CN-122016028-A - Grating array vibration sensing demodulator and train positioning system

CN122016028ACN 122016028 ACN122016028 ACN 122016028ACN-122016028-A

Abstract

The invention provides a grating array vibration sensing demodulator and a train positioning system, wherein the grating array vibration sensing demodulator comprises a light source, a sensing optical cable, an interferometer and a processing unit, wherein the light source is used for generating and outputting detection pulse light to the sensing optical cable, the sensing optical cable is arranged along a train track and used for sensing vibration caused by train running and generating a return light signal, the interferometer is used for converting the return light signal into a target light signal carrying vibration phase information, the processing unit is used for receiving the target light signal and carrying out double-channel independent demodulation on the target light signal to obtain a first demodulation result and a second demodulation result, and when the first demodulation result and the second demodulation result are identical, the first demodulation result or the second demodulation result is used as an effective vibration sensing state signal. The invention adopts a dual-channel independent demodulation and result comparison mechanism, improves the demodulation reliability of the grating array vibration sensing demodulator, and can be directly applied to train control scenes with extremely high safety requirements.

Inventors

XU YIMIN
WANG HONGHAI
HUANG LONGTING
JIANG DESHENG
WANG LIXIN

Assignees

武汉理工大学

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (10)

1. A grating array vibration sensing demodulator is characterized by comprising a light source, a sensing optical cable, an interferometer and a processing unit; The light source is used for generating and outputting detection pulse light to the sensing optical cable; The sensing optical cable is arranged along the train track and is used for sensing vibration caused by train running and generating a return light signal; the interferometer is used for converting the return optical signal into a target optical signal carrying vibration phase information; The processing unit is used for receiving the target optical signal, performing dual-channel independent demodulation on the target optical signal to obtain a first demodulation result and a second demodulation result, and taking the first demodulation result or the second demodulation result as an effective vibration perception state signal when the first demodulation result and the second demodulation result are the same.
2. The grating array vibration sensor demodulator of claim 1, wherein the processing unit comprises a splitter and independent first path processing unit, second path processing unit and comparison unit; The splitter is used for splitting the target optical signal into a first path of optical signal and a second path of optical signal; the first path of processing unit is used for demodulating the first path of optical signals to generate a first demodulation result; The second path processing unit is used for demodulating the second path optical signal to generate a second demodulation result; The comparison unit is configured to determine whether the first demodulation result and the second demodulation result are the same, if so, take the first demodulation result or the second demodulation result as the effective vibration sensing state signal, and if not, discard the first demodulation result and the second demodulation result.
3. The grating array vibration sensor demodulator of claim 2, wherein the first path processing unit and the second path processing unit each comprise a photodetector, an analog-to-digital converter, a first FPGA chip and a second FPGA chip; the photoelectric detector is used for converting the first path of optical signals or the second path of optical signals into analog electric signals; the analog-to-digital converter is used for converting the analog electric signal into a digital electric signal; The first FPGA chip is used for demodulating the digital electric signal to obtain a vibration phase signal; The second FPGA chip is used for generating the first demodulation result or the second demodulation result based on the vibration phase signal.
4. A grating array vibration transducer demodulator according to claim 3, wherein the sampling rate of the analog-to-digital converter is not less than 250MHz.
5. The grating array vibration sensor demodulator of claim 1, wherein the light source comprises a laser and a pulse modulation module; The laser is used for generating laser, and the pulse modulation module is used for carrying out pulse modulation on the laser to generate pulse light.
6. The grating array vibration sensor demodulator of claim 5, wherein the line width of the pulsed light is less than or equal to 100kHz.
7. The grating array vibration sensor demodulator of claim 1, further comprising a power supply for powering the light source and the processing unit.
8. The grating array vibration sensor demodulator of claim 1, wherein the interferometer is a mach-zehnder interferometer.
9. The grating array vibration sensor demodulator of claim 1, further comprising an amplifier disposed between the sensing fiber optic cable and the interferometer, the amplifier configured to amplify the return optical signal for transmission to the interferometer.
10. The train positioning system is characterized by comprising a grating array vibration sensing demodulator and an upper computer; the grating array vibration sensing demodulator is used for acquiring an effective vibration sensing state signal in the running process of the train; The upper computer is used for determining the train position, the train running direction and the train running speed based on the effective vibration sensing state signal; Wherein the grating array vibration sensing demodulator is the grating array vibration sensing demodulator according to any one of claims 1 to 9.

Description

Grating array vibration sensing demodulator and train positioning system Technical Field The invention relates to the technical field of grating array sensing, in particular to a grating array vibration sensing demodulator and a train positioning system. Background In the fields of train operation control and state monitoring, the realization of high-precision and high-reliability perception of parameters such as train position and the like is a key technology. Conventional train positioning systems rely primarily on electrical type sensors, such as axle gauges or track circuits. These techniques form section positioning capability by deploying sensors at kilometer level intervals (e.g., 1 kilometer) along the track. The method has inherent limitations that firstly, the positioning accuracy is limited by the distance between the sensors, which is usually only kilometer level, and the method can not meet the requirements of the modern train on fine control, and secondly, the system is complex in layout, high in cost and easy to be subjected to electromagnetic interference. To overcome the above drawbacks, the industry is beginning to explore new generation solutions based on grating array sensing technology. The technology uses the grating continuously inscribed in the optical fiber as a sensing unit, and can carry out distributed and high-precision measurement on physical quantities such as vibration, strain, temperature and the like along the line. In theory, the positioning accuracy and the information richness far exceeding the traditional technology can be realized by sensing the rail vibration caused by the train operation and positioning by utilizing the grating with the meter-level interval in the sensing optical cable. However, applying this theory to high safety demand train control still faces a key challenge in constructing a dedicated demodulator that can meet the ultra-high reliability requirements of the train control system. The existing general optical fiber sensing demodulation scheme generally adopts a single signal processing link, the reliability of the single signal processing link cannot meet the level requirement of train safety, and single-point faults can cause wrong vibration or positioning signal output, which is absolutely impermissible in a train control scene. Therefore, it is desirable to provide a grating array vibration sensing demodulator and a train positioning system, which can accurately determine a train vibration sensing state signal so as to improve the accuracy of train positioning based on the signal. Disclosure of Invention In view of the above, it is necessary to provide a grating array vibration sensing demodulator and a train positioning system for solving the technical problems that in the prior art, demodulation is performed based on a single demodulation channel, reliability is insufficient, and thus, the high-reliability and high-safety requirements of train positioning cannot be adapted, and the demodulation result is incorrect, and thus, the train positioning cannot be effectively realized. In order to solve the technical problems, the first aspect of the invention provides a grating array vibration sensing demodulator, which comprises a light source, a sensing optical cable, an interferometer and a processing unit; The light source is used for generating and outputting detection pulse light to the sensing optical cable; The sensing optical cable is arranged along the train track and is used for sensing vibration caused by train running and generating a return light signal; the interferometer is used for converting the return optical signal into a target optical signal carrying vibration phase information; The processing unit is used for receiving the target optical signal, performing dual-channel independent demodulation on the target optical signal to obtain a first demodulation result and a second demodulation result, and taking the first demodulation result or the second demodulation result as an effective vibration perception state signal when the first demodulation result and the second demodulation result are the same. In one possible implementation manner, the processing unit comprises a splitter, a first path of processing unit, a second path of processing unit and an alignment unit which are independent; The splitter is used for splitting the target optical signal into a first path of optical signal and a second path of optical signal; the first path of processing unit is used for demodulating the first path of optical signals to generate a first demodulation result; The second path processing unit is used for demodulating the second path optical signal to generate a second demodulation result; The comparison unit is configured to determine whether the first demodulation result and the second demodulation result are the same, if so, take the first demodulation result or the second demodulation result as the effective vibration sensing state signa