High-speed magnetic suspension system positioning and speed measuring device and method based on wavelength detection

Abstract

The invention provides a high-speed magnetic suspension system positioning and speed measuring device and method based on wavelength detection. The device comprises a vehicle-mounted light source assembly arranged at a vehicle-mounted end, and a ground detection assembly and a control unit which are arranged at a ground end, the vehicle-mounted light source assembly comprises a plurality of laser emitters which are sequentially arranged at equal intervals in the train running direction. Each laser emitter is used for emitting laser with different wavelengths; the ground detection assembly comprises a plurality of ground detectors which are sequentially arranged at equal intervals in the running direction of the train; the ground detector in the light source coverage area is used for receiving laser emitted by the corresponding laser emitter and sending the laser to the control unit; the control unit is used for acquiring the absolute position of the ground detector corresponding to the wavelength of the received laser; the distance acquisition module is used for acquiring the distance between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end; and acquiring the position and speed of the train.

Description

Technical Field

[0001] This invention relates to the field of high-speed magnetic levitation technology, and in particular to a positioning and speed measuring device and method for a high-speed magnetic levitation system based on wavelength detection. Background Technology

[0002] High-speed magnetic levitation systems require high-precision positioning and speed measurement systems for superconducting synchronous motor control during high-speed operation. Due to the high operating speed and short control cycle of the system, the requirements for the accuracy, time delay and reliability of the positioning and speed measurement system are extremely high. It is necessary to design a positioning and speed measurement system with high precision, low delay and high reliability in strong electromagnetic interference environment.

[0003] Currently, there are two main methods for positioning and speed measurement in high-speed maglev systems:

[0004] One method involves detecting the wavelength of fiber Bragg gratings (FBGs). This method involves etching multiple FBGs onto a sensing grating and using an onboard permanent magnet to apply continuous stress to the FBGs on the sensing fibers along the track, causing a continuous change in the FBG wavelength. The train's position and speed are then calculated by detecting these wavelength changes. However, this method has the following drawbacks: 1. High cost: It requires at least five fibers with FBGs etched onto them to be deployed along the entire track. 2. Large time delay: The wavelength of the fiber needs to be detected at the terminal, resulting in a large calculation time delay. 3. Large error, making it difficult to apply in engineering: Because the high-speed maglev train's attitude is constantly changing and adjusting during operation, the stress on the FBGs is constantly changing, leading to large errors and making engineering applications difficult. 4. The system starts up without an initial position.

[0005] The second method is using a laser rangefinder. This method involves mounting a laser rangefinder on the vehicle and setting up convex and concave structures or triangular rulers on the ground. When the train passes, the onboard laser rangefinder detects the distance changes, thus determining the train's position and speed. However, this method has the following disadvantages: 1. High cost: It requires convex and concave structures or triangular rulers to be installed along the entire track; 2. Large time delay: In high-speed maglev systems, the train's position and speed signals need to be transmitted to the ground traction system, resulting in a large time delay due to the vehicle-to-ground wireless communication system; 3. The system starts up without an initial position. Summary of the Invention

[0006] This invention provides a positioning and speed measuring device and method for a high-speed magnetic levitation system based on wavelength detection, which can solve the above-mentioned technical problems.

[0007] According to one aspect of the present invention, a positioning and speed measuring device for a high-speed magnetic levitation system based on wavelength detection is provided. The device includes an on-board light source assembly disposed on the vehicle end and a ground detection assembly and a control unit disposed on the ground end.

[0008] The vehicle-mounted light source assembly includes multiple laser emitters arranged at equal intervals along the direction of train travel; each laser emitter is used to emit laser light of a different wavelength.

[0009] The ground detection assembly includes multiple ground detectors arranged at equal intervals along the train's direction of travel; the ground detectors within the light source's coverage area are used to receive laser light emitted by the corresponding laser emitter and transmit it to the control unit;

[0010] The control unit is used to obtain the absolute position of the ground detector corresponding to the wavelength of the received laser; to obtain the distance between the laser emitter corresponding to the wavelength of the received laser and the laser emitter at the starting end; and to obtain the position of the train based on the absolute position of the ground detector corresponding to the wavelength of the received laser, the distance between the laser emitter corresponding to the wavelength of the received laser and the laser emitter at the starting end, and the distance between the laser emitter at the starting end and the center position of the train, and to obtain the speed of the train based on the position of the train; wherein, the laser emitter at the starting end is the laser emitter at the foremost point along the direction of train operation.

[0011] Preferably, the train's position is obtained using the following formula:

[0012] S T =S1+S2-S3

[0013] Wherein, if the laser transmitter corresponding to the wavelength of the received laser is the laser transmitter at the starting end, S2 = 0; if the laser transmitter corresponding to the wavelength of the received laser is not the laser transmitter at the starting end, S2 = (N+1)*A.

[0014] In the formula, S T S1 represents the absolute position of the ground detector corresponding to the wavelength of the received laser, S2 represents the distance between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, N represents the number of laser transmitters between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, A represents the spacing between two adjacent laser transmitters, and S3 represents the distance between the laser transmitter at the starting end and the center position of the train.

[0015] Preferably, the train speed is obtained by the following formula:

[0016] V T =(S T2 -S T1 ) / t

[0017] In the formula, V T S represents the speed of the train. T1 S represents the train's position at the previous moment. T2This indicates the position of the train after time t since the previous moment, where t represents time.

[0018] Preferably, the spacing between two adjacent ground detectors is less than half the length of the vehicle-mounted light source assembly. In this case, the control unit is also used to perform redundant switching based on the train position obtained by the covered ground detectors.

[0019] Preferably, the ground detector is switched when the train position corresponding to the ground detector currently covered by the train is the same as the train position corresponding to the ground detector newly entering the light source coverage area.

[0020] Preferably, the wavelength of each laser emitter is sequentially increased by a preset wavelength in either the forward or reverse direction of the train's running direction.

[0021] Preferably, the laser wavelength range of the plurality of laser emitters is 400nm to 1300nm, and the preset wavelength range is 5 to 10nm.

[0022] Preferably, each of the ground detectors includes two photoelectric sensors arranged along the direction of train operation, the distance between the two photoelectric sensors is (A*n+A / 2), and the width of the receiving window of each photoelectric sensor is A / 2, where A is the interval between adjacent laser emitters and n is any positive integer.

[0023] According to another aspect of the present invention, a positioning and speed measurement method for a high-speed magnetic levitation system based on wavelength detection is provided. The method performs positioning and speed measurement on any of the aforementioned devices, and includes:

[0024] During train operation, each laser emitter emits laser light of a different wavelength.

[0025] The ground detector within the light source's coverage area receives the laser emitted by the corresponding laser emitter and transmits it to the control unit;

[0026] The control unit obtains the absolute position of the ground detector corresponding to the wavelength of the received laser;

[0027] The control unit obtains the distance between the laser emitter corresponding to the wavelength of the received laser and the laser emitter at the starting end;

[0028] The control unit obtains the train's position based on the absolute position of the ground detector corresponding to the wavelength of the received laser, the distance between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, and the distance between the laser transmitter at the starting end and the center position of the train.

[0029] The control unit obtains the train's speed based on the train's location.

[0030] Preferably, when the distance between two adjacent ground detectors is less than half the length of the vehicle-mounted light source assembly, the control unit simultaneously obtains the train position corresponding to the ground detector currently covered by the train and the train position corresponding to the ground detector newly entering the light source coverage area.

[0031] The control unit determines whether the train position corresponding to the ground detector currently covered by the train is the same as the train position corresponding to the ground detector newly entering the light source coverage area. If so, the control unit determines that the ground detector newly entering the light source coverage area is functioning normally and obtains the train position through the ground detector newly entering the light source coverage area; otherwise, the control unit determines that the ground detector newly entering the light source coverage area is malfunctioning, continues to use the train position corresponding to the currently covered ground detector, and waits for the next ground detector newly entering the light source coverage area to perform verification.

[0032] By applying the technical solution of this invention and designing different wavelength codes, structured optical positioning and velocimetry are achieved. Compared with the prior art, this invention has the following beneficial effects:

[0033] 1. Capable of high-precision position detection with a value not exceeding A / 2mm;

[0034] 2. It can achieve extremely low latency detection of no more than 10µs;

[0035] 3. It can achieve a speed measurement range from 0km / h to 1800km / h;

[0036] 4. Design redundancy functions for the system to achieve high reliability. Attached Figure Description

[0037] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0038] Figure 1 A schematic diagram of a positioning and speed measuring device for a high-speed magnetic levitation system based on wavelength detection is shown according to an embodiment of the present invention.

[0039] Figure 2 It shows Figure 1 Top view of the CRRC onboard light source assembly;

[0040] Figure 3 It shows Figure 1 Side view of the CRRC vehicle's onboard light source assembly;

[0041] Figure 4 It shows Figure 1 Side view of the ground-based detector.

[0042] The above figures include the following reference numerals:

[0043] 10. Vehicle-mounted light source assembly; 11. Laser emitter; 20. Ground detection assembly; 21. Ground detector; 211. Receiving window; 30. Control unit. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0047] like Figures 1-3As shown, the present invention provides a positioning and speed measuring device for a high-speed magnetic levitation system based on wavelength detection. The device includes an on-board light source assembly 10 installed on the vehicle and a ground detection assembly 20 and a control unit 30 installed on the ground.

[0048] The vehicle-mounted light source assembly 10 includes a plurality of laser emitters 11 arranged at equal intervals along the direction of train travel; each laser emitter 11 is used to emit lasers of different wavelengths;

[0049] The ground detection component 20 includes a plurality of ground detectors 21 arranged at equal intervals along the train's direction of travel; the ground detectors 21 located within the light source coverage area are used to receive lasers emitted by the corresponding laser emitter 11 and transmit them to the control unit 30;

[0050] The control unit 30 is used to obtain the absolute position of the ground detector 21 corresponding to the wavelength of the received laser; to obtain the distance between the laser emitter 11 corresponding to the wavelength of the received laser and the laser emitter 11 at the starting end; and to obtain the position of the train based on the absolute position of the ground detector 21 corresponding to the wavelength of the received laser, the distance between the laser emitter 11 corresponding to the wavelength of the received laser and the laser emitter 11 at the starting end, and the distance between the laser emitter 11 at the starting end and the center position of the train, and to obtain the speed of the train based on the position of the train; wherein, the laser emitter 11 at the starting end is the laser emitter 11 at the very front along the direction of train travel. Figure 2 Laser emitter 11, numbered 1 in the middle.

[0051] By applying the technical solution of this invention and designing different wavelength codes, structured optical positioning and velocimetry are achieved. Compared with the prior art, this invention has the following beneficial effects:

[0052] 1. Capable of high-precision position detection with a value not exceeding A / 2mm;

[0053] 2. It can achieve extremely low latency detection of no more than 10µs;

[0054] 3. It can achieve a speed measurement range from 0km / h to 1800km / h;

[0055] 4. Design redundancy functions for the system to achieve high reliability.

[0056] In this invention, multiple laser emitters 11 form a fan-shaped light array with alternating bright and dark areas to create a precise optical environment. The length of the array can be set according to the vehicle length. Each laser emitter 11 has a redundant structure consisting of two laser light sources. When one light source fails, a switching circuit automatically activates the backup light source.

[0057] According to one embodiment of the present invention, each laser emitter 11 uses a different wavelength, which can be selected between 400nm and 1300nm. When used outdoors, the wavelength is limited to between 820nm and 1300nm. To facilitate calculation and engineering maintenance by the control unit 30, the wavelength of each laser emitter 11 is increased by a preset wavelength sequentially in the forward or reverse direction of the train's running direction. That is, the laser wavelength can be increased by B (nm) sequentially from left to right or from right to left. The value of B ranges from 5 to 10nm.

[0058] According to one embodiment of the present invention, the distance between two adjacent ground detectors 21 is less than half the length of the vehicle-mounted light source assembly 10. In this case, the control unit 30 is also used to perform redundant switching based on the train position obtained by the covered ground detectors 21.

[0059] With the above settings, the vehicle-mounted light source assembly 10 can simultaneously cover two ground detectors 21, realizing the redundancy function of the ground detectors 21 receiving signals; the interval can also be set to 1 / 3 of the length of the vehicle-mounted light source assembly 10 to realize the 3-out-of-2 redundancy mode, which can realize the redundancy function of the ground detectors 21 receiving signals.

[0060] According to one embodiment of the present invention, when the train position corresponding to the ground detector 21 currently covered by the train is the same as the train position corresponding to the ground detector 21 newly entering the light source coverage area, the ground detector 21 is switched.

[0061] According to one embodiment of the present invention, such as Figure 4 As shown, each of the ground detectors 21 includes two photoelectric sensors arranged along the train running direction. The distance between the two photoelectric sensors is (A*n+A / 2), and the width of the receiving window 211 of each photoelectric sensor is A / 2, where A is the interval between adjacent laser emitters 11, and n is any positive integer.

[0062] With the above setup, the two photoelectric sensors form orthogonal signals, enabling absolute position detection after power-on.

[0063] According to one embodiment of the present invention, the control unit 30 receives signals from the ground detector 21 and calculates the train's speed and position based on the installation position of the ground detector 21 and the wavelength of the received laser. The control unit 30 uses FPGA high-speed computing, which can achieve a position detection error of no more than A / 2mm, a detection delay of no more than 10µs, and a speed measurement range from 0km / h to 1800km / h.

[0064] Specifically, the train's location is obtained using the following formula:

[0065] ST =S1+S2-S3

[0066] Wherein, if the laser transmitter corresponding to the wavelength of the received laser is the laser transmitter at the starting end, S2 = 0; if the laser transmitter corresponding to the wavelength of the received laser is not the laser transmitter at the starting end, S2 = (N+1)*A.

[0067] In the formula, S T S1 represents the absolute position of the ground detector corresponding to the wavelength of the received laser, S2 represents the distance between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, N represents the number of laser transmitters between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, A represents the spacing between two adjacent laser transmitters, and S3 represents the distance between the laser transmitter at the starting end and the center position of the train.

[0068] After the train moves, as the received laser wavelength changes, the change in position is calculated. The train speed is then calculated by differentiating the position with respect to time. Specifically, the train speed is obtained using the following formula:

[0069] V T =(S T2 -S T1 ) / t

[0070] In the formula, V T S represents the speed of the train. T1 S represents the train's position at the previous moment. T2 This indicates the position of the train after time t since the previous moment, where t represents time.

[0071] The present invention also provides a positioning and speed measurement method for a high-speed magnetic levitation system based on wavelength detection, the method performing positioning and speed measurement on any of the above-mentioned devices, the method comprising:

[0072] During train operation, each laser emitter 11 emits lasers of different wavelengths;

[0073] The ground detector 21, located within the coverage area of ​​the light source, receives the laser emitted by the corresponding laser emitter 11 and transmits it to the control unit 30;

[0074] The control unit 30 obtains the absolute position of the ground detector 21 corresponding to the wavelength of the received laser;

[0075] The control unit 30 obtains the distance between the laser emitter 11 corresponding to the wavelength of the received laser and the laser emitter 11 at the starting end;

[0076] The control unit 30 obtains the position of the train based on the absolute position of the ground detector 21 corresponding to the wavelength of the received laser, the distance between the laser transmitter 11 corresponding to the wavelength of the received laser and the laser transmitter 11 at the starting end, and the distance between the laser transmitter 11 at the starting end and the center position of the train.

[0077] The control unit 30 obtains the train speed based on the train's position.

[0078] According to one embodiment of the present invention, when the distance between two adjacent ground detectors 21 is less than half the length of the vehicle-mounted light source assembly 10, the control unit 30 simultaneously obtains the train position corresponding to the ground detector 21 currently covered by the train and the train position corresponding to the ground detector 21 newly entering the light source coverage area.

[0079] The control unit 30 determines whether the train position corresponding to the ground detector 21 currently covered by the train is the same as the train position corresponding to the ground detector 21 newly entering the light source coverage area. If so, the control unit 30 determines that the ground detector 21 newly entering the light source coverage area is functioning normally and obtains the train position through the ground detector 21 newly entering the light source coverage area; otherwise, the control unit 30 determines that the ground detector 21 newly entering the light source coverage area is malfunctioning, continues to use the train position corresponding to the currently covered ground detector 21, and waits for the next ground detector 21 newly entering the light source coverage area to perform verification.

[0080] For example, if the ground detector 21 currently covered by the train is R1, and a new ground detector 21 R2 enters the coverage area of ​​the light source, the control unit 30 simultaneously calculates the train's position S from the feedback signals of the two ground detectors 21. C1 and S C2 During the train's movement of S (mm), the control unit 30 verifies S. C1 and S C2 If the two positions are the same, the newly entered ground detector 21R2 is considered to be functioning normally, and the position data is calculated using the result of the newly entered ground detector 21R2; otherwise, the newly entered ground detector 21R2 is considered to be functioning abnormally, and the calculation result of ground detector 21R1 is used again, waiting for the next newly entered ground detector 21 to perform verification.

[0081] In summary, this invention provides a positioning and speed measurement device and method for a high-speed magnetic levitation system based on wavelength detection. Compared with the prior art, this invention has the following advantages:

[0082] 1. Capable of high-precision position detection with a value not exceeding A / 2mm;

[0083] 2. It can achieve extremely low latency detection of no more than 10µs;

[0084] 3. It can achieve a speed measurement range from 0km / h to 1800km / h;

[0085] 4. Design redundancy functions for the system to achieve high reliability.

[0086] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0087] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0088] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0089] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A positioning and speed measuring device for a high-speed magnetic levitation system based on wavelength detection, characterized in that, The device includes an on-board light source assembly mounted on the vehicle and a ground detection assembly and control unit mounted on the ground. The vehicle-mounted light source assembly includes multiple laser emitters arranged at equal intervals along the direction of train travel; each laser emitter is used to emit laser light of a different wavelength. The ground detection assembly includes multiple ground detectors arranged at equal intervals along the train's direction of travel; the ground detectors within the light source's coverage area are used to receive laser light emitted by the corresponding laser emitter and transmit it to the control unit; The control unit is used to obtain the absolute position of the ground detector corresponding to the wavelength of the received laser; to obtain the distance between the laser emitter corresponding to the wavelength of the received laser and the laser emitter at the starting end; and to obtain the position of the train based on the absolute position of the ground detector corresponding to the wavelength of the received laser, the distance between the laser emitter corresponding to the wavelength of the received laser and the laser emitter at the starting end, and the distance between the laser emitter at the starting end and the center position of the train, and to obtain the speed of the train based on the position of the train; wherein, the laser emitter at the starting end is the laser emitter at the foremost point along the direction of train operation.

2. The apparatus according to claim 1, characterized in that, The train's position can be obtained using the following formula: S T S1+S2-S3 Wherein, if the laser transmitter corresponding to the wavelength of the received laser is the laser transmitter at the starting end, S2 = 0; if the laser transmitter corresponding to the wavelength of the received laser is not the laser transmitter at the starting end, S2 = (N+1)*A. In the formula, S T S1 represents the absolute position of the ground detector corresponding to the wavelength of the received laser, S2 represents the distance between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, N represents the number of laser transmitters between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, A represents the spacing between two adjacent laser transmitters, and S3 represents the distance between the laser transmitter at the starting end and the center position of the train.

3. The apparatus according to claim 1 or 2, characterized in that, The train speed is obtained using the following formula: V T =(S T2 -S T1 ) / t In the formula, V T S represents the speed of the train. T1 S represents the train's position at the previous moment. T2 This indicates the position of the train after time t since the previous moment, where t represents time.

4. The apparatus according to any one of claims 1-3, characterized in that, When the distance between two adjacent ground detectors is less than half the length of the vehicle-mounted light source assembly, the control unit is also used to perform redundant switching based on the train position obtained by the covered ground detectors.

5. The apparatus according to claim 4, characterized in that, When the train position corresponding to the ground detector currently covered by the train is the same as the train position corresponding to the ground detector newly entering the light source coverage area, the ground detector is switched.

6. The apparatus according to claim 1, characterized in that, The wavelength of each laser emitter is sequentially increased by a preset wavelength in either the forward or reverse direction of the train's running direction.

7. The apparatus according to claim 1, characterized in that, The laser wavelength range of the multiple laser emitters is 400nm to 1300nm, and the preset wavelength range is 5-10nm.

8. The apparatus according to claim 1, characterized in that, Each of the ground detectors includes two photoelectric sensors arranged along the direction of train operation, with a spacing of (A*n+A / 2) between the two photoelectric sensors and a receiving window width of A / 2 for each photoelectric sensor, where A is the interval between adjacent laser emitters and n is any positive integer.

9. A positioning and speed measurement method for a high-speed magnetic levitation system based on wavelength detection, characterized in that, The method performs positioning and speed measurement on the device according to any one of claims 1-8, the method comprising: During train operation, each laser emitter emits laser light of a different wavelength. The ground detector within the light source's coverage area receives the laser emitted by the corresponding laser emitter and transmits it to the control unit; The control unit obtains the absolute position of the ground detector corresponding to the wavelength of the received laser; The control unit obtains the distance between the laser emitter corresponding to the wavelength of the received laser and the laser emitter at the starting end; The control unit obtains the train's position based on the absolute position of the ground detector corresponding to the wavelength of the received laser, the distance between the laser transmitter corresponding to the wavelength of the received laser and the laser transmitter at the starting end, and the distance between the laser transmitter at the starting end and the center position of the train. The control unit obtains the train's speed based on the train's location.

10. The method according to claim 9, characterized in that, When the distance between two adjacent ground detectors is less than half the length of the on-board light source assembly, the control unit simultaneously obtains the train position corresponding to the ground detector currently covered by the train and the train position corresponding to the ground detector newly entering the light source coverage area. The control unit determines whether the train position corresponding to the ground detector currently covered by the train is the same as the train position corresponding to the ground detector newly entering the light source coverage area. If so, the control unit determines that the ground detector newly entering the light source coverage area is functioning normally and obtains the train position through the ground detector newly entering the light source coverage area; otherwise, the control unit determines that the ground detector newly entering the light source coverage area is malfunctioning, continues to use the train position corresponding to the currently covered ground detector, and waits for the next ground detector newly entering the light source coverage area to perform verification.

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