A ranging device and method based on distributed fiber sensing technology
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST
- Filing Date
- 2023-06-25
- Publication Date
- 2026-06-12
AI Technical Summary
In existing distributed fiber optic sensor ranging systems, time delay errors affect ranging and positioning accuracy. In particular, the time delay of the electronic device varies with changes in the environment and component drift, and existing technologies are difficult to effectively compensate for and calibrate.
By employing components such as a dual-wavelength laser source, optical splitter, tunable fiber optic filter, photodetector, and digital controller, the system performs synchronous measurements at both ends of the ring fiber, calculates and corrects systematic errors in real time, and reduces the impact of time delay.
It achieves higher ranging accuracy and reliability, reduces sensitivity to changes in the environment and components, reduces calibration frequency and cost, and improves the online availability and lifespan of the equipment.
Smart Images
Figure CN116953718B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of distributed fiber optic sensor ranging, and more specifically, relates to a ranging device and method based on distributed fiber optic sensing technology. Background Technology
[0002] Common distributed fiber optic sensor ranging systems employ a method similar to lidar, based on optical frequency domain reflectometry (OFDR) technology. The basic structure of a fiber optic ranging system includes both optical and electrical signal processing components. In practical devices, the electronic components require time for sampling, conversion, and computation, resulting in a time lag. This time lag directly and significantly impacts ranging and positioning accuracy. For a specific device, this time lag remains relatively constant in the short term, but over the long term, it changes due to variations in environmental parameters and drift in electronic component parameters. While compensation can be implemented in the program to minimize the impact of time lag, it cannot be completely eliminated, and frequent calibration and adjustment of compensation parameters are necessary, making it impractical in many situations.
[0003] Time delay error can be divided into two parts: systematic error and random error. Systematic error is mainly caused by the fixed deviation of the measured value from the true value due to factors such as the device, measurement method, and procedure. Random error is caused by the small random fluctuations of a series of related factors during the measurement process, resulting in mutually compensating errors. Theoretically, the factors that generate systematic error already exist before the measurement begins. How to reduce this part of the error by eliminating its root cause or by compensating or correcting it is one of the urgent problems to be solved in fiber optic ranging. Therefore, it is necessary to find a method that can effectively reduce the effects of time delay over a long period of time.
[0004] Prior art document 1 discloses a dual-end measurement type distributed optical fiber temperature sensing device (CN101403644), which mainly includes a laser. The input end of the laser is connected to the output end of a laser driver, the input end of the laser driver is connected to the output end of a synchronization controller, and the output end of the laser is connected to the input end of a coupler. The output end of the coupler is connected to the input end of an optical path switcher, which switches the optical path between two ports of a ring-shaped detection optical cable. A computer is connected to a data processor, which controls the synchronization controller and receives data from a data acquisition unit. After receiving the data measured from the ring-shaped detection optical cable, the data processor performs calculations on the data. Then, the optical path switcher switches the optical path to another port, acquires and processes the signal, and finally obtains the temperature data, which is displayed on the computer in the form of a curve.
[0005] The problems with the existing technical document 1 include: (1) It does not analyze the source of error, does not specifically explain the principle and implementation method of automatic calibration of measurement error, and therefore cannot accurately reproduce the error; (2) There is a time difference when the optical path switcher switches, and even if the switching speed is very fast, such as milliseconds, time delay error will still be introduced. Summary of the Invention
[0006] To address the shortcomings of existing technologies, this invention provides a ranging device based on distributed optical fiber sensing technology, which can effectively reduce the effects of time lag in optical fiber ranging over a long period of time, making the measurement results more accurate.
[0007] The present invention adopts the following technical solution.
[0008] A ranging device based on distributed optical fiber sensing technology includes: a dual-wavelength laser source, an optical fiber coupler, an optical splitter, a tunable optical fiber filter, a photodetector, a signal amplifier, a high-speed A / D converter card, a digital controller, a high-speed D / A converter card, and a computer;
[0009] The output of the dual-wavelength laser source is connected to the input of the fiber optic coupler via an optical isolator. The output of the fiber optic coupler is connected to the input of the optical splitter and the tunable fiber optic filter, respectively. The output of the tunable fiber optic filter is connected to the input of the photodetector. The output of the photodetector is connected to the input of the signal amplifier. The output of the signal amplifier is connected to the input of the high-speed A / D conversion card. The output of the high-speed A / D conversion card is connected to the input of the digital controller. The output of the digital controller is connected to the input of the high-speed D / A conversion card and the computer, respectively. The output of the high-speed D / A conversion card is connected to the input of the tunable fiber optic filter.
[0010] Preferably, the optical demultiplexer connects both the beginning and end of the ring fiber. The composite optical signal emitted by the dual-wavelength laser source passes through the optical isolator, the fiber coupler, and the optical demultiplexer. The optical demultiplexer splits the signal into two independent single-wavelength lasers, which are then sent to the beginning and end of the fiber, respectively.
[0011] Preferably, the composite optical signal propagates along the optical fiber and illuminates a point x on the optical fiber, generating reflected light of two wavelengths, which is then reflected back to the optical fiber coupler.
[0012] Preferably, after the composite optical signal passes through the fiber coupler and enters the tunable fiber filter, the tunable fiber filter selects only one wavelength of reflected light signal at a time and inputs it into the photodetector. The photodetector converts the reflected light signal of a single wavelength into an electrical signal, and measures the beginning and end of the fiber according to the reflected light of a single wavelength to calculate the measurement distance information of the fiber.
[0013] Preferably, filtering the reflected light signal using a tunable fiber optic filter further includes:
[0014] The high-speed D / A converter card converts two discrete signals of specific wavelengths into continuous analog signals, and the analog signals are used as modulation signals for tunable fiber optic filters.
[0015] The modulation signal provided by the high-speed D / A converter card controls the tunable fiber filter to allow the reflected light signal of a specified wavelength to pass through. The modulation signal can adjust the passband center frequency of the tunable fiber filter to the frequency corresponding to a single reflected light signal.
[0016] The tunable fiber optic filter receives and processes the reflected light signal corresponding to the wavelength, filters out the reflected light signal of a single wavelength required for each calculation by the digital controller, and realizes separate calculation and processing of the reflected light of the two wavelengths.
[0017] Preferably, the digital controller performs time-division parallel processing on the two wavelengths of reflected light signals.
[0018] Preferably, the reflected light signal of a specified wavelength selected by the tunable fiber optic filter enters the photodetector and is converted into an electrical signal. The electrical signal enters the signal amplifier for amplification. The amplified electrical signal is converted into a discrete digital signal by a high-speed A / D conversion card and sent to the digital controller for high-speed real-time processing.
[0019] The digital controller can obtain the first and second measurement values based on the reflected light signals of two wavelengths, and can calculate the measurement distance information of the optical fiber based on the first and second measurement values.
[0020] Preferably, the calculation of the optical fiber's measurement distance information further includes:
[0021] When measuring the beginning of the fiber, assuming the true distance from a point on the fiber to the beginning is x, and considering the systematic error in distance calculation caused by time delay during the measurement process, denoted as Δl, the first measured value m1 is obtained as follows:
[0022] m1=x+Δl
[0023] When measuring the end, the distance from the point on the fiber previously at the true distance x from the beginning to the true distance sx from the end, where s is the total length of the measuring fiber, and the systematic error Δl remains constant during the measurement process, then the second measured value m2 is:
[0024] m2=s-x+Δl
[0025] Based on the first measurement value m1 and the second measurement value m2, the systematic error Δl is obtained as follows:
[0026] m1+m2=s+2Δl
[0027]
[0028] This invention also provides a ranging method based on distributed optical fiber sensing technology, comprising the following steps:
[0029] Step 1: Initialize the ranging device by simultaneously connecting the optical splitter in the ranging device to both the beginning and end of the ring fiber.
[0030] Step 2: The dual-wavelength laser source emits a composite optical signal. The composite optical signal passes through an optical isolator and an optical fiber coupler, propagates along the optical fiber, and illuminates a point x on the optical fiber, generating a composite reflected optical signal.
[0031] Step 3: The composite reflected light signal returns to the fiber coupler, and the reflected light is filtered by a tunable fiber filter to obtain reflected light of a single wavelength.
[0032] Step 4: The tunable fiber optic filter sequentially transmits the filtered single-wavelength reflected light signals to the photodetector, signal amplifier, and high-speed A / D converter, and the ranging result of the fiber is calculated by the digital controller.
[0033] Step 5: Return to step 1 and repeat steps 1 to 4 to obtain multiple systematic error values. Take the average value as the final systematic error value to correct the ranging result. The obtained ranging result is displayed on the computer.
[0034] Preferably, in step 5, random errors in a single measurement are reduced by taking multiple measurements, abnormal data are eliminated, and the average value of all systematic error values is calculated as the final measurement result.
[0035] The present invention also provides a terminal, including a processor and a storage medium;
[0036] The storage medium is used to store instructions;
[0037] The processor is configured to operate according to the instructions to execute the steps of the ranging method.
[0038] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the ranging method.
[0039] The beneficial effects of the present invention are as follows: Compared with the prior art, the present invention has at least the following beneficial effects:
[0040] (1) The present invention can measure the systematic error of distance measurement caused by the time delay of the electronic device part in real time, relax the time delay index limit of the electronic device part, on the one hand, lower cost components can be used, and on the other hand, the stringent requirements of factory inspection are reduced.
[0041] (2) This invention uses an optical splitter and a dual-wavelength laser light source to achieve synchronous measurement of the beginning and end of the ring fiber, thus avoiding the switching error of the optical path switcher.
[0042] (3) The ranging method proposed in this invention is not affected by changes in environmental parameters and component parameters in principle, and no longer requires periodic calibration, which greatly saves costs and manpower and resources, improves the online availability of equipment, and extends its service life.
[0043] (4) The ranging device of the present invention does not require changes to the main structure of the distributed optical fiber sensor, making it easier to upgrade and transform the existing system. Attached Figure Description
[0044] Figure 1 This is a schematic diagram of the ranging device based on distributed optical fiber sensing technology in this invention.
[0045] Figure 2 This is a flowchart illustrating the ranging method based on distributed optical fiber sensing technology in this invention. Detailed Implementation
[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.
[0047] like Figure 1 As shown, this invention proposes a ranging device based on distributed optical fiber sensing technology. The device includes: a dual-wavelength laser source, an optical isolator, an optical fiber coupler, an optical demultiplexer, a tunable optical fiber filter, a photodetector, a signal amplifier, a high-speed A / D conversion card, a digital controller, a high-speed D / A conversion card, and a computer.
[0048] The output of the dual-wavelength laser source is connected to the input of the fiber optic coupler via an optical isolator. The output of the fiber optic coupler is connected to the input of the optical splitter and the tunable fiber optic filter, respectively. The output of the tunable fiber optic filter is connected to the input of the photodetector. The output of the photodetector is connected to the input of the signal amplifier. The output of the signal amplifier is connected to the input of the high-speed A / D conversion card. The output of the high-speed A / D conversion card is connected to the input of the digital controller. The output of the digital controller is connected to the input of the high-speed D / A conversion card and the computer. The output of the high-speed D / A conversion card is connected to the input of the tunable fiber optic filter.
[0049] The dual-wavelength laser source can output composite optical signals of different wavelengths; the optical demultiplexer can separate the composite optical signals of different wavelengths output by the dual-wavelength laser source according to their different wavelengths, thus obtaining lasers of different wavelengths. Therefore, two lasers of different wavelengths can be obtained by using a dual-wavelength laser source and an optical demultiplexer, thereby enabling synchronous measurement of the beginning and end of a ring optical fiber using two lasers of different wavelengths.
[0050] Optical isolators are placed between the dual-wavelength laser source and the fiber coupler to reduce the adverse effects of reflected light on the stability of the spectral output power of the source. Backward transmission of light generates additional noise, which degrades system performance and also requires optical isolators to eliminate.
[0051] Fiber optic couplers can precisely connect the two end faces of an optical fiber to maximize the coupling of the light energy output from the transmitting fiber to the receiving fiber and integrate it into the optical link, thereby minimizing the impact on the system. Their function is to multiplex light of different wavelengths into a single optical fiber, with different wavelengths carrying different information, thus realizing the splitting / combining of optical signals.
[0052] Preferably, the wavelength of the composite optical signal output by the dual-wavelength laser source can be set by the user, and the fiber coupler and optical demultiplexer are located in the same place.
[0053] An optical demultiplexer connects both the beginning and end of a ring fiber. The composite optical signal emitted by the dual-wavelength laser source passes through an optical isolator, a fiber coupler, and the optical demultiplexer. The optical demultiplexer splits the signal into two independent single-wavelength lasers, which are then sent to the beginning and end of the fiber, respectively. The lasers propagate along the fiber and illuminate a point x on the fiber, producing two wavelengths of reflected light. According to the principle of optical reversibility, the reflected light returns to the fiber coupler, passes through a tunable fiber filter, and is detected by a photodetector and its measurement circuit. The distance can be calculated based on the time difference between the laser pulse emission and the received echo.
[0054] Tunable fiber optic filters are bandpass filters with a certain filtering range, filtering area, and tunable range. They can select the desired wavelength from multiple wavelengths, filter out useless or unwanted wavelength components in the signal, ensure maximum signal transmission efficiency, and also have the functions of filtering noise, improving signal-to-noise ratio, and equalizing gain.
[0055] The composite laser pulse emits a forward composite optical signal containing two different wavelengths. The two ends of the ring fiber are synchronously measured by an optical splitter. The composite optical signal illuminates the fiber and generates reflected light carrying ranging information. The reflected light carrying ranging information returns through the fiber coupler and is still a backward composite optical signal of two wavelengths. The reflected light of one wavelength is filtered out each time by a tunable fiber filter and processed by a digital controller to filter out the reflected light of the other wavelength and other noise.
[0056] Filtering the composite optical signal of reflected light also includes:
[0057] The high-speed D / A converter card converts two discrete signals of specific wavelengths into continuous analog signals, and the analog signals are used as modulation signals for tunable fiber optic filters. Since the wavelength of the emitted light signal is known, the wavelength of the reflected light is also known. The digital controller can set the wavelength of the reflected light to be filtered, thereby obtaining two discrete signals of specific wavelengths and inputting them into the high-speed D / A converter card.
[0058] The modulation signal provided by the high-speed D / A converter card controls the tunable fiber filter to allow the reflected light signal of a specified wavelength to pass through. The modulation signal can adjust the passband center frequency of the tunable fiber filter to the frequency corresponding to a single reflected light signal.
[0059] The tunable fiber optic filter receives and processes the reflected wave signal corresponding to the wavelength, filters out the reflected light signal of a single wavelength required for each calculation by the digital controller, and realizes separate calculation and processing of the reflected light of two wavelengths.
[0060] Furthermore, the tunable fiber optic filter selects the reflected light of a specified wavelength, which is then converted into an electrical signal by a photodetector. This signal is then amplified by a signal amplifier. The amplified electrical signal is converted from continuous reflected light into discrete digital signals by a high-speed A / D converter card and sent to a digital controller for high-speed real-time processing. The digital controller can obtain the first measurement value m1 and the second measurement value m2 based on the two wavelengths of reflected light signals, and further calculate the ranging result.
[0061] Preferably, the present invention utilizes the high-speed parallel computing capability of the digital controller to perform time-division parallel processing on the reflected light signals of the two wavelengths, rather than performing multi-processor parallel processing in a strict sense.
[0062] Specifically, the digital controller in this invention can employ a Harvard architecture DSP, separating program and data processing, and possessing parallel processing capabilities, which can alleviate data access bottlenecks during program execution. It primarily performs real-time data processing functions such as digital smoothing filtering, discrete Fourier transform for spectrum analysis, discrete cosine transform for data compression, as well as functions such as specific wavelength optical signal selection, ranging calculation, and tunable fiber optic filter control.
[0063] During the measurement process, the digital controller performs high-speed sampling and calculates time, distance, etc., while the computer performs general functions such as database management, device interface, interface, and communication, realizing the calculation of systematic errors of synchronous measurement values at both ends of the ring fiber and correcting the output results.
[0064] The output of the digital controller is also connected to a computer. The digital controller can control the port connected to the optical splitter and the fiber coupler. In this invention, the digital controller calculates the systematic error by measuring the synchronous values at both ends of the ring fiber and corrects the output result. The computer can display the final result, and the user can control each device in the system through the computer.
[0065] Specifically, the ranging of the optical fiber by the digital controller also includes:
[0066] The total length s of the optical fiber can be obtained by printing length markings on the surface of the optical cable during optical fiber production to obtain an accurate value, or by using a meter counter of an optical fiber screening machine during the laying and deployment of the optical cable.
[0067] When using a distributed optical fiber sensor system, the optical path of the optical fiber coupler is synchronously connected to the beginning and end of the ring optical fiber by controlling the optical demultiplexer, and the reflected light from the beginning and end of the optical fiber is synchronously measured to obtain the first measurement value m1 and the second measurement value m2.
[0068] When measuring the fiber optic cable's head end, assuming the true distance from a point on the fiber to the head end is x, and considering the systematic error in distance calculation caused by time delay during the measurement process, denoted as Δl, the first measured value m1 is:
[0069] m1=x+Δl
[0070] When measuring the end of the optical fiber, the true distance x from the point on the fiber previously at the beginning is sx from the end. Since this invention can achieve synchronous measurement of both ends of the loop fiber using an optical splitter, the systematic error Δl during the measurement process can be considered constant. Therefore, the second measured value m2 is:
[0071] m2=s-x+Δl
[0072] Where s is the total length of the optical fiber.
[0073] Comparing the two equations above, the systematic error Δl can be obtained as follows:
[0074] m1+m2=s+2Δl
[0075]
[0076] Therefore, by taking two synchronized measurements, the systematic error caused by the time delay of the electronic device during the measurement process can be calculated, and then corrected in real time in the computer program to obtain an accurate final distance measurement result.
[0077] like Figure 2As shown, this invention also proposes a ranging method based on distributed optical fiber sensing technology. The ranging device based on distributed optical fiber sensing technology can achieve light ranging through this method. The ranging method specifically includes the following steps:
[0078] Step 1: Initialize the ranging device by simultaneously connecting the optical splitter in the ranging device to both the beginning and end of the ring fiber.
[0079] Step 2: The dual-wavelength laser source emits a composite optical signal. The composite optical signal passes through an optical isolator and an optical fiber coupler, propagates along the optical fiber, and illuminates a point x on the optical fiber, generating a composite reflected optical signal.
[0080] Dual-wavelength laser sources can output composite optical signals of different wavelengths. When the composite light shines on an optical fiber, the reflected light also includes two wavelengths.
[0081] Step 3: The composite reflected light signal returns to the fiber coupler, and the reflected light is filtered by a tunable fiber filter to obtain reflected light of a single wavelength.
[0082] Specifically, the reflected light carrying ranging information returns as a composite optical signal of two wavelengths after passing through the fiber coupler. After the composite optical signal passes through the fiber coupler and enters the tunable fiber filter, the tunable fiber filter selects only one wavelength of optical signal at a time and inputs it into the photodetector for subsequent processing. The two synchronously measured optical signals are processed in a time-division parallel manner using the high-speed parallel computing capability of the digital controller.
[0083] The filtering of composite reflected light signals by tunable fiber optic filters also includes:
[0084] The digital controller selects one of the wavelengths of the composite reflected light signal and provides a discrete signal of the corresponding wavelength to the high-speed D / A converter card, which converts it into a continuous analog signal as the modulation signal for the tunable fiber optic filter.
[0085] The modulation signal can control the wavelength of reflected light allowed to pass through the tunable fiber filter, and adjust the passband center frequency of the tunable fiber filter to the frequency corresponding to that wavelength.
[0086] Specifically, the signal is converted into an analog modulation signal by a high-speed D / A converter card, which is used as the modulation frequency of the tunable fiber optic filter. This adjusts the passband center frequency of the tunable fiber optic filter to the frequency corresponding to the wavelength, and then the reflected wave signal corresponding to the wavelength is received and processed.
[0087] Step 4: The tunable fiber optic filter sequentially transmits the filtered single-wavelength reflected light signals to the photodetector, signal amplifier, and high-speed A / D converter, and the ranging result of the fiber is calculated by the digital controller.
[0088] Specifically, step 4 also includes:
[0089] Step 4-1: The reflected light signal of a single wavelength enters the photodetector and is converted into an electrical signal, then enters the signal amplifier for amplification, and is converted into a digital signal by a high-speed A / D conversion card;
[0090] Understandably, the reflected light signal of a single wavelength filtered by the tunable fiber optic filter is a continuous analog signal, so it needs to be converted into a digital signal by a high-speed A / D converter card so that it can be processed by a digital controller.
[0091] Step 4-2: The converted digital signal is sent to the digital controller for processing, and the systematic error value of the optical fiber is measured.
[0092] The distance information contained in the reflected wave signal is obtained through high-speed real-time processing by a digital controller, and the systematic error value is calculated based on the distance information. Step 4-2 specifically includes:
[0093] Step 4-2-1: The digital controller obtains the first and second measurement values based on the digital signals corresponding to the reflected light signals of the two wavelengths.
[0094] Wherein, the first measured value m1 and the second measured value m2 respectively satisfy:
[0095] Assuming the true distance from a point on the optical fiber to the beginning is x, and considering the systematic error in distance calculation caused by time delay during the measurement process, denoted as Δl, then the first measured value m1 satisfies:
[0096] m1=x+Δl
[0097] The second measurement value m2 is the measurement value of the point on the fiber optic cable whose true distance to the beginning is x. The second measurement value m2 satisfies:
[0098] m ， =s-x+Δl
[0099] Where s is the total length of the optical fiber.
[0100] Step 4-2-1: Calculate the systematic error value based on the first and second measured values;
[0101] The systematic error value Δl satisfies:
[0102]
[0103] Complete one measurement according to steps 1 to 4 to obtain a systematic error value.
[0104] Step 5: Return to step 1 and repeat steps 1 to 4 to obtain multiple systematic error values. Take the average value as the final systematic error value to correct the ranging result. The obtained ranging result is displayed on the computer.
[0105] Specifically, by reducing the random error of a single measurement through multiple measurements, the theoretical allowable value of measurement error can be calculated based on the wavelength of light used and the sampling rate. When measurements that deviate significantly from previous measurements are removed, and the difference between the values of multiple measurements and the average value is within the range of the theoretical allowable error, the average value of the measurement results can be considered as the measurement result after eliminating random errors.
[0106] Preferably, in this invention, the systematic error value is measured at least twice, and the random error is averaged after multiple measurements, and the average value is taken as the final systematic error value; when multiple measurements are performed and there are values that deviate too much from the average value, that is, there are obvious deviation values, the systematic error values with obvious deviations are removed.
[0107] Users can view the ranging results and calculation process on a computer, and can also control the operation of various components in the system via computer.
[0108] The beneficial effects of this invention are that, compared with the prior art, the dual-wavelength laser source of this invention theoretically does not introduce errors through the optical demultiplexer, and the errors of the optical demultiplexer itself are also canceled out in the calculation formula for the measurement distance. Since there is no need to switch optical paths back and forth, the measurement speed is faster and the reliability is higher.
[0109] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.
[0110] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.
[0111] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.
[0112] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages such as Smalltalk, C++, etc., and conventional procedural programming languages such as C++ or similar languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of this disclosure.
[0113] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.
[0114] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.
[0115] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.
[0116] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.
[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.
Claims
1. A ranging device based on distributed fiber optic sensing technology, characterized in that, include: Dual-wavelength laser source, fiber optic coupler, optical splitter, tunable fiber optic filter, photodetector, signal amplifier, high-speed A / D converter card, digital controller, high-speed D / A converter card and computer; The output of the dual-wavelength laser source is connected to the input of the fiber optic coupler via an optical isolator. The output of the fiber optic coupler is connected to the input of the optical splitter and the tunable fiber optic filter, respectively. The output of the tunable fiber optic filter is connected to the input of the photodetector. The output of the photodetector is connected to the input of the signal amplifier. The output of the signal amplifier is connected to the input of the high-speed A / D conversion card. The output of the high-speed A / D conversion card is connected to the input of the digital controller. The output of the digital controller is connected to the input of the high-speed D / A conversion card and the computer, respectively. The output of the high-speed D / A conversion card is connected to the input of the tunable fiber optic filter. The composite optical signal emitted by the dual-wavelength laser source is sent to both ends of the optical fiber. The composite optical signal propagates along the optical fiber and illuminates a certain point on the fiber. x The system generates two wavelengths of reflected light, which are reflected back to the fiber coupler. The composite optical signal passes through the fiber coupler and enters the tunable fiber filter. The tunable fiber filter selects the reflected light signal of the specified wavelength, which is then converted into an electrical signal by a photodetector. The electrical signal then enters the signal amplifier and the high-speed A / D converter card in sequence, where it is converted into a discrete digital signal and sent to the digital controller for processing. The digital controller can obtain the first measurement value and the second measurement value respectively based on the reflected light signals of two wavelengths. Based on the first measurement value and the second measurement value, the digital controller can calculate the measurement distance information of the optical fiber. The calculated fiber optic distance information also includes: When measuring the beginning of the fiber, assume the true distance from a point on the fiber to the beginning is... x Considering the systematic error in distance calculation caused by time delay during the measurement process, it is denoted as... The first measurement value obtained is... for: When measuring the end, the true value of the distance from the beginning of the fiber on the previous fiber. x The true value of the distance from the end is , s To measure the total length of the optical fiber, systematic errors during the measurement process are considered. If it remains unchanged, the second measurement value is obtained. for: According to the first measurement value Second measurement value The systematic error was obtained. as follows: 。 2. The ranging device based on distributed optical fiber sensing technology according to claim 1, characterized in that, The optical demultiplexer connects both the beginning and end of the ring fiber. The composite optical signal emitted by the dual-wavelength laser source passes through the optical isolator, fiber coupler, and optical demultiplexer. The optical demultiplexer splits the signal into two independent single-wavelength lasers, which are then sent to the beginning and end of the fiber, respectively.
3. The ranging device based on distributed optical fiber sensing technology according to claim 1, characterized in that, The photodetector converts the reflected light signal of a single wavelength into an electrical signal. Based on the reflected light of a single wavelength, the beginning and end of the optical fiber are measured and the measurement distance of the optical fiber is calculated.
4. The ranging device based on distributed optical fiber sensing technology according to claim 1, characterized in that, Filtering reflected light signals using tunable fiber optic filters also includes: The high-speed D / A converter card converts two discrete signals of specific wavelengths into continuous analog signals, and the analog signals are used as modulation signals for tunable fiber optic filters. The modulation signal provided by the high-speed D / A converter card controls the tunable fiber filter to allow the reflected light signal of a specified wavelength to pass through. The modulation signal can adjust the passband center frequency of the tunable fiber filter to the frequency corresponding to a single reflected light signal. The tunable fiber optic filter receives and processes the reflected light signal corresponding to the wavelength, filters out the reflected light signal of a single wavelength required for each calculation by the digital controller, and realizes separate calculation and processing of the reflected light of the two wavelengths.
5. The ranging device based on distributed optical fiber sensing technology according to claim 1, characterized in that, The digital controller performs time-division parallel processing on the two wavelengths of reflected light signals.
6. The ranging device based on distributed optical fiber sensing technology according to claim 1, characterized in that, The electrical signal is amplified by a signal amplifier. The amplified electrical signal is then converted into discrete digital signals by a high-speed A / D converter card and sent to a digital controller for high-speed real-time processing.
7. A ranging method based on distributed fiber optic sensing technology using the ranging device according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Initialize the ranging device by simultaneously connecting the optical splitter in the ranging device to both the beginning and end of the ring fiber. Step 2: The dual-wavelength laser source emits a composite optical signal. The composite optical signal propagates along the optical fiber through the optical isolator and fiber coupler, illuminating a point on the optical fiber. x This generates a composite reflected light signal; Step 3: The composite reflected light signal returns to the fiber coupler, and the reflected light is filtered by a tunable fiber filter to obtain reflected light of a single wavelength. Step 4: The tunable fiber optic filter sequentially transmits the filtered single-wavelength reflected light signals to the photodetector, signal amplifier, and high-speed A / D converter, and the ranging result of the fiber is calculated by the digital controller. Step 5: Return to step 1 and repeat steps 1 to 4 to obtain multiple systematic error values. Take the average value as the final systematic error value to correct the ranging result. The obtained ranging result is displayed on the computer.
8. The ranging method based on distributed optical fiber sensing technology according to claim 7, characterized in that, In step 5, random errors in a single measurement are reduced by taking multiple measurements, outlier data is eliminated, and the average of all systematic error values is calculated as the final measurement result.
9. A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 7 to 8.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method described in any one of claims 7 to 8.