GNSS train positioning method and system based on two-out-of-three redundant structure

Abstract

The invention provides a GNSS train positioning method and system based on a two-out-of-three redundant structure, and belongs to the technical field of train navigation positioning. GNSS original observation data are independently received, and positioning fusion calculation and map matching processing are executed; performing multi-layer consistency judgment on GNSS original observation data of three channels, fusion positioning coordinates and map matching results; and on the basis of consistency judgment, outputting a final positioning result or an alarm abnormal state by adopting a majority voting mechanism. The method can effectively improve the positioning reliability and fault-tolerant capability of the GNSS train positioning system in a complex environment, has high system integrity and safety, and is suitable for a train positioning scene with a high safety level requirement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of train navigation positioning, and particularly relates to a GNSS train positioning method and system based on a two-out-of-three redundancy structure. BACKGROUND

[0002] The train operation control system based on mobile block has very high requirements for the accuracy and continuity of real-time positioning of trains, and is one of the core technologies for ensuring the safety of railway transportation and improving the efficiency of transportation. At present, train positioning mainly adopts a combination of an odometer (ODO) and a balise transmission module (BTM), although this method is relatively mature in engineering applications, it requires a large number of trackside infrastructure, has high maintenance costs, and cannot balance high-frequency and high-precision train positioning.

[0003] With the development of global satellite navigation system technology, the GNSS-based train positioning method has gradually been applied in the field of railway transportation due to its advantages of not needing to rely on trackside equipment, supporting dynamic scheduling, and strong adaptability. However, there are still some problems in the actual application of GNSS positioning that cannot be ignored. On the one hand, GNSS signals are easily affected by obstructions (such as tunnels, mountains, urban buildings, etc.) or interference (such as malicious attacks, adjacent frequency interference, equipment failure, etc.), resulting in increased positioning errors or abnormal data; on the other hand, GNSS devices themselves also have potential failure risks, such as signal loss, data drift, etc. Once the GNSS output is abnormal, it will pose a threat to the safety of train operation. SUMMARY

[0004] The present application aims to provide a GNSS train positioning method and system based on a two-out-of-three redundancy structure that effectively improves the positioning reliability and fault tolerance capability of the GNSS train positioning system in complex environments, making it have high integrity and safety, to solve at least one of the technical problems in the background art.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a GNSS train positioning method based on a two-out-of-three redundancy structure, comprising:

[0007] Establishing a three-channel positioning system: constructing a GNSS train positioning system composed of three independent positioning processing channels, each channel including a GNSS receiving module, an ODO module, a data fusion module, and a map matching module;

[0008] Three-channel parallel data acquisition: Each module observes data through three independent information channels, and synchronously acquires satellite observation data and positioning information, including pseudo-range, pseudo-range rate, time stamp and other original data.

[0009] GNSS original observation data consistency judgment: The original GNSS observation data collected by the three channels are compared with each other, and the consistency is judged according to the set error threshold, so as to identify the possible data abnormality or signal interference;

[0010] Fusion positioning coordinate consistency judgment: Each channel uses extended Kalman filter to fuse GNSS original data and ODO information to form three groups of preliminary positioning results; The consistency of the fusion coordinates is judged by performing consistency check on the three groups of fusion results.

[0011] Map matching result consistency judgment: Each channel matches its fusion positioning result with the train track electronic map to output the map matching positioning point; The consistency of the three groups of map matching results is judged to test the rationality and spatial consistency of the trajectory.

[0012] Majority voting and validity determination: In the above three comparisons, as long as any two groups of comparison results meet the threshold requirement, the comparison is considered to pass; If all three comparisons pass, the current positioning is determined to be valid; If the comparison result is abnormal, the system outputs a marked abnormal state to trigger data shielding and ensure safe operation of the system.

[0013] As a further limitation of the first aspect of the application, the consistency of the original observation data is judged based on the two-out-of-three majority voting. After receiving three sets of GNSS original data from different channels at each time, the common satellite number set under the current ephemeris time is obtained from the three channels, and for each satellite, the pseudo-range error between channels is calculated:

[0014]

[0015] When the errors of all common satellites of two channels are less than the set threshold, the observation values of the two channels are determined to be consistent; If the difference between more than two groups of data is within the set threshold range, the group of observation data is considered to be consistent and can enter the next stage of processing; Otherwise, it is marked that the observation data is abnormal and will be shielded in subsequent processing.

[0016] As a further limitation of the first aspect of the application, the consistency of the fusion positioning result is judged based on the two-out-of-three majority voting. The position coordinates output by the three-channel EKF fusion are taken as input, and the position coordinates (x, y, z) of the three channels are compared with each other, and the Euclidean distance is used to calculate the coordinate difference between channels:

[0017]

[0018] Similarly, D AC With D BC When the distances of the two pairs are both less than the set threshold, it is considered that the two positioning results in the pair comparison are consistent; if more than two groups of results are consistent with each other, it is considered that the current fusion result is reliable and can be used as a majority vote input; otherwise, if the three groups of results are significantly different, it is considered that the current fusion result is not reliable, and the fusion positioning data is marked as abnormal.

[0019] As a further limitation of the first aspect of the application, the map matching result is subjected to a consistency judgment based on a two-out-of-three majority vote. After each channel completes map matching and outputs coordinates, the three groups of matching points are compared in pairs in terms of Euclidean distance. If the distance between two groups of matching points is less than a threshold, it is considered that the map matching result is consistent. Otherwise, if the three groups of results are significantly different, it is considered that the current map matching positioning result is not reliable, and the map matching positioning data is marked as abnormal.

[0020] As a further limitation of the first aspect of the application, after the fusion positioning is completed, the position coordinates of the three channels are matched with the track database of the train operation line, and the nearest projection point of each channel on the track center line is extracted as the matched coordinate. The vertical projection algorithm for map matching includes: converting the coordinates using UTM projection method; finding the nearest point in the DTM, which is determined by calculating the Euclidean distance between all points and G; calculating the matching position of the vertical projection method.

[0021] As a further limitation of the first aspect of the application, the final positioning result depends on the comprehensive judgment of the three-layer comparison mechanism. If the three-layer comparison passes the majority consistency judgment, the system will consider the current positioning result reliable and output the fusion positioning value of the majority channel as the current real-time position of the train. If any layer of comparison fails, the system will trigger an internal alarm mechanism to prompt possible positioning abnormalities, thereby ensuring the operational safety of the train positioning system.

[0022] In a second aspect, the application provides a GNSS train positioning system based on a two-out-of-three redundant structure, comprising:

[0023] A three-channel parallel data acquisition module is used to acquire observation data of each module, synchronized satellite observation data and positioning information, including raw data such as pseudo-range, pseudo-range rate, and time stamp, through three independent information channels;

[0024] A GNSS raw observation data consistency judgment module is used to compare the raw GNSS observation data collected by the three channels in pairs, make a consistency judgment according to a set error threshold, and identify possible data abnormalities or signal interference conditions;

[0025] The fusion positioning coordinate consistency judgment module is used for fusing and solving GNSS raw data and ODO information by using an extended Kalman filter for each channel to form three groups of preliminary positioning results; consistency checking is performed on the three groups of fusion results to judge the consistency of the fusion coordinates;

[0026] The map matching result consistency judgment module is used for matching the fusion positioning results of each channel with a train track electronic map to output map matching positioning points; consistency of the three groups of map matching results is judged to check the track rationality and spatial consistency;

[0027] The majority voting and validity determination module is used for passing the comparison as long as any two groups of comparison results in the above three comparisons meet the threshold requirement; if the three comparisons are all passed, the current positioning is determined to be valid; if the comparison result is abnormal, the system outputs a marked abnormal state to trigger data shielding to ensure safe operation of the system.

[0028] In a third aspect, the present application provides a non-transitory computer readable storage medium for storing computer instructions, which, when executed by a processor, implement the GNSS train positioning method based on the two-out-of-three redundancy structure as described in the first aspect.

[0029] In a fourth aspect, the present application provides a computer device comprising a memory and a processor, which communicate with each other, and the memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the GNSS train positioning method based on the two-out-of-three redundancy structure as described in the first aspect.

[0030] In a fifth aspect, the present application provides an electronic device comprising a processor, a memory and a computer program; wherein the processor is connected with the memory, and the computer program is stored in the memory; when the electronic device is running, the processor executes the computer program stored in the memory to make the electronic device execute instructions for implementing the GNSS train positioning method based on the two-out-of-three redundancy structure as described in the first aspect.

[0031] The present application has the advantages of improving the fault tolerance to single point failure, and significantly enhancing the identification and isolation ability to potential errors of the system through the three-layer consistency comparison mechanism; even if one channel is interfered, the system can still obtain a reliable positioning result through majority voting, and is particularly suitable for railway train positioning scenarios with high safety requirements and complex interference environment.

[0032] The advantages of the additional aspects of the present application will be more apparent from the following description part or be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description only show some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0034] Figure 1 A flow chart of one embodiment of the GNSS train positioning method based on a two-of-three architecture described in the embodiments of the present application. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, in which the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with the drawings are exemplary and are only used to explain the present application, and cannot be interpreted as a limitation on the present application.

[0036] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0037] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted with idealized or overly formal meanings unless defined as such.

[0038] Those skilled in the art can understand that, unless otherwise stated, the singular forms "a", "an" and "the" used herein also include the plural forms. It should be further understood that the use of the phrase "comprising" in the specification of the present application means that the features, integers, steps, operations, elements and / or groups thereof are present, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0039] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Those skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without any creative effort, provided that they do not contradict each other.

[0040] For the convenience of understanding the present application, the present application is further explained and described below with specific embodiments in conjunction with the accompanying drawings, and the specific embodiments do not constitute limitations to the embodiments of the present application.

[0041] Those skilled in the art should understand that the drawings are only schematic views of the embodiments, and the components in the drawings are not necessarily essential for implementing the present application.

[0042] In order to improve the reliability and fault-tolerant capability of the train positioning system in complex environments, a redundant architecture design scheme can be used, such as two-out-of-two redundancy, three-out-of-two redundancy, etc. Among them, the three-out-of-two architecture is a typical fault-tolerant structure, which introduces three independent positioning information sources, uses a two-by-two comparison strategy to judge the output of the reliable positioning result, and can effectively eliminate single abnormal data, and improve the safety and availability of the system.

[0043] Therefore, it is of important research value and engineering application prospect to design a GNSS train positioning method based on a three-out-of-two structure, combine multi-source data redundancy and consistency decision mechanism, ensure the effectiveness and continuity of the positioning data, and improve the operation ability of the system under fault or interference conditions.

[0044] The train positioning system and method based on GNSS and electronic map topology structure provided by the application comprise a GNSS satellite positioning receiver module, a Kalman filter module, a map matching algorithm module and a vehicle-mounted electronic map module; the GNSS satellite positioning receiver module is connected with the Kalman filter module and the map matching algorithm module, the map matching algorithm module is connected with the vehicle-mounted electronic map module; the map matching algorithm module accurately matches the train positioning data output by the Kalman filter module to a certain track segment on the electronic map of the vehicle-mounted electronic map module, and realizes accurate positioning of the train.

[0045] Embodiment 1

[0046] In this embodiment 1, a GNSS train positioning method based on a three-out-of-two redundancy structure is provided, which comprises: establishing a three-channel GNSS train positioning system, and constructing channels A, B and C respectively; independently receiving GNSS raw observation data, performing positioning fusion calculation and map matching processing; performing multi-layer consistency judgment on the GNSS raw observation data, the fusion positioning coordinates and the map matching results of the three channels; on the basis of the consistency judgment, using a majority voting mechanism to output the final positioning result or an abnormal state alarm. Through the above method, the present application can effectively improve the positioning reliability and fault-tolerant capability of the GNSS train positioning system in complex environments, has high system integrity and safety, and is suitable for train positioning scenes with high safety level requirements.

[0047] The GNSS train positioning method based on a two-out-of-three redundancy structure is suitable for a train positioning scene with high safety level requirements, and the method comprises the following steps:

[0048] Establishing a three-channel positioning system: a GNSS train positioning system composed of three independent positioning processing channels is constructed, each channel comprising a GNSS receiving module, an ODO module, a data fusion module, a map matching module and other subsystems, and supporting independent parallel processing;

[0049] Three-channel parallel data acquisition: GNSS, ODO and other module observation data are acquired through three independent information channels, and synchronous satellite observation data and positioning information, including raw data such as pseudorange, pseudorange rate and timestamp, are acquired;

[0050] GNSS raw observation data consistency judgment: the raw GNSS observation data collected by the three channels are compared with each other, and consistency judgment is performed according to the set error threshold to identify possible data anomalies or signal interference;

[0051] Fusion positioning coordinate consistency judgment: each channel uses an extended Kalman filter (EKF) to fuse GNSS raw data and ODO information to form three sets of preliminary positioning results. The system performs consistency verification on the three sets of fusion results to judge the consistency of the fusion coordinates;

[0052] Map matching result consistency judgment: each channel matches its fusion positioning result with a train track electronic map (Digital Track Map, DTM) to output a map matching positioning point. The consistency of the three map matching results is judged to test the rationality and spatial consistency of the trajectory;

[0053] Majority voting and validity determination: in the above three comparisons, as long as any two comparison results meet the threshold requirements, the comparison is considered to pass. If all three comparisons pass, the current positioning is determined to be valid. If the comparison result is abnormal, the system outputs a marked abnormal state and triggers data shielding to ensure safe operation of the system.

[0054] The method further comprises: the system sets up three independent positioning data processing channels, denoted as channel A, channel B and channel C, each channel comprising the following functional modules: GNSS raw observation data receiving and solving module, EKF positioning fusion calculation module, map matching module. Each channel defines a fixed time step (for example, 1 second), and independently executes the receiving, calculation and output process to ensure logical independence and path redundancy.

[0055] The method further comprises: three-channel parallel data acquisition, at each time step, three channels simultaneously receive respective raw observation data, and the satellite data comprises pseudorange, pseudorange rate, ephemeris time, etc.

[0056] The method further comprises: consistency judgment of the raw observation data based on two-out-of-three majority voting. After the system receives three sets of GNSS raw data from different channels at each time, the common satellite number set under the current ephemeris time is obtained from the three channels, and for each satellite, the inter-channel pseudorange error is calculated respectively:

[0057]

[0058] When the errors of all common satellites of two channels are less than a set threshold, the observation values of the two channels are determined to be consistent. If the difference values of more than two groups of data are within the set threshold range, it is considered that the observation data are consistent, and can enter the next stage of processing; otherwise, it is marked that the observation data are abnormal and will be shielded in subsequent processing.

[0059] The method further comprises consistency judgment of the fusion positioning result based on two-out-of-three majority voting. The position coordinates output by the three-channel EKF fusion are taken as input, and the position coordinates (x, y, z) of the three channels are compared in pairs, and the inter-channel coordinate difference is calculated by using the Euclidean distance:

[0060]

[0061] Similarly, D AC and D BC When the two pairs of distances are less than a set threshold, it is considered that the two positioning results in the group comparison are consistent. Further, if more than two groups of results are consistent with each other, it is considered that the current fusion result is reliable and can be used as the majority voting input; otherwise, if the three groups of results are significantly different, the system considers that the current fusion result is not reliable, and marks that the fusion positioning data is abnormal.

[0062] The method further comprises consistency judgment of the map matching result based on two-out-of-three majority voting. After each channel completes the map matching and outputs the coordinates, the three groups of matching points are compared in pairs by using the Euclidean distance, and if the distance between two groups of matching points is less than a threshold, it is considered that the map matching result is consistent. Otherwise, if the three groups of results are significantly different, the system considers that the current map matching positioning result is not reliable, and marks that the map matching positioning data is abnormal.

[0063] The method further comprises: after completing the fusion positioning, the system matches the position coordinates of the three channels with the track database of the train running line, and extracts the nearest projection point of each channel on the track center line as the matched coordinate.

[0064] The specific steps of the vertical projection algorithm of map matching can be described as follows:

[0065] Converting coordinates using UTM projection method: the EKF fusion positioning position and the selected DTM database position point are converted to the UTM coordinate system using the Mercator UTM (Universal Transverse Mercator) projection method, and the respective three-dimensional plane coordinates (x, y, z) are obtained. The UTM projection method is used to convert geographic coordinates (longitude and latitude) into plane coordinates (east coordinate, north coordinate and elevation). Assuming that the initial geographic coordinates are (λ, φ, h), the converted plane coordinates are (x, y, z).

[0066] Finding the nearest point in the DTM: according to the fusion positioning position G (x G ,y G ,z G ), find the nearest position point M i (x i ,y i ,z i ) in the DTM, and search for two points M i (x i-1 ,y i-1 ,z i-1 ) and M i-1 (x i+1 ,y i+1 ,z i+1 ) adjacent to M i+1 , calculate and compare to obtain the second nearest position point.

[0067] The nearest point calculation can be determined by calculating the Euclidean distance between all points and G, and the calculation formula is as follows:

[0068]

[0069] Calculating the matching position of the vertical projection method: using the three-dimensional vertical projection method, the coordinates P (x P ,y P ,z P ) of the matching position are calculated to correct the train position to the nearest track. According to the coordinates of the nearest point and the second nearest point, the coordinates of P are determined by solving the straight line equation y = kx + b. The specific formula is as follows:

[0070]

[0071] wherein,

[0072] The output of the final positioning result of the system depends on the comprehensive judgment of the three-layer comparison mechanism. If the majority consistency judgment of the three-layer comparison is passed, the system will consider the current positioning result reliable, and output the fusion positioning value of the majority channel as the current real-time position of the train; if any layer comparison fails, the system will trigger the internal alarm mechanism to prompt that there may be positioning abnormalities, thereby ensuring the operation safety of the train positioning system.

[0073] Embodiment 2

[0074] As shown in Figure 1 , the embodiment provides a GNSS train positioning method and system based on a two-out-of-three architecture, which is suitable for railway transportation scenarios with high requirements for positioning reliability and safety. The method obtains GNSS data through three independent positioning channels, performs multi-sensor fusion positioning and map matching processing respectively, and introduces a three-layer consistency verification mechanism based on raw observations, fused coordinates and map matching results. The majority voting strategy is used to automatically identify and isolate abnormal channel data. Compared with existing GNSS positioning systems, the method significantly enhances the detection and fault tolerance capability of the system to single-point faults, data mutations and signal interference while maintaining high-precision positioning, and has good scalability and environmental adaptability.

[0075] The GNSS train positioning method based on a two-out-of-three architecture includes the following steps:

[0076] 1) Establish a three-channel positioning system: build a GNSS train positioning system composed of three independent positioning processing channels, each channel including GNSS receiving module, ODO module, data fusion module, map matching module and other subsystems, supporting independent parallel processing;

[0077] 2) Three-channel parallel data acquisition: obtain GNSS, ODO and other module observation data through three independent information channels, synchronize satellite observation data and positioning information, including raw data such as pseudorange, pseudorange rate, timestamp, etc.

[0078] 3) Consistency judgment of GNSS raw observation data: compare the raw GNSS observation data collected by the three channels pairwise, and make consistency judgment according to the set error threshold to identify possible data abnormalities or signal interference;

[0079] 4) Consistency judgment of fused positioning coordinates: each channel uses Extended Kalman Filter (EKF) to fuse GNSS raw data and ODO information for solving, forming three sets of preliminary positioning results. The system performs consistency verification on the three sets of fusion results to judge the consistency of the fused coordinates;

[0080] 5) Map matching result consistency judgment: each channel matches its fused positioning result with the train track electronic map (Digital Track Map, DTM) to output a map matching positioning point. The consistency of the three sets of map matching results is judged to test the rationality and spatial consistency of the trajectory;

[0081] 6) Majority voting and validity determination: in the above three comparisons, as long as any two sets of comparison results meet the threshold requirement, it is considered that the comparison passes. If all three comparisons pass, it is determined that the current positioning is valid. If the comparison result is abnormal, the system outputs a marked abnormal state to trigger data shielding to ensure safe operation of the system.

[0082] The three-channel positioning fusion architecture adopted in this embodiment fully considers the high safety requirement of railway application in structural design. In actual operation, the system processes positioning data in parallel by three independent GNSS, ODO and track electronic map databases. Each channel is based on a unified or independently designed fusion algorithm process, but remains independent in hardware and processing logic to avoid potential common cause failures. After independent processing, the three sets of data are compared at each link to ensure that even if one set of data is disturbed or fails, the system can still obtain a reliable result through multi-channel comparison.

[0083] To ensure that the positioning results output by the train positioning system have high safety, reliability and stability, and to improve the anti-interference ability, this embodiment further introduces a three-layer consistency verification mechanism based on three-channel parallel fusion. The original observation data, fused positioning results and map matching output are compared and analyzed layer by layer, and multiple error thresholds are set for determination to realize automatic identification and fault tolerance processing of inconsistent data by the system. The 2oo3 majority voting mechanism is introduced as the core decision logic in the redundant safety structure. The design goal of this mechanism is to ensure that only two channels are normal in the three channels to output a reliable positioning result, thereby tolerating one channel failure or deviation, effectively improving the fault tolerance ability and integrity level of the system.

[0084] Specifically includes the following steps:

[0085] S1: Establish a three-channel GNSS train positioning system

[0086] This system sets up three independent positioning data processing channels, denoted as channel A, channel B and channel C. Each channel includes the following functional modules: GNSS raw observation data reception and calculation module, EKF positioning fusion calculation module, and map matching module. Each channel defines a fixed time step (for example, 1 second), and independently executes the reception, calculation and output process to ensure logical independence and path redundancy.

[0087] S2: Three-channel parallel data acquisition

[0088] At each time step, three channels receive respective raw observation data simultaneously, and satellite data includes pseudorange, pseudorange rate, ephemeris time, etc.

[0089] S3: Consistency judgment of raw observation data based on two-out-of-three majority voting

[0090] The first layer of consistency check based on two-out-of-three majority voting determines GNSS raw observation data. After the system receives three sets of GNSS raw data from different channels at each time, it obtains the common satellite number set under the current ephemeris time from the three channels, and calculates the inter-channel pseudorange error for each satellite:

[0091]

[0092] When the errors of all common satellites of two channels are less than the set threshold, the observation values of the two channels are determined to be consistent. If the difference between more than two sets of data is within the set threshold, the observation data is considered consistent and can enter the next stage of processing; otherwise, the observation data is marked as abnormal and will be screened out in subsequent processing.

[0093] S4: Consistency judgment of fusion positioning results based on two-out-of-three majority voting

[0094] The second layer of consistency check based on two-out-of-three majority voting determines the fusion positioning results. In this stage, the position coordinates output by the three-channel EKF fusion are taken as input, and the position coordinates (x, y, z) of the three channels are compared pairwise, and the Euclidean distance is used to calculate the inter-channel coordinate difference:

[0095]

[0096] Similarly, D AC and D BC When the two distances are less than the set threshold, it is considered that the two positioning results in the group are consistent. Further, if there are more than two consistent results, it is considered that the current fusion result is reliable and can be used as the majority vote input; otherwise, if the three results differ significantly, the system considers that the current fusion result is not reliable and marks the fusion positioning data as abnormal.

[0097] S5: Consistency judgment of map matching results based on two-out-of-three majority voting

[0098] The third layer of consistency check based on three-out-of-two majority voting determines the map matching output result. After completing the fusion positioning, the system further matches the three-channel position coordinates with the track database of the train operation line, extracts the nearest projection point of each channel current coordinate on the track center line as the matched coordinate.

[0099] The specific steps of the vertical projection algorithm of map matching can be described as:

[0100] 1. Convert coordinates using UTM projection method

[0101] Convert the EKF fusion positioning position and the selected DTM database position point to the UTM coordinate system using the Mercator UTM (Universal Transverse Mercator) projection method, and obtain their respective three-dimensional plane coordinates (x, y, z).

[0102] The UTM projection method is used to convert geographic coordinates (longitude and latitude) to plane coordinates (east coordinate, north coordinate and elevation). Assuming that the initial geographic coordinates are (λ, φ, h), the converted plane coordinates are (x, y, z).

[0103] 2. Find the nearest point in DTM

[0104] According to the fusion positioning position G(x G ,y G ,z G ), find the nearest position point M i (x i ,y i ,z i ) in DTM to G, and search for two points M i (x i-1 ,y i-1 ,z i-1 ) and M i-1 (x i+1 ,y i+1 ,z i+1 ) adjacent to M i+1 , calculate and compare to obtain the second nearest position point to G.

[0105] The nearest point calculation can be determined by calculating the Euclidean distance between all points and G, and the calculation formula is as follows:

[0106]

[0107] 3. Calculate the matching position of the vertical projection method

[0108] Using the three-dimensional vertical projection method, calculate the coordinates P(x P ,y P ,zP ), to correct the train position to the nearest track. According to the coordinates of the nearest point and the second nearest point, the coordinates of P are determined by solving the linear equation y = kx + b. The specific formula is as follows:

[0109]

[0110] wherein,

[0111] After each channel completes map matching and outputs coordinates, the Euclidean distances between each two of the three sets of matching points are compared. If the distance between any two sets of matching points is less than a threshold, it is considered that the map matching results are consistent. Otherwise, if the differences between the three sets of results are significant, the system considers that the current map matching positioning result is not reliable, and marks that the map matching positioning data is abnormal.

[0112] S6: output the final positioning result

[0113] The output of the final positioning result of the system depends on the comprehensive judgment of the three-layer comparison mechanism. If the majority consistency judgment of the three-layer comparison is passed, the system will consider that the current positioning result is reliable, and output the fusion positioning value of the majority channel as the current real-time position of the train. If any layer comparison fails, the system will trigger an internal alarm mechanism to prompt that there may be a positioning abnormality, thereby ensuring the operation safety of the train positioning system.

[0114] The three-layer consistency verification mechanism filters step by step from the bottom up, from the original observation layer, the fusion estimation layer, to the map matching layer, and judges whether the data between channels is logically consistent and error reasonable in multiple dimensions, thereby effectively improving the positioning robustness of the system in complex interference environment. The error threshold is pre-configured according to the system application requirements and the train operation safety standards, and can be dynamically adjusted according to the running data to adapt to the precision requirements in different line environments (such as mountainous areas, tunnels, cities, etc.). This mechanism not only can identify single-channel abnormalities in time, but also can assist in judging the probability of multi-channel cooperative failure.

[0115] Compared with the existing GNSS positioning method, the three-out-of-two redundancy structure proposed in the present application not only improves the fault tolerance ability to single-point faults compared with the traditional single-channel structure and two-out-of-two structure, but also significantly enhances the identification and isolation ability of potential errors of the system through the three-layer consistency comparison mechanism. Even if one channel is disturbed, the system can still obtain a reliable positioning result through majority voting, which is particularly suitable for railway train positioning scenarios with high safety requirements and complex interference environment.

[0116] Example 3

[0117] The embodiment 3 provides a non-transitory computer readable storage medium for storing computer instructions, the computer instructions are executed by a processor to realize the GNSS train positioning method based on a two-out-of-three redundancy structure as described above, and the method comprises the following steps of:

[0118] Establishing a three-channel positioning system: constructing a GNSS train positioning system composed of three independent positioning processing channels, each channel comprising a GNSS receiving module, an ODO module, a data fusion module and a map matching module;

[0119] Three-channel parallel data acquisition: acquiring observation data of each module through three independent information channels, synchronously acquiring satellite observation data and positioning information, including raw data such as pseudo-range, pseudo-range rate and time stamp;

[0120] GNSS raw observation data consistency judgment: comparing the raw GNSS observation data collected by the three channels two by two, performing consistency judgment according to a set error threshold, and identifying possible data abnormality or signal interference;

[0121] Fusion positioning coordinate consistency judgment: each channel uses an extended Kalman filter to fuse GNSS raw data and ODO information to form three sets of preliminary positioning results; consistency of the fusion coordinates is judged by performing consistency verification on the three sets of fusion results;

[0122] Map matching result consistency judgment: each channel matches the fusion positioning result with a train track electronic map to output a map matching positioning point; the consistency of the three sets of map matching results is judged to test the rationality of the trajectory and the spatial consistency;

[0123] Majority voting and validity determination: in the above three comparisons, as long as any two comparison results in each comparison meet the threshold requirement, the comparison is considered to pass; if the three comparisons all pass, the current positioning is determined to be valid; if the comparison result is abnormal, the system outputs a marked abnormal state, triggers data shielding and ensures safe operation of the system.

[0124] Embodiment 4

[0125] The embodiment 4 provides a computer device, comprising a memory and a processor, the processor and the memory communicate with each other, the memory stores program instructions executable by the processor, and the processor calls the program instructions to execute the GNSS train positioning method based on a two-out-of-three redundancy structure as described above, and the method comprises the following steps of:

[0126] establishing a three-channel positioning system: constructing a GNSS train positioning system composed of three independent positioning processing channels, each channel including a GNSS receiving module, an ODO module, a data fusion module, and a map matching module;

[0127] Three-channel parallel data acquisition: through three independent information channels, the observation data of each module, synchronized satellite observation data and positioning information, including pseudo-range, pseudo-range rate, timestamp and other raw data are obtained;

[0128] GNSS raw observation data consistency judgment: comparing the raw GNSS observation data collected by the three channels with each other, and judging the consistency according to the set error threshold, identifying possible data anomalies or signal interference;

[0129] Fusion positioning coordinate consistency judgment: each channel uses extended Kalman filter to fuse GNSS raw data and ODO information to form three sets of preliminary positioning results; consistency check is performed on the three sets of fusion results to judge the consistency of the fusion coordinates;

[0130] Map matching result consistency judgment: each channel matches its fusion positioning result with the train track electronic map to output the map matching positioning point; consistency judgment is performed on the three sets of map matching results to test the trajectory rationality and spatial consistency;

[0131] Majority voting and validity determination: in the above three comparisons, as long as any two comparison results meet the threshold requirement, the comparison is considered to pass; if all three comparisons pass, the current positioning is considered valid; if the comparison result is abnormal, the system outputs a marked abnormal state, triggers data shielding, and ensures the safe operation of the system.

[0132] Embodiment 5

[0133] The embodiment 5 provides an electronic device, comprising: a processor, a memory and a computer program; wherein the processor is connected with the memory, and the computer program is stored in the memory; when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the instructions for realizing the GNSS train positioning method based on the two-out-of-three redundancy structure as described above, the method comprising:

[0134] establishing a three-channel positioning system: constructing a GNSS train positioning system composed of three independent positioning processing channels, each channel including a GNSS receiving module, an ODO module, a data fusion module, and a map matching module;

[0135] Three-channel parallel data acquisition: through three independent information channels, the observation data of each module, synchronized satellite observation data and positioning information, including pseudo-range, pseudo-range rate, timestamp and other raw data are obtained;

[0136] GNSS raw observation data consistency judgment: the raw GNSS observation data collected by the three channels are compared with each other, and the consistency is judged according to the set error threshold, and the possible data abnormality or signal interference is identified;

[0137] Fusion positioning coordinate consistency judgment: the extended Kalman filter is used respectively in each channel to fuse the GNSS raw data and the ODO information, and three groups of preliminary positioning results are formed; the consistency of the fusion coordinates is judged by performing consistency checking on the three groups of fusion results;

[0138] Map matching result consistency judgment: each channel matches the fusion positioning result with the train track electronic map, and outputs the map matching positioning point; the consistency of the three groups of map matching results is judged to test the rationality of the trajectory and the spatial consistency;

[0139] Majority voting and validity determination: in the above three comparisons, as long as any two groups of comparison results in each item meet the threshold requirement, it is considered that the comparison passes; if the three comparisons all pass, it is determined that the current positioning is valid; if the comparison result is abnormal, the system outputs a marked abnormal state, triggers data shielding, and ensures the safe operation of the system.

[0140] Those skilled in the art will appreciate that embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0141] The present application is described with reference to flowcharts and / or block diagrams according to the method, device (system), and computer program product of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The functions specified in one flow or multiple flows and / or blocks

[0142] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow Figure 1 The functions of a flow or multiple flows and / or a block or multiple blocks in conjunction with the disclosed aspects can be implemented on a single device or distributed across several devices. Figure 1

[0143] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flow Figure 1 The functions of a flow or multiple flows and / or a block or multiple blocks in conjunction with the disclosed aspects can be implemented on a single device or distributed across several devices. Figure 1

[0144] The above description is only a specific implementation of the present application, and is not intended to limit the protection scope of the present application. It should be understood by those skilled in the art that various modifications or changes can be made to the disclosed technical solutions without inventive labor, and all these modifications or changes should be covered within the protection scope of the present application.​​

Claims

1. A GNSS train positioning method based on a two-out-of-three redundancy structure, characterized in that, Comprise: Establish a three-channel positioning system: build a GNSS train positioning system composed of three independent positioning processing channels, each channel contains GNSS receiving module, ODO module, data fusion module and map matching module; Three-channel parallel data acquisition: through three independent information channels, the observation data of each module, synchronous satellite observation data and positioning information, including pseudo-range, pseudo-range rate, time stamp and other raw data; GNSS raw observation data consistency judgment: compare the raw GNSS observation data collected by the three channels with each other, and judge the consistency according to the set error threshold, identify possible data anomalies or signal interference; Fusion positioning coordinate consistency judgment: each channel uses extended Kalman filter to fuse GNSS raw data and ODO information to form three sets of preliminary positioning results; consistency check is performed on the three sets of fusion results to judge the consistency of the fusion coordinates; Map matching result consistency judgment: each channel matches its fusion positioning result with the train track electronic map to output the map matching positioning point; Consistency judgment is performed on the three sets of map matching results to test the rationality and spatial consistency of the trajectory; Majority voting and validity determination: in the above three comparisons, as long as any two comparison results meet the threshold requirements, the comparison is considered to pass; if all three comparisons pass, the current positioning is considered valid; if the comparison result is abnormal, the system outputs a marked abnormal state and triggers data shielding to ensure safe operation of the system.

2. The GNSS train positioning method based on a two-out-of-three redundancy structure according to claim 1, characterized in that, The consistency of the raw observation data is judged based on the three-out-of-two majority voting. After receiving three sets of GNSS raw data from different channels at each time, the common satellite number set under the current ephemeris time is obtained from the three channels. For each satellite, the pseudo-range error between channels is calculated: When the error of all common satellites of two channels is less than the set threshold, the observation values of the two channels are determined to be consistent; if the difference between more than two groups of data is within the set threshold, the observation data is considered consistent and can enter the next stage of processing; otherwise, the observation data is marked as abnormal and will be shielded in subsequent processing.

3. The GNSS train positioning method based on a two-out-of-three redundancy structure according to claim 1, characterized in that, The consistency of the fusion positioning result is judged based on the three-out-of-two majority voting. The position coordinates output by the three-channel EKF fusion are input, and the position coordinates (x, y, z) of the three channels are compared with each other. The Euclidean distance is used to calculate the coordinate difference between channels: By analogy, D AC With D BC When the distances of two pairs are both less than a set threshold, it is considered that the two positioning results in the pair are consistent; if there are more than two groups of results consistent with each other, it is considered that the current fusion result is reliable and can be used as a majority vote input; On the contrary, if the difference between the three results is significant, it is considered that the current fusion result is not reliable, and the fusion positioning data is marked as abnormal.

4. The GNSS train positioning method based on a two-out-of-three redundancy structure according to claim 1, characterized in that, The consistency of the map matching result is judged based on the three-out-of-two majority voting. After each channel completes map matching and outputs the coordinates, the Euclidean distance between the three sets of matching points is compared. If the distance between two sets of matching points is less than the threshold, the map matching result is considered consistent; otherwise, if the difference between the three results is significant, it is considered that the current map matching positioning result is not reliable, and the map matching positioning data is marked as abnormal.

5. The GNSS train positioning method based on a two-out-of-three redundancy structure according to claim 4, characterized in that, After the fusion positioning is completed, the three-channel position coordinates are matched with a track database of a train operation line, and a nearest projection point of each channel current coordinate on a track center line is extracted as a matched coordinate; The vertical projection algorithm of the map matching includes: converting the coordinates using the UTM projection method; finding the nearest point in the DTM, the nearest point being calculated by calculating the Euclidean distance between all points and G; and calculating the matching position of the vertical projection method.

6. The GNSS train positioning method based on a two-out-of-three redundancy structure according to claim 1, characterized in that, The final positioning result depends on the comprehensive judgment of the three-layer comparison mechanism. If the majority consistency judgment of the three-layer comparison is passed, the system will consider that the current positioning result is reliable, and output the fusion positioning value of the majority channel as the real-time position of the train. If any layer comparison fails, the system will trigger an internal alarm mechanism to prompt possible positioning abnormalities, thereby ensuring the operation safety of the train positioning system.

7. A GNSS train positioning system based on a two-out-of-three redundancy structure, characterized in that, The three-channel parallel data acquisition module is used to obtain observation data of each module, synchronized satellite observation data and positioning information, including original data such as pseudo-range, pseudo-range rate and time stamp through three independent information channels. The GNSS original observation data consistency judgment module is used to compare the original GNSS observation data collected by the three channels with each other, and to make consistency judgment according to the set error threshold, to identify possible data abnormalities or signal interference. The fusion positioning coordinate consistency judgment module is used to use the extended Kalman filter to fuse the GNSS original data and ODO information by each channel, to form three groups of preliminary positioning results, and to perform consistency verification on the three groups of fusion results to judge the consistency of the fusion coordinates. The map matching result consistency judgment module is used to match the fusion positioning result of each channel with the train track electronic map, and to output the map matching positioning point. The majority voting and validity determination module is used to pass the comparison as long as any two groups of comparison results meet the threshold requirement in the above three comparisons. If the three comparisons are passed, the current positioning is determined to be valid. If the comparison result is abnormal, the system outputs a marked abnormal state, triggers data shielding, and ensures the safe operation of the system. The non-transitory computer readable storage medium is used to store computer instructions, which are executed by a processor to implement the GNSS train positioning method based on the two-out-of-three redundancy structure according to any one of claims 1-6. The processor and the memory are in communication with each other, the memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the GNSS train positioning method based on the two-out-of-three redundancy structure according to any one of claims 1-6.

8. A non-transitory computer-readable storage medium, comprising: The three-channel parallel data acquisition module is used to obtain observation data of each module, synchronized satellite observation data and positioning information, including original data such as pseudo-range, pseudo-range rate and time stamp through three independent information channels.

9. A computer device, comprising: ​ 10. An electronic device, comprising: ​ A processor, a memory and a computer program; wherein the processor is connected with the memory, the computer program is stored in the memory, when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the instructions for realizing the GNSS train positioning method based on the two-out-of-three redundancy structure according to any one of claims 1-6.

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