the case 2 and connected with the coupler 4 and a sensing optical fiber section 12 which is positioned outside the case 2 and connected with the reference optical fiber section 11, wherein the length omega of the reference optical fiber section 11 is less than 150m;
the data _ as and the data _ s are both one-dimensional arrays, the size of the arrays is M, the value of M depends on the length lambda of the optical fiber 1, omega < M < lambda, and M is an integer larger than 0.
Meanwhile, the control module 7 reads the temperature B of the environment where the reference optical fiber section 11 is located through the digital temperature sensor 8;
2) Obtaining the original waveform ratio
Comparing the Anti-Stokes raman light Anti-Stokes original waveform data _ as with the Stokes raman light Stokes original waveform data _ s to obtain data _ X, wherein the data _ X is expressed as follows:
wherein, the data _ X is a one-dimensional array, and the size of the array is M;
3) Selecting valid waveforms
Intercepting effective waveforms of the Anti-Stokes Raman light Anti-Stokes original waveform data _ AS and the Stokes Raman light Stokes original waveform data _ S, and respectively representing the effective waveforms AS an effective waveform data _ AS and an effective waveform data _ S;
the data _ AS and the data _ S are both one-dimensional arrays, the size of the array is N, and N is smaller than M;
4) Calculating the attenuation coefficient alpha a 、α s And maximum amplitude I a 、I s
4.1 S is an integer greater than 80, usually s is 100 to 150, and the fitting model is AS follows:
in the formula: i is ax Represents the specific amplitude of data _ AS, I a Represents the maximum amplitude (i.e., the starting amplitude), α, of data _ AS a Represents the attenuation coefficient of Anti-Stokes Raman light Anti-Stokes;
the attenuation coefficient alpha of the Anti-Stokes Raman light Anti-Stokes can be obtained through fitting a And maximum amplitude I of data _ AS a ；
And intercepting the first S data sampling points of the effective waveform data _ S reference optical fiber section 11 for fitting, wherein the fitting model is as follows:
in the formula: i is sx Represents the specific amplitude of data _ S, I s Represents the maximum amplitude (i.e., the starting amplitude), α, of data _ S s An attenuation coefficient representing Stokes raman light Stokes;
the attenuation coefficient alpha of Stokes Raman light Stokes can be obtained through fitting s And dataMaximum amplitude of S I s ；
Further, the following can be obtained:
(α a -α s )/10 (4)
5) Get array data _ Y
Selecting an effective waveform for the data _ X to obtain an array data _ Y;
wherein, data _ Y is a one-dimensional array, the size of the array is N, and the data _ Y oscillogram is shown in fig. 4;
6) Segment compensation
6.1 As shown in fig. 3), the array data _ Y is divided into equal parts by length L, where 10< -L < -30 > and the equal parts are Q, where L takes the value of 20 in this embodiment; the rest array is data _ r with the length of epsilon, wherein 0< epsilon < L, and the bisection effect is shown in FIG. 5;
6.2 ) the array data _ Y is equally divided into arrays denoted as data _ Y q Array, Q =1,2, \ 8230, Q, Q is the number of equal parts of array data _ Y, the size of array is L, data _ Y q Is a one-dimensional array with an array size of L, and is a peer-to-peer fractional group data _ Y q Loss compensation is carried out, and the data _ Z is expressed after compensation q ：
Wherein,
delta is a first compensation factor and a second compensation factor respectively,
first compensation factor
Comprises the following steps:
wherein x =0,1,2, \ 8230; (L-1);
the second compensation factor δ is:
substituting the formula (6) and the formula (7) into the formula (5) to obtain the data _ Z q ：
Wherein x =0,1,2, \ 8230; (L-1);
6.3 Compensation array data _ R, expressed as data _ R:
wherein y =0,1,2, \ 8230; (ε -1);
6.4 Output the global compensation array data _ Z from the data _ Z 1 、data_Z 2 、data_Z 3 、…data_Z Q The data _ R are sequentially connected to form a waveform diagram after compensation is shown in FIG. 6;
7) Analytic temperature
The measured temperature T of the distribution optical fiber 1 is calculated according to the following formula:
T＝k×(data_Z-I a /I s )+B
in the formula: k is a coefficient relating Anti-Stokes/Stokes ratio to temperature, and is a constant, where k is 210.984, b is the temperature of the environment of the cabinet 2 where the reference fiber section 11 is located, and the analytic temperature graph is shown in fig. 7.
The invention adopts a sectional compensation method, can effectively eliminate the insufficient compensation, solves the problem that the analytic temperature value is far lower than the actual temperature value along with the increase of the length of the optical fiber, and thus improves the accuracy of the system demodulation temperature. The reference optical fiber and the digital temperature sensor are selected, so that the attenuation coefficients of Anti-Stokes and Stokes can be directly calculated conveniently, the Anti-Stokes/Stokes ratio of the reference optical fiber and the actual temperature value of the reference optical fiber can be obtained conveniently, the calibration of a constant temperature tank of the system can be effectively avoided, and the use convenience of the system can be improved.
Example two
The difference from the first embodiment is that: step 5) is moved to after step 2).
The above description is only for the preferred embodiment of the present invention and does not limit the technical solution of the present invention, and any modifications made by those skilled in the art based on the main technical idea of the present invention belong to the technical scope of the present invention.
Claims (4)
1. A distributed optical fiber temperature measurement calculation method is characterized by comprising the following steps:
1) Obtaining the original waveform and the temperature of the reference fiber segment (11)
Pulse light enters an optical fiber (1) through a coupler (4), raman scattering occurs in the optical fiber (1), the generated Raman scattering light is divided into Anti-Stokes Raman light Anti-Stokes and Stokes Raman light Stokes through a wavelength division multiplexer (5), then the Raman scattering light enters a photoelectric conversion module (6), and Anti-Stokes Raman light Anti-Stokes and Stokes original waveforms data _ as and Stokes original waveforms data _ s are obtained through sampling;
the optical fiber (1) comprises a reference optical fiber section (11) which is positioned in the case (2) and connected with the coupler (4) and a sensing optical fiber section (12) which is positioned outside the case (2) and connected with the reference optical fiber section (11); the data _ as and the data _ s are both one-dimensional arrays, the sizes of the arrays are both M, and M is an integer larger than 0;
meanwhile, obtaining the temperature B of the environment of the case (2) where the reference optical fiber section (11) is located;
2) Obtaining the original waveform ratio
The ratio data _ X of the Anti-Stokes raman light Anti-Stokes original waveform data _ as to the Stokes raman light Stokes original waveform data _ s is expressed as follows:
3) Selecting valid waveforms
Selecting effective waveforms of Anti-Stokes Raman light Anti-Stokes original waveform data _ AS and Stokes Raman light Stokes original waveform data _ S, and respectively representing the effective waveforms AS effective waveform data _ AS and effective waveform data _ S;
the data _ AS and the data _ S are both one-dimensional arrays, the size of the array is N, and N is smaller than M;
4) Calculating the attenuation coefficient alpha a 、α s And maximum amplitude I a 、I s
Selecting the first s data sampling points of the effective waveform data _ AS reference optical fiber section (11) for fitting to obtain the attenuation coefficient alpha of the Anti-Stokes Raman light Anti-Stokes a And maximum amplitude I of data _ AS a S is an integer greater than 80;
wherein, the fitting model of the data _ AS is AS follows:
in the formula: i is ax Represents data _ AS specific amplitude, x =0,1, \8230;, s-1;
and selecting the first S data sampling points of the effective waveform data _ S reference optical fiber section (11) for fitting to obtain the attenuation coefficient alpha of the Stokes Raman light Stokes s And maximum amplitude I of data _ S s ；
Wherein, the fitting model of the data _ S is as follows:
in the formula: i is sx Representing the specific amplitude of the data _ S;
between step 2) and step 3), or after step 4), obtaining the array data _ Y:
selecting an effective waveform of the data _ X to obtain an array data _ Y;
wherein, the data _ Y is a one-dimensional array, and the size of the array is N;
5) Segment compensation
5.1 Equally dividing the array data _ Y into lengths L, wherein 10 & ltl & lt 30 > the remaining array is data _ r, length is ε, where 0< ε < L;
5.2 ) the array data _ Y is equally divided into arrays denoted as data _ Y q Array, Q =1,2, \ 8230, Q, Q being an aliquot of the array data _ Y, data _ Y q Is a one-dimensional array with an array size of L, and is a peer-to-peer fractional group data _ Y q Loss compensation is carried out, and the data _ Z is expressed after compensation q ：
Wherein x =0,1,2, \8230; (L-1);
5.3 Carry on the loss compensation to the remaining array data _ R, expressed as data _ R after compensating:
wherein y =0,1,2, \ 8230; (ε -1);
5.4 Output the global compensation array data _ Z composed of data _ Z 1 、data_Z 2 、data_Z 3 、…data_Z Q The data _ R are connected in sequence;
6) Analytic temperature
The measured temperature T of the distribution optical fiber (1) is calculated according to the following formula:
T＝k×(data_Z-I a /I s )+B
in the formula: and k is the correlation coefficient of the Anti-Stokes/Stokes ratio and the temperature.
2. The distributed optical fiber temperature measurement calculation method according to claim 1, characterized in that: step 7), k =210.984.
3. The distributed optical fiber temperature measurement calculation method according to claim 1 or 2, characterized in that: in step 1), the length ω of the reference fiber segment (11) is less than 150m;
in the step 4), s is 100 to 150.
4. The distributed optical fiber temperature measurement computing method according to claim 3, characterized in that: in the step 1), obtaining the temperature B of the environment of the chassis (2) where the reference optical fiber section (11) is located is achieved through a digital temperature sensor (8) arranged on the reference optical fiber section (11).
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