Method and system for dispersion correction of distributed Raman fiber temperature measurement system
阅读说明：本技术 用于分布式拉曼光纤测温系统色散修正的方法和系统 (Method and system for dispersion correction of distributed Raman fiber temperature measurement system ) 是由 王青山 郭旭 毛丽娜 王伟杰 梁武民 范冬冬 王胜辉 和红伟 兰五胜 杨金鑫 云 于 2020-06-09 设计创作，主要内容包括：本发明公开了一种分布式拉曼光纤测温系统色散修正的方法,包括：同步采集同一传感光纤的斯托克斯光(Stokes光)和反斯托克斯光(Anti-Stokes光)的光信号；以Stokes光作为参考光信号,修正Anti-Stokes光的光信号散射点位置信息。该方法能够完全消除两束信号的错位,提高温度测量精度和升温区域的定位准确度。(The invention discloses a dispersion correction method for a distributed Raman fiber temperature measurement system, which comprises the following steps: synchronously acquiring optical signals of Stokes light (Stokes light) and Anti-Stokes light (Anti-Stokes light) of the same sensing optical fiber; and correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal. The method can completely eliminate the dislocation of the two beams of signals and improve the temperature measurement precision and the positioning accuracy of the temperature rising area.)
1. The method for correcting the dispersion of the distributed Raman fiber temperature measurement system is characterized by comprising the following steps of:
synchronously collecting optical signals of Stokes light and Anti-Stokes light of the same sensing optical fiber;
and correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal.
2. The method of claim 1, wherein the synchronously acquiring optical signals of Stokes light and Anti-Stokes light of the same sensing fiber comprises:
acquiring the number of sampling points of the Stokes optical signal and the Anti-Stokes optical signal and corresponding signal intensity thereof, wherein the number of the sampling points of the Stokes optical signal and the Anti-Stokes optical signal is respectively recorded as Ns and Nas, and the signal intensity corresponding to each sampling point of the Stokes optical signal and the Anti-Stokes optical signal is respectively phi s and phi as;
obtaining the length L of the optical fiber;
respectively mapping sampling point positions of the Stokes optical signal and the Anti-Stokes optical signal to an optical fiber with the length of L, wherein sampling point position information Xs corresponding to the Stokes optical signal is L/Ns,2L/Ns,. The sampling point signal intensity phi s (n) corresponding to the Stokes optical signal, n is 1,2,3 …, Ns, and the sampling point signal intensity phi as (n) corresponding to the Anti-Stokes optical signal, n is 1,2,3 …, Nas.
3. The method according to claim 1 or 2, wherein the correcting the scattering point position information of the Anti-Stokes light by using Stokes as the optical reference light signal comprises:
obtaining the signal intensity phi as at the same position as the sampling point position corresponding to the Stokes optical signal by adopting an interpolation algorithm to the signal intensity of the corresponding sampling point of the Anti-Stokes optical signal*；
According to the signal strength phi as*And correcting the position information of the sampling points corresponding to the Stokes light signals.
4. The system for correcting the dispersion of the distributed Raman fiber temperature measurement system is characterized by comprising:
the acquisition unit is used for synchronously acquiring optical signals of optical Stokes light and Anti-Stokes light of the same sensing optical fiber;
and the correcting unit is used for correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal.
5. The system of claim 4, wherein the acquisition unit comprises:
the system comprises a first acquisition module, a second acquisition module and a third acquisition module, wherein the first acquisition module is used for acquiring the number of sampling points of a Stokes optical signal and an Anti-Stokes optical signal and the corresponding signal intensity thereof, the number of the sampling points of the Stokes optical signal and the Anti-Stokes optical signal is respectively recorded as Ns and Nas, and the signal intensity corresponding to each sampling point of the Stokes optical signal and the Anti-Stokes optical signal is respectively phi s and phi as;
the second acquisition module is used for acquiring the length L of the optical fiber;
the mapping module is used for mapping sampling point positions of the Stokes optical signal and the Anti-Stokes optical signal to an optical fiber with the length of L respectively, and sampling point position information Xs corresponding to the Stokes optical signal is L/Ns,2L/Ns, a. The sampling point signal intensity phi s (n) corresponding to the Stokes optical signal, n is 1,2,3 …, Ns, and the sampling point signal intensity phi as (n) corresponding to the Anti-Stokes optical signal, n is 1,2,3 …, Nas.
6. The system according to claim 4 or 5, wherein the correction unit comprises:
a first calculating unit, configured to obtain, by using an interpolation algorithm, a signal intensity phias at a same position as a corresponding sampling point of the Stokes optical signal with respect to the corresponding sampling point signal intensity of the Anti-Stokes optical signal*；
A second calculation unit for calculating the signal strength phi as*And correcting the position information of the sampling points corresponding to the Stokes light signals.
7. A smart device, comprising: a memory, a processor;
a memory; a memory for storing the processor-executable instructions;
wherein the processor is configured to: a method for processing the dispersion correction of the distributed raman fiber thermometry system of claims 1 to 3.
8. A computer-readable storage medium having stored thereon computer-executable instructions for performing the method of dispersion correction for a distributed raman fiber thermometry system according to any one of claims 1 to 3 when executed by a processor.
Technical Field
The invention relates to the technical field of temperature measurement, in particular to a method and a system for dispersion correction of a distributed Raman fiber temperature measurement system.
Background
A Distributed optical fiber Temperature measuring system (Distributed Temperature Sensor) based on Raman scattering takes an optical signal as a carrier, and calculates corresponding Temperature by detecting the change of a scattered light parameter in an optical fiber. The optical fiber sensor has the advantages of electromagnetic interference resistance, compact structure, easiness in laying, economy, flexibility, easiness in realizing remote measurement and the like, overcomes the defects of the traditional temperature-sensing detector, can realize real-time monitoring of temperature, and can perform early warning and accurate positioning on abnormal points of temperature and temperature rise rate. The device is widely applied to various occasions such as temperature monitoring of power cables, pipe galleries/power tunnels, cable ducts, switch cabinets and electric reactors, local overheat point positioning of transformers and the like.
In the distributed optical fiber temperature measurement system, the intensity of the backscattered light is uncertain due to the fact that the instability of a resonant cavity and the change of the environmental temperature influence the change of an optical power function. In order to eliminate the optical power fluctuation, the Stokes light is usually used as reference light, the temperature demodulation is carried out by utilizing the intensity ratio of the Anti-Stokes light to the Stokes light signal, but the influence of dispersion on the demodulated temperature accuracy cannot be eliminated.
The existing method for eliminating the influence of chromatic dispersion on a temperature measurement system comprises a matching optical fiber method, an interpolation algorithm, a translation algorithm or a light speed correction method which are added with different lengths, the method for adding the matching optical fiber can only compensate data with a specific length, and because the influence of chromatic dispersion on two paths of signals in an optical fiber exists everywhere, the method has great limitation and cannot accurately compensate length difference; the translation algorithm is characterized in that corresponding sampling points are added or removed through the difference of the number of sampling points of two paths of signals, so that the positioning of a temperature value is deviated; the light velocity correction increases the complexity of the system, and the optical fibers of different batches need to be calibrated and calculated again, so that the practical engineering application cannot be met.
Disclosure of Invention
The invention aims to provide a method for correcting the dispersion of a distributed Raman optical fiber temperature measurement system, which solves the problem that Stokes light and Anti-Stokes light signals synchronously collected by a collection card due to dispersion correspond to different scattering point positions on an optical fiber by a Linear interpolation algorithm for received signals, can completely eliminate the dislocation of the two beams of signals, and improves the temperature measurement precision and the positioning accuracy of a temperature rising area.
In order to solve the above problem, an aspect of the present invention provides a method for correcting chromatic dispersion of a distributed raman optical fiber thermometry system, including: and synchronously acquiring the optical signals of the Stokes light and the Anti-Stokes light of the same sensing optical fiber. And correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal.
According to an embodiment of the present invention, the synchronously acquiring optical signals of Stokes light and Anti-Stokes light of the same sensing fiber comprises:
the synchronous collection of the optical signals of the Stokes light and the Anti-Stokes light of the same sensing optical fiber comprises the following steps: acquiring the number of sampling points of the Stokes optical signal and the Anti-Stokes optical signal and corresponding signal intensity thereof, respectively recording the number of the sampling points of the Stokes optical signal and the Anti-Stokes optical signal as Ns and Nas, and respectively setting the corresponding signal intensity of the Stokes optical signal and the Anti-Stokes optical signal of each sampling point as φ s and φ as. The fiber length L is obtained.
Respectively mapping sampling point positions of the Stokes optical signal and the Anti-Stokes optical signal to an optical fiber with the length of L, wherein sampling point position information Xs corresponding to the Stokes optical signal is L/Ns,2L/Ns,. The sampling point signal intensity phi s (n) corresponding to the Stokes optical signal, n is 1,2,3 …, Ns, and the sampling point signal intensity phi as (n) corresponding to the Anti-Stokes optical signal, n is 1,2,3 …, Nas.
According to an embodiment of the invention, the correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking Stokes as the optical reference optical signal comprises the following steps: obtaining the signal intensity phi as at the same position as the sampling point position corresponding to the Stokes optical signal by adopting an interpolation algorithm to the signal intensity of the corresponding sampling point of the Anti-Stokes optical signal*。
According to the signal strength phi as*And correcting the position information of the sampling points corresponding to the Stokes light signals.
According to a second aspect of the present invention, there is provided a system for dispersion correction of a distributed raman optical fiber thermometry system, comprising: and the acquisition unit is used for synchronously acquiring optical signals of the optical Stokes light and the Anti-Stokes light of the same sensing optical fiber.
And the correcting unit is used for correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal.
The acquisition unit includes: the first acquisition module is used for acquiring the number of sampling points of the Stokes optical signal and the Anti-Stokes optical signal and the corresponding signal intensity of the sampling points, the number of the sampling points of the Stokes optical signal and the Anti-Stokes optical signal is respectively recorded as Ns and Nas, and the signal intensity corresponding to each sampling point of the Stokes optical signal and the Anti-Stokes optical signal is respectively phi s and phi as.
And the second acquisition module is used for acquiring the length L of the optical fiber.
The mapping module is used for mapping sampling point positions of the Stokes optical signal and the Anti-Stokes optical signal to an optical fiber with the length of L respectively, and sampling point position information Xs corresponding to the Stokes optical signal is L/Ns,2L/Ns, a. The sampling point signal intensity phi s (n) corresponding to the Stokes optical signal, n is 1,2,3 …, Ns, and the sampling point signal intensity phi as (n) corresponding to the Anti-Stokes optical signal, n is 1,2,3 …, Nas.
The correction unit includes: a first calculating unit, configured to obtain, by using an interpolation algorithm, a signal intensity phias at a same position as a corresponding sampling point of the Stokes optical signal with respect to the corresponding sampling point signal intensity of the Anti-Stokes optical signal*。
A second calculation unit for calculating the signal strength phi as*And correcting the position information of the sampling points corresponding to the Stokes light signals.
The third invention of the present invention discloses an intelligent device, which includes: a memory, a processor;
a memory; a memory for storing the processor-executable instructions;
wherein the processor is configured to: the method is used for processing the dispersion correction of the distributed Raman fiber temperature measurement system.
The fourth invention discloses a computer-readable storage medium, in which computer-executable instructions are stored, and the computer-executable instructions are executed by a processor to implement the method for chromatic dispersion correction of the distributed raman optical fiber thermometry system described above.
The dispersion correction method of the distributed Raman fiber temperature measurement system provided by the invention can be used for demodulating temperature information by synchronously acquiring Stokes light and Anti-Stokes light signals of the same sensing fiber by using the Stokes light as reference light and utilizing the light intensity ratio of Anti-Stokes light to Stokes light, and acquiring position information of corresponding sampling points by utilizing an optical time domain reflection principle. The dislocation of two bundles of signals can be eliminated completely, and the temperature measurement precision and the positioning accuracy of a temperature rising area are improved.
Drawings
FIG. 1 is a flow chart of a Linear interpolation algorithm disclosed in the embodiments of the present invention;
FIG. 2 is a block diagram of a test system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of Raman scattering signals of collected Stokes light and Anti-Stokes light according to the embodiment of the present invention;
FIG. 4 is a graph illustrating a dispersion shift compensation comparison for different interpolation algorithms disclosed in accordance with an embodiment of the present invention;
FIG. 5 is a graph of temperature values before and after dispersion compensation as disclosed in an embodiment of the present invention;
fig. 6 is a flowchart of a method for correcting dispersion of a distributed raman optical fiber temperature measurement system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1: a method for correcting dispersion of a distributed Raman fiber temperature measurement system comprises the step of synchronously acquiring Stokes light and Anti-Stokes light signals of the same sensing fiber, wherein the signals comprise sampling point numbers Ns and Nas of the Stokes light and the Anti-Stokes light and corresponding signal intensity values φ s (n) and φ as (n). The method comprises the steps of using Stokes light as reference light, demodulating temperature information by using the ratio of Anti-Stokes light to Stokes light intensity, and obtaining position information of corresponding sampling points by using an optical time domain reflection principle to obtain temperature distribution information along an optical fiber, wherein the correction method is as follows.
The first step is to determine the length information L of the optical fiber, the sampling point number Ns and the signal intensity φ s (n) of the Stokes optical signal, wherein n is 1,2,3 …, Ns, the sampling point number Nas and the signal intensity φ as (n) of the Anti-Stokes optical signal, and n is 1,2,3 …, Nas.
Secondly, mapping the number of sampling points of the Stokes and Anti-Stokes optical signals with the total length of the optical fiber, wherein the positions of the optical fibers corresponding to the corresponding sampling points are as follows: L/Ns,2L/Ns, …, L and L/Nas,2L/Nas, …, L.
And thirdly, mapping the signal position and the optical fiber length, and then obtaining the Anti-Stokes signal intensity at the same position as the Stokes signal position by adopting an interpolation algorithm for the Anti-Stokes light signal intensity. That is, the interpolation algorithm obtains the values of φ as (n), n is 1,2,3 …, Nas at L/Ns,2L/Ns, …, L.
Further description is provided for a better understanding and experimental validation of the examples described.
As shown in fig. 2, the distributed optical fiber temperature measurement system is composed of a high-speed pulse light source, a wavelength division multiplexer, a calibration optical fiber, an avalanche photodetector, a high-speed data acquisition card, an industrial personal computer, an optical switch, a temperature sensor, and the like. The industrial personal computer comprises control of components, temperature demodulation and a positioning algorithm.
When the system works, a narrow pulse width laser is used for generating a series of pulse light with specific pulse width and repetition frequency, the pulse light is incident into the optical fiber and transmitted along the whole optical fiber, Raman scattering can occur to the light in the transmission process, other stray light and interference light are filtered out through a wavelength division multiplexer, and Stokes light and Anti-Stokes light are separated and enter different light paths respectively. The Raman scattering signal contains loss and temperature information of the whole optical fiber but has weak signal intensity, the Raman signal is subjected to photoelectric conversion and amplification by an avalanche photodetector, and the converted signal is acquired by a high-speed data acquisition card. The location of the temperature change is determined by measuring the time for the scattered light to return to the light source, enabling the location of the change to be pinpointed.
Example distributed optical fiber thermometry systems, the performance parameters of each component are shown in table 1 below.
TABLE 1
Raman signal acquisition and temperature demodulation: the system is used for collecting and temperature demodulating the Raman scattering signals. The optical fiber used in the example was 8km in length and was placed in a room temperature environment. Coiling a section of optical fiber with the length of about 10m (8014-8024m) at the tail end of the temperature measuring optical fiber into an optical fiber ring with the diameter of 20cm, placing the optical fiber ring into a constant-temperature water tank, reserving the optical fiber with the length of 20m at the tail end in order to eliminate the influence of Fresnel reflection of the section of the tail end on a sampling value, and then collecting a Raman signal.
Distributed optical fiber temperature measurement principle based on Raman scattering. When a laser pulse propagates in the fiber, the light flux of the Stokes raman backscattered light generated by each light pulse is:
the luminous flux of Anti-Stokes raman backscattered light can be expressed as:
wherein Ks and Ka are coefficients related to Stokes scattering cross section and Anti-Stokes scattering cross section of the optical fiber respectively, ν s and ν a are frequencies of the Stokes scattering light and the Anti-Stokes scattering light respectively,
Rs(T)＝[1-exp(-hΔv/kT)]-1(3)
Ra(T)＝[exp(hΔv/kT)-1]-1(4)
the nonlinear interaction of laser photons and optical fiber molecules, wherein incident photons are scattered into another low-frequency Stokes Raman scattered photon or high-frequency Anti-Stokes Raman scattered photon by the molecules, the corresponding molecules complete the transition between two energy states, one phonon is released into the Stokes Raman scattered photon, one phonon is absorbed into the Anti-Stokes Raman scattered photon, the population thermal distribution on the optical fiber molecular energy level follows Boltzmann law, and the intensity ratio I (T) of the Anti-Stokes Raman scattered light to the Stokes Raman scattered light:
and selecting two points on the optical fiber to calculate the loss coefficients of the Stokes optical signal and the Anti-Stokes optical signal according to the definition of the loss coefficient of the optical fiber. An Anti-Stokes fiber loss coefficient calculation formula (Stokes loss coefficient calculation method is similar):
where φ a1 and φ a2 are the light fluxes at
and (5) dividing the two intensity ratios by a formula (5) and a formula (7) to obtain a function containing temperature information of each section of the optical fiber:
is obtained by the formula:
where h is the Planck constant, h is 6.626 × 10-34J.s, Δ ν is the phonon frequency of the fiber molecules 13.2THz, k is boltzmann constant, k is 1.380 × 10-23J/K, T is Kelvin temperature, φ a (T) and φ s (T) are voltage values of the light flux after photoelectric conversion. In actual measurement, φ a (T), φ s (T), and the calibration curves φ a (T0), φ s (T0) are obtained, the voltage value after photoelectric conversion, and the temperature T0 at the calibration fiber are obtained, and the temperature T can be obtained by the formula (9).
Optical Time Domain Reflectometry (OTDR) principle. When an incident laser pulse is transmitted in the optical fiber, scattered light is generated at each point along the optical fiber, and the scattered light in the middle of the scattered light is transmitted back to the incident end of the optical fiber. Assuming that the time taken for the pulse to return from the emission is t, the scattering occurs in the fiber at a distance from the laser incident end of:
Ls＝Vt/2 (10)
wherein Ls is the position of the scattering point, and V is the speed of the pulse light in the optical fiber.
And (5) analyzing temperature demodulation errors. As can be seen from the raman scattering signal of fig. 3, the raman scattering signal is enhanced after constant temperature heating at the tail end of the optical fiber. Since the Anti-Stokes optical signal is more sensitive to temperature, the amount of the Anti-Stokes optical signal burst is larger than the amount of the Stokes optical signal burst. Due to the dispersion effect, the positions of the protrusions of the Stokes light and the Anti-Stokes light signals are slightly deviated, and temperature abnormal points exist at two ends of the heating area after the temperature signals are demodulated, as shown in fig. 5. The chromatic dispersion is corrected through a linear interpolation algorithm, the correction result is shown in fig. 4, the heating areas of the two corrected signals correspond to the same position, the shapes of the signals are not distorted, abnormal points at two ends of the heating area disappear after the chromatic dispersion is compensated, an ideal temperature demodulation curve is obtained, and the practical application is met.
The dispersion correction method of the distributed Raman fiber temperature measurement system provided by the invention can be used for demodulating temperature information by synchronously acquiring Stokes light and Anti-Stokes light signals of the same sensing fiber by using the Stokes light as reference light and utilizing the ratio of the intensity of the Anti-Stokes light to the intensity of the Stokes light, and acquiring position information of corresponding sampling points by utilizing an optical time domain reflection principle. The dislocation of two bundles of signals can be eliminated completely, and the temperature measurement precision and the positioning accuracy of a temperature rising area are improved.
Fig. 6 is a flowchart of a method for correcting dispersion of a distributed raman optical fiber temperature measurement system according to an embodiment of the present invention.
A method for correcting dispersion of a distributed Raman fiber temperature measurement system comprises the following steps:
and S101, synchronously acquiring optical signals of Stokes light and Anti-Stokes light of the same sensing optical fiber.
The synchronous collection of the optical signals of the Stokes light and the Anti-Stokes light of the same sensing optical fiber comprises the following steps:
acquiring the number of sampling points of the Stokes optical signal and the Anti-Stokes optical signal and corresponding voltage amplitudes thereof, wherein the number of the sampling points of the Stokes optical signal and the Anti-Stokes optical signal is respectively recorded as Ns and Nas, and the voltage amplitudes corresponding to the Stokes optical signal and the Anti-Stokes optical signal at each sampling point are respectively phi s and phi as.
The fiber length L is obtained.
And mapping sampling point positions of the Stokes optical signal and the Anti-Stokes optical signal to an optical fiber with the length of L respectively, wherein sampling point position information Xs corresponding to the Stokes optical signal is L/Ns,2L/Ns,.
And S102, correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal.
The method for correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as the reference optical signal comprises the following steps:
obtaining voltage amplitude phi as of sampling point position information Xs of the Stokes optical signal according to sampling point position information Xas of the Anti-Stokes optical signal and corresponding voltage amplitude phi as*(ii) a And obtaining the voltage amplitude of the Anti-Stokes optical signal after dispersion compensation.
According to the Stokes optical signal phi s and the Anti-Stokes optical signal voltage amplitude phi as after dispersion compensation*And modulating the position information of corresponding scattering points of Stokes light and Anti-Stokes light Anti-Stoke.
Obtaining the voltage amplitude phi as of the Stokes light signal sampling point position information Xs by adopting an interpolation algorithm*。
According to another aspect of the present invention, there is provided a system for dispersion correction of a distributed raman fiber thermometry system, comprising: and the acquisition unit is used for synchronously acquiring optical signals of the Stokes light and the Anti-Stokes light of the same sensing optical fiber.
And the correcting unit is used for correcting the position information of the scattering point of the optical signal of the Anti-Stokes light by taking the Stokes light as a reference optical signal.
The acquisition unit includes: the first acquisition module is used for acquiring the number of sampling points of the Stokes optical signal and the Anti-Stokes optical signal and corresponding voltage amplitudes thereof, the number of the sampling points of the Stokes optical signal and the Anti-Stokes optical signal is respectively recorded as Ns and Nas, and the voltage amplitudes corresponding to the Stokes optical signal and the Anti-Stokes optical signal at each sampling point are respectively phi s and phi as.
And the second acquisition module is used for acquiring the length L of the optical fiber.
The mapping module is used for mapping sampling point positions of the Stokes optical signal and the Anti-Stokes optical signal to an optical fiber with the length of L, and sampling point position information Xs (L/Ns, 2L/Ns, 10.... times.) corresponding to the Stokes optical signal, and sampling point position information Xas (L/Nas, 2L/Nas, 1.. times.) corresponding to the L, Anti-Stokes optical signal.
The correction unitThe method comprises the following steps: a first correction module for obtaining voltage amplitude φ as of the sampling point position information Xs of the Stokes optical signal according to the sampling point position information Xas of the Anti-Stokes optical signal of the first obtaining module and the corresponding voltage amplitude φ as*(ii) a And obtaining the voltage amplitude of the Anti-Stokes optical signal after dispersion compensation.
A second correction module for correcting the voltage amplitude φ as of the Anti-Stokes optical signal according to the Stokes optical signal φ s and the dispersion compensated voltage amplitude φ as*And modulating the position information of corresponding scattering points of Stokes light and Anti-Stokes light Anti-Stoke.
According to one embodiment of the invention, an interpolation algorithm is adopted to obtain the voltage amplitude phi as of the Stokes optical signal sampling point position information Xs*。
The dispersion correction method of the distributed Raman fiber temperature measurement system provided by the invention can be used for demodulating temperature information by synchronously acquiring Stokes light and Anti-Stokes light signals of the same sensing fiber by using the Stokes light as reference light and utilizing the light intensity ratio of Anti-Stokes light to Stokes light, and acquiring position information of corresponding sampling points by utilizing an optical time domain reflection principle. The dislocation of two bundles of signals can be eliminated completely, and the temperature measurement precision and the positioning accuracy of a temperature rising area are improved.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.