A train positioning method based on sleeper coding

Abstract

A train positioning method based on sleeper coding comprises the following steps: formulating a coding protocol, and drawing the sleeper coding on the sleeper along the track line according to the coding protocol as a positioning target for the train positioning; installing a point cloud acquisition module on the train body, using the point cloud acquisition module to obtain all point cloud data in front of the train, and sending it to the train on-board computer; the train on-board computer uses a sleeper extraction algorithm to extract sleeper target point cloud data from all point cloud data; the train on-board computer decodes the sleeper target point cloud data and converts it into the absolute position information of the train's current positioning target, that is, the absolute position information of the sleeper coding; the train on-board computer performs comprehensive calculations to obtain the accurate absolute position information of the current train. The present invention uses sleepers to carry coding information and supports any form of coding protocol. It is highly versatile and can be customized according to different line conditions and different user needs. It is easy to transplant.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit train positioning, and in particular to a train positioning method based on sleeper coding. Background Art

[0002] Rail transit safety, crucial to the safety of life and property, has always been a key concern for the rail transit industry. Train positioning technology, a fundamental function of rail transit signal control, plays a crucial role in ensuring train safety and improving operational efficiency. More accurate and robust positioning methods can not only enhance train safety but also improve the operational efficiency of the entire transportation network.

[0003] In the existing technology, traditional train positioning technologies can be mainly divided into continuous positioning technology and point positioning technology. Continuous positioning includes: cumulative positioning based on on-board equipment, positioning based on GNSS, track circuit positioning, and positioning based on Simultaneous Localization and Mapping (SLAM); while point positioning includes: beacon positioning, kilometer marker positioning, ultra-wideband (UWB) positioning, and secondary radar positioning.

[0004] However, the above vehicle positioning solutions have problems such as high additional equipment cost, poor versatility, low accuracy, difficulty in eliminating cumulative errors, and poor safety. Therefore, it is very necessary to design a train positioning method to overcome the above technical problems.

[0005] It will be understood that the above statements merely provide background technology related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a train positioning method based on sleeper coding, which is simple to implement and has extremely high positioning accuracy, and can realize autonomous train positioning of the entire line.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a train positioning method based on sleeper coding, which comprises the following steps: S1, formulating a coding protocol, and drawing the sleeper coding on the sleeper along the track line according to the coding protocol as a positioning target for train positioning; S2, installing a point cloud acquisition module on the train body, using the point cloud acquisition module to obtain all point cloud data in front of the train, and sending it to the train on-board computer; S3, the train on-board computer uses a sleeper extraction algorithm to extract sleeper target point cloud data from all the point cloud data; S4, the train on-board computer decodes the sleeper target point cloud data and converts it into the absolute position information of the train's current positioning target, that is, the absolute position information of the sleeper coding; S5, the train on-board computer performs comprehensive calculations to obtain the precise absolute position information of the current train.

[0008] Preferably, the encoding protocol adopts binary, ternary, multi-base or pattern.

[0009] Preferably, a plurality of groups of sleeper codes are arranged at intervals on the sleepers along the track line, and each group of sleeper codes is composed of a plurality of adjacent sleepers.

[0010] A plurality of adjacent sleepers carrying sleeper codes constitute a sleeper group, and each sleeper in the sleeper group represents a different coding position of the sleeper code.

[0011] Preferably, in S2, the point cloud acquisition module detects all targets in front of the train by emitting detection signals, obtains distance information of each target, and converts them into position coordinates one by one to constitute the point cloud data of the current detection.

[0012] Preferably, in S2, the point cloud acquisition module uses millimeter wave radar, laser radar or depth camera.

[0013] Preferably, the millimeter wave radar emits electromagnetic wave signals to detect targets, the lidar emits laser beams to detect targets, and the depth camera emits infrared light or structured light to detect targets.

[0014] Preferably, in S3, the sleeper extraction algorithm clusters the sleeper targets carrying sleeper codes in front of the train from all the point cloud data, separates the sleeper targets from other targets, and extracts the sleeper target point cloud data that only carries sleeper codes and does not contain other irrelevant point cloud data.

[0015] Preferably, the decoding principle is compatible with the established coding protocol, and the train onboard computer decodes the extracted sleeper target point cloud data according to the coding protocol established in S1.

[0016] Preferably, in the above S5, the precise absolute position information of the current train = the absolute position information of the sleeper code - the ranging information of the point cloud data.

[0017] Preferably, the absolute position of the sleeper code is the position of the first sleeper closest to the train in the sleeper group corresponding to the sleeper code; the ranging information of the point cloud data is the distance between the point cloud acquisition module and the absolute position of the sleeper code.

[0018] Preferably, in said S1, the code is drawn on the sleeper by spraying with a high reflectivity material or a sticker.

[0019] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the train positioning method based on sleeper coding is implemented.

[0020] The present invention also provides an electronic device, comprising a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the train positioning method based on sleeper coding is implemented.

[0021] In summary, compared with the prior art, the train positioning method based on sleeper coding provided by the present invention has at least the following beneficial effects:

[0022] (1) The present invention can realize autonomous train positioning along the entire line and segmented train positioning in any section of the entire line, such as tunnels, elevated tracks, turnouts, and platforms, without relying on any external equipment or signal support. It can still function normally when CC, BLS, and GNSS fail.

[0023] (2) The algorithm of the present invention is simple to implement, requires low computing power, and can ensure real-time calculation;

[0024] (3) The present invention has no cumulative error and high positioning accuracy. The theoretical positioning accuracy only depends on the ranging accuracy of the point cloud;

[0025] (4) The present invention has high repositioning efficiency. When a train loses its position due to anomalies, failures, etc., the train's position can be quickly regained at one time by identifying the next sleeper coding information;

[0026] (5) The present invention innovatively uses rail sleepers to carry coding information and supports any form of coding protocol. It is highly versatile and can be customized according to different line conditions and different user needs. For different cities and different lines, the solution is highly reusable and easy to transplant. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of the train positioning method based on sleeper coding in the present invention;

[0028] Figure 2 Schematic diagram of the principle of the train positioning method based on sleeper coding in the present invention;

[0029] Figure 3 This is an embodiment of a sleeper coding method for train positioning based on sleeper coding in the present invention;

[0030] Figure 4 This is another sleeper coding embodiment of the train positioning method based on sleeper coding in the present invention. DETAILED DESCRIPTION

[0031] The following is combined with Figures 1 to 4 , the present invention is further explained by describing a preferred specific embodiment in detail.

[0032] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0033] It should be noted that, in the present invention, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0034] like Figure 1 As shown, the present invention provides a train positioning method based on sleeper coding, comprising the following steps:

[0035] S1. Develop a coding protocol and draw rail sleeper codes on the rail sleepers along the track according to the coding protocol to serve as positioning targets for train positioning;

[0036] S2. Install a point cloud acquisition module on the train body, use the point cloud acquisition module to acquire all point cloud data ahead of the train, and send it to the train onboard computer;

[0037] S3, the train onboard computer uses a sleeper extraction algorithm to extract sleeper target point cloud data from all the point cloud data;

[0038] S4. The train onboard computer decodes the sleeper target point cloud data and converts it into the absolute position information of the train's current positioning target, that is, the absolute position information of the sleeper code;

[0039] S5. The train's onboard computer performs comprehensive calculations to obtain the precise absolute position information of the current train.

[0040] Furthermore, in the S1, the coding protocol is a customized rule, which can be expressed in binary, ternary, or multi-base form, or can be expressed in a special pattern or any other customized coding format that can be used as a special identifier, etc.

[0041] Furthermore, several groups of sleeper codes are arranged at intervals on the sleepers along the track line, and each group of sleeper codes is composed of multiple adjacent sleepers. Therefore, only when multiple adjacent sleepers work together can a group of sleeper codes be fully displayed; wherein, multiple adjacent sleepers carrying sleeper codes constitute a sleeper group, and each sleeper in the sleeper group represents a different coding position of the sleeper code.

[0042] like Figure 3 As shown, in this embodiment, the coding protocol adopts binary form. A complete set of sleeper codes includes 1 start bit, 8 sleeper code bits, 1 even parity bit and 1 end bit. It can be understood that in this coding protocol, each set of sleeper codes is composed of 11 (1+8+1+1) sleepers, so these 11 sleepers are called a sleeper group. Figure 4 As shown, in this embodiment, the coding protocol adopts a ternary form, and a complete set of sleeper codes only includes 6 sleeper code bits. It can be understood that in this coding protocol, each set of sleeper codes is composed of 6 sleepers, and thus these 6 sleepers are said to constitute a sleeper group.

[0043] It is understandable that, in the embodiment of the present invention, the sleeper codes on the sleepers can be used as reference objects for train positioning, which is equivalent to the role played by road signs on the highway.

[0044] Furthermore, in S2, the point cloud acquisition module may employ a point cloud data detection device such as a millimeter-wave radar, a lidar, a depth camera, or any other detector capable of collecting point cloud data. By emitting detection signals, the module detects all targets ahead of the train, obtains distance information for each target, and converts this information into point cloud data in a Cartesian coordinate system. This means that all the resulting point cloud data represents the position and shape of each target in the form of three-dimensional coordinates, thereby providing a basis for subsequent processing and analysis. The targets ahead of the train include all detectable targets, such as sleepers, buildings, and the background environment.

[0045] Among them, the millimeter wave radar emits electromagnetic wave signals to detect targets, the laser radar emits laser beams to detect targets, and the depth camera emits infrared light or structured light to detect targets.

[0046] Furthermore, in S3, the sleeper extraction algorithm can cluster the sleeper targets carrying sleeper codes in front of the train from all the point cloud data, separate the sleeper targets from other targets, and extract separate sleeper target point cloud data that only carries sleeper codes and does not contain other irrelevant point cloud data.

[0047] Furthermore, in said S4, the principle of decoding is adapted to the established coding protocol, and the train onboard computer decodes the extracted sleeper target point cloud data according to the coding protocol established in said S1.

[0048] Furthermore, in the above S5, the precise absolute position information of the current train = the absolute position information of the sleeper code - the ranging information of the point cloud data.

[0049] It is understandable that when decoding, a complete set of sleeper codes must be fully decoded to determine whether the set of sleeper codes is valid. Therefore, after decoding is completed, the position of the first sleeper closest to the train in the sleeper group corresponding to the sleeper code is the absolute position of the sleeper code. Figure 2 As shown, the distance measurement information x of the point cloud data is the distance between the point cloud acquisition module and the position of the first sleeper closest to the train in the sleeper group corresponding to the sleeper code.

[0050] In one embodiment of the present invention, Figure 3 As shown, first, a coding protocol is formulated. The coding protocol adopts binary form and includes 1 start bit, 8 sleeper coding bits, 1 even parity bit and 1 end bit. Secondly, according to the coding protocol, the sleeper code is drawn on the sleeper along the track line using high reflectivity material / sticker to distinguish the start bit, end bit, sleeper coding bit 0 and sleeper coding bit 1. Among them, in this embodiment, normal sleepers are not sprayed, the start / end bits are all sprayed, the sleeper coding bit 0 is sprayed on the left half in front of the train, and the sleeper coding bit 1 is sprayed on the right half in front of the train. Then, the point cloud acquisition module obtains all the point cloud data in front of the train. It can be understood that the position where the high reflectivity material / sticker is sprayed will have a higher reflectivity, which can be significantly distinguished in the point cloud. Then, the sleeper extraction algorithm can extract a complete sleeper code (1+8+1+1 bit) and perform a parity check. Finally, the train's onboard computer decodes the sleeper code and calculates the precise absolute position information of the current train by combining the ranging information with the point cloud data.

[0051] It should be noted that the materials of sleepers include wood and concrete, and the number of sleepers generally ranges from 1440 to 1920 per kilometer. In this embodiment, based on 1667 sleepers per kilometer and a 60 cm spacing between two adjacent sleepers, each complete sleeper code corresponds to 11 sleepers, sleeper code length = 10 × 60 cm = 6m, sleeper code capacity = 2 8 =256, which means it can represent 256 different locations. It can be understood that for a 40km long route, if the sleeper code positions are evenly distributed, the adjacent interval between two adjacent sleeper codes = 40km / 256≈156m. This positioning density is sufficient for the train positioning requirements.

[0052] If you want to further improve the positioning density, in addition to increasing the number of sleeper code bits, you can also increase the sleeper code depth to increase the sleeper code capacity at the same length.

[0053] In another embodiment of the present invention, Figure 4 As shown, the sleeper coding eliminates the start bit, end bit and parity bit, but changes the coding protocol to 3-base form, which not only shortens the number of bits required, but also increases the sleeper coding capacity. Specifically, the coding protocol only includes 6 sleeper coding bits, which are also sprayed with high reflectivity materials. Normal sleepers are not sprayed. Sleeper coding bit 0 is sprayed on the left half, sleeper coding bit 1 is sprayed on the right half, and sleeper coding bit 2 is sprayed all over. Therefore, for this coding protocol, the sleeper coding length = 5×60cm = 3m, and the sleeper coding capacity = 3 6 =729, meaning it can represent 729 different locations. Similarly, for a 40km route, if the sleeper code positions are evenly distributed, the interval between two adjacent sleeper codes = 40km / 729 ≈ 55m. It can be understood that in this embodiment, by shortening the sleeper code length, not only the sleeper code capacity is increased, but also the efficiency of sleeper target extraction and decoding is improved. Furthermore, a positioning density of 55m intervals fully meets the train positioning granularity requirements.

[0054] Furthermore, the present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the above-mentioned train positioning method based on sleeper coding is implemented.

[0055] Furthermore, the present invention also provides an electronic device, including a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the above-mentioned train positioning method based on sleeper coding is implemented.

[0056] In summary, the train positioning method based on sleeper coding of the present invention can realize autonomous train positioning of the entire line, and realize segmented positioning of trains in any section of the entire line such as tunnels, elevated roads, switches, platforms, etc., without relying on any external equipment or signal support. Normal functions can still be achieved when CC, BLS, and GNSS fail; the algorithm is simple to implement, with low requirements on computing power, and real-time calculation can be guaranteed; there is no cumulative error, and the positioning accuracy is high, and the theoretical positioning accuracy only depends on the ranging accuracy of the point cloud; the repositioning efficiency is high, and when the train loses its positioning due to anomalies, failures, etc., the positioning of the train can be quickly regained at one time by identifying the next coding information; the sleepers are innovatively used to carry coding information, and any form of coding protocol is supported, with high versatility, and can be customized according to different line conditions and different user needs. For different cities and different lines, the solution has high reusability and is easy to transplant.

[0057] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A train positioning method based on sleeper coding, characterized in that: The following steps are involved: S1. Develop a coding protocol and draw rail sleeper codes on the rail sleepers along the track according to the coding protocol to serve as positioning targets for train positioning; S2. Install a point cloud acquisition module on the train body, use the point cloud acquisition module to acquire all point cloud data ahead of the train, and send it to the train onboard computer; S3, the train onboard computer uses a sleeper extraction algorithm to extract sleeper target point cloud data from all the point cloud data; S4. The train onboard computer decodes the sleeper target point cloud data and converts it into the absolute position information of the train's current positioning target, that is, the absolute position information of the sleeper code; S5. The train's onboard computer performs comprehensive calculations to obtain the current train's precise absolute position information; Wherein, in said S5, the accurate absolute position information of the current train = the absolute position information of the sleeper code - the ranging information of the point cloud data; The absolute position of the sleeper code is the position of the first sleeper of the sleeper group corresponding to the sleeper code that is closest to the train; The distance measurement information of the point cloud data is the distance between the point cloud acquisition module and the absolute position of the sleeper code.

2. The train positioning method based on sleeper coding according to claim 1, characterized in that: The coding protocol adopts binary, ternary, multi-ary or pattern.

3. The train positioning method based on sleeper coding according to claim 2, characterized in that: Several groups of sleeper codes are set at intervals on the sleepers along the track line, and each group of sleeper codes is composed of multiple adjacent sleepers; A plurality of adjacent sleepers carrying sleeper codes constitute a sleeper group, and each sleeper in the sleeper group represents a different coding position of the sleeper code.

4. The train positioning method based on sleeper coding according to claim 1, characterized in that: In the above-mentioned S2, the point cloud acquisition module detects all targets in front of the train by emitting detection signals, obtains distance information of each target, and converts it into position coordinates one by one to constitute the currently detected point cloud data.

5. The train positioning method based on sleeper coding according to claim 4, characterized in that: In the above-mentioned S2, the point cloud acquisition module adopts millimeter wave radar, laser radar or depth camera.

6. The train positioning method based on sleeper coding according to claim 5, characterized in that: The millimeter wave radar emits electromagnetic wave signals to detect targets, the laser radar emits laser beams to detect targets, and the depth camera emits infrared light or structured light to detect targets.

7. The train positioning method based on sleeper coding according to claim 1, characterized in that: In S3, the sleeper extraction algorithm clusters the sleeper targets carrying sleeper codes in front of the train from all the point cloud data, separates the sleeper targets from other targets, and extracts the sleeper target point cloud data that only carries sleeper codes and does not contain other irrelevant point cloud data.

8. The train positioning method based on sleeper coding according to claim 3, characterized in that: The principle of decoding is compatible with the established coding protocol, and the train onboard computer decodes the extracted sleeper target point cloud data according to the coding protocol established in S1.

9. The train positioning method based on sleeper coding according to claim 3, characterized in that: In the above-mentioned S1, the code is drawn on the sleeper by spraying with a high reflectivity material or a sticker.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the train positioning method based on sleeper coding according to any one of claims 1 to 9 is implemented.

11. An electronic device, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the train positioning method based on sleeper coding according to any one of claims 1 to 9 is implemented.

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