CN113639652A

CN113639652A - Automatic testing and analyzing method for strain distribution of optical fiber hydrophone

Info

Publication number: CN113639652A
Application number: CN202111015471.6A
Authority: CN
Inventors: 李立功; 袁明; 盛立文; 闫继送; 闫宝东; 郎金鹏; 徐瑞; 黄红伟; 李述标; 方玉朝
Original assignee: CLP Kesiyi Technology Co Ltd
Current assignee: CLP Kesiyi Technology Co Ltd
Priority date: 2021-08-31
Filing date: 2021-08-31
Publication date: 2021-11-12
Anticipated expiration: 2041-08-31
Also published as: CN113639652B

Abstract

The invention provides an automatic testing and analyzing method for strain distribution of an optical fiber hydrophone, which comprises the following steps: acquiring the length of a long interference arm of the optical fiber hydrophone, the length of a short interference arm of the optical fiber hydrophone and the length of an optical fiber of a transmission part in each optical switch channel; initializing a counting variable of an optical switch channel, and remotely setting parameters of an optical fiber strain distribution tester; testing the strain distribution of the optical fiber hydrophone to obtain strain distribution test data; rapidly analyzing original Brillouin distribution data in the strain distribution test data to obtain the total optical fiber length, the interference arm reflector position and the long interference arm reflector position of the strain data; judging the rule, and directly carrying out the next step when the judgment rule is met; analyzing original Brillouin distribution data and original strain data to obtain strain data of a long interference arm and strain data of a short interference arm; and judging whether the current optical switch channel counting variable is not less than the number of the optical switch optical channels, and if so, directly outputting strain data of the long interference arm and the short interference arm of all channels.

Description

Automatic testing and analyzing method for strain distribution of optical fiber hydrophone

Technical Field

The disclosure belongs to the technical field of underwater acoustic detection, and particularly relates to an automatic test and analysis method for strain distribution of an optical fiber hydrophone.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

The fiber optic hydrophone is a novel underwater sound detection technology developed in recent years and has important significance for maintaining ocean safety. Compared with the traditional piezoelectric hydrophone, the optical fiber hydrophone has the advantages of high sensitivity, full light at a wet end, good stability and frequency response characteristics, hydrostatic pressure resistance, corrosion resistance, long transmission distance, easiness in large-scale multiplexing and the like. The sensing principle is that parameters such as intensity, polarization state and phase of optical wave in the optical fiber are modulated by the acoustic wave to obtain information such as frequency and intensity of the acoustic wave. The phase interference type optical fiber hydrophone is the most mature hydrophone type researched at home and abroad at present. The Michelson interference type optical fiber hydrophone converts an underwater sound signal into phase change of an optical signal, extracts underwater sound information from the phase change of the optical signal through an optical coherent detection technology and a signal processing system, and has the advantages of high sensitivity, convenience in multiplexing and the like.

The optical fiber hydrophone needs to work in a severe marine environment for a long time with high reliability, which puts high requirements on the manufacturing process of the optical fiber hydrophone. The optical fiber coil is one of key devices in the optical fiber hydrophone, and when the optical fiber hydrophone is disturbed by external sound pressure, the optical fiber coil can deform, so that the intensity, polarization state, frequency or phase of optical waves in the optical fiber are modulated, and then a detection signal is demodulated by adopting a corresponding signal demodulation method through the rear end of the optical fiber hydrophone, so that external sound field information is obtained. Therefore, the performance of the fiber coil will directly affect the optical and acoustic performance and long-term reliability of the fiber optic hydrophone.

The optical fiber coil winding process is to wind an optical fiber on an elastic body according to a certain winding method to prepare an optical fiber coil, wherein the winding tension is an important process parameter when the optical fiber coil is wound, and the winding tension is usually determined according to the performance parameters of the wound optical fiber and the elastic body material, the working water depth and the hydrostatic pressure of an optical fiber hydrophone and other factors. In the process of improving the winding process of the optical fiber coil and the process of developing and inspecting the optical fiber hydrophone, the winding tension of the optical fiber coil can be accurately measured, and the improvement of the winding process and the development and inspection of the optical fiber coil are particularly important.

According to the inventor's understanding, at present mainly adopt optic fibre strain distribution tester test optic fibre coil received strain distribution state, but because optic fibre coil utilizes two interference arms of michelson optic fibre hydrophone to twine, and two interference arm length are different, when adopting optic fibre strain tester to test, thereby two parts of interfering arm length coincidence can lead to the strain data difficult with accurate analysis because spontaneous brillouin scattering signal coincidence causes mutual interference, only longer interference arm compares the surplus length part of short interference arm in two interference arms, owing to can not receive the interference of the spontaneous brillouin scattering signal of other interference arm, just can obtain more accurate strain data. Therefore, the strain data of the coincident part of the two interference arms cannot be obtained by adopting the prior art, only the strain data of the residual length part of the longer interference arm can be obtained, the strain distribution state of the whole optical fiber coil is difficult to accurately reflect, the accurate judgment on the performance of the optical fiber coil in the winding process improvement process of the optical fiber hydrophone and the development and inspection process of the optical fiber hydrophone is influenced, especially the judgment capability on the deformation state of the shorter interference arm is greatly influenced, and the rapid development of the optical fiber hydrophone technology is severely limited.

Disclosure of Invention

In order to solve the problems, the disclosure provides an automatic testing and analyzing method for strain distribution of an optical fiber hydrophone, and the method solves the problem that the traditional technology cannot test the interference double-arm strain distribution of the Michelson optical fiber hydrophone, and realizes comprehensive distributed testing of strain distribution data of two interference optical fiber arms in an optical fiber coil.

According to some embodiments, the scheme of the present disclosure provides an automatic testing and analyzing method for strain distribution of an optical fiber hydrophone, which adopts the following technical scheme:

an automatic testing and analyzing method for strain distribution of an optical fiber hydrophone comprises the following steps:

step S01: acquiring the length of a long interference arm of the optical fiber hydrophone, the length of a short interference arm of the optical fiber hydrophone and the length of an optical fiber of a transmission part in each optical switch channel;

step S02: initializing a counting variable of an optical switch channel, and remotely setting parameters of an optical fiber strain distribution tester;

step S03: the optical fiber strain distribution tester performs strain distribution test on the optical fiber hydrophone to obtain strain distribution test data;

step S04: rapidly analyzing original Brillouin distribution data in the strain distribution test data to respectively obtain the total optical fiber length of the strain data, the position of an interference arm reflector and the position of a long interference arm reflector;

step S05: judging whether the total optical fiber length, the interference arm reflector position and the long interference arm reflector position of the obtained strain data meet judgment rules, and directly performing the step S06 when the judgment rules are met; otherwise, continuously adjusting the parameters of the optical fiber strain distribution tester, and turning to the step S03;

step S06: analyzing original Brillouin distribution data and original strain data to obtain strain data of a long interference arm and strain data of a short interference arm; and judging whether the current optical switch channel counting variable is not less than the number of optical switch optical channels, if so, directly outputting strain data of the long interference arms and the strain data of the short interference arms of all channels, and if not, adding 1 to the current optical switch channel counting variable to transfer to the step S02.

Compared with the prior art, the beneficial effect of this disclosure is:

the method solves the problem that the traditional technology can not test the interference double-arm strain distribution of the Michelson type optical fiber hydrophone, and realizes the comprehensive distributed test of the strain distribution data of two interference optical fiber arms in the optical fiber coil; the efficiency and the test accuracy of the development and improvement process of the optical fiber coil winding process, the development and inspection process of the optical fiber hydrophone are improved; further expand the application scope of the distribution tester of the strain of optic fibre, increase the application scene for BOTDR.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

FIG. 1 is a schematic diagram of a method for automatically testing and analyzing strain distribution of a fiber optic hydrophone according to an embodiment of the disclosure;

FIG. 2 is a schematic diagram of an automatic test and analysis process of strain distribution of a dual interference arm of an optical fiber hydrophone according to an embodiment of the present disclosure;

FIG. 3 is a flow chart of a fast optical fiber length analysis method based on optical fiber Brillouin scattering spectrum in an embodiment of the disclosure;

fig. 4 is a schematic flow chart of calculation of temporary brillouin spectral data with a substrate removed in the embodiment of the present disclosure;

FIG. 5 is a schematic diagram illustrating an analysis flow of valid labeled data based on spectral maximum distribution data and spectral mean distribution data according to an embodiment of the present disclosure;

FIG. 6 is a schematic flow chart of LSM and LLM analysis based on valid tagged data in an embodiment of the present disclosure;

FIG. 7 is a schematic flow chart of strain data analysis based on long and short interferometric arms in an embodiment of the disclosure;

FIG. 8 is a schematic diagram of an analysis flow of a redundant single-ghost-mirror Brillouin scattering spectrum reconstruction algorithm in an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of an analysis flow of a redundant-free single-ghost-mirror Brillouin scattering spectrum reconstruction algorithm in an embodiment of the present disclosure;

fig. 10 is a schematic diagram of an analysis flow (first part) of a multiple reflection mirror brillouin scattering spectrum reconstruction algorithm in an embodiment of the disclosure;

fig. 11 is a schematic diagram of an analysis flow (second part) of a multiple reflection mirror brillouin scattering spectrum reconstruction algorithm in an embodiment of the disclosure.

The specific implementation mode is as follows:

the present disclosure is further described with reference to the following drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.

In the method for automatically testing and analyzing strain distribution of an optical fiber hydrophone in this embodiment, a fiber strain distribution tester (brillouin optical time domain reflectometer, BOTDR for short) is used as a testing device to test a michelson interference type optical fiber hydrophone fiber coil, and interference double-arm strain distribution data obtained through the test is automatically analyzed, so that respective fiber strain distribution data of two interference arms are obtained, a typical embodiment is shown in fig. 1, and the method specifically includes the following steps:

(1) and the control computer is used for testing the strain distribution by controlling the optical fiber strain distribution tester and simultaneously controlling the optical switch to switch the tested optical fiber coil.

(2) The optical fiber strain distribution tester is typically a Brillouin optical time domain reflectometer based on a spontaneous Brillouin scattering technology.

(3) The 1 XN optical switch is controlled by the control computer to switch the detected optical path.

(4) The michelson fiber optic hydrophone under test.

As shown in fig. 2, an automatic testing and analyzing method for strain distribution of an optical fiber hydrophone includes the following steps:

step 101: starting a fiber coil strain distribution test, and turning to step 102;

step 102: controlling the computer 1 to read the number N of channels of the 1 XN optical switch, and turning to step 103;

step 103: the user inputs the length LL 1-N of the long interference arm of the optical fiber hydrophone of each channel, the length LS 1-N of the short interference arm of each channel, the length L0 1-N of the optical fiber of the transmission part of each channel, and then the step 104 is carried out;

step 104: initializing a current channel counting variable OSI of the 1 × N optical switch to 1, and going to step 105;

step 105: the control computer 1 remotely controls the 1 xN optical switch to the OSI channel, and the step 106 is proceeded

Step 106: remotely setting parameters of the optical fiber strain distribution tester 2 by the control computer 1, setting the spatial resolution SR as a settable minimum value, setting the range value RAN as a minimum settable value exceeding LL +100m, setting the sampling resolution DR as a settable minimum value, setting the starting frequency FS as a settable minimum value, setting the frequency interval FI as a settable minimum value and setting the ending frequency FE as a settable maximum value, and turning to step 107;

step 107: the control computer 1 remotely starts a strain distribution test, and then the step 108 is carried out;

step 108: after the optical fiber strain distribution tester 2 finishes the strain distribution test, reading the strain data point number SN, the frequency data point number FM, the original Brillouin distribution data BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the original strain data SORIDATA [ OSI ] [ 1-SN ], the distance data LDATA [ OSI ] [ 1-SN ] and the like by the control computer 1, and turning to step 109;

step 109: analyzing the BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ] to obtain the total optical fiber length SL, the interference arm reflector position LSM and the long interference arm reflector position LLM of the strain data, turning to step 110 in step 201;

step 110: judging whether the analyzed SL, LSM and LLM meet basic data requirements or not, wherein LSTH is an analysis length difference judgment threshold, if the difference between SL and (LL [ OSI ] + L0) × 2 exceeds LSTH, namely SL- (LL [ OSI ] + L0) × 2 > LSTH or LSM ═ 0 or LLM ═ 0, considering that the analyzed SL, LSM and LLM are invalid data and needing to change test parameters, and turning to step 111, otherwise, turning to step 112;

the LSTH typical value taking method comprises the following steps:

step 111: remotely increasing the spatial resolution/pulse width SR set value by 1 gear by the control computer 1, and turning to step 107;

step 112: analyzing original Brillouin distribution data BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ] and original strain data SORIDATA [ OSI ] [ 1-SN ] to obtain long interference arm strain data SSDATA [ OSI ] [ 1-SN ] and short interference arm strain data SSDATA [ OSI ] [ 1-SN ], turning to step 401 and turning to step 113;

step 113: judging whether OSI is more than or equal to N, if yes, turning to step 115, otherwise, turning to step 114;

step 114: assigning OSI as OSI +1, turning to step 105;

step 115: and outputting all the channel long interference arm strain data SSDATA [ 1-N ] [ 1-SN ] and short interference arm strain data SSDATA [ 1-N ] [ 1-SN ].

As shown in fig. 3, the original brillouin spectrum data is rapidly analyzed to obtain the optical fiber length SL, the short interference arm mirror position LSM, and the long interference arm mirror position LLM, and the specific steps are as follows:

step 201: reading original Brillouin distribution data BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], distance data LDATA [ OSI ] [ 1-SN ], long interference arm length LL [ OSI ] of the optical fiber hydrophone, optical fiber length L0[ OSI ] of a transmission part, spatial resolution SR, sampling resolution DR, starting frequency FS, frequency interval FI and ending frequency FE, and turning to step 202;

step 202: initializing count variables II and JJ to 1, initializing temporary brillouin data BDATA [1 to SN ] [1 to FM ], all center frequency data CFDATA [1 to SN ] being 0, all valid flags BGSPU [1 to SN ] being 0, all brillouin spectrum intensity data BGSPDATA [1 to FM ] being 0, all brillouin spectrum frequency data BGSFDATA [1 to FM ] being 0, and noise intensity NOISEAVE being 0, and going to step 203;

step 203: calculating temporary Brillouin data BDATA [ 1-SN ] [ 1-FM ] according to the original Brillouin distribution data BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], in detail, step 20301, and turning to step 204;

step 204: calculating effective Brillouin spectrum markers BGSPU [ 1-SN ] according to BDATA [ 1-SN ] [ 1-FM ], and turning to step 20401 for details;

step 205: calculating a decision threshold SLTH, which is rounding up (SR/DR), that is, rounding up the value of SR/DR, if SLTH < 3, the value of SLTH is 3, and go to step 206;

step 206: initializing a counting variable II (SN), initializing an effective Brillouin spectrum counting BGSPUNUM (0), and turning to step 207;

step 207: judging whether the Brillouin spectrum effective mark BGSPU [ II ] is greater than a fiber end judgment threshold value FETH, if so, turning to a step 213, otherwise, turning to a step 208;

the typical value taking method of the fiber tail end judgment threshold value FETH is as follows:

step 208: BGSPUNUM is 0, go to step 214;

step 209: judging that II is less than 2, if yes, turning to step 211, otherwise, turning to step 210;

step 210: turning to step 207 when II is II-1;

step 211: turning to step 212 when the fiber length subscript SLN is 0;

step 212: assigning the value of the LSM of the short interference arm mirror position to 0 (indicating that the LSMs is 0 and the LSME is 0), assigning the value of the LLM of the long interference arm mirror position to 0 (indicating that the LLMs is 0 and the LLME is 0), and turning to step 217;

step 213: BGSPUNUM +1, go to step 214;

step 214: BGSPUNUM > SLTH, go to step 215;

step 215: turning to step 216 when the index SLN is equal to II;

step 216: calculating the position LSM of the short interference arm reflector and the position LLM of the long interference arm reflector according to BGSPU [ 1-SN ], and turning to step 217 in detail in step 301;

step 217: fiber length SL ═ LDATA [ OSI ] [ LSN ], go to step 218;

step 218: output fiber length SL, short interference arm mirror position LSM, and long interference arm mirror position LLM.

As shown in fig. 4, the noise floor removal calculation is performed on the original brillouin distribution data to obtain temporary brillouin data BDATA, and the specific steps are as follows:

step 20301: reading original Brillouin distribution data BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], sampling resolution DR, initializing counting variables II to 1 and JJ to 1, initializing temporary Brillouin data BDATA [ 1-SN ] [ 1-FM ] and noise intensity NOISEAVE to 0, and turning to step 20302;

step 20302: turning to step 20303 when the noise count NOISENUM is 100 m/DR;

step 20303: noisieve + BORIDATA [ OSI ] [ SN-II +1] [ JJ ], go to step 20304;

step 20304: judging whether JJ > FM is established, if yes, turning to the step 20306, otherwise, turning to the step 20305;

step 20305: step 20303 is executed if JJ is equal to JJ + 1;

step 20306: step 20307 is executed if JJ is 1;

step 20307: judging whether II is greater than NOISENUM, if yes, turning to step 20309, and if not, turning to step 20308;

step 20308: turning to step 20303 when II is equal to II + 1;

step 20309: noisieve ═ noisieve/noisienum, go to step 203010;

step 20310: if II is 1 and JJ is 1, go to step 20311;

step 20311: BDATA [ II ] [ JJ ] ═ BORIDATA [ OSI ] [ II ] [ JJ ] -noiseive, go to step 20312;

step 20312: judging whether JJ > FM is established, if true, turning to step 20314, if false, turning to step 20313;

step 20313: step 20311 is executed if JJ is equal to JJ + 1;

step 20314: step 20315 is executed if JJ is 1;

step 20315: judging whether II is greater than SN, if yes, turning to step 20317, and if not, turning to step 20316;

step 20316: if II is II +1, go to step 20311;

step 20317: and outputting temporary Brillouin data BDATA [ 1-SN ] [ 1-FM ].

As shown in fig. 5, the temporary brillouin spectrum data is further analyzed to obtain effective labeled data, and the specific steps are as follows:

step 20401: reading temporary Brillouin data BDATA [ 1-SN ] [ 1-FM ] initialization counting variables II and JJ 1, wherein initialization VMAX [ 1-SN ] is all 0, VAVE [ 1-SN ] is all 0, and turning to step 20401;

step 20402: VMAX [ II ] ═ BDATABDATA [ II ] [ JJ ], VAVE [ II ] ═ 0, go to step 20403;

step 20403: judging whether VMAX [ II ] < BDATABDATA [ II ] [ JJ ] is true, if true, turning to step 20404, and if false, turning to step 20405;

step 20404: VMAX [ II ] ═ BDATABDATA [ II ] [ JJ ], go to step 20405;

step 20405: VAVE [ II ] + BDATABDATA [ II ] [ JJ ], go to step 20406;

step 20406: judging whether JJ > FM is established, if yes, turning to step 20408, and if not, turning to step 20407;

step 20407: step 20403 is performed after JJ is equal to JJ + 1;

step 20408: turning to step 20409 if VAVE [ II ]/FM;

step 20409: judging whether II is more than SN, and turning to step 20411, and turning to step 20410;

step 20410: turning to step 20402 when II is II + 1;

step 20411: initializing temporary variable MAXVMAX ═ 0, MAVVAVE ═ 0, II ═ 1, go to step 20412;

step 20412: initializing temporary variables MAXVMAX ═ VMAX [ II ], MAXVAVE ═ VAVE [ II ], go to step 20413;

step 20413: judging whether MAXVMAX < VMAX [ II ] is true, if true, turning to step 20414, otherwise, turning to step 20415;

step 20414: MAXVMAX ═ VMAX [ II ], go to step 20415;

step 20415: judging whether MAXVAVE < VAVE [ II ] is true, if true, turning to step 20416, otherwise, turning to step 20417;

step 20416: MAXVAVE ═ VAVE [ II ], go to step 20417;

step 20417: judging whether II is more than SN, if yes, turning to step 20419, otherwise, turning to step 20418;

step 20418: turning to step 20413 when II is II + 1;

step 20419: initializing all effective marks BGSPU [ 1-SN ] to be 0, setting II to be 1, and turning to step 20420;

step 20420:

BGSPU [ II ] ═ VMAX [ II ]/MAXVMAX [ II ]/MAXVAVE, go to step 20421;

step 20421: judging whether II is more than SN, if yes, turning to step 20423, otherwise, turning to step 20422;

step 20422: turning to step 20420 when II is II + 1;

step 20423: output BGSPU [ 1-SN ].

As shown in fig. 6, the effective mark data is further analyzed to obtain a short interference arm mirror position LSM and a long interference arm mirror position LLM, and the specific steps are as follows:

step 301: reading BGSPU [1 to SN ], distance data LDATA [ OSI ] [1 to SN ], fiber length SL, initializing counting variables II as 1 and PTEMP as 1, initializing a short interference arm reflector position LSM, wherein the LSM comprises a starting position LSMS, an ending position LSME and a long interference arm reflector position LLM, the LLM comprises a starting position LLMS and an ending position LLME, and turning to step 302;

step 302: judging whether BGSPU [ II ] is more than or equal to 0.9, if so, turning to step 305, otherwise, turning to step 303;

step 303: judging whether II is more than SN, if yes, turning to a step 339, otherwise, turning to a step 304;

step 304: turning to step 302 when II is II + 1;

step 305: initializing JJ to be 0 and LNUM to be 0, and turning to step 306;

step 306: judging whether BGSPU [ II + JJ ] is more than or equal to 0.9, if so, turning to step 307, otherwise, turning to step 310;

step 307: step 308 is executed if LNUM is LNUM + 1;

step 308: judging whether II + JJ > SN is established or not, if so, turning to step 310, otherwise, turning to step 309;

step 309: step 306 is executed if JJ is JJ + 1;

step 310: judging whether LNUM > SLTH is established, if yes, turning to step 311, otherwise, turning to step 308;

step 311: turning to step 312 if PTEMP is II + JJ;

step 312: judging whether BGSPU [ II ] -BGSPU [ II-1] < 0, if yes, turning to step 315, otherwise, turning to step 313;

step 313: judging whether II is more than 2, if yes, turning to step 314, otherwise, turning to step 339;

step 314: turning to step 312 if II is II-1;

step 315: turning to step 315 if LSMS is II;

step 316: turning to step 317, if II is PTEMP;

step 317: judging whether BGSPU [ II ] -BGSPU [ II ] < 0, if yes, turning to step 320, otherwise, turning to step 318;

step 318: judging whether II is more than SN-1, if yes, turning to a step 319, and if not, turning to a step 339;

step 319: turning to step 317, if II is equal to II + 1;

step 320: turning to step 321 when LSME is II;

step 321: judging whether BGSPU [ II ] is equal to or more than 0.9, if yes, turning to step 324, otherwise, turning to step 322;

step 322: judging whether II is more than SN, if yes, turning to a step 339, otherwise, turning to a step 323;

step 323: turning to step 321 when II is II + 1;

step 324: initializing JJ to be 0 and LNUM to be 0, and turning to step 325;

step 325: judging whether BGSPU [ II + JJ ] is greater than or equal to 0.9, if yes, turning to step 326, otherwise, turning to step 329;

step 326: LNUM +1, go to step 327;

step 327: judging whether II + JJ > SN is established, if yes, turning to step 329, otherwise, turning to step 328;

step 328: step 325 if JJ is JJ + 1;

step 329: judging whether LNUM > SLTH is established, if yes, turning to step 330, otherwise, turning to step 327;

step 330: turning to step 331 if PTEMP is II + JJ;

step 331: judging whether BGSPU [ II ] -BGSPU [ II-1] < 0, if yes, turning to step 334, otherwise, turning to step 332;

step 332: judging whether II is more than 2, if so, turning to a step 333, otherwise, turning to a step 339;

step 333: turning to step 331 when II is II-1;

step 334: turning to step 334 if LLMS is II;

step 335: go to step 336 if II is PTEMP;

step 336: judging whether BGSPU [ II ] -BGSPU [ II ] < 0, if yes, turning to step 340, otherwise, turning to step 337;

step 337: judging whether II is more than SN-1, if so, turning to step 338, otherwise, turning to step 339;

step 338: turning to step 336 if II is II + 1;

step 339: the calculated data is wrong, the LSM value is 0 (LSMs is 0, LSME is 0), and the LLM value is 0 (LLMs is 0, LLME is 0);

step 340: turning to step 341 if LSME is II;

step 341: and outputting the LSM and the LLM.

As shown in FIG. 7, the strain data SSDATA [ OSI ] [ 1-SN ] of the long interference arm and the strain data SSDATA [ OSI ] [ 1-SN ] of the short interference arm are calculated, and the specific steps are as follows:

step 401: reading BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], SORIDATA [ OSI ] [ 1-SN ], long interference arm length LL [ OSI ], short interference arm length LS [ OSI ], transmission portion fiber length L0[ OSI ], fiber length SL, interference arm mirror position LSM, and long interference arm mirror position LLM;

step 402: judging whether LLMS is established or not at 2 × LSMS, if so, turning to a step 403, otherwise, turning to a step 404;

step 403: performing redundant single reflection mirror image Brillouin scattering spectrum reconstruction on BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the optical fiber length SL, the short interference arm reflector position LSM and the long interference arm reflector position LLM to construct short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ], in detail, in step 501, turning to step 407;

step 404: judging whether 3 LSMS is less than or equal to 2 LLMS, if yes, turning to step 405, otherwise, turning to step 406;

step 405: performing redundancy-free single-reflection mirror image Brillouin scattering spectrum reconstruction on BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the optical fiber length SL, the short interference arm reflector position LSM and the long interference arm reflector position LLM to construct short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ], turning to step 601 in detail;

step 406: performing multiple reflection mirror image Brillouin scattering spectrum reconstruction on BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the optical fiber length SL, the short interference arm reflector position LSM and the long interference arm reflector position LLM to construct short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ], in detail in step 701, and turning to step 407;

step 407: analyzing the short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] according to a Brillouin scattering spectrum strain demodulation algorithm to obtain short interference arm strain data SSDATA [ OSI ] [ 1-SN ], and turning to step 408;

step 408: analyzing the long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] according to a Brillouin scattering spectrum strain demodulation algorithm to obtain long interference arm strain data SSDATA [ OSI ] [ 1-SN ], and turning to step 409;

step 409: and outputting strain data SSDATA [ OSI ] [1 to SN ] of the long interference arm and strain data SSDATA [ OSI ] [1 to SN ] of the short interference arm.

As shown in fig. 8, for the case where 2 × LSMS is not greater than LLMS, the redundant single-ghost-mirror brillouin spectrum reconstruction algorithm is used to construct short-interference-arm brillouin spectrum data BSDATA [1 to SN ] [1 to FM ], and long-interference-arm brillouin spectrum data BLDATA [1 to SN ] [1 to FM ], and the specific steps are as follows:

step 501: reading BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the long interference arm length LL [ OSI ], the short interference arm length LS [ OSI ], the transmission portion fiber length L0[ OSI ], the fiber length SL, the interference arm mirror position LSM and the long interference arm mirror position LLM, and turning to step 502;

step 502: initializing short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] to be 0, initializing long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] to be 0, and turning to step 503, wherein II is 1;

step 503: turning to step 504 if JJ is 1;

step 504:

BSDATA [ LSMS +1-II ] [ JJ ] ═ BORIDATA [ OSI ] [ LSMS +1-II ] [ JJ ] -BORIDATA [ OSI ] [2 × LLMS-LSMS + II-1] [ JJ ], go to step 505.

Step 505: judging whether JJ > FM is established, if yes, turning to a step 507, otherwise, turning to a step 506;

step 506: turning to step 504 if JJ is JJ + 1;

step 507: judging whether II is more than LSMS, if yes, turning to a step 509, otherwise, turning to a step 508;

step 508: turning to step 503 when II is II + 1;

step 509: turning to step 510 when II is equal to 1;

step 510: turning to step 511 when JJ is 1;

step 511:

BLDATA [ LSME +1-II ] [ JJ ] ═ BORIDATA [ OSI ] [2 × LLMS-LSME + II-1] [ JJ ], go to step 512;

step 512: judging whether JJ > FM is established, if yes, turning to step 514, otherwise, turning to step 513;

step 513: step 511 is executed if JJ is JJ + 1;

step 514: judging whether II is more than LSME, if so, turning to step 516, otherwise, turning to step 515;

step 515: turning to step 510 if II is equal to II + 1;

step 516: turning to step 517 when II is equal to 1;

517: turning to step 518 when JJ is 1;

step 518:

BLDATA[LSME+II][JJ]＝BORIDATA[OSI][LSME+II][JJ]-BSDATA[OSI]

[2 ] LSMS-LSME-II ] [ JJ ], go to step 519;

step 519: judging whether JJ > FM is established, if yes, turning to step 521, otherwise, turning to step 520;

step 520: step 518 is executed if JJ is JJ + 1;

step 521: judging whether II is more than 2LSMS-LSME-1, if yes, turning to step 523, otherwise, turning to step 522;

step 522: turning to step 517 when II is II + 1;

step 523: turning to step 524 when II is equal to 1;

step 524: turning to step 525 if JJ is 1;

step 525: BLDATA [2 × LSME + II ] [ JJ ] ═ BORIDATA [ OSI ] [2 × LSME + II ] [ JJ ], go to step 526;

step 526: judging whether JJ > FM is established, if yes, turning to a step 528, otherwise, turning to a step 527;

step 527: step 525 is executed if JJ is JJ + 1;

step 528: judging whether II is more than LLMS-2LSMS, if yes, turning to step 530, otherwise, turning to step 529;

step 529: turning to step 524 when II is equal to II + 1;

step 530: and outputting short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ].

As shown in fig. 9, for the situation that 2/3 × LLMS is greater than or equal to LSMS > 0.5 × LLMS, the non-redundant single-ghost-mirror brillouin spectrum reconstruction algorithm is used to construct short-interference-arm brillouin spectrum data BSDATA [1 to SN ] [1 to FM ], and long-interference-arm brillouin spectrum data BLDATA [1 to SN ] [1 to FM ], and the specific steps are as follows:

step 601: reading BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the long interference arm length LL [ OSI ], the short interference arm length LS [ OSI ], the transmission portion fiber length L0[ OSI ], the fiber length SL, the interference arm mirror position LSM, and the long interference arm mirror position LLM, and going to step 602;

step 602: initializing short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] to be 0, initializing long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] to be 0, and turning to the step 603;

step 603: turning to step 604 when JJ is equal to 1;

step 604:

BSDATA [ LSMS +1-II ] [ JJ ] ═ BORIDATA [ OSI ] [ LSMS +1-II ] [ JJ ] -BORIDATA [ O SI ] [2 × LLMS-LSMS + II-1] [ JJ ], go to step 605;

step 605: judging whether JJ > FM is established, if yes, turning to step 607, otherwise, turning to step 606;

step 606: turning to step 604 if JJ is JJ + 1;

step 607: judging whether II is more than LSMS, if yes, turning to step 609, otherwise, turning to step 608;

step 608: turning to step 603 if II is II + 1;

step 609: turning to step 610 when II is equal to 1;

step 610: turning to step 611 when JJ is equal to 1;

step 611:

BLDATA [ LSME +1-II ] [ JJ ] ═ BORIDATA [ OSI ] [2 × LLMS-LSME + II-1] [ JJ ], go to step 612;

step 612: judging whether JJ > FM is established, if yes, turning to step 614, otherwise, turning to step 613;

step 613: if JJ is JJ +1, go to step 611;

step 614: judging whether II is greater than LSME, if yes, turning to step 616, otherwise, turning to step 615;

step 615: turning to step 610 when II is equal to II + 1;

step 616: turning to step 617 when II is equal to 1;

step 617: step 618 is executed if JJ is 1;

step 618:

BLDATA [ LSME + II ] [ JJ ] ═ BORIDATA [ OSI ] [ LSME + II ] [ JJ ] -BSDATA [ OSI ] [2 × LSMS-LSME-II ] [ JJ ], go to step 619;

step 619: judging whether JJ > FM is established, if yes, turning to a step 621, otherwise, turning to a step 620;

step 620: step 618 is executed if JJ is JJ + 1;

step 621: judging whether II is more than LLMS-LSME-1, if yes, turning to step 623, otherwise, turning to step 622;

step 622: turning to step 617 when II is equal to II + 1;

step 623: and outputting short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ].

As shown in fig. 10 and 11, for the case of not less than LSMS2/3 × LLMS, the multiple reflection mirror image brillouin spectrum reconstruction algorithm is used to construct short interference arm brillouin spectrum data BSDATA [1 to SN ] [1 to FM ], and long interference arm brillouin spectrum data BLDATA [1 to SN ] [1 to FM ], and the specific steps are as follows:

step 701: reading BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the long interference arm length LL [ OSI ], the short interference arm length LS [ OSI ], the transmission portion fiber length L0[ OSI ], the fiber length SL, the interference arm mirror position LSM, and the long interference arm mirror position LLM, and turning to step 702;

step 702: initializing temporary Brillouin data TBORIDATA [ 1-SN ] [ 1-FM ] to Brillodata [ OSI ] [ 1-SN ] [ 1-FM ], setting short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] to 0 and setting long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] to 0, and going to step 703;

step 703: calculating Δ LM ═ LLMS-LSMS, initializing LE ═ 0, LS ═ 2 ═ Δ LM, RE ═ LLMS ═ 2, RS ═ 2 ═ LLMS-2 ═ Δ LM, II ═ 1, go to step 704;

step 704: judging whether LS is less than or equal to LSMS, if yes, turning to step 705, otherwise, turning to step 719;

step 705: turning to step 706 when JJ is 1;

step 706:

BSDATA [ LS +1-II ] [ JJ ] ═ TBORIDATA [ LS +1-II ] [ JJ ] -TBORIDATA [ RS + II-1] [ JJ ], BLDATA [ LS +1-II ] [ JJ ] ═ TBORIDATA [ RS + II-1] [ JJ ], go to step 707;

step 707: judging whether JJ > FM is established, if yes, turning to step 709, otherwise, turning to step 708;

step 708: step 706 is executed if JJ is JJ + 1;

step 709: judging whether II is more than 2 × Δ LM, if yes, turning to step 711, otherwise, turning to step 710;

step 710: turning to step 705 when II is equal to II + 1;

step 711: RE-2 × Δ LM, RS-2 × Δ LM, and II-1, go to step 712;

step 712: step 713 is executed if JJ is 1;

step 713:

TBORIDATA [ RS-1+ II ] [ JJ ] ═ TBORIDATA [ RS-1+ II ] [ JJ ] -BSDATA [ LS-II +1] [ JJ ], go to step 714;

step 714: judging whether JJ > FM is established, if yes, turning to a step 716, otherwise, turning to a step 715;

step 715: step 713 is executed if JJ is JJ + 1;

step 716: judging whether II is more than 2 × Δ LM, if yes, turning to step 718, otherwise, turning to step 717;

step 717: turning to step 712 if II is II + 1;

step 718: e, LE +2 Δ LM, LS +2 Δ LM, and II is 1, go to step 704;

step 719: LS ═ LSMS, RS ═ LLMS + Δ LM, go to step 720;

step 720: step 721, if JJ is 1;

step 721:

BSDATA [ LS +1-II ] [ JJ ] ═ TBORIDATA [ LS +1-II ] [ JJ ] -TBORIDATA [ RS + II-1] [ JJ ], BLDATA [ LS +1-II ] [ JJ ] ═ TBORIDATA [ RS + II-1] [ JJ ], go to step 722;

step 722: judging whether JJ > FM is established, if yes, turning to step 724, otherwise, turning to step 723;

step 723: JJ +1, go to step 721;

step 724: judging whether II is more than LS-LE, if yes, turning to step 726, otherwise, turning to step 725;

step 725: turning to step 720 if II is II + 1;

step 726: RE-2 × Δ LM, RS ═ LLMS, II ═ 1, go to step 727;

step 727: turning to step 728 when JJ is equal to 1;

step 728:

BLDATA [ RS-1+ II ] [ JJ ] ═ TBORIDATA [ RS-1+ II ] [ JJ ] -BSDATA [ LS-II +1] [ JJ ], go to step 729;

step 729: judging whether JJ > FM is established, if yes, turning to step 731, otherwise, turning to step 730;

step 730: if JJ is JJ +1, go to step 728;

step 731: judging whether II is more than LS-LE, if yes, turning to step 733, otherwise, turning to step 732;

step 732: turning to step 727 when II is equal to II + 1;

step 733: LS ═ LSME, LE ═ LSMS, RE ═ LSMS + Δ LM, RS ═ RE + LSMS-LSME, II ═ 1, go to step 734;

step 734: turning to step 735 if JJ is 1;

step 735: BLDATA [ LS +1-II ] [ JJ ] ═ TBORIDATA [ RS-1+ II ] [ JJ ], go to step 736;

step 736: judging whether JJ > FM is established, if yes, turning to step 738, otherwise, turning to step 737;

step 737: step 735 if JJ is JJ + 1;

step 738: judging whether II is more than LS-LE, if yes, turning to step 740, otherwise, turning to step 739;

step 739: turning to step 734 when II is equal to II + 1;

step 740: and outputting short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ].

Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.

Claims

1. An automatic testing and analyzing method for strain distribution of an optical fiber hydrophone is characterized by comprising the following steps:

2. The method for automatically testing and analyzing the strain distribution of the fiber optic hydrophone of claim 1, wherein in step S02, in the process of remotely setting the parameters of the fiber optic strain distribution tester, the spatial resolution is set to a minimum value, the span value is set to a minimum value larger than the sum of the length of the long interference arm of the fiber optic hydrophone and 100m, the sampling resolution is set to a minimum value, the start frequency is set to a minimum value, the frequency interval is set to a minimum value, and the end frequency is set to a maximum value.

3. The method for automatically testing and analyzing the strain distribution of the fiber optic hydrophone according to claim 2, wherein in step S03, the strain distribution test data further includes strain data point numbers, frequency data point numbers, raw strain data and distance data.

4. The method for automatically testing and analyzing the strain distribution of the optical fiber hydrophone as claimed in claim 3, wherein in step S04, the strain data total fiber length, the interference arm reflector position and the long interference arm reflector position are obtained by the following specific processes:

step S401: reading original Brillouin distribution data, distance data, the length of a long interference arm of an optical fiber hydrophone, the length of a transmission part optical fiber, spatial resolution, sampling resolution, initial frequency, frequency interval and termination frequency, setting initial values of counting variables to be 1, setting initial values of temporary Brillouin data, central frequency data, an effective mark, Brillouin spectrum intensity data, Brillouin spectrum frequency data and noise intensity to be 0,

step S402: calculating temporary Brillouin data according to the original Brillouin distribution data;

step S403, calculating an effective mark according to the temporary Brillouin data;

step S404: rounding up the calculation judgment threshold, and if the calculation judgment threshold is less than 3, taking the calculation judgment threshold as 3; setting the value of a counting variable as the number of points of strain data, and setting the initial value of BGSPUNUM as 0;

step S405: judging whether BGSPU [ II ] is larger than the fiber end judgment threshold, if yes, directly entering step S409, otherwise, entering step S406;

step S406, when BGSPUNUM is 0, the step S4010 is carried out;

step S407, judging whether the counting variable is less than 2, if so, directly marking the index of the optical fiber length as 0, otherwise, subtracting 1 from the counting variable and then executing the step S405;

step S408: assigning the value of the short interference arm reflector position L to be 0, assigning the value of the long interference arm reflector position LLM to be 0, and entering the step S4011;

step S409: setting BGSPUNUM as BGSPUNUM + 1;

step S4010, setting BGSPUNUM larger than the calculation judgment threshold;

and S4011, when the subscript of the optical fiber length is equal to the counting variable, calculating the position of the short interference arm reflector and the position of the long interference arm reflector according to the effective mark, and outputting the optical fiber length, the position of the short interference arm reflector and the position of the long interference arm reflector.

5. The method for automatically testing and analyzing the strain distribution of the optical fiber hydrophone as claimed in claim 4, wherein the specific process of the step S402 is as follows:

step S40201: reading original Brillouin distribution data and sampling resolution, setting initial values of counting variables to be 1, setting initial values of noise intensity to be 0, initializing temporary Brillouin data, and setting a noise count NOISENUM to be 100 m/DR;

step S40202: calculating average noise

NOISEAVE＝NOISEAVE+BORIDATA[OSI][SN-II+1][JJ]；

Step S40203: judging whether the counting variable is larger than the frequency data point number, if so, outputting the counting variable as 1 and then executing the step S40204, otherwise, adding 1 to the counting variable and then switching to the step S40202;

step S40204: judging whether the counting variable is larger than the noise count, if so, outputting average noise NOISEAVE ═ NOISEAVE/NOISENUM, then executing step S40205, otherwise, adding 1 to the counting variable, and then switching to step S40202;

step S40205: the design number variables are all 1;

step S40206: temporary brillouin data BDATA [ II ] [ JJ ] ═ original brillouin data BORIDATA [ OSI ] [ II ] [ JJ ] -, average noise noiseive;

step S40207: judging whether the counting variable is larger than the frequency data point number, if so, outputting the counting variable as 1 and then executing a step S40208, and if not, adding 1 to the counting variable and then switching to the step S40206;

step S40208: and judging whether the counting variable is larger than the number of the strain data points, if so, directly outputting temporary Brillouin data, and if not, adding 1 to the counting variable and then, turning to the step S40206.

6. The method for automatically testing and analyzing the strain distribution of the optical fiber hydrophone as claimed in claim 4, wherein the concrete process of the step S403 is as follows:

step S40301: reading temporary Brillouin data, setting initial values of count variables to 1, initial values of VMAX [1 to SN ] and VAVE [1 to SN ] to 0,

step S40302 sets VMAX [ II ] ═ BDATABDATA [ II ] [ JJ ], VAVE [ II ] ═ 0;

step S40303: judging whether VMAX [ II ] is larger than BDATABDATA [ II ] [ JJ ], if yes, firstly setting VMAX [ II ] ═ BDATABDATA [ II ] [ JJ ], and then executing step S40304, otherwise, directly executing step S40304;

step S40304: setting VAVE [ II ] + BDATABDATA [ II ] [ JJ, judging whether the counting variable is larger than the frequency data point number, if yes, executing the step S40305, and if not, adding 1 to the counting variable and then switching to the step S40303;

step S40305: setting VAVE [ II ] as VAVE [ II ]/FM, judging whether the counting variable is larger than the number of the strain data points, if so, directly executing the step S40306, otherwise, adding 1 to the counting variable and then switching to the step S40302;

step S40306: initializing temporary variable maxvvmax ═ 0, MAVVAVE ═ 0, II ═ 1, initializing temporary variable MAXVMAX ═ VMAX [ II ], MAXVAVE ═ VAVE [ II ];

step S40307: judging whether MAXVMAX is larger than VMAX [ II ], if so, setting MAXVMAX to VMAX [ II ], and executing step S40308, otherwise, directly executing step S40308;

step S40308: judging whether MAXVAVE is larger than VAVE [ II ], if yes, setting MAXVAVE as VAVE [ II ] and then executing step S40309, otherwise, directly executing step S40309;

step S40309: judging whether the counting variable is larger than the number of the strain data points, if so, executing a step S40310, and if not, adding 1 to the counting variable and then switching to a step S40307;

step S40310: initializing effective marks BGSPU [1 to SN ] to be 0, and setting II to be 1;

step S40311: BGSPU [ II ] ═ VMAX [ II ]/MAXVMAX VAVE [ II ]/MAXVAVE;

step S40312: and judging whether the counting variable is larger than the number of the strain data points, if so, directly outputting an effective mark, and otherwise, adding 1 to the counting variable and then transferring to a step S40311.

7. The method for automatically testing and analyzing the strain distribution of the fiber optic hydrophone according to claim 4, wherein in step S4011, the calculation of the LSM and LLM positions of the short-interference arm reflectors and the long-interference arm reflectors according to the valid markers comprises the following specific steps:

step S401101: reading BGSPU [1 to SN ], distance data LDATA [ OSI ] [1 to SN ], fiber length SL, initializing counting variables II equal to 1 and PTEMP equal to 1, initializing a short interference arm reflector position LSM, wherein the LSM comprises a starting position LSMS, an ending position LSME and a long interference arm reflector position LLM, and the LLM comprises a starting position LLMS and an ending position LLME;

step S401102: judging whether BGSPU [ II ] is greater than or equal to 0.9, if yes, executing step S401105, otherwise, executing step S401103;

step S401103: judging whether II is more than SN, if yes, executing step S401139, otherwise executing step S401104;

step S401104: II +1, step S401102 is performed;

step S401105: initializing JJ ═ 0, LNUM ═ 0;

step S401106: judging whether BGSPU [ II + JJ ] is greater than or equal to 0.9, if yes, executing step S401107, otherwise, executing step S401110;

step S401107: LNUM ═ LNUM + 1;

step S401108: judging whether II + JJ > SN is true, if yes, executing step S40110, otherwise, executing step S40109;

step S401109: step S401106 is performed if JJ is JJ + 1;

step S401110: judging whether LNUM & gtSLTH is established, if yes, executing step S401111, otherwise, turning to step S401108;

step S401111: PTEMP ═ II + JJ;

step S401112: judging whether BGSPU [ II ] -BGSPU [ II-1] < 0 is true, if true, executing step S401115, otherwise executing step S401113;

step S401113: judging whether II is more than 2, if so, executing step S401114, otherwise, executing step S401139;

step S401114: if II is II-1, the process proceeds to step S401112;

step S401115: LSMS ═ II;

step S401116: II is PTEMP;

step S401117: judging whether BGSPU [ II ] -BGSPU [ II ] < 0 is true, if true, executing step S401120, otherwise, executing step S401118;

step S401118: judging whether II is less than SN-1, if so, executing step S401119, otherwise, executing step S401139;

step S401119: II + 1;

step S401120: LSME ═ II;

step S401121: judging whether BGSPU [ II ] is equal to or larger than 0.9, if yes, executing step S401124, otherwise, executing step S401122;

step S401122: judging whether II is more than SN, if yes, executing step S401139, otherwise, executing step S401123;

step S401123: if II is II +1, the process proceeds to step S401121;

step S401124: initializing JJ ═ 0, LNUM ═ 0;

step S401125: judging whether BGSPU [ II + JJ ] is greater than or equal to 0.9, if so, executing step S401126, otherwise, executing step S401129;

step S401126: LNUM ═ LNUM +1

Step S401127: judging whether II + JJ > SN is true, if yes, executing step S401129, otherwise, executing step S401128;

step S401128: JJ is JJ + 1;

step S401129: judging whether LNUM > SLTH is satisfied, if so, executing step S401130, otherwise, executing step S401127;

step S401130: PTEMP ═ II + JJ;

step S401131: judging whether BGSPU [ II ] -BGSPU [ II-1] < 0 is true, if true, executing step S401134, otherwise executing step S401132;

step S401132: judging whether II is more than 2, if so, executing step S401133, otherwise, executing step S401139;

step S401133: II is II-1;

step S401134: LLMS ═ II;

step S401135: II is PTEMP;

step S401136: judging whether BGSPU [ II ] -BGSPU [ II ] < 0 is established, if so, executing step S401140, otherwise, executing step S401137;

step S401137: judging whether II is less than SN-1, if yes, executing step S401138, otherwise, executing step S401139;

step S401138: II + 1;

step S401139: if the calculated data is wrong, the LSM value is 0, namely LSMS is 0, and LSME is 0; the LLM value is 0, namely LLMS is 0 and LLME is 0;

step S401140: LSME ═ II;

step S401141: and outputting the LSM and the LLM.

8. The method for automatically testing and analyzing the strain distribution of the optical fiber hydrophone as claimed in claim 1, wherein in step S06, the strain data of the long interference arm and the strain data of the short interference arm are obtained by the following specific processes:

step S601: taking BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], SORIDATA [ OSI ] [ 1-SN ], long interference arm length LL [ OSI ], short interference arm length LS [ OSI ], transmission portion fiber length L0[ OSI ], fiber length SL, interference arm mirror position LSM, and long interference arm mirror position LLM;

step S602: judging whether LLMS is not less than 2 and LSMS is true, if yes, executing step S603, otherwise, executing step S604;

step S603: performing redundant single reflection mirror Brillouin scattering spectrum reconstruction on BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the optical fiber length SL, the short interference arm mirror position LSM and the long interference arm mirror position LLM to construct short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ], and executing step S607;

step S604: judging whether 3 LSMS is less than or equal to 2 LLMS, if yes, executing step S605, otherwise, executing step S606;

step S605: performing redundancy-free single-reflection mirror image Brillouin scattering spectrum reconstruction on BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the optical fiber length SL, the short interference arm reflector position LSM and the long interference arm reflector position LLM to construct short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ], turning to step 601 in detail;

step S606: performing multiple reflection mirror image Brillouin scattering spectrum reconstruction on BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], the optical fiber length SL, the short interference arm reflector position LSM and the long interference arm reflector position LLM to construct short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] in step 701, and executing step S607;

step S607: analyzing the short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] according to a Brillouin scattering spectrum strain demodulation algorithm to obtain short interference arm strain data SSDATA [ OSI ] [ 1-SN ], and executing step S08;

step S608: analyzing the long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] according to a Brillouin scattering spectrum strain demodulation algorithm to obtain long interference arm strain data SSDATA [ OSI ] [ 1-SN ], and executing step S09;

step S609: and outputting strain data SSDATA [ OSI ] [1 to SN ] of the long interference arm and strain data SSDATA [ OSI ] [1 to SN ] of the short interference arm.

9. The method for automatically testing and analyzing the strain distribution of the optical fiber hydrophone as claimed in claim 8, wherein the concrete process of the step S603 is as follows:

step S60301: reading BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], a long interference arm length LL [ OSI ], a short interference arm length LS [ OSI ], a transmission portion fiber length L0[ OSI ], a fiber length SL, an interference arm mirror position LSM, and a long interference arm mirror position LLM;

step S60302: initializing short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] to be 0, initializing long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] to be 0, and setting II to be 1;

step S60303: JJ is 1;

step S60304:

BSDATA[LSMS+1-II][JJ]＝BORIDATA[OSI][LSMS+1-II][JJ]-BORIDATA[OSI][2*LLMS-LSMS+II-1][JJ]；

step S60305: judging whether JJ > FM is true, if true, executing step S60307, otherwise executing step S60306;

step S60306: JJ is JJ + 1;

step S60307: judging whether II is greater than LSMS, if so, executing step S60309, otherwise, executing step S60308;

step S60308: if II is II +1, the process proceeds to step S60303;

step S60309: II is 1;

step S60310: JJ is 1;

step S60311:

BLDATA[LSME+1-II][JJ]＝BORIDATA[OSI][2*LLMS-LSME+II-1][JJ]；

step S60312: judging whether JJ > FM is true, if yes, executing step S60314, otherwise executing step S60313;

step S60313: JJ is JJ + 1;

step S60314: judging whether II is greater than LSME, if so, executing step S60316, otherwise, executing step S60315;

step S60315: II + 1;

step S60316: II is 1;

step S60317: JJ is 1;

step S60318:

BLDATA[LSME+II][JJ]＝BORIDATA[OSI][LSME+II][JJ]-BSDATA[OSI][2*LSMS-LSME-II][JJ]；

step S60319: judging whether JJ > FM is true, if true, executing step S60321, otherwise executing step S60320;

step S60320: step S60318 if JJ is JJ + 1;

step S60321: judging whether II is more than 2LSMS-LSME-1, if yes, executing step S60323, otherwise, executing step S60322;

step S60322: if II is II +1, the process proceeds to step S60317;

step S60323: II is 1;

step S60324: JJ is 1;

step S60325: BLDATA [2 × LSME + II ] [ JJ ] ═ BORIDATA [ OSI ] [2 × LSME + II ] [ JJ ];

step S60326: judging whether JJ > FM is true, if true, executing step S60328, otherwise executing step S60327;

step S60327: step S60325 if JJ is JJ + 1;

step S60328: judging whether II is more than LLMS-2LSMS, if so, executing a step S60330, otherwise, executing a step S60329;

step S60329: if II is II +1, the process proceeds to step S60324;

step S60330: and outputting short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ].

10. The method for automatically testing and analyzing the strain distribution of the optical fiber hydrophone as claimed in claim 8, wherein the concrete process of the step S605 is as follows:

step S60501: reading BORIDATA [ OSI ] [ 1-SN ] [ 1-FM ], a long interference arm length LL [ OSI ], a short interference arm length LS [ OSI ], a transmission portion fiber length L0[ OSI ], a fiber length SL, an interference arm mirror position LSM, and a long interference arm mirror position LLM;

step S60502: initializing short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] to be 0, initializing long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ] to be 0, and setting II to be 1;

step S60503: JJ is 1;

step S60504:

step S60505: judging whether JJ > FM is true, if yes, executing step S60507, otherwise executing step S60506:

step S60506: step S60504 if JJ is JJ + 1;

step S60507: judging whether II is greater than LSMS, if so, executing step S60509, otherwise, executing step S60508;

step S60508: if II is II +1, the process proceeds to step S60503;

step S60509: II is 1;

step S60510: JJ is 1;

step S60511:

BLDATA[LSME+1-II][JJ]＝BORIDATA[OSI][2*LLMS-LSME+II-1][JJ]；

step S60512: judging whether JJ > FM is true, if yes, executing step S60514, otherwise executing step S60513;

step S60513: step S60511 if JJ is JJ + 1;

step S60514: judging whether II is more than LSME, if so, executing step S60516, otherwise, executing step S60515;

step S60515: if II is II +1, the process proceeds to step S60510;

step S60516: II is 1;

step S60517: JJ is 1;

step S60518:

BLDATA[LSME+II][JJ]＝BORIDATA[OSI][LSME+II][JJ]-BSDATA[OSI]

[2*LSMS-LSME-II][JJ]；

step S60519: judging whether JJ > FM is true, if yes, executing step S60521, otherwise, executing step S60520;

step S60520: step S60518 if JJ is JJ + 1;

step S60521: judging whether II is more than LLMS-LSME-1, if so, executing a step S60523, otherwise, executing a step S60522;

step S60522: if II is II +1, the process proceeds to step S60517;

step S60523: and outputting short interference arm Brillouin spectrum data BSDATA [ 1-SN ] [ 1-FM ] and long interference arm Brillouin spectrum data BLDATA [ 1-SN ] [ 1-FM ].