CN112050967A - Optical fiber temperature automatic calibration and compensation method of optical fiber temperature distribution tester - Google Patents

Abstract

The invention discloses an optical fiber temperature automatic calibration and compensation method of an optical fiber temperature distribution tester, and relates to the field of optical fiber temperature calibration and compensation. According to the method, the Stokes and anti-Stokes automatic calculation is taken as the basis, and the Stokes and anti-Stokes data in the optical fiber temperature distribution tester are deeply analyzed, so that the automatic identification of the temperature calibration point and the automatic calculation of the temperature compensation are realized. Meanwhile, aiming at the condition that the actual application length is changed, the method for compensating the power of the reflected signal is provided, and the function of automatically correcting and calculating parameters is realized.

Description

Optical fiber temperature automatic calibration and compensation method of optical fiber temperature distribution tester

Technical Field

The invention relates to the field of optical fiber temperature calibration and compensation, in particular to an optical fiber temperature automatic calibration and compensation method of an optical fiber temperature distribution tester.

Background

An optical fiber temperature distribution tester (also known as a raman optical time domain reflectometer, abbreviated as ROTDR) has been widely used in the fields of power cable temperature measurement monitoring, intelligent pipe gallery temperature monitoring, oil transportation and storage facility temperature monitoring, fire early warning and the like due to the characteristics of distributed continuity, long test distance, corrosion resistance, intrinsic safety, electromagnetic interference resistance, lightning stroke resistance, long service life and the like, but in the research, production and use processes of the ROTDR, the temperature is often required to be calibrated and compensated according to different actual use scenes, and in addition, when the length of an optical fiber changes, the length parameter and the calculation parameter are often required to be recalibrated so as to ensure the accuracy of the test.

At present, temperature compensation and calibration work of the ROTDR are mainly completed manually, and the calibration effect is influenced due to more subjective factors in manual analysis; moreover, the manual calibration efficiency is very low, and the requirements in the production and use processes of the ROTDR are difficult to meet; recalibration and calculation caused by length change require field debugging of professionals, time cost is increased, and meanwhile manual calibration also causes labor cost increase.

Disclosure of Invention

The invention aims to provide a method for realizing automatic identification of temperature calibration points and automatic calculation of temperature compensation by deeply analyzing stokes and anti-stokes data in an optical fiber temperature distribution tester on the basis of automatic stokes and anti-stokes calculation.

The invention specifically adopts the following technical scheme:

an optical fiber temperature automatic calibration and compensation method of an optical fiber temperature distribution tester is carried out based on the optical fiber temperature distribution tester and two high-low temperature constant temperature devices, and comprises the following steps:

step 101: starting an optical fiber temperature distribution tester, and connecting the tested optical fiber;

step 102: inputting the actual length FL of the optical fiber, setting a spatial resolution parameter SFR, setting a typical value to be 1m, sampling resolution SAMF, setting a typical value to be 0.5m, and setting a test range FR to be (FL +1) km;

step 103: starting a temperature distribution test function of the optical fiber temperature distribution tester, reading Stokes test data DS and anti-Stokes test data DAS, analyzing the data to obtain de-noising Stokes data DS _ SN, de-noising anti-Stokes test data DAS _ SN and temperature data T;

step 104: reading a calibration zone bit bAPDCali, a power compensation zone bit bPowerCali and a temperature calibration zone bit bTemCali of a detector module from an optical fiber temperature distribution tester, wherein the three zone bits are defaulted to 0 during initial test;

step 105: judging whether bAPDCali is greater than or equal to 1, if so, performing step 106, otherwise, performing step 107;

step 106: putting the optical fiber temperature distribution tester into a high-low temperature constant temperature device, and starting temperature compensation of the detector module;

step 107: judging whether bPowerCali is greater than or equal to 1, if so, performing step 108, otherwise, performing step 109;

step 108: starting a power compensation function;

step 109: judging whether bTemClai is more than or equal to 1, if so, performing a step 110, otherwise, performing a step 111;

step 110: starting a temperature calibration function;

step 111: and finishing the temperature distribution measurement of the optical fiber temperature distribution tester.

Preferably, in step 103, the specific process of acquiring the noise-removed stokes data and the noise-removed anti-stokes data is as follows:

step 201: starting a temperature distribution test function of the optical fiber temperature analysis tester, reading Stokes test data and anti-Stokes test data, wherein N is the number of the test data;

step 202: filtering the data to obtain filtering Stokes data and anti-Stokes test data;

step 203: calculating the Stokes test data noise DNS as the average value of 500 data points after Stokes, and calculating the anti-Stokes test data noise DNAS as the average value of 500 data points after anti-Stokes;

step 204: calculating de-noised stokes data and de-noised anti-stokes data;

step 205: obtaining temperature data according to the Stokes data with noise removed and the anti-Stokes data with noise removed, and storing temperature coefficients KTA and KTB;

step 206: and finishing filtering and denoising.

Preferably, the specific steps of filtering the data to obtain the filtered stokes data and the anti-stokes test data are as follows:

step 301: reading Stokes test data and anti-Stokes test data, and setting a filtering threshold TH with a typical value of 20;

step 302: initializing setting J to be N/2, NUM to be 0, and I to be 0;

step 303: judging whether J is less than 100, if so, turning to step 305, otherwise, turning to step 304;

step 304: setting NUM to NUM + 1;

step 305: setting a filter starting point coordinate set START [0] to START [ NUM ] to be 0;

step 306: performing wavelet decomposition, wherein dwt is a wavelet decomposition function;

step 307: judging whether I is smaller than NUM, if so, turning to step 309, otherwise, turning to step 308;

step 308: setting I as I +1 and L as N/2;

step 309: setting K to be 0;

step 310: judging whether a Stokes data wavelet decomposition high-frequency part cdDS [ I ] [ K ] is greater than or equal to a threshold TH or not, and judging whether an anti-Stokes data wavelet decomposition high-frequency part cdDAS [ I ] [ K ] is greater than or equal to the threshold TH or not, if yes, turning to a step 314, otherwise, turning to a step 311;

step 311: setting K to K + 1;

step 312: judging whether K is larger than J, if so, turning to step 310, otherwise, turning to step 313;

step 313: setting a threshold TH to TH-5;

step 314: setting the value of a filter starting point coordinate set START [ I ] as K;

step 315: setting high-frequency parts cdDS [ I ] [0] to cd [ I ] [ DSK ] of Stokes data wavelet decomposition to be 0, and setting high-frequency parts cdDAS [ I ] [0] to cdDAS [ I ] [ K ] of anti-Stokes data wavelet decomposition to be 0;

step 316: setting a counting position II as I, a counting position II as II-1 and a counting position K as 2 as K + 1;

step 317: judging whether II is greater than or equal to 0, if yes, turning to step 318, otherwise, turning to step 314;

step 318: performing wavelet reconstruction, wherein idwt is a wavelet reconstruction function;

step 319: judging whether I is smaller than NUM, if so, turning to a step 321, and otherwise, turning to a step 320;

step 320: setting I-1 and L-2;

step 321: judging whether L is equal to N, if so, turning to step 323, otherwise, turning to step 322;

step 323: setting filtered stokes data DSF [0] to DSF [ N ] as values of tempDS [0] to tempDS [ N ], respectively, filtered anti-stokes data DASF [0] to DASF [ N ] as values of tempDAS [0] to tempDAS [ N ], respectively, outputting the filtered stokes data and the filtered anti-stokes data;

step 322: the wavelet reconstruction fails and an error is returned.

Preferably, the temperature compensation process of the detector module is as follows:

step 401: controlling the high-low temperature constant temperature device to cool to the lower limit of the working temperature of the optical fiber temperature distribution tester and keeping the temperature;

step 402: reading the temperature of the high-low temperature constant temperature device and storing the temperature to a memory of an optical fiber temperature distribution tester, wherein the initialization temperature I of the optical fiber temperature distribution tester is 0;

step 403: after the temperature of the high-low temperature constant temperature device is stable, continuously reading and storing the temperature in the machine;

step 404: slope KT of temperature data in the computer;

step 405: judging whether KT is less than or equal to 0.01, if so, performing step 406, and if not, turning to step 403;

step 406: continuously testing for three times, acquiring noise-removed Stokes data and noise-removed anti-Stokes data, respectively storing, and calculating the average value of N +1 values;

step 407: controlling the high-low temperature constant temperature device to heat up, and sending a set temperature value to the optical fiber temperature distribution tester;

step 408: judging whether the temperature of the optical fiber temperature distribution tester is more than 50, if so, turning to a step 410, and if not, turning to a step 409;

step 409: setting I as I + 1;

step 410: calculating a temperature compensation coefficient;

step 411: and (4) finishing temperature compensation of a detector in the optical fiber temperature distribution tester, and outputting a compensation coefficient.

Preferably, the specific process in step 110 is as follows:

step 601: reading test data, obtaining de-noised data DS _ SN [ 0-N ], DAS _ SN [ 0-N ], initializing NUM, and typical value is 20;

step 602: initializing count bits C, I, J, K, KAPPA, S and SUM to be 0;

step 603: selecting an optical fiber fixing position, wherein the length LF of the optical fiber fixing position is more than or equal to 10 times of SAMF, and heating, wherein the typical value is 20 ℃;

step 604: analyzing data to obtain a break-out point, recording the position of the break-out point as RX and obtaining temperature values from TL [0] to TL [ NUM ];

step 605: setting the value of KAPPA to be the difference of KAPPA divided by T [ I ] and T [ I +1 ];

step 606: judging whether I is greater than or equal to NUM, if so, turning to step 608, otherwise, turning to step 607;

step 607: setting I as I + 1;

step 608: setting the value of S to be the product of S and the difference between R [ RX ] and R [ RX + J ];

step 609: judging whether J is more than or equal to NUM, if yes, turning to step 611, otherwise, turning to step 610;

step 610: setting J to J + 1;

step 611: setting a SUM bit SUM as the SUM of SUM and T [ K ];

step 612: judging whether K is greater than or equal to NUM, if so, turning to step 614, and otherwise, turning to step 613;

step 613: setting K to K + 1;

step 614: solving a simultaneous equation set TL [0] ═ KTS/KAPPA R [ RX ]. SUM + KTB, and T [0] ═ KTS/KAPPA R [0 ]. SUM + KTB to obtain new temperature coefficients KT and KTB;

step 615: and outputting the temperature coefficient, and finishing temperature calibration.

Preferably, the specific process in step 604 is:

step 701: acquiring Stokes de-noising data from DS _ SN [0] to DS _ SN [ N ], anti-Stokes de-noising data from DAS _ SN [0] to DAS _ SN [ N ], wherein initialization I is 0, Stokes difference data DS _ DF [0] to DS _ DF [ N ] are all 0, anti-Stokes difference data DAS _ DF [0] to DAS _ DF [ N ] are all 0, Stokes difference accumulated data DS _ DFA [0] to DS _ DFA [ N ] are all 0, and anti-Stokes difference accumulated data DAS _ DFA [0] to DAS _ DFA [ N ] are all 0;

step 702: setting DS _ DF [0] to DS _ DF [ N ] as the difference between DS _ SN [0] to DS _ SN [ N-1] and DAS _ SN [1] to DAS _ SN [ N ], DAS _ DF [0] to DAS _ DF [ N ] as the difference between DAS _ SN [0] to DAS _ SN [ N-1] and DAS _ SN [1] to DAS _ SN [ N ];

step 703: the value of DS _ DFA [ I ] is DS _ DFA [ I ] + DS _ DF [ I ], and the value of DAS _ DFA [ I ] is DAS _ DFA [ I ] + DAS _ DF [ I ];

step 704: judging whether I is larger than or equal to N, if so, turning to a step 706, otherwise, turning to a step 705;

step 705: setting I as I + 1;

step 706: initializing NUM (number of bits) 5, setting an initial coordinate RX as 0, setting a counting bit II as NUM, setting a counting bit J as II-NUM, and setting a flag bit BF as 1;

step 707: judging whether Stokes differential accumulated data DS _ DFA [ J ] is less than or equal to DS _ DFA [ II ], whether anti-Stokes differential accumulated data DAS _ DFA [ J ] is less than or equal to DAS _ DFA [ II ], if so, turning to step 709, otherwise, turning to step 708;

step 708: setting a counting position II as II + 1;

step 709: setting a flag bit BF as BF +1 and a counting bit J as J + 1;

step 710: judging whether BF is greater than or equal to 5 and J is less than I, if yes, turning to step 711, otherwise, turning to step 708;

step 711: setting a flag bit BF to 1;

step 712: judging whether the Stokes differential accumulated data DS _ DFA [ J ] is greater than or equal to DS _ DFA [ II +1], whether the anti-Stokes differential accumulated data DAS _ DFA [ J ] is greater than or equal to DAS _ DFA [ II +1], if so, turning to step 713, otherwise, turning to step 708;

step 713: setting a flag bit BF as BF +1 and a counting bit J as J + 1;

step 714: judging whether the flag bit BF is greater than or equal to 5, whether J is smaller than the sum of the counting bit I and the data amount NUM, if yes, turning to step 715, otherwise, turning to step 708;

step 715: recording the coordinates RX of the point as II, outputting TL [0] to TL [ NUM ] as the values of the temperature T [ RX + NUM ], and finishing the calculation.

Preferably, when the length of the measured optical fiber changes, the power compensation is performed on the reflected signal, and the specific process is as follows:

step 501: acquiring noise-removed stokes data of DS _ SN [0] to DS _ SN [ N ], noise-removed anti-stokes data of DAS _ SN [0] to DAS _ SN [ N ], and initializing I to 0;

step 502: removing the optical fiber with the tail end length of L (km), wherein the typical value is 2.5, testing to obtain Stokes and anti-Stokes data, and respectively recording the data from DSP [ I ] [0] to DSP [ I ] [ N ], DASP [ I ] [0] to DASP [ I ] [ N ];

step 503: calculating the length of the optical fiber LENF;

step 504: judging whether the LENF is less than or equal to 0.1, if yes, turning to a step 506, and if not, turning to a step 505;

step 505: setting a counting bit I plus 1;

step 506: calculating the Stokes compensation coefficients CALCOFFS [0] to CALCOFFS [ I ] as the quotient of DS _ SN [0] to DS _ SN [ N ] and DSP [ I ] [0] to DSP [ I ] [ N ], and calculating the anti-Stokes compensation coefficients CALCOFFAS [0] to CALCOFFAS [ I ] as the quotient of DS _ ASN [0] to DS _ ASN [ N ] and DASP [ I ] [0] to DASP [ I ] [ N ];

step 507: and outputting a compensation coefficient, finishing power compensation, setting a flag bit bPowerCali to be 0, and storing the flag bit bPowerCali into a parameter file PARAFILE.

The invention has the following beneficial effects:

the method is based on Stokes and anti-Stokes automatic calculation, realizes automatic identification of temperature calibration points and automatic calculation of temperature compensation by deeply analyzing Stokes and anti-Stokes data in the ROTDR system, simultaneously provides a method for compensating the power of a reflected signal aiming at the condition that the practical application length is changed, and realizes the function of automatically correcting and calculating parameters.

Drawings

FIG. 1 is a schematic view of an optical fiber temperature distribution tester;

FIG. 2 is a schematic view of a testing process of the fiber temperature distribution tester;

FIG. 3 is a schematic flow chart of acquiring denoised Stokes and denoised anti-Stokes data;

FIG. 4 is a schematic representation of a Stokes and anti-Stokes data filtering flow;

FIG. 5 is a schematic diagram of an APD temperature calibration functional system;

FIG. 6 is a schematic diagram of an APD temperature calibration flow;

FIG. 7 is a schematic diagram of a power compensation process;

FIG. 8 is a schematic diagram of a temperature calibration process;

FIG. 9 is a schematic diagram of a process for finding a temperature discontinuity.

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings:

the invention specifically adopts the following technical scheme:

with reference to fig. 1 and 5, the method for automatically calibrating and compensating the fiber temperature of the fiber temperature distribution tester is performed based on the fiber temperature distribution tester and two high-low temperature constant temperature devices, wherein the fiber temperature distribution tester comprises a CPU module for controlling the instrument; the high-speed acquisition module acquires 1460nm channel data and sends the 1460nm channel data to the CPU module; the preamplification module 1 is used for amplifying 1460nm channel data; an O/E module, typically an APD/photodiode module; the center wavelength of the stop band is 1460nm, and the bandwidth is +/-5 GHz; the 1460nm/1660nm wavelength division multiplexer has 1460nm interface connected to the optical filter, 1660nm interface connected to the optical filter and COM interface connected to the measured optical fiber; an erbium-doped fiber amplifier module; a 1550nm pulse modulation module; the isolator is used for isolating 1550nm return light; a 1550nm ultra narrow linewidth light source; the high-speed acquisition module acquires 1660nm channel data and sends the channel data to the CPU module; the preamplification module is used for amplifying 1660nm channel data; an O/E module, typically an APD/photodiode module; the center wavelength of a stop band of the optical filter is 1660nm, and the bandwidth is +/-5 GHz; the serial port control interface is used for connecting other controlled instruments through serial ports; and the serial port control interface is used for connecting other controlled instruments through serial ports. The high-low temperature constant temperature device controls the temperature of the optical fiber temperature distribution tester; a control line and an optical fiber temperature distribution tester are controlled by a COM1 port, and the COM1 port is a network port; the control line, the ROTDR, is controlled by COM2 port, COM2 port is the net gape.

With reference to fig. 2, the automatic calibration and compensation method includes the following steps:

step 101: starting an optical fiber temperature distribution tester, and connecting the tested optical fiber;

step 102: inputting the actual length FL of the optical fiber, setting a spatial resolution parameter SFR, setting a typical value to be 1m, sampling resolution SAMF, setting a typical value to be 0.5m, and setting a test range FR to be (FL +1) km;

step 103: starting a temperature distribution test function of the optical fiber temperature distribution tester, reading Stokes test data DS and anti-Stokes test data DAS, analyzing the data to obtain de-noising Stokes data DS _ SN, de-noising anti-Stokes test data DAS _ SN and temperature data T;

step 104: reading a calibration zone bit bAPDCali, a power compensation zone bit bPowerCali and a temperature calibration zone bit bTemCali of a detector module from an optical fiber temperature distribution tester, wherein the three zone bits are defaulted to 0 during initial test;

step 105: judging whether bAPDCali is greater than or equal to 1, if so, performing step 106, otherwise, performing step 107;

step 106: putting the optical fiber temperature distribution tester into a high-low temperature constant temperature device, and starting the temperature compensation function of the detector module;

step 107: judging whether bPowerCali is greater than or equal to 1, if so, performing step 108, otherwise, performing step 109;

step 108: starting a power compensation function;

step 109: judging whether bTemClai is more than or equal to 1, if so, performing a step 110, otherwise, performing a step 111;

step 110: starting a temperature calibration function;

step 111: and finishing the temperature distribution measurement of the optical fiber temperature distribution tester.

In step 103, the specific process of acquiring the noise-removed stokes data and the noise-removed anti-stokes data is as follows:

with reference to fig. 3, step 201: starting a temperature distribution test function of the optical fiber temperature analysis tester, reading Stokes test data and anti-Stokes test data, wherein N is the number of the test data;

step 202: filtering the data to obtain filtering Stokes data and anti-Stokes test data;

step 203: calculating the Stokes test data noise DNS as the average value of 500 data points after Stokes, and calculating the anti-Stokes test data noise DNAS as the average value of 500 data points after anti-Stokes;

step 204: calculating de-noised stokes data and de-noised anti-stokes data;

step 205: obtaining temperature data according to the Stokes data with noise removed and the anti-Stokes data with noise removed, and storing temperature coefficients KTA and KTB;

step 206: and finishing filtering and denoising.

With reference to fig. 4, the specific steps of filtering the data to obtain filtered stokes data and anti-stokes test data include:

step 301: reading Stokes test data and anti-Stokes test data, and setting a filtering threshold TH with a typical value of 20;

step 302: initializing setting J to be N/2, NUM to be 0, and I to be 0;

step 303: judging whether J is less than 100, if so, turning to step 305, otherwise, turning to step 304;

step 304: setting NUM to NUM + 1;

step 305: setting a filter starting point coordinate set START [0] to START [ NUM ] to be 0;

step 306: performing wavelet decomposition, wherein dwt is a wavelet decomposition function;

step 307: judging whether I is smaller than NUM, if so, turning to step 309, otherwise, turning to step 308;

step 308: setting I as I +1 and L as N/2;

step 309: setting K to be 0;

step 310: judging whether a Stokes data wavelet decomposition high-frequency part cdDS [ I ] [ K ] is greater than or equal to a threshold TH or not, and judging whether an anti-Stokes data wavelet decomposition high-frequency part cdDAS [ I ] [ K ] is greater than or equal to the threshold TH or not, if yes, turning to a step 314, otherwise, turning to a step 311;

step 311: setting K to K + 1;

step 312: judging whether K is larger than J, if so, turning to step 310, otherwise, turning to step 313;

step 313: setting a threshold TH to TH-5;

step 314: setting the value of a filter starting point coordinate set START [ I ] as K;

step 315: setting high-frequency parts cdDS [ I ] [0] to cd [ I ] [ DSK ] of Stokes data wavelet decomposition to be 0, and setting high-frequency parts cdDAS [ I ] [0] to cdDAS [ I ] [ K ] of anti-Stokes data wavelet decomposition to be 0;

step 316: setting a counting position II as I, a counting position II as II-1 and a counting position K as 2 as K + 1;

step 317: judging whether II is greater than or equal to 0, if yes, turning to step 318, otherwise, turning to step 314;

step 318: performing wavelet reconstruction, wherein idwt is a wavelet reconstruction function;

step 319: judging whether I is smaller than NUM, if so, turning to a step 321, and otherwise, turning to a step 320;

step 320: setting I-1 and L-2;

step 321: judging whether L is equal to N, if so, turning to step 323, otherwise, turning to step 322;

step 323: setting filtered stokes data DSF [0] to DSF [ N ] as values of tempDS [0] to tempDS [ N ], respectively, filtered anti-stokes data DASF [0] to DASF [ N ] as values of tempDAS [0] to tempDAS [ N ], respectively, outputting the filtered stokes data and the filtered anti-stokes data;

step 322: the wavelet reconstruction fails and an error is returned.

With reference to fig. 6, the temperature compensation process of the detector module is:

step 401: controlling the high-low temperature constant temperature device to cool to the lower limit of the working temperature of the optical fiber temperature distribution tester and keeping the temperature;

step 402: reading the temperature of the high-low temperature constant temperature device and storing the temperature to a memory of an optical fiber temperature distribution tester, wherein the initialization temperature I of the optical fiber temperature distribution tester is 0;

step 403: after the temperature of the high-low temperature constant temperature device is stable, continuously reading and storing the temperature in the machine;

step 404: slope KT of temperature data in the computer;

step 405: judging whether KT is less than or equal to 0.01, if so, performing step 406, and if not, turning to step 403;

step 406: continuously testing for three times, acquiring noise-removed Stokes data and noise-removed anti-Stokes data, respectively storing, and calculating the average value of N +1 values;

step 407: controlling the high-low temperature constant temperature device to heat up, and sending a set temperature value to the optical fiber temperature distribution tester;

step 408: judging whether the temperature of the optical fiber temperature distribution tester is more than 50, if so, turning to a step 410, and if not, turning to a step 409;

step 409: setting I as I + 1;

step 410: calculating a temperature compensation coefficient;

step 411: and (4) finishing temperature compensation of a detector in the optical fiber temperature distribution tester, and outputting a compensation coefficient.

With reference to fig. 8, the specific process in step 110 is:

step 601: reading test data, obtaining de-noised data DS _ SN [ 0-N ], DAS _ SN [ 0-N ], initializing NUM, and typical value is 20;

step 602: initializing count bits C, I, J, K, KAPPA, S and SUM to be 0;

step 603: selecting an optical fiber fixing position, wherein the length LF of the optical fiber fixing position is more than or equal to 10 times of SAMF, and heating, wherein the typical value is 20 ℃;

step 604: analyzing data to obtain a break-out point, recording the position of the break-out point as RX and obtaining temperature values from TL [0] to TL [ NUM ];

step 605: setting the value of KAPPA to be the difference of KAPPA divided by T [ I ] and T [ I +1 ];

step 606: judging whether I is greater than or equal to NUM, if so, turning to step 608, otherwise, turning to step 607;

step 607: setting I as I + 1;

step 608: setting the value of S to be the product of S and the difference between R [ RX ] and R [ RX + J ];

step 609: judging whether J is more than or equal to NUM, if yes, turning to step 611, otherwise, turning to step 610;

step 610: setting J to J + 1;

step 611: setting a SUM bit SUM as the SUM of SUM and T [ K ];

step 612: and judging whether K is greater than or equal to NUM. If yes, go to step 614, otherwise go to step 613;

step 613: setting K to K + 1;

step 614: solving a simultaneous equation set TL [0] ═ KTS/KAPPA R [ RX ]. SUM + KTB, and T [0] ═ KTS/KAPPA R [0 ]. SUM + KTB to obtain new temperature coefficients KT and KTB;

step 615: and outputting the temperature coefficient, and finishing temperature calibration.

With reference to fig. 9, the specific process in step 604 is:

step 701: acquiring Stokes de-noising data from DS _ SN [0] to DS _ SN [ N ], anti-Stokes de-noising data from DAS _ SN [0] to DAS _ SN [ N ], wherein initialization I is 0, Stokes difference data DS _ DF [0] to DS _ DF [ N ] are all 0, anti-Stokes difference data DAS _ DF [0] to DAS _ DF [ N ] are all 0, Stokes difference accumulated data DS _ DFA [0] to DS _ DFA [ N ] are all 0, and anti-Stokes difference accumulated data DAS _ DFA [0] to DAS _ DFA [ N ] are all 0;

step 702: setting DS _ DF [0] to DS _ DF [ N ] as the difference between DS _ SN [0] to DS _ SN [ N-1] and DAS _ SN [1] to DAS _ SN [ N ], DAS _ DF [0] to DAS _ DF [ N ] as the difference between DAS _ SN [0] to DAS _ SN [ N-1] and DAS _ SN [1] to DAS _ SN [ N ];

step 703: the value of DS _ DFA [ I ] is DS _ DFA [ I ] + DS _ DF [ I ], and the value of DAS _ DFA [ I ] is DAS _ DFA [ I ] + DAS _ DF [ I ];

step 704: judging whether I is larger than or equal to N, if so, turning to a step 706, otherwise, turning to a step 705;

step 705: setting I as I + 1;

step 706: initializing NUM (number of bits) 5, setting an initial coordinate RX as 0, setting a counting bit II as NUM, setting a counting bit J as II-NUM, and setting a flag bit BF as 1;

step 707: judging whether Stokes differential accumulated data DS _ DFA [ J ] is less than or equal to DS _ DFA [ II ], whether anti-Stokes differential accumulated data DAS _ DFA [ J ] is less than or equal to DAS _ DFA [ II ], if so, turning to step 709, otherwise, turning to step 708;

step 708: setting a counting position II as II + 1;

step 709: setting a flag bit BF as BF +1 and a counting bit J as J + 1;

step 710: judging whether BF is greater than or equal to 5 and J is less than I, if yes, turning to step 711, otherwise, turning to step 708;

step 711: setting a flag bit BF to 1;

step 712: judging whether the Stokes differential accumulated data DS _ DFA [ J ] is greater than or equal to DS _ DFA [ II +1], whether the anti-Stokes differential accumulated data DAS _ DFA [ J ] is greater than or equal to DAS _ DFA [ II +1], if so, turning to step 713, otherwise, turning to step 708;

step 713: setting a flag bit BF as BF +1 and a counting bit J as J + 1;

step 714: judging whether the flag bit BF is greater than or equal to 5, whether J is smaller than the sum of the counting bit I and the data amount NUM, if yes, turning to step 715, otherwise, turning to step 708;

step 715: recording the coordinates RX of the point as II, outputting TL [0] to TL [ NUM ] as the values of the temperature T [ RX + NUM ], and finishing the calculation.

With reference to fig. 7, when the length of the measured optical fiber changes, the reflected signal is power compensated, which includes the following specific processes:

step 501: acquiring noise-removed stokes data of DS _ SN [0] to DS _ SN [ N ], noise-removed anti-stokes data of DAS _ SN [0] to DAS _ SN [ N ], and initializing I to 0;

step 502: removing the optical fiber with the tail end length of L (km), wherein the typical value is 2.5, testing to obtain Stokes and anti-Stokes data, and respectively recording the data from DSP [ I ] [0] to DSP [ I ] [ N ], DASP [ I ] [0] to DASP [ I ] [ N ];

step 503: calculating the length of the optical fiber LENF;

step 504: judging whether the LENF is less than or equal to 0.1, if yes, turning to a step 506, and if not, turning to a step 505;

step 505: setting a counting bit I plus 1;

step 506: calculating the Stokes compensation coefficients CALCOFFS [0] to CALCOFFS [ I ] as the quotient of DS _ SN [0] to DS _ SN [ N ] and DSP [ I ] [0] to DSP [ I ] [ N ], and calculating the anti-Stokes compensation coefficients CALCOFFAS [0] to CALCOFFAS [ I ] as the quotient of DS _ ASN [0] to DS _ ASN [ N ] and DASP [ I ] [0] to DASP [ I ] [ N ];

step 507: and outputting a compensation coefficient, finishing power compensation, setting a flag bit bPowerCali to be 0, and storing the flag bit bPowerCali into a parameter file PARAFILE.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.

Claims (7)

1. An optical fiber temperature automatic calibration and compensation method of an optical fiber temperature distribution tester is carried out based on the optical fiber temperature distribution tester and two high-low temperature constant temperature devices, and is characterized by comprising the following steps:

step 101: starting an optical fiber temperature distribution tester, and connecting the tested optical fiber;

step 102: inputting the actual length FL of the optical fiber, setting a spatial resolution parameter SFR, setting a typical value to be 1m, sampling resolution SAMF, setting a typical value to be 0.5m, and setting a test range FR to be (FL +1) km;

step 103: starting a temperature distribution test function of the optical fiber temperature distribution tester, reading Stokes test data DS and anti-Stokes test data DAS, analyzing the data to obtain de-noising Stokes data DS _ SN, de-noising anti-Stokes test data DAS _ SN and temperature data T;

step 104: reading a calibration zone bit bAPDCali, a power compensation zone bit bPowerCali and a temperature calibration zone bit bTemCali of a detector module from an optical fiber temperature distribution tester, wherein the three zone bits are defaulted to 0 during initial test;

step 105: judging whether bAPDCali is greater than or equal to 1, if so, performing step 106, otherwise, performing step 107;

step 106: putting the optical fiber temperature distribution tester into a high-low temperature constant temperature device, and starting temperature compensation of the detector module;

step 107: judging whether bPowerCali is greater than or equal to 1, if so, performing step 108, otherwise, performing step 109;

step 108: starting a power compensation function;

step 109: judging whether bTemClai is more than or equal to 1, if so, performing a step 110, otherwise, performing a step 111;

step 110: starting a temperature calibration function;

step 111: and finishing the temperature distribution measurement of the optical fiber temperature distribution tester.

2. The method according to claim 1, wherein the specific process of obtaining the noise-removed stokes data and the noise-removed anti-stokes data in step 103 is as follows:

step 201: starting a temperature distribution test function of the optical fiber temperature analysis tester, reading Stokes test data and anti-Stokes test data, wherein N is the number of the test data;

step 202: filtering the data to obtain filtering Stokes data and anti-Stokes test data;

step 203: calculating the Stokes test data noise DNS as the average value of 500 data points after Stokes, and calculating the anti-Stokes test data noise DNAS as the average value of 500 data points after anti-Stokes;

step 204: calculating de-noised stokes data and de-noised anti-stokes data;

step 205: obtaining temperature data according to the Stokes data with noise removed and the anti-Stokes data with noise removed, and storing temperature coefficients KTA and KTB;

step 206: and finishing filtering and denoising.

3. The method for automatically calibrating and compensating the fiber temperature of the fiber temperature distribution tester as claimed in claim 2, wherein the step of filtering the data to obtain the filtered stokes data and the anti-stokes test data comprises the steps of:

step 301: reading Stokes test data and anti-Stokes test data, and setting a filtering threshold TH with a typical value of 20;

step 302: initializing setting J to be N/2, NUM to be 0, and I to be 0;

step 303: judging whether J is less than 100, if so, turning to step 305, otherwise, turning to step 304;

step 304: setting NUM to NUM + 1;

step 305: setting a filter starting point coordinate set START [0] to START [ NUM ] to be 0;

step 306: performing wavelet decomposition, wherein dwt is a wavelet decomposition function;

step 307: judging whether I is smaller than NUM, if so, turning to step 309, otherwise, turning to step 308;

step 308: setting I as I +1 and L as N/2;

step 309: setting K to be 0;

step 310: judging whether a Stokes data wavelet decomposition high-frequency part cdDS [ I ] [ K ] is greater than or equal to a threshold TH or not, and judging whether an anti-Stokes data wavelet decomposition high-frequency part cdDAS [ I ] [ K ] is greater than or equal to the threshold TH or not, if yes, turning to a step 314, otherwise, turning to a step 311;

step 311: setting K to K + 1;

step 312: judging whether K is larger than J, if so, turning to step 310, otherwise, turning to step 313;

step 313: setting a threshold TH to TH-5;

step 314: setting the value of a filter starting point coordinate set START [ I ] as K;

step 315: setting high-frequency parts cdDS [ I ] [0] to cd [ I ] [ DSK ] of Stokes data wavelet decomposition to be 0, and setting high-frequency parts cdDAS [ I ] [0] to cdDAS [ I ] [ K ] of anti-Stokes data wavelet decomposition to be 0;

step 316: setting a counting position II as I, a counting position II as II-1 and a counting position K as 2 as K + 1;

step 317: judging whether II is greater than or equal to 0, if yes, turning to step 318, otherwise, turning to step 314;

step 318: performing wavelet reconstruction, wherein idwt is a wavelet reconstruction function;

step 319: judging whether I is smaller than NUM, if so, turning to a step 321, and otherwise, turning to a step 320;

step 320: setting I-1 and L-2;

step 321: judging whether L is equal to N, if so, turning to step 323, otherwise, turning to step 322;

step 323: setting filtered stokes data DSF [0] to DSF [ N ] as values of tempDS [0] to tempDS [ N ], respectively, filtered anti-stokes data DASF [0] to DASF [ N ] as values of tempDAS [0] to tempDAS [ N ], respectively, outputting the filtered stokes data and the filtered anti-stokes data;

step 322: the wavelet reconstruction fails and an error is returned.

4. The method for automatically calibrating and compensating the temperature of the optical fiber temperature distribution tester as claimed in claim 1, wherein the temperature compensation process of the detector module is as follows:

step 401: controlling the high-low temperature constant temperature device to cool to the lower limit of the working temperature of the optical fiber temperature distribution tester and keeping the temperature;

step 402: reading the temperature of the high-low temperature constant temperature device and storing the temperature to a memory of an optical fiber temperature distribution tester, wherein the initialization temperature I of the optical fiber temperature distribution tester is 0;

step 403: after the temperature of the high-low temperature constant temperature device is stable, continuously reading and storing the temperature in the machine;

step 404: slope KT of temperature data in the computer;

step 405: judging whether KT is less than or equal to 0.01, if so, performing step 406, and if not, turning to step 403;

step 406: continuously testing for three times, acquiring noise-removed Stokes data and noise-removed anti-Stokes data, respectively storing, and calculating the average value of N +1 values;

step 407: controlling the high-low temperature constant temperature device to heat up, and sending a set temperature value to the optical fiber temperature distribution tester;

step 408: judging whether the temperature of the optical fiber temperature distribution tester is more than 50, if so, turning to a step 410, and if not, turning to a step 409;

step 409: setting I as I + 1;

step 410: calculating a temperature compensation coefficient;

step 411: and (4) finishing temperature compensation of a detector in the optical fiber temperature distribution tester, and outputting a compensation coefficient.

5. The method according to claim 1, wherein the step 110 comprises the following steps:

step 601: reading test data, obtaining de-noised data DS _ SN [ 0-N ], DAS _ SN [ 0-N ], initializing NUM, and typical value is 20;

step 602: initializing count bits C, I, J, K, KAPPA, S and SUM to be 0;

step 603: selecting an optical fiber fixing position, wherein the length LF of the optical fiber fixing position is more than or equal to 10 times of SAMF, and heating, wherein the typical value is 20 ℃;

step 604: analyzing data to obtain a break-out point, recording the position of the break-out point as RX and obtaining temperature values from TL [0] to TL [ NUM ];

step 605: setting the value of KAPPA to be the difference of KAPPA divided by T [ I ] and T [ I +1 ];

step 606: judging whether I is greater than or equal to NUM, if so, turning to step 608, otherwise, turning to step 607;

step 607: setting I as I + 1;

step 608: setting the value of S to be the product of S and the difference between R [ RX ] and R [ RX + J ];

step 609: judging whether J is more than or equal to NUM, if yes, turning to step 611, otherwise, turning to step 610;

step 610: setting J to J + 1;

step 611: setting a SUM bit SUM as the SUM of SUM and T [ K ];

step 612: judging whether K is greater than or equal to NUM, if so, turning to step 614, and otherwise, turning to step 613;

step 613: setting K to K + 1;

step 614: solving a simultaneous equation set TL [0] ═ KTS/KAPPA R [ RX ]. SUM + KTB, and T [0] ═ KTS/KAPPA R [0 ]. SUM + KTB to obtain new temperature coefficients KT and KTB;

step 615: and outputting the temperature coefficient, and finishing temperature calibration.

6. The method according to claim 5, wherein the step 604 comprises the following steps:

step 701: acquiring Stokes de-noising data from DS _ SN [0] to DS _ SN [ N ], anti-Stokes de-noising data from DAS _ SN [0] to DAS _ SN [ N ], wherein initialization I is 0, Stokes difference data DS _ DF [0] to DS _ DF [ N ] are all 0, anti-Stokes difference data DAS _ DF [0] to DAS _ DF [ N ] are all 0, Stokes difference accumulated data DS _ DFA [0] to DS _ DFA [ N ] are all 0, and anti-Stokes difference accumulated data DAS _ DFA [0] to DAS _ DFA [ N ] are all 0;

step 702: setting DS _ DF [0] to DS _ DF [ N ] as the difference between DS _ SN [0] to DS _ SN [ N-1] and DAS _ SN [1] to DAS _ SN [ N ], DAS _ DF [0] to DAS _ DF [ N ] as the difference between DAS _ SN [0] to DAS _ SN [ N-1] and DAS _ SN [1] to DAS _ SN [ N ];

step 703: the value of DS _ DFA [ I ] is DS _ DFA [ I ] + DS _ DF [ I ], and the value of DAS _ DFA [ I ] is DAS _ DFA [ I ] + DAS _ DF [ I ];

step 704: judging whether I is larger than or equal to N, if so, turning to a step 706, otherwise, turning to a step 705;

step 705: setting I as I + 1;

step 706: initializing NUM (number of bits) 5, setting an initial coordinate RX as 0, setting a counting bit II as NUM, setting a counting bit J as II-NUM, and setting a flag bit BF as 1;

step 707: judging whether Stokes differential accumulated data DS _ DFA [ J ] is less than or equal to DS _ DFA [ II ], whether anti-Stokes differential accumulated data DAS _ DFA [ J ] is less than or equal to DAS _ DFA [ II ], if so, turning to step 709, otherwise, turning to step 708;

step 708: setting a counting position II as II + 1;

step 709: setting a flag bit BF as BF +1 and a counting bit J as J + 1;

step 710: judging whether BF is greater than or equal to 5 and J is less than I, if yes, turning to step 711, otherwise, turning to step 708;

step 711: setting a flag bit BF to 1;

step 712: judging whether the Stokes differential accumulated data DS _ DFA [ J ] is greater than or equal to DS _ DFA [ II +1], whether the anti-Stokes differential accumulated data DAS _ DFA [ J ] is greater than or equal to DAS _ DFA [ II +1], if so, turning to step 713, otherwise, turning to step 708;

step 713: setting a flag bit BF as BF +1 and a counting bit J as J + 1;

step 714: judging whether the flag bit BF is greater than or equal to 5, whether J is smaller than the sum of the counting bit I and the data amount NUM, if yes, turning to step 715, otherwise, turning to step 708;

step 715: recording the coordinates RX of the point as II, outputting TL [0] to TL [ NUM ] as the values of the temperature T [ RX + NUM ], and finishing the calculation.

7. The method for automatically calibrating and compensating the temperature of the optical fiber temperature distribution tester as claimed in claim 1, wherein when the length of the measured optical fiber changes, the power compensation is performed on the reflected signal, and the specific process is as follows:

step 501: acquiring noise-removed stokes data of DS _ SN [0] to DS _ SN [ N ], noise-removed anti-stokes data of DAS _ SN [0] to DAS _ SN [ N ], and initializing I to 0;

step 502: removing the optical fiber with the tail end length of L (km), wherein the typical value is 2.5, testing to obtain Stokes and anti-Stokes data, and respectively recording the data from DSP [ I ] [0] to DSP [ I ] [ N ], DASP [ I ] [0] to DASP [ I ] [ N ];

step 503: calculating the length of the optical fiber LENF;

step 504: judging whether the LENF is less than or equal to 0.1, if yes, turning to a step 506, and if not, turning to a step 505;

step 505: setting a counting bit I plus 1;

step 506: calculating the Stokes compensation coefficients CALCOFFS [0] to CALCOFFS [ I ] as the quotient of DS _ SN [0] to DS _ SN [ N ] and DSP [ I ] [0] to DSP [ I ] [ N ], and calculating the anti-Stokes compensation coefficients CALCOFFAS [0] to CALCOFFAS [ I ] as the quotient of DS _ ASN [0] to DS _ ASN [ N ] and DASP [ I ] [0] to DASP [ I ] [ N ];

step 507: and outputting a compensation coefficient, finishing power compensation, setting a flag bit bPowerCali to be 0, and storing the flag bit bPowerCali into a parameter file PARAFILE.

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