CN116086645A - Temperature measurement method applied to optical fiber Raman distributed system - Google Patents
Temperature measurement method applied to optical fiber Raman distributed system Download PDFInfo
- Publication number
- CN116086645A CN116086645A CN202310368462.8A CN202310368462A CN116086645A CN 116086645 A CN116086645 A CN 116086645A CN 202310368462 A CN202310368462 A CN 202310368462A CN 116086645 A CN116086645 A CN 116086645A
- Authority
- CN
- China
- Prior art keywords
- raman
- temperature
- light intensity
- intensity value
- length
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
- G01K11/324—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres using Raman scattering
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Abstract
The application relates to the field of temperature measurement in optical fiber sensing, and provides a temperature measurement method applied to an optical fiber Raman distributed system, which comprises the following steps: determining the length of the abnormal temperature zone according to the length of the target zone and the length of the optical pulse signal; calculating a first Raman light intensity value excited by the optical pulse signal at the first temperature and the second temperature based on the length relation between the optical pulse signal and the abnormal temperature region, the first temperature and the second temperature at the first moment; fitting to obtain a second Raman light intensity value based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval; subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference; transforming the first Raman light intensity difference to obtain a second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal; and based on the second Raman light intensity difference, obtaining a reconstructed Raman signal, and further obtaining the temperature of the abnormal temperature region.
Description
Technical Field
The application relates to the field of temperature measurement in optical fiber sensing, in particular to a temperature measurement method applied to an optical fiber Raman distributed system.
Background
The optical fiber Raman distributed system can realize distributed measurement of a temperature field based on an optical time domain reflection technology and a temperature effect of back Raman scattering in the optical fiber. Compared with the traditional temperature sensor, the optical fiber Raman distributed system has the advantages of electromagnetic interference resistance, high temperature and high pressure resistance, wide temperature detection range, easiness in laying and the like, and is widely applied to the fields of oil pipeline leakage monitoring, cable temperature monitoring, high-temperature oil well temperature monitoring and the like.
In a fiber raman distributed system, spatial resolution is an important indicator of temperature measurement, meaning the minimum fiber length required to be able to achieve accurate measurement of ambient temperature. When the length of the optical fiber laid in the temperature change region is smaller than the spatial resolution, the optical fiber raman distributed system may not accurately measure the temperature change of the region. In general, the pulse width of the incident light is compressed, so that the spatial resolution can be improved, and the temperature measurement precision is improved. However, lasers with the ability to compress the pulse width of the incident light are expensive and costly to apply, and compressing the pulse width of the incident light also results in a lower intensity of the incident light, affecting the signal-to-noise ratio of the fiber raman distributed system.
In view of the foregoing, there is a need for a method for improving the temperature measurement accuracy in a fiber raman distributed system without reducing the pulse width in the case of low spatial resolution.
Disclosure of Invention
The application provides a temperature measurement method applied to an optical fiber Raman distributed system, which is used for solving the problem of low temperature measurement precision caused by low spatial resolution in the optical fiber Raman distributed system.
A first aspect of the present application provides a temperature measurement method applied to an optical fiber raman distributed system, the optical fiber raman distributed system including a sensing optical fiber in which an optical pulse signal is transmitted to generate a raman signal, wherein when the optical pulse signal passes through an abnormal temperature region in the sensing optical fiber, an optical intensity of the raman signal is affected to be increased, the method comprising:
determining a target interval in which the light intensity value in the Raman signal is increased, and determining the length of an abnormal temperature zone according to the length of the target interval and the length of the optical pulse signal;
calculating a first Raman light intensity value excited by the optical pulse signal at a first temperature and a second temperature based on the lengths of the optical pulse signal and the abnormal temperature region, the first temperature and the second temperature at a first moment, wherein the optical pulse signal completely covers the abnormal temperature region at the first moment, the first temperature is the temperature of the abnormal temperature region, and the second temperature is the temperature around the abnormal temperature region;
fitting to obtain a second Raman light intensity value excited by the target interval at a second temperature based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval;
subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone;
transforming the first Raman light intensity difference based on the length relation between the abnormal temperature area and the optical pulse signal in the target area to obtain a second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal;
obtaining a reconstructed Raman signal based on the second Raman light intensity value and the second Raman light intensity difference;
demodulating the reconstructed Raman signal based on a preset demodulation formula of the Raman signal and the temperature to obtain the temperature of the abnormal temperature region.
In one embodiment, determining the length of the abnormal temperature region according to the length of the target zone and the length of the optical pulse signal includes:
and subtracting the length of the target interval from the length of the optical pulse signal to obtain the length of the abnormal temperature region.
In one embodiment, at a first time, calculating a first raman intensity value of the optical pulse signal excited at the first temperature and the second temperature based on a length relationship between the optical pulse signal and the abnormal temperature region, the first temperature, and the second temperature includes:
at a first moment, determining the length of the optical pulse signal in an abnormal temperature zone and the length of the optical pulse signal outside the abnormal temperature zone;
obtaining first Raman optical power based on the length of the optical pulse signal in the abnormal temperature region and the first temperature, and obtaining second Raman optical power based on the length of the optical pulse signal outside the abnormal temperature region and the second temperature; the first Raman optical power represents the Raman optical power of the optical pulse signal in the abnormal temperature region, and the second Raman optical power represents the Raman optical power of the optical pulse signal outside the abnormal temperature region;
and adding the first Raman optical power and the second Raman optical power to obtain a first Raman light intensity value.
In one manner of implementation, fitting the second raman intensity value of the target interval excited at the second temperature based on the raman intensity value of the first acquisition point of the rising edge and the raman intensity value of the last acquisition point of the falling edge of the target interval includes:
determining a third raman intensity value representing a raman intensity value of the first collection point and a fourth raman intensity value representing a raman intensity value of the last collection point based on the second temperature;
and taking the average value of the third Raman light intensity value and the fourth Raman light intensity value to obtain a second Raman light intensity value excited by the target interval at the second temperature.
In one embodiment, the method includes transforming the first raman light intensity difference based on a relationship between a length of an abnormal temperature region and a length of an optical pulse signal in a target region to obtain a second raman light intensity difference excited by a first temperature and a second temperature of the optical pulse signal, where the second raman light intensity difference comprises:
determining the ratio of the length of the abnormal temperature region to the length of the optical pulse signal, multiplying the ratio by the first Raman light intensity difference, and converting the first Raman light intensity difference to obtain a second Raman light intensity difference.
In one manner of implementation, the step of obtaining the reconstructed raman signal based on the second raman intensity value and the second raman intensity difference comprises:
and adding the second Raman light intensity value and the second Raman light intensity difference to obtain a reconstructed Raman signal.
In one embodiment, the method includes demodulating the reconstructed raman signal based on a demodulation formula of a preset raman signal and a temperature to obtain a temperature of an abnormal temperature region, where the demodulation formula of the temperature is:
wherein, the liquid crystal display device comprises a liquid crystal display device,
for the first temperature, +.>
At a second temperature, +.>
Is Boltzmann constant, & gt>
Is Planck constant, +.>
For Raman frequency shift amount, < >>
Is the Raman Anti-stokes light intensity value,/->
Is Stokes light intensity value, and the Anti-Stokes light intensity value and Stokes light intensity value form Raman signal, ">
And->
For the second Raman intensity difference, +.>
And->
Is the second raman intensity value. />
A second aspect of the present application provides a temperature measurement system for use in a fiber raman distributed system, for use in the aforementioned method, the fiber raman distributed system comprising a sensing fiber in which an optical pulse signal is transmitted to generate a raman signal, wherein when the optical pulse signal passes through an abnormal temperature region in the sensing fiber, the intensity of the raman signal is affected to increase, the system comprising:
a determining unit for determining a target interval in which the light intensity value in the raman signal is raised, and determining the length of the abnormal temperature zone according to the length of the target interval and the length of the optical pulse signal;
the Raman light intensity value calculation unit is used for calculating a first Raman light intensity value excited by the optical pulse signal at the first temperature and the second temperature based on the length relation between the optical pulse signal and the abnormal temperature region, the first temperature and the second temperature at the first moment, wherein the optical pulse signal completely covers the abnormal temperature region at the first moment, the first temperature is the temperature of the abnormal temperature region, and the second temperature is the temperature around the abnormal temperature region;
the fitting unit is used for fitting to obtain a second Raman light intensity value of the target interval excited at the second temperature based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval;
the first Raman light intensity difference calculation unit is used for subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone;
the second Raman light intensity difference calculation unit is used for converting the first Raman light intensity difference based on the length relation between the abnormal temperature area and the optical pulse signal in the target interval to obtain a second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal;
a reconstructed Raman signal unit, configured to obtain a reconstructed Raman signal based on the second Raman light intensity value and the second Raman light intensity difference;
and the demodulation unit is used for demodulating the reconstructed Raman signal based on a preset demodulation formula of the Raman signal and the temperature to obtain the temperature of the abnormal temperature zone.
A third aspect of the present application provides a computer device comprising a memory storing a computer program and a processor implementing the aforementioned method when executing the computer program.
A fourth aspect of the present application provides a computer storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the method described above.
Advantageous effects
The optical fiber raman distributed system includes a sensing optical fiber in which an optical pulse signal is transmitted, the optical pulse signal being capable of generating a raman signal, and when the optical pulse signal passes through an abnormal temperature zone in the sensing optical fiber, the optical intensity of the raman signal is influenced to rise, so that a target zone in which the optical intensity value in the raman signal rises is first determined, and the length of the abnormal temperature zone is determined according to the length of the target zone and the length of the optical pulse signal. Next, at a first time instant, a first raman intensity value of the optical pulse signal excited at the first temperature and the second temperature is calculated based on a length relationship of the optical pulse signal and the abnormal temperature region, the first temperature, and the second temperature. Thus, a second raman intensity value of the target interval excited at the second temperature is fitted based on the raman intensity value of the first acquisition point of the rising edge and the raman intensity value of the last acquisition point of the falling edge of the target interval. Then, the first Raman light intensity value and the second Raman light intensity value are subtracted to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone. In addition, based on the relation between the length of the abnormal temperature zone and the length of the optical pulse signal in the target zone, the first Raman light intensity difference is transformed, and the second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal is obtained. And finally, based on the second Raman light intensity value and the second Raman light intensity difference, obtaining a reconstructed Raman signal, and demodulating the reconstructed Raman signal by utilizing a preset demodulation formula of the Raman signal and the temperature to obtain the temperature of the abnormal temperature region.
According to the method, the temperature of the abnormal temperature region can be obtained by the reconstructed Raman signal under the condition that the pulse width is not reduced, the temperature measurement precision and the spatial resolution of the system are improved, and the complexity of the system and the hardware cost of the system are not required to be increased.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a temperature measurement method applied to a fiber Raman distributed system;
FIG. 2 is a schematic diagram of a target interval length of a temperature measurement method applied to a fiber Raman distributed system;
FIG. 3 is a schematic diagram of optical pulse signal transmission applied to a temperature measurement method of a fiber Raman distributed system;
FIG. 4 is a flow chart of the extraction of abnormal temperature zone information for a temperature measurement method applied to a fiber Raman distributed system;
FIG. 5 is a flow chart of fitting a temperature measurement method applied to a fiber Raman distributed system to obtain a second Raman light intensity value;
FIG. 6 is a schematic diagram of a temperature measurement method applied to a fiber Raman distributed system;
FIG. 7 is a graph of Raman Stokes signal intensity for a temperature measurement method applied to a fiber Raman distributed system;
fig. 8 is a graph of raman Anti-stokes signal intensity for a temperature measurement method applied to a fiber raman distributed system.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments.
All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention. The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. Furthermore, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In embodiments of the invention, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.
The following examples merely illustrate specific embodiments of the invention, which are described in greater detail and are not to be construed as limiting the scope of the invention.
It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.
For convenience in describing the technical solutions of the present application, some concepts related to the present application will be described below in the following, which is specifically described as follows:
the light pulse signal is a light signal generated by the light source which emits light intermittently at a certain time interval, and the light source emits light each time to generate a light pulse signal.
Pulse width refers to the time scale corresponding to the width of the full width at half maximum of a single optical pulse signal of gaussian energy distribution.
Stokes, stokes line, refers to a spectral line generated when the frequency of scattered light is lower than the frequency of incident light in raman spectrum.
Anti-stokes, an Anti-stokes line, refers to a spectral line with a frequency greater than the frequency of the incident light.
One way to increase the spatial resolution for fiber raman distributed systems is to compress the pulse width of the light. However, the width disadvantage of compressed light pulses is more pronounced, for example: lasers capable of compressing light pulses are expensive, increasing costs, and shortening of the light pulses can reduce the intensity of the incident light, affecting the signal-to-noise ratio of the system.
In addition, the spatial resolution can be improved by a light source modulation method, a deconvolution algorithm, a double pulse modulation method, a ramp assist method, or the like, but the above methods have drawbacks, for example:
the light source modulation method belongs to the mode of replacing the laser, and is high in price and high in cost.
The deconvolution algorithm corrects the whole optical fiber signal, which leads to a significant degradation of the optical fiber signal-to-noise ratio at normal temperature, and the bandwidth in the optical fiber raman distributed system is not infinite, that is, the system measures a set of temperature points instead of a continuous temperature curve, and then fits the temperature curve according to the measured temperature points. However, the fitting process by deconvolution involves a large number of arithmetic calculations, and delays are easily formed, resulting in no guarantee of real-time.
The double pulse modulation method needs to add a pulse light source and an optical switch for controlling the pulse light source on the existing optical fiber Raman distributed system, and forms optical pulses by utilizing the combined action of the existing pulse light source and the added pulse light source, wherein the difference value of the two optical pulses needs to be controlled to be 0.1ns nanosecond. However, there is a great difficulty in modulating the device for this difference. In addition, fluctuations in the optical power of the pulsed light source, optical attenuation at the optical switch, etc., can cause considerable interference with the difference in the back Anti-Stokes (Anti-Stokes) signals generated by the two pulsed light sources.
The slope assist method has the following disadvantages: the slope equation needs to be re-fitted when the fiber temperature outside the abnormal temperature region changes. In practical applications, the ramp down edge is not linear due to the limitation of the system bandwidth, so that if the ramp coefficient of the down edge is carelessly valued, a relatively large temperature error is caused.
Based on the above reasons, the application provides a temperature measurement method applied to an optical fiber Raman distributed system, which can improve the temperature measurement precision of the optical fiber Raman distributed system to the ambient temperature under the condition that the spatial resolution is insufficient and the pulse width is not reduced. The application discloses a temperature measurement method applied to an optical fiber Raman distributed system.
The optical fiber Raman distributed system comprises a sensing optical fiber, wherein an optical pulse signal is transmitted in the sensing optical fiber so as to generate a Raman signal. When the optical pulse signal passes through an abnormal temperature region in the sensing fiber, the light intensity of the raman signal is affected to rise.
As shown in fig. 1, the method includes:
s100: and determining a target interval in which the light intensity value in the Raman signal is increased, and determining the length of the abnormal temperature zone according to the length of the target interval and the length of the optical pulse signal.
In some embodiments, the length of the target interval may be determined from the change in the rise in the intensity value of the raman signal.
As shown in fig. 2, the raman signal enters the target zone from the start point, forms a rising edge in the target zone, increases the light intensity value, then decreases the light intensity value after the light intensity value is maintained for a certain period of time, and leaves the target zone at the end point of the falling edge. The target interval is the length between the start point and the end point.
In the present application, the length of the optical pulse signal refers to the length of the optical pulse signal generated by the light source (e.g., laser) in the optical fiber. The longer the pulse width of the optical pulse signal is, the longer the length of the optical pulse signal is, the smaller the pulse width of the optical pulse signal is, and the shorter the length of the optical pulse signal is.
Specifically, the length of the target zone may be subtracted from the length of the optical pulse signal to obtain the length of the abnormal temperature zone. For example, the calculation is performed by the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
for the length of the abnormal temperature zone, +.>
For the length of the target interval>
Is the length of the optical pulse signal.
S200: at a first time, a first raman intensity value of the optical pulse signal excited at the first temperature and the second temperature is calculated based on the lengths of the optical pulse signal and the abnormal temperature region, the first temperature, and the second temperature.
The first time refers to any time when the optical pulse signal completely covers the abnormal temperature region, the first temperature is the temperature of the abnormal temperature region, and the second temperature is the temperature around the abnormal temperature region.
Specifically, the first timing represents a timing at which the abnormal temperature region is completely covered by the optical pulse signal. Further, at the first moment, there may be two cases in the positional relationship between the optical pulse signal and the abnormal temperature region, where in the first case, the optical pulse signal just covers the abnormal temperature region completely; in the second case, the light pulse signal partially passes through the timing of the abnormal temperature region.
As shown in fig. 3, wherein,
this is indicated as a case where the optical pulse signal does not enter the target section. />
Indicating that the optical pulse signal portion enters the abnormal temperature region. />
Indicating that the light pulse signal just covers the abnormal temperature region, i.e. the first moment. />
Indicating that the optical pulse signal is not in the abnormal temperature region.
In FIG. 3, in
At moment, the optical pulse signal just covers the abnormal temperature area to form three position nodes which are respectively +.>
、/>
And->
，/>
Representation->
The starting position of the time-of-day light pulse signal has not passed through the abnormal temperature zone +.>
Representation of
Starting position of light pulse signal entering abnormal temperature zone at moment,/->
Representation->
The time light pulse signal is positioned at the end position of the abnormal temperature zone.
It will be appreciated that the length of the optical pulse signal in the abnormal temperature region is expressed as
The length of the optical pulse signal outside the abnormal temperature region is expressed as +.>
。
To be used for
The first case will be exemplarily described with respect to time. In the first case, two temperatures exist in the area where the optical pulse signal is located, and the two temperatures include a first temperature and a second temperature. For example, in->
At the moment +.>
Length of optical pulse signal outside abnormal temperature zone at second temperature +.>
。
To be used for
For example, as shown in fig. 4, in some embodiments, step S200 may include the following steps S201 to S203.
S201: at a first time, a length of the optical pulse signal within the abnormal temperature region and a length of the optical pulse signal outside the abnormal temperature region are determined.
S202: and obtaining the first Raman optical power based on the length of the optical pulse signal in the abnormal temperature region and the first temperature, and obtaining the second Raman optical power based on the length of the optical pulse signal outside the abnormal temperature region and the second temperature.
The first Raman optical power represents the Raman optical power of the optical pulse signal in the abnormal temperature region, and the second Raman optical power represents the Raman optical power of the optical pulse signal outside the abnormal temperature region.
In particular, in
At the moment, at the first temperature, integrating the length of the optical pulse signal in the abnormal temperature region to obtain the first Raman optical power, wherein the first Raman optical power can be calculated by adopting the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
is the first raman optical power; />
Is a first temperature; />
Raman optical power generated for the optical pulse signal; />
Representing integration over length.
In addition, at
At the moment, at the second temperature, integrating the length of the optical pulse signal outside the abnormal temperature region to obtain a second Raman optical power, wherein the second Raman optical power can be calculated by adopting the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
is the second raman optical power; />
Is a temperature outside the abnormal temperature region, i.e., the second temperature.
So that the first raman light intensity value is calculated according to the first raman light power and the second raman light power in the subsequent steps.
S203: and adding the first Raman optical power and the second Raman optical power to obtain a first Raman light intensity value.
Wherein the first raman light intensity value can be calculated by the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
is the first raman light intensity value.
In this embodiment, the first raman optical power of the optical pulse signal in the abnormal temperature region and the second raman optical power of the optical pulse signal outside the abnormal temperature region are obtained respectively, and then the first raman optical power and the second raman optical power are added to obtain the first raman optical intensity value of the optical pulse signal at the first moment.
S300: and fitting to obtain a second Raman light intensity value excited by the target interval at the second temperature based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval.
The temperature of the optical pulse signal outside the target interval is not affected by the abnormal temperature region in the target interval, and can be understood to have the same temperature, that is, the sensing optical fiber outside the target interval has the second temperature.
Specifically, the raman intensity value of the first acquisition point entering the target interval and the raman intensity value of the last acquisition point forming the falling edge due to the falling of the raman intensity value of the target interval can be fitted, and the second raman intensity value excited at the second temperature can be obtained through fitting.
As shown in fig. 5, fitting to obtain the second raman light intensity value includes steps S301 and S302.
S301: a third raman intensity value and a fourth raman intensity value are determined based on the second temperature.
As shown in fig. 6, wherein the third raman intensity value represents the raman intensity value of the first acquisition point, the fourth raman intensity value represents the raman intensity value of the last acquisition point, and wherein the point a in fig. 7 represents the first acquisition point and the point B represents the last acquisition point.
Specifically, since the distance between the target intervals is short, the average value of the intensities of the first acquisition point and the last acquisition point of the rising edge of the raman signal can be used as the raman intensity fitting value of the position under the small distance scale of the target intervals.
Illustratively, as shown in FIG. 3, in
At the moment, the optical pulse signal starts to enter an abnormal temperature region, and the Raman track reaches the first acquisition point of the rising edge.
Wherein at t n At the moment, the optical pulse signal completely leaves the abnormal temperature region, and the Raman track reaches the last acquisition point of the falling edge.
Thus, at t 1 At the moment, at the second temperature
Integrating the length of the optical pulse signal of the segment to obtain a third Raman light intensity value, wherein the third Raman light intensity value is calculated by the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
is the third raman intensity value.
And, at
At the moment, at the second temperature, p ∈>
Integrating the length of the optical pulse signal of the segment to obtain a fourth Raman light intensity value, wherein the fourth Raman light intensity value is calculated by the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
is the fourth raman light intensity value.
S302: and taking the average value of the third Raman light intensity value and the fourth Raman light intensity value to obtain a second Raman light intensity value excited by the target interval at the second temperature.
Wherein the average value is calculated in the case where the third raman light intensity value and the fourth raman light intensity value are obtained, the second raman light intensity value can be calculated by the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
is a second pullManchurian intensity value->
Is->
Raman intensity values acquired at a moment, +.>
Is->
Raman intensity value acquired at time of day, < >>
Is the second temperature.
S400: and subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone.
Wherein the first raman light intensity difference at the abnormal temperature zone length can be expressed by the following formula:
s500: and transforming the first Raman light intensity difference based on the length relation between the abnormal temperature area and the optical pulse signal in the target interval to obtain a second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal.
In some embodiments, a ratio of the length of the abnormal temperature region to the length of the optical pulse signal may be determined, and the ratio may be multiplied by the first raman light intensity difference to transform the first raman light intensity difference to obtain the second raman light intensity difference.
For example, the first raman light intensity difference transform may be calculated by the following formula:
wherein, the mapping of the first Raman light intensity difference is formed by utilizing the transformation of the first Raman light intensity difference, so as to obtain the second Raman light intensity difference according to the mapped first Raman light intensity difference. And then, reconstructing the Raman signal by using the second Raman light intensity difference.
S600: and obtaining a reconstructed Raman signal based on the second Raman light intensity value and the second Raman light intensity difference.
In some embodiments, the second raman light intensity value and the second raman light intensity difference may be added to obtain a reconstructed raman signal, which may be specifically calculated by the following formula:
s700: demodulating the reconstructed Raman signal based on a preset demodulation formula of the Raman signal and the temperature to obtain the temperature of the abnormal temperature region.
In some embodiments, the raman signal may be comprised of a raman Stokes signal and a raman Anti-Stokes signal. And respectively reconstructing a Raman Stokes signal and a Raman Anti-Stokes signal by using a formula for reconstructing the Raman signal, so as to obtain the Raman signal.
The demodulation formula for temperature can be calculated by the following formula:
wherein, the liquid crystal display device comprises a liquid crystal display device,
for the first temperature, +.>
At a second temperature, +.>
Is Boltzmann constant, & gt>
Is Planck constant, +.>
For Raman frequency shift amount, < >>
Is the intensity value of the Raman Anti-stokes signal, < >>
Is the intensity value of the raman Stokes signal, < >>
And
for the second Raman intensity difference, +.>
And->
Is the second raman intensity value.
According to the technical scheme provided by the embodiment, the temperature point with inaccurate temperature measurement caused by the fact that the spatial resolution of the optical fiber Raman distributed system is not met in the target zone can be corrected, and the accuracy of temperature measurement is improved.
Compared with a light source modulation method, a deconvolution algorithm, a double pulse modulation method or a slope auxiliary method, the method has the following advantages:
compared with a light source modulation method, the embodiment does not need to replace a laser, does not increase the cost, and can improve the temperature measurement precision and the spatial resolution of the system under the condition of not reducing the pulse width. Compared with a deconvolution algorithm, the method has the advantages that the whole signal-to-noise ratio of the optical fiber Raman distributed system is not deteriorated after the temperature measurement precision and the spatial resolution of the target interval are improved, the temperature measurement precision of other areas is not reduced, the calculated amount is lower than that of the deconvolution algorithm, and the instantaneity is ensured. Compared to the double pulse modulation method. The embodiment does not need to increase a laser and an optical switch, does not need to control a plurality of lasers to work together with the optical switch, reduces complexity and saves hardware cost. Compared with a slope auxiliary method, the method does not need to carry out a plurality of groups of functional relation formulas of experimental fit slope auxiliary coefficients and temperature in the early stage, avoids the problem that the relation formulas need to be re-fitted when the laser power and the pulse width are changed, and is simple to operate.
The following describes specific implementation of the technical solution provided in this embodiment with reference to an example.
In this example, the pulse width of the laser connected to the sensing fiber was set to 100ns (nanoseconds), 2m of the test sensing fiber was placed in a constant temperature oven at 92.13 ℃ and the remaining sensing fiber was placed at room temperature (31.31 ℃) with the interior of the oven as the target zone.
The experimental data are collected as shown in table 1.
TABLE 1
In table 1, reference numerals 3 to 34 denote raman optical data of the target zone.
Step 1: reference numerals 3 to 34 correspond to the column in fig. 7 and 8 as a target section, and if the length of the target section is 12.24m and the length of the optical pulse signal is 10m, the length of the abnormal temperature region is 2.24m.
Step 2: a group of raman optical data is selected from the sequence numbers 3 to 34, for example, the raman optical data with the sequence number 18 in table 1 is used as the first time, and at this time, the optical pulse signal already covers the abnormal temperature region, so as to obtain a first raman light intensity value: the intensity of the raman Stokes signal was 409.9595539 and the intensity of the raman Anti-Stokes signal was 301.6562625.
Step 3: fitting the Raman light intensity value of the sensing optical fiber at the position corresponding to the sequence number 18 at the temperature of 31 ℃, wherein the sequence number 2 is the first acquisition point, the sequence number 35 is the last acquisition point, and fitting the Raman light intensity values of the sequence numbers 2 and 5 to obtain a second Raman light intensity value excited by the target interval at the second temperature: the intensity of the raman Stokes signal was 401.969324 and the intensity of the raman Anti-Stokes signal was 273.7925225.
Step 4: subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone: the corresponding intensity differences of the raman Stokes signal and the raman Anti-Stokes signal were 7.99 and 27.87.
Step 5: solving a second raman light intensity difference excited by the first temperature and the second temperature at the optical pulse signal length of 10m according to the formula in step S500, wherein,
10->
The second raman intensity difference was calculated to be 2.24: the raman Stokes signal was 35.67 and the raman Anti-Stokes signal was 124.42.
Step 6: adding the second Raman light intensity value obtained in the step 3 and the second Raman light intensity difference obtained in the step 5 to obtain a reconstructed Raman signal at 90 ℃: the intensity of the raman Stokes signal was 445.63 and the intensity of the raman Anti-Stokes signal was 426.08.
Step 7: substituting the raman signal reconstructed in step 6 into the formula demodulation in step S700, wherein,
and (3) with
For the intensities of the Raman Stokes signal and the Raman Anti-Stokes signal in step 6,/the method is used for the detection of the Raman signal>
And->
Obtaining the temperature of the abnormal temperature zone for the second Raman light intensity value obtained by fitting in the third step>
Is close to the true temperature 92.13 ℃ at 90.16 ℃.
Corresponding to the foregoing embodiment of a temperature measurement method applied to a fiber raman distributed system, the present application further provides an embodiment of a temperature measurement system applied to a fiber raman distributed system, the fiber raman distributed system including a sensing fiber having an optical pulse signal transmitted therein to generate a raman signal, wherein when the optical pulse signal passes through an abnormal temperature region in the sensing fiber, an optical intensity of the raman signal is affected to be increased, the system comprising:
a determining unit for determining a target interval in which the light intensity value in the raman signal is raised, and determining the length of the abnormal temperature zone according to the length of the target interval and the length of the optical pulse signal;
a raman light intensity value calculating unit configured to calculate, at a first time, a first raman light intensity value excited by the optical pulse signal at a first temperature and a second temperature based on a length of the optical pulse signal and the abnormal temperature region, the first temperature being a temperature of the abnormal temperature region, and the second temperature being a temperature around the abnormal temperature region;
the fitting unit is used for fitting to obtain a second Raman light intensity value of the target interval excited at the second temperature based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval;
the first Raman light intensity difference calculation unit is used for subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone;
the second Raman light intensity difference calculation unit is used for converting the first Raman light intensity difference based on the length relation between the abnormal temperature area and the optical pulse signal in the target interval to obtain a second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal;
a reconstructed Raman signal unit, configured to obtain a reconstructed Raman signal based on the second Raman light intensity value and the second Raman light intensity difference;
and the demodulation unit is used for demodulating the reconstructed Raman signal based on a preset demodulation formula of the Raman signal and the temperature to obtain the temperature of the abnormal temperature zone.
The present application provides a computer device comprising a memory storing a computer program and a processor implementing the aforementioned method when executing the computer program.
The present application provides a computer storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the aforementioned method.
Claims (10)
1. A temperature measurement method applied to a fiber raman distributed system, the fiber raman distributed system comprising a sensing fiber having an optical pulse signal transmitted therein to generate a raman signal, wherein when the optical pulse signal passes through an abnormal temperature zone in the sensing fiber, an optical intensity of the raman signal is affected to rise, the method comprising:
determining a target interval in which the light intensity value in the Raman signal is increased, and determining the length of the abnormal temperature zone according to the length of the target interval and the length of the optical pulse signal;
calculating a first Raman light intensity value excited by the optical pulse signal at the first temperature and the second temperature based on the length relation between the optical pulse signal and the abnormal temperature region, a first temperature and a second temperature at a first moment, wherein the optical pulse signal completely covers the abnormal temperature region at the first moment, the first temperature is the temperature of the abnormal temperature region, and the second temperature is the temperature around the abnormal temperature region;
fitting to obtain a second Raman light intensity value excited by the target interval at a second temperature based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval;
subtracting the first Raman light intensity value from the second Raman light intensity value to obtain a first Raman light intensity difference excited by the first temperature and the second temperature under the length of the abnormal temperature zone;
transforming the first Raman light intensity difference based on the length relation between the abnormal temperature region and the optical pulse signal in the target region to obtain a second Raman light intensity difference excited by the first temperature and the second temperature under the length of the optical pulse signal;
obtaining a reconstructed raman signal based on the second raman intensity value and the second raman intensity difference;
and demodulating the reconstructed Raman signal based on a preset demodulation formula of the Raman signal and the temperature to obtain the temperature of the abnormal temperature region.
2. The method according to claim 1, wherein the determining the length of the abnormal temperature zone according to the length of the target zone and the length of the optical pulse signal includes:
and subtracting the length of the target interval from the length of the optical pulse signal to obtain the length of the abnormal temperature region.
3. The method of claim 1, wherein calculating a first raman intensity value of the optical pulse signal excited at the first temperature and the second temperature based on a length relationship of the optical pulse signal to the abnormal temperature zone, the first temperature, and the second temperature at the first time instant comprises:
determining the length of the optical pulse signal in the abnormal temperature zone and the length of the optical pulse signal outside the abnormal temperature zone at the first moment;
obtaining a first Raman optical power based on the length of the optical pulse signal in the abnormal temperature region and the first temperature, and obtaining a second Raman optical power based on the length of the optical pulse signal outside the abnormal temperature region and the second temperature; wherein the first raman optical power represents raman optical power of the optical pulse signal in the abnormal temperature region, and the second raman optical power represents raman optical power of the optical pulse signal outside the abnormal temperature region;
and adding the first Raman optical power and the second Raman optical power to obtain the first Raman optical intensity value.
4. The method of claim 1, wherein fitting the raman intensity values based on the first one of the collection points of the rising edge and the last one of the collection points of the falling edge of the target interval to obtain a second raman intensity value of the target interval excited at the second temperature comprises:
determining a third raman intensity value and a fourth raman intensity value based on the second temperature, wherein the third raman intensity value represents a raman intensity value of the first collection point and the fourth raman intensity value represents a raman intensity value of the last collection point;
and taking the average value of the third Raman light intensity value and the fourth Raman light intensity value to obtain a second Raman light intensity value excited by the target interval at the second temperature.
5. The method according to claim 1, wherein said transforming the first raman intensity difference based on the relationship between the length of the abnormal temperature zone and the length of the optical pulse signal in the target zone to obtain a second raman intensity difference excited by the first temperature and the second temperature at the length of the optical pulse signal comprises:
determining the ratio of the length of the abnormal temperature region to the length of the optical pulse signal, multiplying the ratio by the first Raman light intensity difference, and transforming the first Raman light intensity difference to obtain the second Raman light intensity difference.
6. The method of claim 1, wherein the step of deriving a reconstructed raman signal based on the second raman intensity value and the second raman intensity difference comprises:
and adding the second Raman light intensity value and the second Raman light intensity difference to obtain a reconstructed Raman signal.
7. The method according to claim 1, wherein the step of demodulating the reconstructed raman signal based on a demodulation formula of a preset raman signal and a temperature to obtain a temperature of the abnormal temperature zone, the demodulation formula of the temperature is:
wherein, for the first temperature, for the second temperature, for boltzmann constant, for planck constant, for raman shift amount, for raman Anti-Stokes light intensity value, for Anti-Stokes light intensity value and Stokes light intensity value constitute the raman signal, and for the second raman light intensity difference, and for the second raman light intensity value.
8. A temperature measurement system for use in a fiber optic raman distributed system comprising a sensing fiber having an optical pulse signal transmitted therein to produce a raman signal, wherein the optical intensity of the raman signal is affected to increase when the optical pulse signal passes through an abnormal temperature zone in the sensing fiber, the system comprising:
a determining unit, configured to determine a target interval in which a light intensity value in the raman signal increases, and determine a length of the abnormal temperature zone according to a length of the target interval and a length of the optical pulse signal;
a raman light intensity value calculating unit configured to calculate, at a first time, a first raman light intensity value of the optical pulse signal excited at the first temperature and the second temperature based on a length relation between the optical pulse signal and the abnormal temperature region, a first temperature, and a second temperature, wherein the optical pulse signal completely covers the abnormal temperature region at the first time, the first temperature is a temperature of the abnormal temperature region, and the second temperature is a temperature around the abnormal temperature region;
the fitting unit is used for fitting to obtain a second Raman light intensity value of the target interval excited at the second temperature based on the Raman light intensity value of the first acquisition point of the rising edge and the Raman light intensity value of the last acquisition point of the falling edge of the target interval;
a first raman light intensity difference calculation unit configured to subtract the first raman light intensity value and the second raman light intensity value to obtain a first raman light intensity difference excited by the first temperature and the second temperature in the abnormal temperature region;
the second raman light intensity difference calculating unit is used for converting the first raman light intensity difference based on the length relation between the abnormal temperature area length and the optical pulse signal in the target area to obtain a second raman light intensity difference excited by the first temperature and the second temperature under the optical pulse signal length;
a reconstructed raman signal unit configured to obtain a reconstructed raman signal based on the second raman light intensity value and the second raman light intensity difference;
and the demodulation unit is used for demodulating the reconstructed Raman signal based on a demodulation formula of the preset Raman signal and the temperature to obtain the temperature of the abnormal temperature region.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the method of any of claims 1 to 7 when executing the computer program.
10. A computer storage medium having stored thereon a computer program, which when executed by a processor realizes the steps of the method according to any of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310368462.8A CN116086645B (en) | 2023-04-10 | 2023-04-10 | Temperature measurement method applied to optical fiber Raman distributed system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310368462.8A CN116086645B (en) | 2023-04-10 | 2023-04-10 | Temperature measurement method applied to optical fiber Raman distributed system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116086645A true CN116086645A (en) | 2023-05-09 |
| CN116086645B CN116086645B (en) | 2023-06-27 |
Family
ID=86210514
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310368462.8A Active CN116086645B (en) | 2023-04-10 | 2023-04-10 | Temperature measurement method applied to optical fiber Raman distributed system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116086645B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116907677A (en) * | 2023-09-15 | 2023-10-20 | 山东省科学院激光研究所 | Distributed optical fiber temperature sensing system for concrete structure and measuring method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000074697A (en) * | 1998-06-19 | 2000-03-14 | Mitsubishi Electric Corp | Measuring equipment |
| US20070273961A1 (en) * | 2004-07-06 | 2007-11-29 | Shell Oil Company | Light Pulse Amplification In Long Optical Fibers |
| KR20110047484A (en) * | 2009-10-30 | 2011-05-09 | 동의대학교 산학협력단 | Method for measuring temperature distribution using Raman ???? temperature sensor |
| CN103292928A (en) * | 2013-05-31 | 2013-09-11 | 威海北洋电气集团股份有限公司 | High-resolution distributed optical fiber temperature sensor, temperature measuring device and application method of high-resolution distributed optical fiber temperature sensor and temperature measuring device |
| CN110887579A (en) * | 2019-11-08 | 2020-03-17 | 华中科技大学 | Dynamic temperature demodulation method based on distributed optical fiber Raman temperature measurement system |
| CN111238680A (en) * | 2020-01-20 | 2020-06-05 | 上海波汇科技有限公司 | Method for improving spatial resolution of distributed Raman temperature measurement of double-width pulse optical fiber |
| CN112697303A (en) * | 2020-12-01 | 2021-04-23 | 太原理工大学 | Distributed optical fiber sensing system and detection method for smart grid |
-
2023
- 2023-04-10 CN CN202310368462.8A patent/CN116086645B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000074697A (en) * | 1998-06-19 | 2000-03-14 | Mitsubishi Electric Corp | Measuring equipment |
| US20070273961A1 (en) * | 2004-07-06 | 2007-11-29 | Shell Oil Company | Light Pulse Amplification In Long Optical Fibers |
| KR20110047484A (en) * | 2009-10-30 | 2011-05-09 | 동의대학교 산학협력단 | Method for measuring temperature distribution using Raman ???? temperature sensor |
| CN103292928A (en) * | 2013-05-31 | 2013-09-11 | 威海北洋电气集团股份有限公司 | High-resolution distributed optical fiber temperature sensor, temperature measuring device and application method of high-resolution distributed optical fiber temperature sensor and temperature measuring device |
| CN110887579A (en) * | 2019-11-08 | 2020-03-17 | 华中科技大学 | Dynamic temperature demodulation method based on distributed optical fiber Raman temperature measurement system |
| CN111238680A (en) * | 2020-01-20 | 2020-06-05 | 上海波汇科技有限公司 | Method for improving spatial resolution of distributed Raman temperature measurement of double-width pulse optical fiber |
| CN112697303A (en) * | 2020-12-01 | 2021-04-23 | 太原理工大学 | Distributed optical fiber sensing system and detection method for smart grid |
Non-Patent Citations (3)
| Title |
|---|
| JIAN LI 等: "reconstruction compression correlation demodulation for raman optical time domain reflection", ADVANCED PHOTONICS RESEARCH, vol. 2, no. 10 * |
| XINXIN ZHOU 等: "Chaos Raman Optical Time-Domain Reflectometry for millimeter-level spatial resolution temperature sensing", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 39, no. 23, XP011889983, DOI: 10.1109/JLT.2021.3116203 * |
| 张丽萍 等: "分布式光纤温度传感器与其性能参数检测方法的研究", 工业计量, vol. 23, no. 5 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116907677A (en) * | 2023-09-15 | 2023-10-20 | 山东省科学院激光研究所 | Distributed optical fiber temperature sensing system for concrete structure and measuring method thereof |
| CN116907677B (en) * | 2023-09-15 | 2023-11-21 | 山东省科学院激光研究所 | Distributed optical fiber temperature sensing system for concrete structure and measuring method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116086645B (en) | 2023-06-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100567919C (en) | Collimation optical FMCW backscattering measuring system | |
| EP2587238B1 (en) | Optical fibre temperature distribution measurement apparatus | |
| US8858069B2 (en) | Optical fiber temperature distribution measuring device | |
| CN116086645B (en) | Temperature measurement method applied to optical fiber Raman distributed system | |
| CN108458814B (en) | Self calibration detection device and temperature demodulation method towards fiber Raman temperature-sensing system | |
| CN108871607A (en) | A kind of high-precision temperature demodulation method of Based on Distributed fiber Raman sensor | |
| CN101949745B (en) | Monitoring system of internal temperature and stress of power transformer winding and monitoring method thereof | |
| CN104596670A (en) | Method for solving temperature drift of distributed optical fiber Raman temperature sensing system | |
| US10018517B2 (en) | Optical fiber temperature distribution measuring device | |
| JP4421229B2 (en) | Fiber Bragg Grating Physical Quantity Measuring Method and Apparatus | |
| CN111006788B (en) | High-precision optical fiber Raman temperature detection method based on anti-Stokes light self-demodulation | |
| CN103674916B (en) | Novel fluorescence signal demodulating equipment and fluorescence signal demodulation method | |
| CN111795759A (en) | Method and system for dispersion correction of distributed Raman fiber temperature measurement system | |
| JPWO2018070442A1 (en) | Optical angle modulation measuring apparatus and measuring method | |
| Malakzadeh et al. | SNR enhancement of a Raman distributed temperature sensor using partial window-based non local means method | |
| Vazquez et al. | Distributed temperature sensing using cyclic pseudorandom sequences | |
| JP2010223831A (en) | Temperature measuring device | |
| CN113654683A (en) | Calibration method and device for distributed optical fiber temperature measurement system | |
| CN102607614B (en) | Low-coherence interference demodulation method based on location of center crest of phase gradient | |
| CN106441385A (en) | Wavelength-all-same fiber grating spectrum demodulation method and fiber grating demodulation system | |
| Misbakhov | Combined brillouin OFDA and address FBG sensor system for distributed and point temperature measurements | |
| CN112697303B (en) | Distributed optical fiber sensing system and detection method for smart grid | |
| Wang et al. | Hardware embedded fiber sensor interrogation system using intensive digital signal processing | |
| TW202134607A (en) | Linearity correction method of optical measuring device, optical measuring method and optical measuring device | |
| Zhang et al. | A distributed optical fiber temperature measuring system for oil Wells |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |