Vehicle position detection apparatus and vehicle position detection method

Abstract

To provide a vehicle position detection apparatus and a vehicle position detection method capable of accurately detecting a position of a railway vehicle even when positioning of the railway vehicle using GNSS cannot be accurately performed.SOLUTION: An on-board apparatus 2 calculates GNSS coordinates by a GNSS reception unit 211, measures a speed of a railway vehicle by a radar speedometer 24, measures acceleration and angular velocity by an acceleration sensor 213 and an angular velocity sensor 214, calculates a position of the railway vehicle Tr on the basis of the GNSS coordinates when a positioning accuracy index of a GNSS signal is equal to or greater than a prescribed value, calculates composite coordinates based on the GNSS coordinates, the speed, and inertial momentum when the positioning accuracy index is below the prescribed value, and calculates the position of the railway vehicle Tr on the basis of the composite coordinates.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle position detection device and a vehicle position detection method for detecting the position of a railway vehicle on a railway track. [Background technology]

[0002] A train approach warning system is used to prevent accidents such as contact between a railway vehicle and a worker during railway construction work (see, for example, Patent Document 1). The train approach warning system described in Patent Document 1 uses a global navigation satellite system (GNSS) such as a global positioning system (GPS) to measure the position of the railway vehicle, and calculates the position (specifically, the distance in kilometers) of the railway vehicle traveling on the railway track by referring to a railway geographic information system (GIS), which is map information including the position information of the railway track. Then, when the railway vehicle approaches within a predetermined distance (also called the warning distance) to a worker, an alarm is generated on an alarm terminal carried by the worker, and the alarm is stopped when the railway vehicle passes the worker's work position. The worker takes refuge in a position away from the railway track while the alarm is being transmitted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-212121 A Summary of the Invention [Problem to be solved by the invention]

[0004] GNSS-based positioning of railway vehicles cannot be performed when the railway vehicle is traveling in a tunnel, when there are tall trees or buildings along the line that obstruct positioning, or when the railway vehicle is traveling in the shadow of a mountain. For this reason, for example, when workers are working at the exit side of a tunnel and the warning distance is set inside the tunnel, a warning is issued just before the railway vehicle enters the tunnel, or a notice is given that the train approach warning system cannot be used. In addition, near the exit of a tunnel, multipath occurs in the signal from the GNSS satellite, which can cause unstable positioning, so the warning is stopped after the railway vehicle passes through the tunnel and positioning is completed. For this reason, when railway construction is carried out on a line that has a tunnel, there is a problem that the evacuation time of workers is longer than the actual evacuation time required.

[0005] Therefore, an object of the present invention is to provide a vehicle position detection device and a vehicle position detection method that are capable of detecting the position of a railway vehicle with high accuracy even when accurate positioning of the railway vehicle using GNSS cannot be performed. [Means for solving the problem]

[0006] In order to solve the above problem, the invention described in claim 1 is a vehicle position detection device comprising: positioning means mounted on a railway vehicle running on a railway track and calculating satellite positioning coordinates based on a positioning signal received from a positioning satellite; a radar speedometer mounted on the railway vehicle and transmitting radar waves and receiving reflected waves of the radar waves to measure the speed of the railway vehicle; an inertial sensor mounted on the railway vehicle and measuring the inertial momentum of the railway vehicle; and vehicle position calculation means for calculating a position of the railway vehicle on the railway track based on vehicle-related information related to the railway vehicle, wherein if a positioning accuracy index output from the positioning means is equal to or greater than a predetermined value, the vehicle position calculation means calculates a position of the railway vehicle based on the satellite positioning coordinates as the vehicle-related information, and if the positioning accuracy index is less than the predetermined value, the vehicle position calculation means calculates a composite coordinate based on the satellite positioning coordinates, the speed and the inertial momentum, and calculates the position of the railway vehicle based on the composite coordinates as the vehicle-related information.

[0007] The invention described in claim 2 is characterized in that, in the vehicle position detection device described in claim 1, the vehicle position calculation means compares the composite coordinate with position information of the railway track to determine the accuracy of the composite coordinate, and if the accuracy of the composite coordinate is less than a predetermined value, calculates the position of the railway vehicle based on the speed as the vehicle-related information.

[0008] The invention described in claim 3 is characterized in that, in the vehicle position detection device described in claim 2, the vehicle position calculation means determines the reliability of the speed measured by the radar speedometer based on the reflected wave, and if the reliability is less than a predetermined value, calculates the position of the railway vehicle based on the inertial momentum as the vehicle-related information.

[0009] The invention described in claim 4 is characterized in that, in the vehicle position detection device described in claim 1, the vehicle position calculation means calculates a first recent movement amount, which is the most recent movement amount of the railway vehicle, based on one piece of information selected as the vehicle-related information, and calculates a second recent movement amount, which is the most recent movement amount of the railway vehicle, based on other information not selected as the vehicle-related information, compares the first recent movement amount and the second recent movement amount with a predetermined threshold, and if the first recent movement amount is less than the predetermined threshold, continues calculating the position of the railway vehicle based on the vehicle-related information used in calculating the first recent movement amount, and if the first recent movement amount is equal to or greater than the predetermined threshold, calculates the position of the railway vehicle using, as new vehicle-related information, the information of the second recent movement amount used in calculating the second recent movement amount, which is less than the predetermined threshold.

[0010] The invention described in claim 5 is characterized in that, in the vehicle position detection device described in claim 1, the vehicle position calculation means estimates an amount of error between the satellite positioning coordinates and the composite coordinates, and uses the estimated amount of error in calculating the composite coordinates.

[0011] The invention described in claim 6 is characterized in that, in the vehicle position detection device described in any one of claims 1 to 5, the vehicle position calculation means is provided in an external device mounted on the railway vehicle, or in an external device installed at a location other than the railway vehicle.

[0012] The invention described in claim 7 is a vehicle position detection method comprising the steps of receiving a positioning signal from a positioning satellite by a positioning means and calculating satellite positioning coordinates based on the received positioning signal, transmitting radar waves from a radar speedometer and receiving reflected waves of the radar waves to measure the speed of the railway vehicle, and measuring the inertial momentum of the railway vehicle by an inertial sensor, wherein if a positioning accuracy index output from the positioning means is equal to or greater than a predetermined value, a position of the railway vehicle is calculated based on the satellite positioning coordinates, and if the positioning accuracy index is less than the predetermined value, a composite coordinate is calculated based on the satellite positioning coordinates, the speed, and the inertial momentum, and the position of the railway vehicle is calculated based on the composite coordinate. Effect of the Invention

[0013] According to the inventions of claims 1 and 7, when the positioning accuracy index based on the positioning signal is less than a predetermined value, a composite coordinate based on the satellite positioning coordinates, the speed, and the inertial momentum is calculated, and the position of the railway vehicle is calculated based on the composite coordinate, so that it is possible to detect the position of the railway vehicle with high accuracy even if the positioning accuracy based on the positioning signal is poor. Also, when measuring the speed by detecting the number of rotations of the axles of the railway vehicle, the speed measurement accuracy deteriorates due to wheel spinning and sliding, but since the present invention uses a radar speedometer, it is possible to detect the speed of the railway vehicle with high accuracy.

[0014] According to the invention described in claim 2, when the accuracy of the composite coordinates is less than a predetermined value, the position of the railway vehicle is calculated based on the speed. Therefore, even if the accuracy of the composite coordinates decreases when, for example, the railway vehicle is traveling through a tunnel, it is possible to accurately detect the position of the railway vehicle.

[0015] According to the invention described in claim 3, when the reliability of the speed measured by the radar speedometer is less than a predetermined value (i.e., when it is unreliable), the position of the railway vehicle is calculated based on the inertial momentum. Therefore, even when the radar waves are absorbed by accumulated snow, for example, and the speed cannot be measured by the radar speedometer, it is possible to accurately detect the position of the railway vehicle.

[0016] According to the invention described in claim 4, the amount of recent movement of the railway vehicle calculated based on the vehicle-related information is appropriately compared with the amount of recent movement of the railway vehicle calculated based on information not selected as the vehicle-related information, and if there is a possibility that the amount of recent movement of the railway vehicle calculated based on the vehicle-related information is not appropriate, the position of the railway vehicle is calculated based on information in which the amount of recent movement is considered to be appropriate, thereby making it possible to respond to unknown behavior or abnormal values ​​that may occur instantaneously in the positioning means, radar speedometer, inertial sensor, etc.

[0017] According to the invention described in claim 5, the amount of error between the satellite positioning coordinates and the composite coordinates is used to calculate the composite coordinates, so that it is possible to accurately detect the position of the railway vehicle from measurement values ​​that have errors and noise, such as the satellite positioning coordinates, speed, and inertial momentum.

[0018] According to the invention described in claim 6, the vehicle position calculation means is provided in the external device mounted on the railway vehicle. For example, by using a computer capable of high-speed arithmetic processing in the external device, the position of the railway vehicle can be calculated at high speed, and application software supporting the operation of the railway vehicle can be operated using the calculated position information. In addition, when the vehicle position calculation means is provided in the external device installed in a place other than the railway vehicle, the cost of the on-board devices mounted on many railway vehicles can be reduced. Furthermore, since the position detection of many railway vehicles can be processed collectively by the external device, the processing load of the on-board devices can be reduced and power consumption can be reduced. In addition, when updating the function of the vehicle position calculation means, it is necessary to make changes only to the vehicle position calculation means of the external device, so that the function can be updated more easily than when the vehicle position calculation means is installed in each on-board device. [Brief description of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a schematic configuration of a vehicle approach warning system in accordance with an embodiment 1 of the present invention. [Diagram 2] 2 is a block diagram showing a schematic configuration of the on-board device shown in FIG. 1. [Diagram 3] 3 is an explanatory diagram showing a method of calculating a composite coordinate by the composite positioning unit shown in FIG. 2. [Figure 4] FIG. 3 is an explanatory diagram showing a method of calculating a kilometer distance by the kilometer distance calculation unit shown in FIG. 2. [Diagram 5] 5 is a flowchart showing a procedure for detecting the position of a railway vehicle according to the present embodiment. [Figure 6] FIG. 1A shows a change in the running environment of a railway vehicle, and FIG. 1B shows a calculation method for positioning coordinates that can be switched according to the change in the running environment. [Figure 7] 10 is a flowchart showing a procedure for determining whether or not a position calculation of a railway vehicle is appropriate in a second embodiment. [Figure 8] FIG. 11 is a block diagram showing a schematic configuration of a vehicle approach warning system according to a third embodiment in which a vehicle position calculation unit is provided in an external device mounted on a railway vehicle. [Figure 9] FIG. 11 is a block diagram showing a schematic configuration of a vehicle approach warning system according to a fourth embodiment in which a vehicle position calculation unit is installed in an external device that is installed in a location other than a railway vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the present invention will be described based on the illustrated embodiment.

[0021] (Embodiment 1) 1 is a block diagram showing a schematic configuration of a vehicle approach warning system 1 according to a first embodiment using a vehicle position detection device and a vehicle position detection method of the present invention. The vehicle approach warning system 1 includes, for example, an on-board device (vehicle position detection device) 2 mounted on a railway vehicle Tr, a warning terminal 3 carried by a worker W engaged in railway construction work, a server 4, and a communication network 5 connecting these so that they can communicate with each other. The communication network 5 is, for example, a public communication network such as a mobile phone communication network or the Internet.

[0022] The on-board device 2 is mounted on the railway vehicle Tr and detects the position of the railway vehicle Tr on the railway track R (for example, kilometers indicating the distance from the starting point set for each railway line), speed, and direction (direction of travel), and transmits train information including these detection results to the server 4.

[0023] More specifically, the on-board equipment 2 receives a GNSS signal (e.g., a GPS signal) that is a positioning signal from a GNSS satellite (e.g., a GPS satellite) St, and calculates GNSS coordinates (satellite positioning coordinates) based on the received GNSS signal. The on-board equipment 2 also transmits radar waves from a connected radar speedometer in the rail direction (the direction in which the railway vehicle Tr can travel) and receives reflected waves of the radar waves to measure the speed of the railway vehicle Tr. Furthermore, the on-board equipment 2 measures the inertial momentum of the railway vehicle Tr using an inertial sensor. Note that the rail direction is not limited to the traveling direction when the railway vehicle Tr moves forward, but also includes the rear when the railway vehicle Tr moves backward.

[0024] Then, if the positioning accuracy index received together with the GNSS signal from the GNSS satellite St is equal to or greater than a predetermined value, the on-board device 2 calculates the position of the railway vehicle Tr based on the GNSS coordinates, and if the positioning accuracy index is less than the predetermined value, it calculates a composite coordinate based on the GNSS coordinates, speed, and inertial momentum, and calculates the position of the railway vehicle Tr based on the composite coordinate.

[0025] In addition, the on-board device 2 compares the composite coordinates with the track coordinates (position information) of the railway track R to determine the accuracy of the composite coordinates, and if the accuracy of the composite coordinates is less than a predetermined value, calculates the position of the railway vehicle Tr based on the speed.

[0026] Furthermore, when calculating the position of the railway vehicle Tr based on the speed, the on-board device 2 determines the reliability of the speed measured by the radar speedometer based on the reflected wave, and if the reliability is less than a predetermined value (threshold value) (i.e., unreliable), calculates the position of the railway vehicle Tr based on the inertial momentum.

[0027] In this way, the on-board device 2 according to this embodiment calculates the position of the railway vehicle Tr based on the GNSS coordinates when the positioning accuracy based on the GNSS signal is good, and calculates the position of the railway vehicle Tr based on the composite coordinates when the positioning accuracy based on the GNSS signal is degraded. Also, when the accuracy of the composite coordinates is poor, the position of the railway vehicle Tr is calculated based on the speed of the radar speedometer, and when radar waves are absorbed by snowfall or the like and the speed cannot be measured by the radar speedometer, the position of the railway vehicle Tr is calculated based on the inertial momentum.

[0028] The warning terminal 3 has a function of receiving a GNSS signal from a GNSS satellite St and detecting the position of the warning terminal 3, i.e., the position of the worker W, based on the received GNSS signal, a function of receiving train information of the railway vehicle Tr from the server 4, a function of issuing a warning using sound, light, or the like when the position of the railway vehicle Tr approaches within a warning distance from the position of the worker W, and a function of stopping the warning when the position of the railway vehicle Tr passes the position of the worker W. The function of issuing a warning includes a function of displaying the approach distance and speed of the railway vehicle Tr by text information, or displaying the work position and an icon of the railway vehicle Tr on a track diagram so that the positional relationship can be intuitively grasped.

[0029] In the above, the judgment of whether to issue and stop an alarm is made by the alarm terminal 3, but it may be made by the server 4. In this case, the server 4 collects train information from the on-board device 2, and collects worker information (information including the position of the worker W, the work route, the line type, etc., and the position may be in kilometers or may be latitude and longitude) from the alarm terminal 3. Then, when the position of the railroad vehicle Tr approaches within the alarm distance from the position of the worker W, it transmits an alarm signal to the alarm terminal 3 to issue an alarm, and when the position of the railroad vehicle Tr passes the position of the worker W, it transmits an alarm stop signal to the alarm terminal 3 to stop the alarm.

[0030] 2 is a block diagram showing a schematic configuration of the on-board equipment 2. The on-board equipment 2 includes a device main body 21, a GNSS antenna 22, a communication antenna 23, and a radar speedometer 24. The device main body 21 includes a GNSS receiver 211, a communication module 212, an acceleration sensor 213, an angular velocity sensor 214, a railway GIS 215, and a control unit 216.

[0031] The GNSS antenna 22 receives GNSS signals from multiple GNSS satellites St and outputs them to the GNSS receiver 211. The GNSS receiver 211 calculates GNSS coordinates, speed, and direction based on the GNSS signals and outputs them to the control unit 216. The GNSS signals also include a positioning accuracy index indicating the positioning accuracy of the GNSS coordinates, and this positioning accuracy index is output to the control unit 216 together with the GNSS coordinates. The GNSS antenna 22 and the GNSS receiver 211 constitute the positioning means of the present invention. Note that the method of positioning using GNSS is a well-known technology, so a detailed description will be omitted.

[0032] The communication antenna 23 transmits the train information output from the communication module 212 to the server 4 via the communication network 5.

[0033] The radar speedometer 24 transmits radar waves from a radar antenna (not shown) in the direction of the rails, receives the reflected waves reflected by a railway track on which rails, sleepers, etc. are laid, measures the speed of the railway vehicle Tr, and outputs the measurement result to the control unit 216. When the radar waves are absorbed by accumulated snow or the like and the reflected waves cannot be received, the radar speedometer 24 outputs a measurement NG flag to the control unit 216. Note that the method of measuring speed using a radar speedometer is a well-known technique and therefore a detailed description thereof will be omitted.

[0034] The acceleration sensor 213 and the angular velocity sensor 214 (inertial sensors) measure the acceleration and angular velocity (inertial momentum) generated when the railway vehicle Tr is traveling, and output the measurement results to the control unit 216.

[0035] The railway GIS 215 is a geographic information system that records map information of railway lines, and information on the latitude, longitude, and kilometres of the railway track R for each railway line. For example, as shown in Table 1 below, the railway GIS 215 stores, for each railway line, combination data of a track coordinate number as an identification number for distinguishing a plurality of track coordinates from one another, the latitude and longitude of each track coordinate, and the kilometres indicating the distance from the starting point of the railway line (in other words, the starting station) to each track coordinate, in association with the map information of the railway line.

[0036] [Table 1]

[0037] The control unit 216 has the function of comprehensively controlling the operation of each component that constitutes the on-board device 2, and is configured as a mechanism having, for example, a CPU (Central Processing Unit) that performs calculations related to the calculation of the position (specifically, the kilometer distance) of the railway vehicle Tr.

[0038] The control unit 216 functions as a vehicle position calculation unit (vehicle position calculation means) 25 by the CPU executing a program (not shown) for controlling the operation of the on-board device 2, which is stored in a memory unit (not shown).

[0039] The vehicle position calculation unit 25 is a functional unit for calculating the position (specifically, kilometers) of the railway vehicle Tr based on vehicle-related information related to the railway vehicle Tr, and includes a composite positioning unit 251, a speed positioning unit 252, an inertial positioning unit 253, and a kilometers calculation unit 254.

[0040] The composite positioning unit 251 is a positioning unit for calculating composite coordinates, which are positioning coordinates of the railway vehicle Tr, based on multiple pieces of information. The composite positioning unit 251 calculates the composite coordinates of the railway vehicle Tr based on the GNSS coordinates calculated by the GNSS receiving unit 211, the speed of the railway vehicle Tr measured by the radar speedometer 24, and the acceleration and angular acceleration of the railway vehicle Tr measured by the acceleration sensor 213 and the angular velocity sensor 214.

[0041] 3 shows a method of calculating the compound coordinates by the compound positioning unit 251. The compound positioning unit 251 includes an inertial calculation unit 2511 that calculates and outputs compound positioning information including the compound coordinates, and an error estimation unit 2512 that estimates and outputs an amount of error between the GNSS coordinates and the compound coordinates.

[0042] The composite positioning unit 251 constantly calculates composite coordinates when the railway vehicle Tr starts operation. The GNSS receiving unit 211 initializes the initial position and initial orientation before the railway vehicle Tr starts operation. The initial position is initialized based on the GNSS coordinates calculated from the GNSS signal, and the initial orientation is initialized based on the moving orientation of the railway vehicle Tr at the time of starting operation. The GNSS receiving unit 211 outputs the GNSS positioning information (latitude, longitude, orientation, and speed) calculated after initialization to the error estimating unit 2512.

[0043] The inertia calculation unit 2511 initializes an initial attitude angle before the railcar Tr starts to operate. Specifically, the acceleration of the stopped railcar Tr is resolved into three axial directions of x, y, and z and initialized. The inertia calculation unit 2511 calculates composite positioning information (latitude, longitude, direction, attitude, speed) including composite coordinates based on the speed of the railcar Tr measured by the radar speedometer 24, the acceleration and angular acceleration of the railcar Tr measured by the acceleration sensor 213 and the angular velocity sensor 214, and the amount of error input from the error estimation unit 2512, and outputs the information to the error estimation unit 2512. The error estimation unit 2512 estimates the amount of error between the GNSS coordinates and the composite coordinates, and outputs the information to the inertia calculation unit 2511.

[0044] As described above, the composite positioning unit 251 outputs more accurate positioning coordinates by repeatedly calculating the composite coordinates based on the speed of the railway vehicle Tr measured by the radar speedometer 24, the acceleration and angular acceleration of the railway vehicle Tr measured by the acceleration sensor 213 and the angular velocity sensor 214, and the amount of error between the GNSS coordinates and the composite coordinates input from the error estimation unit 2512.

[0045] When the accuracy of the GNSS coordinates or the composite coordinates is degraded, the speed positioning unit 252 calculates, as vehicle-related information, speed coordinates that are the positioning coordinates of the railway vehicle Tr based on the speed measured by the radar speedometer 24. Specifically, the speed coordinates are calculated based on the GNSS coordinates or the composite coordinates calculated before the accuracy was degraded and a distance obtained by integrating the speed of the railway vehicle Tr measured by the radar speedometer 24.

[0046] The inertial positioning unit 253 calculates, as vehicle-related information, inertial coordinates, which are positioning coordinates of the railway vehicle Tr, based on the inertial momentum, when radar waves are absorbed by snowfall or the like and the speed cannot be measured by the radar speedometer 24. Specifically, the inertial coordinates are calculated based on the GNSS coordinates or composite coordinates calculated before the accuracy of the GNSS coordinates or composite coordinates decreased, or the speed coordinates last calculated by the speed positioning unit 252, and a distance obtained by integrating twice the acceleration and angular acceleration of the railway vehicle Tr measured by the acceleration sensor 213 and the angular velocity sensor 214.

[0047] The kilometre calculation unit 254 calculates the kilometre of the railway vehicle Tr based on the GNSS coordinates, composite coordinates, speed coordinates or inertial coordinates, which are the positioning coordinates of the railway vehicle Tr, and information recorded in the railway GIS 215.

[0048] The kilometer distance calculation unit 254 receives input of positioning coordinates output from the GNSS receiver unit 211, the composite positioning unit 251, the speed positioning unit 252 or the inertial positioning unit 253, and refers to the railway GIS 215 to identify a pair of track coordinates that are closest to the positioning coordinates, and calculates the kilometer distance based on the positioning coordinates and the pair of track coordinates.

[0049] More specifically, as shown in FIG. 4, the positioning coordinate M(x M ,y M ), the pair of closest orbital coordinates A(x A ,y A ) and the orbital coordinates B(x B ,y B) is identified, and a perpendicular line is drawn from the positioning coordinate M to the line segment AB between the orbit coordinates A and B. The position of the intersection point P between the line segment AB and the perpendicular line (x P ,y P ) is the position of a railway vehicle Tr on a railway track R.

[0050] The kilometre distance K of the railway vehicle Tr P is the kilometer distance K of orbital coordinate A A Strictly speaking, the positioning coordinate M is the position of the GNSS antenna 22, so the kilometer distance K P is determined by taking into consideration the distance between the installation position of the GNSS antenna 22 installed on the railcar Tr and the tip of the railcar Tr, and the traveling direction. MA and the distance D from the positioning coordinate M to the orbit coordinate B. MB and the distance between orbit coordinate A and orbit coordinate B, it can be calculated using Pythagoras' theorem.

[0051] Next, the procedure for detecting the position of the railway vehicle Tr will be described based on the flowchart shown in Fig. 5 and the explanatory diagram shown in Fig. 6. Fig. 6(A) shows the change in the running environment of the railway vehicle Tr running in the right direction in the figure, and Fig. 6(B) shows the calculation method of the positioning coordinates that can be switched according to the change in the running environment.

[0052] Before the railway vehicle Tr starts operation, the vehicle position calculation unit 25 of the on-board equipment 2 initializes the initial position and initial orientation of the GNSS receiving unit 211, and initializes the initial attitude angle of the inertial calculation unit of the composite positioning unit 251 (step S1). Note that since the initialization process of step S1 may be performed in an unpositioned environment such as inside a tunnel, the final kilometre stored when the on-board equipment 2 was powered off may be set as the initial position.

[0053] When the railway vehicle Tr starts operation, the composite positioning unit 251 of the vehicle position calculation unit 25 repeatedly calculates composite coordinates based on the speed of the railway vehicle Tr measured by the radar speedometer 24, the acceleration and angular acceleration of the railway vehicle Tr measured by the acceleration sensor 213 and the angular velocity sensor 214, and the amount of error between the GNSS coordinates and the composite coordinates input from the error estimation unit 2512 (step S2).

[0054] The vehicle position calculation unit 25 determines whether the positioning accuracy index input from the GNSS receiver unit 211 is equal to or greater than a predetermined value (threshold) set in advance (step S3), and if the positioning accuracy index is equal to or greater than the predetermined value, it determines that the accuracy of the GNSS positioning is good (YES in step S3), and the mileage calculation unit 254 calculates the mileage of the railway vehicle Tr from the GNSS coordinates as vehicle-related information (step S4).

[0055] As shown in Figure 6 (A), when the GNSS signal from the GNSS satellite St is not blocked by a tunnel T or a forest F and the railway vehicle Tr is not traveling near the exit Te of a tunnel T where multipath of the GNSS signal is likely to occur, the positioning accuracy index will be greater than or equal to a predetermined value, and the kilometre distance of the railway vehicle Tr will be calculated based on the GNSS coordinates measured by the GNSS receiver unit 211, as shown by hatching in the same figure (B).

[0056] Also, in the above step S3, if the positioning accuracy index is less than a predetermined value (NO in step S3), the vehicle position calculation unit 25 judges whether the accuracy of the composite positioning by the composite positioning unit 251 is equal to or greater than a predetermined value (threshold) set in advance (step S5). Note that the threshold value for the positioning accuracy index is stored in advance in the railway GIS 215 at different values ​​for each area, and the threshold value is acquired by referring to the railway GIS 215 even under the positioning environment that differs for each area, so that it is possible to perform more appropriate position calculation. Furthermore, the installation position of the GNSS antenna 22 in the railroad car Tr differs depending on the structural difference of the vehicle due to the difference in the type of vehicle, but by setting the threshold value according to the installation position of the GNSS antenna 22, it is also possible to respond to the change in positioning accuracy caused by the difference in the installation position of the GNSS antenna 22.

[0057] The accuracy of the composite positioning is as shown in Figure 4. M ,y M ), the pair of closest orbital coordinates A(x A ,y A ) and the orbital coordinates B(x B ,y B ) is identified, a perpendicular line is dropped from the positioning coordinate M to the line segment AB between the track coordinate A and track coordinate B, and the distance m between the measurement coordinate M and the line segment AB is obtained. The distance m is obtained by Pythagoras' theorem. If the distance m is shorter than a preset value, it is determined that the accuracy of the composite positioning is equal to or higher than a preset value, that is, the accuracy is good (YES in step S5), and the mileage calculation unit 254 calculates the mileage of the railway vehicle Tr from the composite coordinate as vehicle-related information (step S6).

[0058] As shown in Figure 6 (A), when a railway vehicle Tr is traveling near the exit Te of a tunnel T where multipath of GNSS signals is likely to occur, the positioning accuracy index of the GNSS coordinates is less than a threshold value, but the accuracy of the composite positioning is greater than or equal to a predetermined value, so that the kilometre distance of the railway vehicle Tr is calculated based on the composite coordinates measured by the composite positioning unit 251, as shown in the same figure (B).

[0059] Also, in the above step S5, if the accuracy of the composite positioning by the composite positioning unit 251 is less than a predetermined value set in advance (NO in step S5), the vehicle position calculation unit 25 calculates the reliability of the speed measured by the radar speedometer 24 based on the reflected waves, and determines whether the reliability is less than a predetermined value (threshold value) (step S7).

[0060] The reliability of the speed measured by the radar speedometer 24 can be obtained by various methods, but in this embodiment, the reliability is determined based on the presence or absence of a measurement NG flag output from the radar speedometer 24. That is, if a measurement NG flag is output, the reliability of the speed is determined to be less than a predetermined value (unreliable), and if a measurement NG flag is not output, the reliability of the speed is determined to be equal to or greater than a predetermined value (reliable).

[0061] If the reliability of the speed measured by the radar speedometer 24 is equal to or higher than a predetermined value (i.e., if it is reliable) (YES in step S7), the kilometer distance calculation unit 254 calculates the kilometer distance of the railway vehicle Tr from the speed coordinate as vehicle-related information (step S8).

[0062] As shown in Figure 6 (A), when railway vehicle Tr is traveling inside tunnel T, the positioning accuracy index of the GNSS coordinates is less than a threshold value, and the accuracy of the composite positioning using the GNSS coordinates is also less than a predetermined value, so as shown in the same figure (B), the kilometre distance of the railway vehicle Tr is calculated based on the speed coordinates measured by the speed positioning unit 252.

[0063] Also, in the above step S7, if the reliability of the speed measured by the radar speedometer 24 is less than a predetermined value (i.e., unreliable) (NO in step S7), the kilometre calculation unit 254 calculates the kilometre of the railway vehicle Tr using the inertial coordinates output from the inertial positioning unit 253 as vehicle-related information (step S9).

[0064] 6(A), when the railway vehicle Tr is traveling in a forest F with snowfall Sc, the positioning accuracy index of the GNSS coordinates is below a threshold, the accuracy of the composite positioning using the GNSS coordinates is also below a predetermined value, and the speed cannot be measured by the radar speedometer 24. Therefore, as shown in FIG. 6(B), the kilometre distance of the railway vehicle Tr is calculated based on the inertial coordinates measured by the inertial positioning unit 253.

[0065] Although the presence or absence of a measurement NG flag is used as the reliability of the speed, the strength of the reflected wave may be used. In that case, a different threshold value for each area may be stored in advance in the railway GIS 215, and a different threshold value may be used for each area. In this way, it is possible to perform more appropriate position calculation by acquiring a threshold value with reference to the railway GIS 215 and making a judgment even under a speed measurement environment that differs from area to area.

[0066] As indicated by A to D in FIG. 5, steps S3 to S9 described above are repeated every time a GNSS signal is received from a GNSS satellite St, and the position of the railway vehicle Tr is calculated based on more accurate positioning coordinates.

[0067] According to the vehicle approach warning system 1 of the above embodiment, when the positioning accuracy index based on the GNSS signal is less than a predetermined value, a composite coordinate based on the GNSS coordinate, speed, and inertial momentum is calculated, and the position of the railway vehicle Tr is calculated based on the composite coordinate, so that it is possible to accurately detect the position of the railway vehicle Tr even if the positioning accuracy based on the GNSS signal is poor. Also, when measuring the speed by detecting the number of rotations of the axles of the railway vehicle Tr, the speed measurement accuracy deteriorates due to wheel spinning and skidding, but since the radar speedometer 24 is used in this embodiment, it is possible to accurately detect the speed of the railway vehicle Tr.

[0068] Furthermore, according to the vehicle approach warning system 1 of this embodiment, when the accuracy of the composite coordinates is less than a predetermined value, the position of the railway vehicle is calculated based on the speed. Therefore, for example, even if the railway vehicle Tr is traveling inside a tunnel T and the accuracy of the composite coordinates decreases, it is possible to accurately detect the position of the railway vehicle Tr.

[0069] Furthermore, according to the vehicle approach warning system 1 of this embodiment, when the reliability of the speed measured by the radar speedometer 24 is less than a predetermined value (unreliable), the position of the railway vehicle Tr is calculated based on the inertial momentum, so that it is possible to accurately detect the position of the railway vehicle Tr even when, for example, radar waves are absorbed by snow and the speed cannot be measured by the radar speedometer.

[0070] Furthermore, according to the vehicle approach warning system 1 of this embodiment, the amount of error between the satellite positioning coordinates and the composite coordinates is used to calculate the composite coordinates, so it is possible to accurately detect the position of the railway vehicle Tr from measurement values ​​that include errors and noise, such as GNSS coordinates, speed, and inertial momentum.

[0071] (Embodiment 2) In the above-mentioned first embodiment, the position of the railway vehicle Tr is calculated at a predetermined cycle using any one of the GNSS coordinates, the composite coordinates, the speed coordinates, or the inertial coordinates, but there is a possibility that unknown behavior or abnormal values ​​may instantaneously occur in the GNSS receiver 211, the radar speedometer 24, the acceleration sensor 213, and each speed sensor 214, making it impossible to properly calculate the position of the railway vehicle Tr. In order to deal with such a case, it may be possible to appropriately determine whether the position of the railway vehicle Tr is appropriate.

[0072] As shown in the flowchart of Fig. 7, the vehicle position calculation unit 25 according to this embodiment calculates a first recent movement amount, which is a recent movement amount of the railway vehicle Tr, based on one piece of information selected as the vehicle-related information at any timing (step S10). Here, the recent movement amount is a difference between the latest position of the railway vehicle Tr obtained by the latest calculation and the previous position of the railway vehicle Tr obtained by the calculation performed immediately before the latest calculation. In other words, when the GNSS coordinates are used as the vehicle-related information, the recent movement amount of the railway vehicle Tr calculated based on the GNSS coordinates is calculated as the first recent movement amount.

[0073] Furthermore, the vehicle position calculation unit 25 calculates a second recent movement amount, which is the most recent movement amount of the railway vehicle Tr, based on other information not selected as the vehicle-related information (step S11). Here, the other information not selected as the vehicle-related information corresponds to, for example, a composite coordinate, a speed coordinate, and an inertial coordinate, etc., other than the GNSS coordinate when the GNSS coordinate is used as the vehicle-related information, and the vehicle position calculation unit 25 calculates the second recent movement amount from each of the composite coordinate, the speed coordinate, and the inertial coordinate. Note that, when the GNSS receiver unit 211, the radar speedometer 24, the acceleration sensor 213, and each speed sensor 214 are not functioning effectively, it is not necessary to calculate the recent movement amount based on the sensor that is not functioning.

[0074] Next, the vehicle position calculation unit 25 compares the first recent movement amount and the second recent movement amount with a predetermined threshold value (step S12). Here, the predetermined threshold value is, for example, an upper limit value of the movement amount of the railway vehicle Tr, and is appropriately set according to the operating speed, performance, etc. of the railway vehicle Tr.

[0075] Next, when the first recent movement amount is less than the predetermined threshold (NO in step S13), the vehicle position calculation unit 25 continues to calculate the position of the railcar Tr based on the vehicle-related information used in the calculation of the first recent movement amount (step S14).On the other hand, when the first recent movement amount is equal to or greater than the predetermined threshold (YES in step S13), the vehicle position calculation unit 25 continues to calculate the position of the railcar Tr using the information used in the calculation of the second recent movement amount that is less than the predetermined threshold as new vehicle-related information (step S15).

[0076] In addition, when there are multiple second most recent movement amounts that are less than a predetermined threshold, the vehicle-related information used to calculate the position of the railway vehicle Tr may be determined according to the priority order of the GNSS coordinates, composite coordinates, speed coordinates, and inertial coordinates, as shown in Figure 5, or the current position of the railway vehicle Tr may be corrected using the average value of the multiple second most recent movement amounts that are less than the threshold.

[0077] Furthermore, when all of the second most recent movement amounts are equal to or greater than a predetermined threshold, the position of the railway vehicle Tr is calculated using the current vehicle-related information, and at this time, the fact that the reliability of the position of the railway vehicle Tr is low may be notified to the worker W using the alarm terminal 3 or the like. It is desirable to continue this notification until a position calculation based on a highly reliable GNSS coordinate is performed.

[0078] According to the vehicle approach warning system of this embodiment, the recent movement amount of the railway vehicle Tr calculated based on the vehicle-related information is appropriately compared with the recent movement amount of the railway vehicle Tr calculated based on information that was not selected as the vehicle-related information, and if there is a possibility that the recent movement amount of the railway vehicle Tr calculated based on the vehicle-related information is not appropriate, the position of the railway vehicle Tr is calculated based on information in which the recent movement amount is considered to be appropriate, so that it is possible to respond to unknown behavior and abnormal values ​​that may occur instantaneously in the positioning means, radar speedometer, inertial sensor, etc.

[0079] (Embodiment 3) 8 is a block diagram showing a schematic configuration of a vehicle approach warning system 1A according to a third embodiment using the vehicle position detection device and the vehicle position detection method of the present invention. Note that the same components as those in the vehicle approach warning system 1 according to the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

[0080] The vehicle approach warning system 1A according to this embodiment is mounted on a railway vehicle Tr, and an external device 6 connected to the on-board equipment 2 is equipped with a vehicle position calculation unit (vehicle position calculation means) 25 and a railway GIS 215. That is, in this embodiment, the GNSS coordinates calculated by the GNSS receiving unit 211, the speed measured by the radar speedometer 24, and the acceleration and angular velocity measured by the acceleration sensor 213 and the angular velocity sensor 214 are transmitted from the on-board equipment 2 to the external device 6, and the position of the railway vehicle Tr is detected by the vehicle position calculation unit 25 and the railway GIS 215 of the external device 6.

[0081] According to the vehicle approach warning system 1A of the present embodiment, for example, by using a computer capable of high-speed arithmetic processing as the external device 6, the position of the railway vehicle Tr can be calculated at high speed, and application software for supporting the operation of the railway vehicle Tr can be operated using the calculated position information. In addition, it is possible to reduce the processing load of the on-board device 2 and suppress power consumption.

[0082] (Embodiment 4) 9 is a block diagram showing a schematic configuration of a vehicle approach warning system 1B according to a fourth embodiment using the vehicle position detection device and the vehicle position detection method of the present invention. Note that the same components as those in the vehicle approach warning system 1 according to the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

[0083] The vehicle approach warning system 1B according to this embodiment is equipped with a vehicle position calculation unit (vehicle position calculation means) 25 and a railway GIS 215 in an external device installed in a place other than the railway vehicle Tr, for example, a server 4. That is, in this embodiment, the GNSS coordinates calculated by the GNSS receiving unit 211, the speed measured by the radar speedometer 24, and the acceleration and angular velocity measured by the acceleration sensor 213 and the angular velocity sensor 214 are transmitted from the on-board device 2 to the server 4, and the position of the railway vehicle Tr is detected by the vehicle position calculation unit 25 and the railway GIS 215 of the server 4.

[0084] According to the vehicle approach warning system 1B of this embodiment, the vehicle position calculation unit 25 of the server 4 detects the positions of many railway vehicles Tr, so it is possible to reduce the cost of the on-board devices 2 mounted on many railway vehicles Tr. Furthermore, since the position detection of many railway vehicles Tr can be processed collectively by the server 4, it is possible to reduce the processing load of the on-board devices 2 installed on each railway vehicle Tr and reduce power consumption. Furthermore, when updating the function of the vehicle position calculation unit 25, it is only necessary to make changes to the vehicle position calculation unit 25 of the server 4, so that the function can be updated more easily than when the vehicle position calculation unit 25 is installed in each on-board device 2.

[0085] Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there are design changes and the like within the scope of the gist of the present invention, they are included in the present invention.

[0086] For example, in the fourth embodiment, the vehicle position calculation unit 25 and the railroad GIS 215 are provided in the server 4, but they may be provided in an external device other than the server 4.

[0087] In addition, in the above embodiment, a radar speedometer is used to avoid being affected by errors in the speedometer linked to the axle, but in a system in which errors in the speedometer linked to the axle are acceptable, information may be obtained from an existing speedometer linked to the axle, or this existing speedometer may be used in combination with a radar speedometer.

[0088] Furthermore, in the above embodiment, the position of the railway vehicle Tr is calculated using any one of the four coordinates: the GNSS coordinate based on the GNSS receiver 211, the speed coordinate based on the radar speedometer 24, the inertial coordinate based on the acceleration sensor 213 and the angular velocity sensor 214, and the composite coordinate based on the GNSS receiver 211, the radar speedometer 24, the acceleration sensor 213, and the angular velocity sensor 214. However, in order to simplify the device configuration and reduce costs, the number of types of sensors or means used to calculate the position of the railway vehicle Tr may be reduced. That is, in a vehicle position calculation means that calculates the position of the railway vehicle Tr on the railway track based on vehicle-related information related to the railway vehicle Tr, the number of sensors or means for obtaining the vehicle-related information may be at least two, and the position of the railway vehicle Tr may be calculated using one of the two pieces of vehicle-related information.

[0089] Specifically, when the errors in the speed and distance calculated based on the measurement results of the acceleration sensor 213 and the angular velocity sensor 214 are within an acceptable range, the radar speedometer 24, which has a high device cost, and the composite positioning unit 251, which requires high processing power, may be omitted, and the position of the railway vehicle Tr may be calculated based on either the GNSS coordinates based on the GNSS receiver unit 211 or the inertial coordinates based on the acceleration sensor 213 and the angular velocity sensor 214. More specifically, steps S5, S6 and steps S7, S8 are omitted in the flowchart shown in Fig. 5. This makes it possible to reduce the frequency of failures by simplifying the device, and to promote widespread use by reducing the cost.

[0090] Furthermore, the present invention may have a function of detecting an abnormal state of the vehicle position detection device and the vehicle approach warning system, and issuing a warning or a notification of a system abnormality depending on the level of the abnormal state. The abnormal state to be detected may be, for example, a lack of data input from each sensor or device, a periodic interruption in data reception from a communication network, or a comparison of the respective positions when calculations are possible in each position detection means, and a determination that an abnormality has occurred if the error is greater than a predetermined value.

[0091] 1, 1A, 1B Vehicle Approach Warning System 2 On-board device (vehicle position detection device) 21 Device body 211 GNSS receiver (positioning means) 213 Acceleration sensor (inertial sensor) 214 Angular velocity sensor (inertial sensor) 215 Railway GIS 22 GNSS antenna (positioning means) 24 Radar Speedometer 25 Vehicle position calculation unit (vehicle position calculation means) 251 Composite Positioning Unit 2511 Inertia calculation section 2512 Error amount estimator 252 Speed ​​and Positioning Unit 253 Inertial Positioning Unit 254 Kilometre Calculation Section 3. Alarm terminal 4 Server F Forest R Railway track Sc snowfall St GNSS satellite T-Tunnel Te exit Tr Railway Vehicles W Worker

Claims

1. a positioning means mounted on a railway vehicle running on a railway track and configured to calculate satellite positioning coordinates based on a positioning signal received from a positioning satellite; a radar speedometer mounted on the railroad vehicle, transmitting radar waves and receiving reflected waves of the radar waves to measure the speed of the railroad vehicle; an inertial sensor mounted on the railway vehicle and configured to measure an inertial momentum of the railway vehicle; a vehicle position calculation means for calculating a position of the railway vehicle on the railway track based on vehicle-related information related to the railway vehicle; The vehicle position calculation means When the positioning accuracy index output from the positioning means is equal to or greater than a predetermined value, the position of the railway vehicle is calculated based on the satellite positioning coordinates as the vehicle-related information; if the positioning accuracy index is less than a predetermined value, a composite coordinate is calculated based on the satellite positioning coordinates, the speed, and the inertial momentum, and a position of the railway vehicle is calculated based on the composite coordinate as the vehicle-related information. A vehicle position detection device comprising:

2. The vehicle position calculation means comparing the composite coordinates with position information of the railway track to determine an accuracy of the composite coordinates, and if the accuracy of the composite coordinates is less than a predetermined value, calculating a position of the railway vehicle based on the speed as the vehicle-related information.

2. The vehicle position detection device according to claim 1.

3. The vehicle position calculation means determining a reliability of the speed measured by the radar speedometer based on the reflected wave, and if the reliability is less than a predetermined value, calculating a position of the railway vehicle based on the inertial momentum as the vehicle-related information; 3. The vehicle position detection device according to claim 2.

4. The vehicle position calculation means calculating a first recent movement amount, which is a recent movement amount of the railcar, based on one piece of information selected as the vehicle-related information; Calculating a second most recent movement amount, which is a most recent movement amount of the railcar, based on other information that was not selected as the vehicle-related information; comparing the first most recent movement amount and the second most recent movement amount with a predetermined threshold; if the first recent movement amount is less than the predetermined threshold, continuing to calculate the position of the rail vehicle based on the vehicle-related information used to calculate the first recent movement amount; when the first recent movement amount is equal to or greater than the predetermined threshold, calculating a position of the railway vehicle using information used in calculating the second recent movement amount that is less than the predetermined threshold as new vehicle-related information; 4. The vehicle position detection device according to claim 3.

5. the vehicle position calculation means estimates an amount of error between the satellite positioning coordinates and the composite coordinates, and uses the estimated amount of error in the calculation of the composite coordinates.

2. The vehicle position detection device according to claim 1.

6. the vehicle position calculation means is provided in an external device mounted on the railway vehicle or an external device installed at a location other than the railway vehicle; 6. A vehicle position detection device according to claim 1, wherein the vehicle position detection device detects a vehicle position based on the detected vehicle position.

7. a process of receiving a positioning signal from a positioning satellite by a positioning means and calculating satellite positioning coordinates based on the received positioning signal; a process of transmitting a radar wave from a radar speedometer and receiving a reflected wave of the radar wave to measure the speed of the railway vehicle; measuring an inertial momentum of the railway vehicle by an inertial sensor; When the positioning accuracy index output from the positioning means is equal to or greater than a predetermined value, the position of the railway vehicle is calculated based on the satellite positioning coordinates; if the positioning accuracy index is less than a predetermined value, a composite coordinate is calculated based on the satellite positioning coordinate, the speed, and the inertial momentum, and a position of the railway vehicle is calculated based on the composite coordinate. A vehicle position detection method comprising:

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