Position estimation system and position estimation method

Abstract

To provide a technology capable of accurately estimating a position of a vehicle.SOLUTION: One representative location estimation system of the present disclosure comprises: a railway track information storage unit for storing a railway track information database including the railway track shape at each point on a railway track; a railway track shape measuring unit performing measurement of the railway track shape at least twice, in a train traveling on the railway track; a position measuring unit measuring a position of the train on the railway track; a section determination unit determining a matching section in the railway track information database based on the position measured by the position measuring unit; and a railway track information matching unit for matching, in the matching section, a DB railway track shape that is a railway track shape included in the railway track information database with a measured railway track shape that is the railway track shape measured by the railway track shape measuring unit, and estimates a point on the railway track corresponding to the matched railway track shape as the position of the train on the railway track.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a location estimation system and a location estimation method. [Background technology]

[0002] To realize obstacle detection and advanced train control, which are basic functions for autonomous driving of mobility such as railways and automobiles, it is necessary to estimate the vehicle's position with high accuracy. In the field of railways, for example, a conventional method is to install a ground coil that records the exact absolute position on the track and correct the position using the information transmitted from the ground coil. However, installing a ground coil on the track imposes a large burden in terms of installation and maintenance costs.

[0003] Patent Document 1 discloses a railway vehicle running position detection system that can detect the running position of the vehicle by comparing the shape of a curved section that the railway vehicle has just passed with the shape of any curved section among all curved sections that the railway vehicle can pass. In this system, first, a passing curve information creation unit 40 creates passing curve information R including actual measured values ​​such as an actual measured radius of curvature every time a curved section is passed. In addition, a candidate curve information group creation unit 50A creates each candidate curve information group G which is a collection of candidate curve information K corresponding to all curved sections that the railway vehicle can pass. Next, a matching rate calculation unit 60 calculates an overall matching rate J which indicates how much the immediately preceding passing curve information and the passing curve information immediately before match each candidate curve information group G in the range from 0 to 1. Finally, a curve identification unit 70 compares each overall matching rate J calculated for each candidate curve information group G to identify the curved section that the railway vehicle has just passed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-095981 A Summary of the Invention [Problem to be solved by the invention]

[0005] In some cases, tracks are laid with minimal change in shape, and in such cases, it may be difficult to detect differences in track shape and perform accurate position estimation with the method of Patent Document 1. For this reason, a method is required that allows for accurate position estimation even when changes in track shape are small and matching of track shapes is difficult. Therefore, an object of the present invention is to provide a technique that can estimate the position of a train with high accuracy. [Means for solving the problem]

[0006] In order to solve the above problems, a representative position estimation system of the present invention includes a track information storage unit that stores a track information database including the track geometry of each point on a track, a track geometry measurement unit that measures the track geometry of a train running on the track at least twice, a position measurement unit that measures the position of the train on the track, a section determination unit that determines a comparison section in the track information database based on the position measured by the position measurement unit, and a track information comparison unit that compares, in the comparison section, a DB track geometry, which is the track geometry included in the track information database, with a measured track geometry, which is the track geometry measured by the track geometry measurement unit, and estimates a point on the track corresponding to the compared track geometry as the position of the train on the track. Effect of the Invention

[0007] According to the present invention, the position of a train can be estimated with high accuracy. Problems, configurations and effects other than those described above will become apparent from the description of the following embodiments. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a position estimation system according to the first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the track information database. [Diagram 3]FIG. 3 is a diagram for explaining a method for determining a matching interval. [Figure 4] FIG. 4 is a diagram showing a method for estimating the position of a train by using a database of the track shape at the current position of each vehicle and a comparison section. [Diagram 5] FIG. 5 is a flowchart of position estimation in the first embodiment. [Figure 6] FIG. 6 is a diagram showing an example of the number of times a position is estimated and the result of the matching process. [Figure 7] FIG. 7 is a diagram illustrating a position estimation system according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing a method for measuring track geometry and checking against a database in a time series. [Figure 9] FIG. 9 is a diagram illustrating an example of a track information database in the third embodiment. [Figure 10] FIG. 10 is a diagram showing a method for measuring the track geometry and checking the database when the track information database contains continuous data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] In the first embodiment, a method for estimating the position of a train by measuring the track geometry and checking against a track information database at a plurality of points will be described.

[0010] First, the configuration of the location estimation system and the role of each component will be described with reference to FIG.

[0011] (System Configuration) 1 is a diagram showing a position estimation system 100 according to a first embodiment. The position estimation system 100 according to the first embodiment includes a first track shape measurement unit 101, a second track shape measurement unit 102, a position measurement unit 103, a track information storage unit 104, a section determination unit 105, and a track shape matching unit 106. Information on the position of a train estimated by the position estimation system 100 is output to a vehicle control unit 107, and the vehicle control unit 107 controls the train based on the position of the train.

[0012] The track geometry measurement units 101 and 102 measure the track geometry of a train traveling on the track at least twice. The track geometry measurement units are installed in any of the cars that make up the train, and each has a function of measuring the track geometry at the current location of the car in which it is installed. In the first embodiment, two track geometry measurement units, a first track geometry measurement unit 101 and a second track geometry measurement unit 102, are provided, and each performs at least one measurement, and at least two measurements in total. The first track geometry measurement unit 101 outputs information Sg1 indicating the track geometry measured in the first car to the track geometry comparison unit 106, and the second track geometry measurement unit 102 outputs information Sg2 indicating the track geometry measured in the second car to the track geometry comparison unit 106.

[0013] The information indicating the track shape includes basic information of the track such as the gradient value of the track and the curve radius of the track, as well as characteristic information of the track such as unevenness of the rail joints of the track as information indicating the track shape in a broad sense. For example, in the case of the gradient amount, a sensor capable of measuring the pitch angle such as a level is used. In the following description, the gradient amount is used as an example of the track shape, but the first embodiment is not limited to this, and can be applied to cases where other track shapes such as the curve radius and the rail joints are used, or a combination of multiple pieces of information is used. In addition, the sensor is not limited to a level. For example, a gyro sensor or an angular velocity sensor may be used, or these may be used in combination. It is also possible to measure the state of the vehicle using a sensor that measures three dimensions, and calculate the gradient amount, the curve radius, and the rail joints. In addition, the track information may be extracted using information obtained by an optical sensor such as a LIDAR (light detection and ranging) or a camera, or the track shape may be measured using satellite information such as a GNSS (Global Navigation Satellite System).

[0014] In addition, when selecting a vehicle for measuring track information, for example, the leading vehicle is the first vehicle equipped with the first track measurement unit 101, and the last vehicle is the second vehicle equipped with the second track shape measurement unit 102. Since differences in the measured track information are likely to occur by selecting vehicles that are far apart, even if accurate estimation cannot be performed with track information from only one vehicle, it is expected that the accuracy of position estimation will be improved by using track information from two vehicles. In addition, vehicles whose track information cannot be accurately measured due to the influence of suspensions, etc. may be excluded from the selection of vehicles for measuring track information.

[0015] The number of vehicles whose track geometry is measured is at least two, including the leading vehicle and the trailing vehicle, among the multiple vehicles, but is not limited to two and may be three or more. In addition to cases where a track geometry measurement unit is installed on each vehicle, cases where a track geometry measurement unit is not installed on each vehicle are also included. For example, a sensor may be installed on each vehicle to measure the vehicle state, and the track geometry measurement unit may analyze information indicating the measured vehicle state to calculate the track geometry for each vehicle.

[0016] The position measurement unit 103 has a function of measuring the position of the train on the track. The calculated position may include an error, and is therefore an approximate position of the train (hereinafter, also referred to as an "approximate position"). For example, a method of measuring the approximate position of the train may include a position calculated from an integrated value of the train's speedometer, or a method using information on the train's running inter-stations. The position measurement unit 103 can measure the approximate position of the train or the approximate position of each car based on information on the cars that make up the train. The position measurement unit 103 outputs information Sg3 indicating the approximate position of the train or the approximate position of each car to the section determination unit 105. Note that the measurement means for the approximate position is not limited to a speedometer. For example, the approximate position may be obtained by photographing the track and objects around the track, and matching images of the track and the environment around the track photographed using a LIDAR and a camera. In addition, the approximate position is measured continuously while the train is running, and it is possible to calculate the approximate position at the timing of measurements performed by the first track shape measurement unit 101 and the second track shape measurement unit 102.

[0017] The track information storage unit 104 has a function of storing a track information database including the track shape of each point on the track. FIG. 2 is a diagram showing an example of the track information database DB1. In this example, the track information database DB1 has items such as a location, a gradient amount at each point, a curve radius, and the presence or absence of a rail joint. Note that, although an example including the gradient amount, the curve radius, and the presence or absence of a rail joint as the track shape has been shown, the track shape is not limited to these, and information indicating other track shapes may be stored. In addition, any information indicating the state of the track may be stored as information indicating the track shape in a broad sense. The track information storage unit 104 outputs information Sg4 indicating the track information database to the section determination unit 105. Alternatively, the section determination unit 105 may be configured to appropriately refer to the track shape database stored in the track information storage unit 104.

[0018] In addition, if the values ​​in the track information database differ for different vehicles even at the same point, a database for each vehicle may be stored and used. For example, differences in the data for each vehicle may be due to differences in the measurement results caused by individual differences in the suspension of the vehicle.

[0019] Furthermore, the track information database may be created not only from the measurement results of a single train, but also by combining the measurement results of multiple trains. For example, the position estimation system according to the first embodiment may be applied to a train traffic control system, and the track shape and approximate positions measured for multiple trains may be reflected in the track information database.

[0020] The section determination unit 105 determines a matching section in the track information database based on the positions measured by the first track shape measurement unit 101 and the second track shape measurement unit 102. The section determination unit 105 has a function of determining a section (hereinafter referred to as a "matching section") to be used for matching track shapes within information Sg4 indicating data on track information at each point output from the track information storage unit 104, using the approximate position output from the position measurement unit 103. The matching section may be determined to be a section before or after the approximate position. The length of the section before or after the approximate position is determined according to required performance such as the accuracy of position estimation and the time required for estimation. The section determination unit 105 outputs information Sg5 indicating the determined matching section to the track shape matching unit 106.

[0021] Here, the method of determining the matching interval will be described in detail. Fig. 3 is a diagram for explaining the method of determining the matching interval.

[0022] Consider a case where the position measurement unit 103 measures the approximate position of the first vehicle as point x4 and the approximate position of the second vehicle as point x3. When the section determination unit 105 receives information Sg3 indicating the approximate positions of each vehicle in step S1, it searches for a location corresponding to the approximate positions from the points in the track information database. As a search method, for example, a linear algorithm method that searches sequentially from the top of the database, or other methods can be selected as appropriate.

[0023] The track information database DB1 shown in Fig. 3 has discrete values. On the other hand, the estimated vehicle position has continuous values, and it may be the case that a simple search is not possible. In this case, the section determination unit 105 searches for a point that is closest to the position measured by the position measurement unit among the points included in the track information database DB1. For example, the difference between the point in the track information database and the point indicated by the estimated position is calculated, and the point with the smallest difference can be determined as the search result in step S1.

[0024] In step S2, the section determination unit 105 sets a section length sl before and after the point searched for in step S1 to determine the matching section. For example, if the section length sl is large, the workload of the subsequent matching process increases. On the other hand, if the section length sl is small, there is a risk that the matching process cannot be performed accurately. The section length sl is set according to the operation of the system.

[0025] The track geometry matching unit 106 has a function of estimating the position of the vehicle by matching the track geometry at the current position of each vehicle output from the first track geometry measurement unit 101 and the second track geometry measurement unit 102 with the matching section output from the section determination unit 105. For example, the track geometry matching unit 106 matches the track geometry included in the track geometry database (hereinafter also referred to as the "DB track geometry") with the track geometry measured by the first track geometry measurement unit 101 and the second track geometry measurement unit 102 (hereinafter also referred to as the "measured track geometry") in the matching section, and estimates the point on the track corresponding to the matched track geometry as the position of the train on the track.

[0026] FIG. 4 is a diagram showing a method for estimating the position of a train using a database of track geometry at the train's current location and a comparison section. A first track geometry measurement unit 101 is provided in the leading car as the first car, and a second track geometry measurement unit 102 is provided in the rearmost car as the second car. The arrow indicates the traveling direction of the cars. FIG. 4(a) shows how the track geometry is measured. As shown here, the first track geometry measurement unit 101 measures the amount of inclination θ1, and the second track geometry measurement unit 102 measures the amount of inclination θ2.

[0027] 4(b) shows how database matching is performed. An example is shown in which the matching section is set to the range from point x1a to point x6a in database DB2, and the gradient amount in the first track shape measurement unit 101 is θ1, and the gradient amount in the second track shape measurement unit 102 is θ2.

[0028] The track information database DB2 shown in FIG. 4(b) is set discretely, such as points x1a, x2a, .... The interval between the points is based on the train length, which is the length between the first vehicle and the second vehicle. Such a track information database DB2 based on the train length is created in the section determination unit 105 based on information Sg3 indicating the approximate position of each vehicle in the position measurement unit 103 and information Sg4 indicating the vehicle information database DB1. For example, the section determination unit 105 may extract data based on the train volume from the track information database DB1 to create a database, or may change the data section of the track information database DB1.

[0029] First, in the matching section, a point corresponding to the gradient amount θ1 in the first track shape measurement unit 101 is searched for. In the matching result, it is found that the gradient amount θ1 corresponds to points x2a, x3a, x4a, and x6a. Next, in the matching section, a point corresponding to the gradient amount θ2 in the second track shape measurement unit 102 is searched for. As shown in the matching result, it is found that the point x3a corresponds to the gradient amount θ2. As a result, it is found that the positions in the matching section where the gradient amounts are θ1 and θ2 are points x3a and x4a, and it is possible to estimate the position of the first vehicle as x4a and the position of the second vehicle as x3a. In this manner, the positions can be estimated from the track shape and the matching section. Information Sg6 indicating the estimated positions is output to the vehicle control unit 107.

[0030] In the above-mentioned comparison method, even if the values ​​do not completely match between the track shape and the track information database DB2, they may be accepted and compared as a match if they are within a preset range. The above-mentioned acceptable range may be set according to the position estimation accuracy. For example, in the comparison process, the difference between the gradient amount in the track information database DB2 and the gradient amount measured by the first track shape measurement unit 101 and the second track shape measurement unit 102 may be taken, and if the difference is within a preset range, they may be compared as a match. The preset range may be appropriately selected according to the system operation situation.

[0031] If the result does not fall within the acceptable range and a match is not possible, it is determined that position estimation using this method is not possible, and the position is measured using another position measurement means, or the previous position value is retained.

[0032] In addition, since it is assumed that the measured values ​​of the track shape may vary due to driving operations such as acceleration and deceleration of the vehicle, position estimation may not be performed in sections where the driving operations of the vehicle have changed, or the acceleration and deceleration of the changed driving operations may be taken into consideration in the measured results of the track shape. Note that the driving operations of the vehicle include accelerating driving (powering driving), constant speed driving, coasting driving, and braking driving.

[0033] The vehicle control unit 107 has a function of controlling the train using the position information Sg6 output from the track shape matching unit 106. Examples of a train control method include an automatic control device (ATC) and an automatic driving system (ATO).

[0034] The above is an explanation of the configuration of the position estimation system 100 and each of its components.

[0035] (flowchart) Next, a procedure for estimating a position in a section from departure from a station to arrival at the next station in the first embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram showing a flowchart of position estimation in the first embodiment. Note that the same procedure is performed after arrival at the next station until arrival at the line terminal station, and the description thereof will be omitted.

[0036] In step S11, the first track shape measurement unit 101 and the second track shape measurement unit 102 measure track shape information at the current position.

[0037] In step S12, the position measurement unit 103 calculates the approximate position of the vehicle based on the speedometer and the current station-to-station information.

[0038] In step S13, the section determination unit 105 determines a comparison section using the approximate vehicle position output from the position measurement unit 103 and the track information database for each point output from the track information storage unit 104.

[0039] In step S14, the track shape matching unit 106 matches the track shape at the current position of each vehicle output in step S11 with the matching section output in step S13, searches for a position corresponding to the matched track shape, thereby estimating the position of the vehicle and updating the estimated position of the vehicle. If matching based on the track shape at the current position is not possible, it is determined that position estimation by this method is not possible. Reasons for not being able to match the track shape include when a match is not found by searching for the track shape in step S14, when track information cannot be measured in step S11, when an approximate position cannot be measured in step S12, when a matching section cannot be determined in step S13, etc.

[0040] In step S15, the position estimated in step S14 is output to vehicle control unit 107, and vehicle control unit 107 controls the vehicle in accordance with the position information.

[0041] In step S16, it is determined whether the train has arrived at the next station. If the train has not arrived, the process returns to step S11, and if the train has arrived at the next station, the process ends.

[0042] The above steps S11 to S16 are repeated at a predetermined time interval. Fig. 6 is a diagram showing an example of the number of times the position was estimated and the results of the matching process. As shown in Fig. 6(a), the matching result column shows "O" for the first, third, fourth, seventh, and eighth times the estimation was performed, indicating that the position estimation was performed properly. On the other hand, the matching result column shows "X" for the second, fifth, and sixth times, indicating that the position estimation was not possible.

[0043] FIG. 6(b) shows another example of the estimation round and the result of the matching process. Here, A to C are listed in the matching result column. This is an evaluation of the result of the matching process according to the degree of match between the point and track information in the matching section in the database as a result of the matching, and the approximate position and track information obtained by the first track shape measurement unit 101 and the second track shape measurement unit 102 or the position measurement unit 103. For example, a three-level evaluation standard is set for the difference between the database value and the measured value, and A is the case where the difference is the smallest and the accuracy of the position estimation result is high, C is the case where the difference is the largest and the accuracy of the position estimation result is low, and B is the intermediate case between A and C.

[0044] As shown in Figures 6(a) and (b), if no matching results or results with the desired accuracy are obtained at a certain point, it is possible to interpolate the data using results from previous and subsequent points to perform a location estimate.

[0045] The above is an explanation of the procedure for estimating a position by the method of this embodiment in the section from departure from a station to arrival at the next station.

[0046] (Action and effect) As described above, according to the first embodiment, by measuring the track geometry and comparing it with a track information database at multiple points, it is possible to estimate the position with high accuracy even when the difference in the track geometry is small and matching the track geometry is difficult.

[0047] In addition, there are cases where the shape of the tracks is limited along the entire line, and there are multiple locations with similar shapes along the tracks on which the train runs. In such cases, simply acquiring and comparing track shape information from one vehicle can lead to the risk of extracting a shape at the wrong location, resulting in an erroneous comparison. By measuring track shape information from multiple vehicles and using it for comparison, the train's position can be estimated with high accuracy.

[0048] In principle, it is possible to estimate the position by comparing the track shapes of all points included in the track information database, but this is not realistic because it would require a large processing load and would take a long time to estimate the position. By limiting the comparison section in the track information database where the comparison process is performed, it is possible to reduce the processing load and perform position estimation in a timely manner.

[0049] In addition, it is assumed that the tracks will be laid on terrain with large gradient changes. Compared to flat roads, more power is required on uphill roads, and appropriate braking is required on downhill roads. By estimating the position with high accuracy based on the point and gradient amount, it is possible to control the vehicle's power generation device, braking device, operating speed, etc., and to operate the vehicle safely.

[0050] Furthermore, when a train travels on a curved road, the train body is tilted to increase the passing speed and improve the ride comfort. By accurately estimating the position based on the point and curvature, the amount, timing, and direction of tilting the car body can be calculated with high accuracy, and speed and ride comfort can be improved.

[0051] In addition, when a train passes over a rail joint, vibrations and noise are generated. This affects the ride comfort inside the train and the surrounding environment outside the train. By accurately estimating the position based on the location and the rail joint, it is possible to perform vibration control of the train and suppress the generation of vibrations and noise.

[0052] Second Embodiment In the second embodiment, a method of estimating a position by measuring the track shape and comparing it with a database in a time series will be described. Note that the same components as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

[0053] In the first embodiment, the accuracy of position estimation is improved by measuring the track geometry and comparing the database at multiple points, whereas in the second embodiment, the accuracy of position estimation is improved by measuring the track geometry and comparing the database over a time series, which is a difference from the first embodiment.

[0054] For this reason, whereas the first embodiment required multiple vehicles and sensors to measure the track geometry, the second embodiment requires only one vehicle or sensor to measure the track geometry for the entire train.

[0055] 7 is a diagram showing a position estimation system 100a according to the second embodiment. In the position estimation system 100a, a first track shape measurement unit 101 measures track information.

[0056] FIG. 8 is a diagram showing a method of measuring track geometry and matching the database in a time series. Here, a first track geometry measuring unit 101 is provided in a leading vehicle. The first track geometry measuring unit 101 measures the track geometry at a first time t1 and a second time t2. FIG. 8(a) is a diagram showing a case where a gradient amount θ1 is measured at a first time t1, and FIG. 8(b) is a diagram showing a case where a gradient amount θ2 is measured at a second time t2. FIG. 8(c) is a diagram showing a concept of matching processing in the track information database DB3. The track information database DB3 shown in FIG. 8(c) is set discretely such as points x1b, x2b, .... The interval between the points is based on the travel distance traveled by the vehicle between the first time t1 and the second time t2. The setting of such track information database DB3 is performed in the section determination unit 105 based on information Sg3 indicating the approximate position of each vehicle in the position measurement unit 103.

[0057] First, in the matching section, a point corresponding to the gradient amount θ1 at the first time t1 is searched for. As shown in the matching result, it was found that the gradient amount θ1 corresponds to points x2b, x3b, x4b, and x6b in the track information database DB3. Next, in the matching section, a point corresponding to the gradient amount θ2 at the second time t2 is searched for. As shown in the matching result, it was found that point x3b corresponds to the gradient amount θ2 in the track information database DB3. As a result, it is found that the positions in the matching section where the gradient amounts correspond to θ1 and θ2 are points x3b and x4b, so it is possible to estimate that the position at the first time t1 is x3b and the position at the second time t2 is point x4b. By the method of matching the time series fragmentation of the measured track information in this way, it is possible to estimate the position from the track information on the time series and the matching section.

[0058] In the second embodiment, the number of data points used on the time series is two, the first time t1 and the second time t2, but this is not limited to this, and position estimation may be performed with the number of data points used on the time series being three or more.

[0059] (Action and effect) As described above, according to the second embodiment, by measuring the track geometry and comparing it with a database using multiple measurement values ​​in a time series, it is possible to estimate the position with high accuracy even when the difference in the track geometry is small and matching the track geometry is difficult.

[0060] [Third embodiment] In the first embodiment, a track information database with intervals based on train length is used, and in the second embodiment, a track information database with intervals based on travel distance is used. In either case, the track information database has a fixed interval, but in the third embodiment, the fixed interval of the track information database is subdivided at a specific point. Note that the same components as in the first and second embodiments are given the same reference numerals and their explanations are omitted.

[0061] FIG. 9 is a diagram showing an example of the track information database DB4 in the third embodiment. The track information database DB4 is composed of discrete values, and the intervals between points x1, x2, x3, x4, x5, and x6 are all the same. Here, in the region L1, the point x1 is subdivided into points x11 and x12 at half the interval, and the items of gradient, curvature radius, and rail joint also have data corresponding to points x11 and x12. The point x2 is also subdivided into points x21 and x22. In the region L2, the point x3 is subdivided into points x31, x32, and x33 at one-third the interval, and the items of gradient, curvature radius, and rail joint also have data corresponding to points x31, x32, and x33, respectively. The point x4 is also subdivided into points x41, x42, and x43.

[0062] The matching process is performed in the same manner as in the first and second embodiments.

[0063] (Action and effect) While the points in the track information database are input as discrete values, the positions obtained by measuring the approximate position are continuous values. When comparing the track information database, it is difficult to obtain a perfect match.

[0064] In contrast, in the third embodiment, the data intervals are subdivided in the track information database DB4, which makes it possible to reduce the difference between the position obtained by measuring the approximate position and the point in the track information database DB4, thereby improving the accuracy of position estimation.

[0065] For example, when operating in an energy-saving manner, it is necessary to grasp changes in track geometry in a timely manner and control operations. By selecting locations where changes in track geometry are large as specific points and storing the values ​​in the database in a subdivided form in advance, it is possible to grasp the changes in track geometry and perform operation control that is suited to the changes in the track.

[0066] (Fourth embodiment) The fourth embodiment differs from the first to third embodiments in that the track information database has continuous data on points and track shapes. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals and their description will be omitted.

[0067] FIG. 10 is a diagram showing a method for measuring the track geometry and checking the database when the track information database contains continuous data.

[0068] 10(a) is a diagram showing a case where a gradient amount is measured in the fourth embodiment. A first track shape measurement unit 101 is provided in the leading car, and a second track shape measurement unit 102 is provided in the last car.

[0069] FIG. 10(b) is a diagram showing measured gradient amounts. Gradient amount θ1 is the gradient amount measured by the first track geometry measurement unit 101. Moreover, gradient amount θ2 is the gradient amount measured by the second track geometry measurement unit. As shown here, in the fourth embodiment, the results of measurements in the track geometry measurement unit also have continuous values. For example, it is possible to perform measurements continuously while the train is running, or measurements may be performed at specific points.

[0070] 10(c) is a diagram showing the concept of matching processing in the track information database DB5. As shown here, in the fourth embodiment, the track information database DB5 has continuous values ​​of gradient amounts on the track between Station A and Station B. In the matching section, a pattern is detected between the gradient amount in the track information database DB5 and gradient amount θ1, and a pattern is detected between the track information database DB5 and gradient amount θ2. The position corresponding to the gradient amount matched in either pattern matching is estimated as the position of the train.

[0071] Although the fourth embodiment has been described using the gradient amount, the present invention is not limited thereto. It is also possible to apply information indicating other track shapes. In addition, the case where two track shape measuring units are used as in the first embodiment has been described, but the present invention is not limited thereto. It is also possible to apply the fourth embodiment to a case where three or more track shape measuring units are used. In addition, the fourth embodiment can also be applied to the matching of track shapes in a time series as in the second embodiment.

[0072] (Action and effect) In the fourth embodiment, the track information database DB5 has data on continuous track shapes. By using pattern matching in the matching process, the accuracy of the matching process can be improved, and as a result, the accuracy of the position estimation can be further improved.

[0073] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0074] In the present disclosure, the embodiments have been described separately, but it is also possible to carry out the embodiments in combination.

[0075] The position estimation system according to the present disclosure may be installed on a train to serve as an on-board system. The position estimation system according to the present disclosure may also be adopted in a train traffic control system to estimate the positions and control the operation of multiple trains within a railway section.

[0076] (Other Aspects) The present disclosure also includes the following aspects. (Aspect 1) a track information storage unit that stores a track information database including track shapes at each point on the track; a track geometry measurement unit that measures a track geometry at least twice for a train traveling on the track; a position measurement unit that measures the position of the train on a track; a section determination unit that determines a comparison section in the track information database based on the position measured by the position measurement unit; a track information matching unit that matches, in the matching section, a DB track geometry, which is a track geometry included in the track information database, with a measured track geometry, which is a track geometry measured by the track geometry measuring unit, and estimates a point on the track corresponding to the matched track geometry as the position of the train on the track; 13. A location estimation system comprising: (Aspect 2) 2. The position estimation system according to claim 1, the section determination unit searches for a point that is closest to the position measured by the position measurement unit among the points included in the railway line information database, and sets a predetermined section length before and after the searched point to be the comparison section; Location estimation system. (Aspect 3) 3. The position estimation system according to claim 1, further comprising: The train is made up of a plurality of cars, The track geometry measurement unit measures the track geometry of at least two vehicles among the plurality of vehicles. Location estimation system. (Aspect 4) 4. The position estimation system of any one of aspects 1 to 3, comprising: The at least two vehicles include a leading vehicle and a trailing vehicle among the plurality of vehicles. Location estimation system. (Aspect 5) 5. The position estimation system of any one of aspects 1 to 4, comprising: The track geometry measurement unit measures the track geometry at a first time and a second time. Location estimation system. (Aspect 6) 6. The position estimation system of any one of aspects 1 to 5, comprising: The gradient of the line is used as the line shape. Location estimation system. (Aspect 7) 7. The position estimation system of any one of aspects 1 to 6, comprising: As the line shape, a curve radius of the line is used. Location estimation system. (Aspect 8) 8. The position estimation system of any one of aspects 1 to 7, comprising: The track shape is determined by the presence or absence of unevenness at the rail joints of the track. Location estimation system. (Aspect 9) 9. The position estimation system of any one of aspects 1 to 8, comprising: The position measurement unit calculates the position of the train based on an integrated value of a train's speedometer. Location estimation system. (Aspect 10) 10. The position estimation system of any one of aspects 1 to 9, comprising: The track information database records track shapes at regular intervals, and the regular intervals are subdivided at specific points. Location estimation system. (Aspect 11) A position estimation method using a track information database including track shapes at each point on a track, comprising: a track geometry measuring step of measuring a track geometry at least twice for a train traveling on the track; a position measuring step of measuring a position of the train on a track; a section determination step of determining a comparison section in the track information database based on the position measured in the position measurement step; a track information matching step of matching, in the matching section, a DB track geometry, which is a track geometry included in the track information database, with a measured track geometry, which is a track geometry measured in the track geometry measuring step, and estimating a point on the track corresponding to the matched track geometry as the position of the train on the track; A location estimation method comprising: [Explanation of symbols]

[0077] 100, 100a: Position estimation system 101: First track shape measurement unit 102: Second track shape measurement unit 103: Position measurement unit 104: Track information storage unit 105: Section determination section 106: Track shape matching unit 107: Vehicle control unit DB1, DB2, DB3, DB4, DB5: Track information database

Claims

1. a track information storage unit that stores a track information database including track shapes at each point on the track; a track geometry measurement unit that measures a track geometry at least twice for a train traveling on the track; a position measurement unit that measures the position of the train on a track; a section determination unit that determines a comparison section in the track information database based on the position measured by the position measurement unit; a track information matching unit that matches, in the matching section, a DB track geometry, which is a track geometry included in the track information database, with a measured track geometry, which is a track geometry measured by the track geometry measuring unit, and estimates a point on the track corresponding to the matched track geometry as the position of the train on the track; Including, The track information database records track shapes at regular intervals, and the regular intervals are subdivided at specific points. Location estimation system.

2. 2. The position estimation system of claim 1, the section determination unit searches for a point that is closest to the position measured by the position measurement unit among the points included in the railway line information database, and sets a predetermined section length before and after the searched point to be the comparison section; Location estimation system.

3. 2. The position estimation system of claim 1, The train is made up of a plurality of cars, the track geometry measurement unit measures the track geometry of at least two vehicles among the plurality of vehicles; Location estimation system.

4. 4. The position estimation system of claim 3, The at least two vehicles include a leading vehicle and a trailing vehicle among the plurality of vehicles. Location estimation system.

5. 2. The position estimation system of claim 1, The track shape measurement unit measures the track shape at a first time and a second time. Location estimation system.

6. 2. The position estimation system of claim 1, The gradient of the line is used as the line shape. Location estimation system.

7. 2. The position estimation system of claim 1, As the line shape, a curve radius of the line is used. Location estimation system.

8. 2. The position estimation system of claim 1, The track shape is determined by the presence or absence of unevenness at the rail joints of the track. Location estimation system.

9. 2. The position estimation system of claim 1, The position measurement unit calculates the position of the train based on an integrated value of a train's speedometer. Location estimation system.

10. A position estimation method using a track information database including track shapes at each point on a track, comprising: a track geometry measuring step of measuring a track geometry at least twice for a train traveling on the track; a position measuring step of measuring a position of the train on a track; a section determination step of determining a comparison section in the track information database based on the position measured in the position measurement step; a track information matching step of matching, in the matching section, a DB track geometry, which is a track geometry included in the track information database, with a measured track geometry, which is a track geometry measured in the track geometry measuring step, and estimating a point on the track corresponding to the matched track geometry as the position of the train on the track; Including, The track information database records track shapes at regular intervals, and the regular intervals are subdivided at specific points. Location estimation method.

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