Onboard equipment

Abstract

To provide a train control technique capable of reducing the number of base stations installed on the ground.SOLUTION: An on-board device 40 is an on-board device on a train traveling on a track, and performs communications with a base station installed along the track at intervals where there may be a communication discontinuous area where communication with the train is disabled. The on-board device 40 comprises: a discontinuation detection unit 421 that detects discontinuation of communication with the base station; a determination unit 430 that determines permission of traveling based on the presence or absence of obstacles in front of a travel direction of the train whenever the discontinuation of communication is detected by the discontinuation detection unit 421; and a communication discontinuation traveling control unit 441 that controls traveling of the train in accordance with the determination of the determination unit 430.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an on-vehicle device of a train running on a track.

Background Art

[0002] Conventionally, techniques for detecting the presence of a train on a track and performing running control using wireless communication have been proposed. For example, a train control system is known in which base stations are installed along a track and communicate with an on-vehicle device of a train to be controlled, thereby transmitting and receiving information necessary for presence detection and running control between the ground side and the on-vehicle side. In this type of train control system, each base station is installed so that the entire area on the track is covered by each wireless area so that communication can be performed between the ground side and the on-vehicle side anywhere on the track.

[0003] Also, a technique is known in which train control using wireless communication is performed only in a section where wireless communication is possible on a track, and train control by a point control ATS system is performed in a section where wireless communication is not possible (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to continuously perform reliable wireless communication between the on-vehicle side and the ground side throughout the entire area on the track regardless of the situation of the wireless area of each base station, the installation interval of the base stations has to be narrowed. This is because it is necessary to maintain the received radio wave intensity at a predetermined reference level or higher throughout the entire area on the track in consideration of attenuation with respect to the distance from the base station (long-term variation) and attenuation due to the shielding state of surrounding radio waves (short-term variation).

[0006] However, shortening the spacing between base stations increases the number of base stations required, thus increasing installation and maintenance costs. Other possible solutions include installing multiple antennas on trains to enable diversity reception, or laying loop antennas or leaky coaxial cables (LCX) along the tracks to create a wireless area, but all of these would inevitably lead to increased costs.

[0007] The problem that this invention aims to solve is to provide a technology that can reduce the number of base stations required for train control using wireless communication. [Means for solving the problem]

[0008] The first invention for solving the above problems is an onboard device for a train traveling on a track that communicates with a base station installed along the track, wherein the base station is installed along the track at intervals in which there may be communication discontinuity areas where communication with the train is impossible, and the onboard device comprises: a communication interruption detection unit that detects a communication interruption with the base station; a decision unit that determines whether to allow the train to travel based on the presence or absence of an obstacle in the direction of travel ahead of the train whenever a communication interruption is detected by the communication interruption detection unit; and a communication interruption travel control unit that controls the train's movement according to the decision of the decision unit.

[0009] According to the first invention, base stations are installed along the track on which the train runs, at intervals where communication discontinuities exist where communication with the train is impossible. By installing at such intervals, the spacing of base stations can be wider than that required for continuous wireless communication between the train and the ground across the entire track, in order to allow for the existence of communication discontinuities. When the onboard equipment of a train running on the track on which base stations are installed at such intervals detects a loss of communication with the base station, it decides whether to allow the train to proceed based on the presence or absence of obstacles in the direction of travel ahead of the train. As a result, even if communication with the base station is lost, if there are no obstacles in the direction of travel ahead, the train can be allowed to proceed. Therefore, it is possible to realize train control that can reduce the number of base stations installed on the ground.

[0010] Furthermore, the second invention is an on-board device that further comprises an obstacle detection unit for detecting the obstacle, and the determination unit determines whether or not to allow driving based on the detection result of the obstacle detection unit.

[0011] According to the second invention, when a communication interruption with the base station is detected, it is possible to determine whether or not to allow travel based on the obstacle detection result by the obstacle detection unit.

[0012] Furthermore, the third invention is an on-board device in which the determination unit has a confirmation input unit that receives a predetermined operation input from the crew indicating that they have confirmed that there are no obstacles, and when a communication interruption is detected, the on-board device determines whether or not to allow driving depending on whether or not such operation input is given.

[0013] According to the third invention, when a communication interruption with the base station is detected, the system accepts operational input from the crew, and permission to proceed is granted once the crew has confirmed that there are no obstacles. The crew includes the driver as well as other staff members on board the train.

[0014] Furthermore, the fourth invention is an on-board device in which, in the above-mentioned on-board device, the communication interruption travel control unit performs slow travel control to drive the train at a predetermined slow speed when travel is permitted by the decision unit.

[0015] According to the fourth invention, when a train is operated after receiving a decision to permit its operation, it becomes possible to limit the operating speed to a predetermined slow speed.

[0016] Furthermore, the fifth invention is an on-board device that further includes a forced stop control unit, which stops the train if communication with the base station is not reconnected while the train is traveling a predetermined permissible distance, as controlled by the communication interruption travel control unit.

[0017] According to the fifth invention, when the train cannot communicate even after traveling a predetermined allowable distance, the train can be stopped.

[0018] In addition, according to the sixth invention, in the on-vehicle device described above, the radio area for each base station is divided into a communication unstable area where the reception intensity based on the long-term variation reaches a predetermined reference level but may not reach the reference level due to the superposition of the short-term variation with a predetermined variation width, and a communication stable area that maintains above the reference level, and the communication discontinuous area is the on-vehicle device that is the communication unstable area.

[0019] According to the sixth invention, the base station can be installed so that the communication unstable area when the radio area is divided into a communication unstable area and a communication stable area becomes a communication discontinuous area.

Brief Description of the Drawings

[0020] [Figure 1] A diagram showing an overview of the overall configuration example of the train control system. [Figure 2] A block diagram showing a functional configuration example of the on-vehicle device. [Figure 3] A flowchart showing the flow of processing performed by the on-vehicle device. [Figure 4] A diagram for explaining the installation of the base station when there is no communication discontinuous area on the track. [Figure 5] A diagram for explaining the installation of the base station when a communication discontinuous area may exist on the track.

Modes for Carrying Out the Invention

[0021] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited by the embodiments described below, nor is the applicable form of the present invention limited to the following embodiments. Also, in the description of the drawings, the same reference numerals are assigned to the same parts.

[0022] Figure 1 is a diagram showing an overview of the overall configuration example of the train control system in this embodiment. As shown in Figure 1, the train control system of this embodiment includes a plurality of ground devices 20 constituting the ground radio system 1, an on-vehicle device 40 of a train T running on a track 9 equipped with the ground radio system 1, and a management device 80. In Figure 1, for the sake of convenience, the ground radio system 1 and the management device 80 are illustrated above the track 9 to show the radio area 30 of each base station 3, but these are installed on the ground.

[0023] Any method can be adopted for the communication between the ground device 20 and the on-vehicle device 40. As an example, in the train control system of this embodiment, the ground device 20, which is the primary station, performs wireless communication with the on-vehicle device 40, which is the secondary station, in a polling method (polling communication). Polling communication means that the primary station sequentially makes inquiries to all secondary stations using a list of secondary stations (polling list), and the secondary stations respond to this inquiry to send and receive necessary data (transmission data). In this embodiment, the ground device 20 transmits the control information of the train T to the on-vehicle device 40 by polling communication. Then, in response to the polling from this ground device 20, the on-vehicle device 40 returns train information including the running position and the like.

[0024] The ground device 20 includes a base station 3 that realizes wireless communication with the on-vehicle device 40. In this embodiment, each ground device 20 is provided with one base station 3, and is installed along the track 9 so that each radio area 30 covers the control section 91 of the corresponding ground device 20. Note that the number of base stations 3 provided in the ground device 20 is not limited to one, and two or more may be provided. That is, a configuration in which the control section 91 controlled by one ground device 20 is covered by the radio areas of two or more base stations 3 provided in the ground device 20 may also be adopted.

[0025] The on-board equipment 40 uses control information received from the ground equipment 20 to create a speed check pattern based on the train's position and other factors, and controls the train's movement. The current train's position (distance traveled in kilometers) and speed are calculated by the on-board equipment 40, for example, by counting the rotation speed of a speed generator attached to the axle. The train's position is corrected by the on-board equipment 40 when it passes a ground beacon installed along the track 9 for position correction, using the beacon's installation position (absolute position).

[0026] Furthermore, the on-board device 40 includes an obstacle detection unit 5 for monitoring the area ahead of the train T in the direction of travel and detecting objects (obstacles) such as people or objects that may obstruct its movement. The obstacle detection unit 5 is configured using, for example, a camera such as a CMOS image sensor, a long-range detection sensor such as LiDAR (Light Detection and Ranging), or a millimeter-wave radar, to detect the presence or absence of obstacles within the monitoring area and measure the distance to the detected obstacle. The obstacle detection unit 5 outputs the obstacle detection result ("Obstacle present" or "Obstacle absent") and the measured distance to the obstacle to the on-board control unit 400 (see Figure 2) as needed.

[0027] The management device 80 is connected to each of the on-board devices 20 for data communication and manages a train list for each ground device 20 used for polling communication with the on-board device 40, and distributes it to each on-board device 20 as needed. The train list is a list of trains T located in the control section 91 of the corresponding ground device 20. For each ground device 20, the management device 80 adds train T to the train list when train T enters the control section 91 of that ground device 20, and removes train T from the train list when train T leaves the control section of that ground device 20, thereby updating the train list. The management device 80 then transmits the updated train list to the ground devices 20.

[0028] [detail] In the train control system of this embodiment, the existence of communication discontinuity areas on the track 9 where communication with the train T is impossible is permitted. Therefore, the base stations 3 are installed along the track 9 at intervals where communication discontinuity areas may exist. For example, in Figure 1, two base stations 3 are installed at intervals where communication discontinuity areas 93 exist between wireless areas 30. In other words, the communication discontinuity area 93 in this embodiment is an area outside the wireless area 30, where the onboard equipment 40 cannot communicate with either base station 3.

[0029] The base stations 3 may be positioned such that the communication discontinuity area 93 is always present between the wireless areas 30 of each base station 3, or the base stations 3 may be positioned so that it is present only between the wireless areas 30 of some of the base stations 3. In the latter case, the communication discontinuity area 93 can be provided, for example, in a straight section with good line of sight, and the base stations 3 can be positioned so that the communication discontinuity area 93 does not exist in sections with poor line of sight. The length of the section designated as the communication discontinuity area 93 (the distance of the communication discontinuity area 93 along the trajectory 9) is preferably less than or equal to the monitoring distance at which obstacles can be detected by the obstacle detection unit 5 (the distance in front of the direction of travel that can be monitored as a monitoring area).

[0030] By installing base stations 3 in this manner, the number of base stations 3 can be reduced, thereby lowering the costs required for the installation and maintenance of base stations 3. This is because the spacing between adjacent base stations 3 separated by a communication discontinuity area 93 can be increased by the distance of the said communication discontinuity area 93.

[0031] However, when train T is located in a communication discontinuity area 93, the onboard equipment 40 cannot communicate with any of the base stations 3, and therefore cannot receive control information from the ground equipment 20. As a countermeasure, in the train control system of this embodiment, the onboard equipment 40 detects the loss of communication with the base station 3. The loss of communication can be detected when a predetermined time (for example, 1 second or 2 seconds) has elapsed without receiving control information from the ground equipment 20, or when a predetermined number of attempts to communicate from the onboard equipment 40 to the ground equipment 20 have been made but a communication connection cannot be established.

[0032] The onboard device 40 then determines whether to allow the train to travel based on the detection result of the obstacle detection unit 5 at the time of detection whenever it detects a communication interruption with the base station 3. In this embodiment, if the input of the detection result from the obstacle detection unit 5 is "no obstacle", the onboard device 40 decides to allow the train to travel and performs control to permit the train T to travel. If the input of the detection result from the obstacle detection unit 5 is "obstacle present", the onboard device 40 decides not to allow the train to travel.

[0033] For example, in a scenario where train T is located in a communication discontinuity area 93, the onboard device 40 will be unable to communicate with any of the base stations 3 and will detect a communication failure with the base stations 3. Therefore, the onboard device 40 will decide to allow train T to travel if no obstacles are detected ahead in the direction of travel by the obstacle detection unit 5, and will perform control to allow train T to travel. In this case, the onboard device 40 will perform slow-speed control to make train T travel at a predetermined slow speed. The slow speed can be set in advance based on, for example, the monitoring distance of the obstacle detection unit 5 and the deceleration performance of train T on which the onboard device 40 is mounted. On the other hand, if an obstacle is detected ahead in the direction of travel by the obstacle detection unit 5, the onboard device 40 will decide not to allow travel. In that case, since train T is prohibited from traveling, it will perform forced stop control by activating the brakes (not shown) to stop the train.

[0034] The same control is applied when train T is stopped in a communication discontinuity area 93 and attempts to start moving from there. If the obstacle detection unit 5 detects an obstacle ahead in the direction of travel and decides not to allow movement, the brakes are applied and the train remains stopped.

[0035] According to this, train T is permitted to travel in a state where it cannot communicate with base station 3, but only if a decision has been made to permit its operation. Furthermore, in such a case, the travel speed can be limited to a predetermined slow speed.

[0036] [Functional Configuration] Figure 2 is a block diagram showing an example of the functional configuration of the on-board device 40. As shown in Figure 2, the on-board device 40 is composed of an on-board radio 41, an operation input unit 43, a display unit 45, an on-board control unit 400, a storage unit 470, and an obstacle detection unit 5.

[0037] The onboard radio 41 communicates wirelessly with the base station 3, which is installed along the track 9.

[0038] The operation input unit 43 is, for example, an input device having switches or buttons, and outputs an operation signal corresponding to the operation input to the on-board control unit 400. The display unit 45 is implemented by, for example, a lamp or a liquid crystal display device, and displays information according to the display signal from the on-board control unit 400.

[0039] The on-board control unit 400 comprehensively controls the operation of the on-board equipment 40 based on control information received from the ground equipment 20. The on-board control unit 400 includes a position and speed calculation unit 410, a communication control unit 420, a determination unit 430, and a driving control unit 440. Each of these functional units may be an arithmetic processing block implemented as software by executing a program, or a circuit block implemented by a signal processing circuit. In this embodiment, the on-board control unit 400 is described as an arithmetic processing block implemented as software by executing a predetermined program.

[0040] The position and speed calculation unit 410 calculates the train's position (distance traveled) and speed based on detection signals from rotation detectors such as pulse generators and speed generators that detect the rotation of wheels or axles. The calculated position and speed are stored as calculated position and speed information 473.

[0041] The communication control unit 420 controls the reception of control information transmitted by the ground equipment 20 to its own train via the onboard radio 41. Then, in response to the reception of the control information, the communication control unit 420 generates train information and controls the transmission of it to the ground equipment 20 via the onboard radio 41. This communication control unit 420 is equipped with a disruption detection unit 421 that detects the interruption of communication with the base station 3.

[0042] The decision unit 430 determines whether to allow travel based on the presence or absence of obstacles in the direction of travel of the train whenever the interruption detection unit 421 detects an interruption in communication with the base station 3. In this embodiment, the decision unit 430 decides to allow travel if the input of the detection result from the obstacle detection unit 5 is "no obstacles", and decides not to allow travel if there are obstacles.

[0043] The train control unit 440 controls the train's movement as needed, according to the control information received from the ground equipment 20. The train control unit 440 also includes a communication interruption control unit 441 and a forced stop control unit 443.

[0044] The communication interruption-induced running control unit 441 controls the running of its own train according to the decision of the decision unit 430. In this embodiment, when the decision unit 430 has decided to permit running, the communication interruption-induced running control unit 441 performs slow running control to run its own train at a predetermined slow speed.

[0045] Furthermore, the communication interruption control unit 441 terminates the slow-speed driving control if communication with the base station 3 is re-established while the train is traveling a predetermined permissible distance under slow-speed driving control. The permissible distance can be set, for example, based on the distance of the communication discontinuity area 93 along the track 9. For example, if the distance of the communication discontinuity area 93 along the track 9 is 50m, the permissible distance may be set to the same 50m, or it may be set to a distance slightly increased or decreased from 50m (for example, by 10m).

[0046] Furthermore, the slow-speed driving control may be configured to terminate only when communication with the base station 3 is reconnected, and a predetermined release operation is performed by the driver or other crew members. Alternatively, it may be terminated only when there are no obstacles in the direction of travel of the train. This condition can be determined based on the detection results input from the obstacle detection unit 5.

[0047] The forced stop control unit 443 performs a forced stop control by activating the brakes to stop the train if communication with the base station 3 is not re-established while the train is traveling a predetermined permissible distance under the slow-speed driving control by the communication interruption driving control unit 441. In addition, the forced stop control unit 443 performs a forced stop control by activating the brakes to stop the train if the interruption detection unit 421 detects a communication interruption with the base station 3 while the train is in motion, and the decision unit 430 decides not to permit travel.

[0048] The memory unit 470 is implemented using a storage medium such as an IC memory or a hard disk. This memory unit 470 pre-stores programs for operating the on-board device 40 and realizing the various functions of the on-board device 40, as well as data used during the execution of such programs, or temporarily stores them each time processing is performed. In this embodiment, the memory unit 470 stores calculated position and speed information 473.

[0049] [Process Flow] Figure 3 is a flowchart showing the processing flow performed by the on-board device 40. In this process, first, the interruption detection unit 421 detects a communication interruption with the base station 3. If the interruption detection unit 421 detects a communication interruption with the base station 3 (step S1: YES), the decision unit 430 decides whether to allow driving based on the detection result of the obstacle detection unit 5 (step S3). Here, the decision unit 430 decides to allow driving if the input of the detection result from the obstacle detection unit 5 is "no obstacles," and decides not to allow driving if it is "obstacles present."

[0050] Then, if a decision is made in step S3 to permit travel (step S5: YES), the communication interruption travel control unit 441 performs slow travel control to allow the train to travel at a predetermined slow speed (step S7). If a decision is made not to permit travel (step S5: NO), the forced stop control unit 443 performs forced stop control to stop the train by applying the brakes if the train is in motion (step S9).

[0051] Furthermore, if slow-speed driving control is initiated in step S7, the communication interruption driving control unit 441 monitors for the reconnection of communication with the base station 3. If communication with the base station 3 is reconnected while the train travels a predetermined permissible distance under the slow-speed driving control (step S11: YES), the slow-speed driving control initiated in step S7 is terminated (step S13). On the other hand, if communication with the base station 3 is not reconnected even after traveling the predetermined permissible distance (step S11: NO → step S15: YES), the forced stop control unit 443 performs forced stop control by activating the brakes to stop the train (step S17).

[0052] As explained above, according to this embodiment, base stations 3 are installed along the track 9 on which the train runs, at intervals where communication discontinuities with the train may exist. This allows the installation intervals of base stations 3 to be widened by the amount of the communication discontinuity areas. Therefore, the number of base stations 3 can be reduced, and the cost required for installation can be reduced.

[0053] On the other hand, by creating a communication discontinuity area, the on-board equipment 40 will be unable to communicate with the base station 3 if the train is located within the communication discontinuity area. To counter this, the on-board equipment 40 detects the loss of communication with the base station 3. In response to the detection of the communication loss, it decides whether to allow the train to travel based on the detection results of obstacles ahead in the direction of travel. Specifically, if no obstacles are detected by the obstacle detection unit 5, it decides to allow the train to travel; if obstacles are detected, it decides not to allow the train to travel. As a result, the train T can be operated without communication with the base station 3 only if the decision to allow the train to travel has been made. Therefore, it is possible to provide a train control technology that can reduce the number of base stations installed on the ground.

[0054] [Example 1] In the above embodiment, the wireless area 30 was exemplified as an area where communication is reliably possible, and the communication discontinuity area 93 was exemplified as an area where communication is reliably impossible. However, in reality, there are areas where communication becomes possible or is interrupted depending on the wireless communication conditions.

[0055] In wireless communication, radio wave attenuation manifests as a superposition of long-range fluctuations (attenuation due to distance from base station 3) and short-range fluctuations (fluctuations caused by shielding from surrounding buildings, etc.). The received radio wave strength within the wireless area 30 for each base station 3 can be represented by a radio wave propagation model in which short-range fluctuations are superimposed on long-range fluctuations. Therefore, by using this radio wave propagation model, the wireless area 30 can be interpreted broadly, and it can be understood that the wireless area 30 includes both communication stable areas and communication unstable areas.

[0056] Specifically, a communication stable area can be defined as the range in which the received radio wave strength is determined to remain above a reference level using a radio wave propagation model. This communication stable area is the area in which stable communication with the corresponding base station 3 can be performed, and is an area where communication is reliably possible. On the other hand, outside the communication stable area, where the distance from the base station 3 is greater than the communication stable area, there is a range in which the received strength based on long-term fluctuations reaches the reference level, but may not reach the reference level due to the superposition of short-term fluctuations, and this range can be defined as the communication unstable area. This communication unstable area is the area in which communication may be possible or interrupted depending on the wireless communication conditions. The reference level can be set based on the received strength required for communication between the on-board device 40 and the base station 3.

[0057] In the above embodiment, let's consider the case where the communication discontinuity area is considered a communication unstable area. In this case, the communication discontinuity area, which is a communication unstable area, can be considered to be included in the wireless area 30. Figure 4 shows an example of the installation of a base station 3 in which the communication discontinuity area, which is a communication unstable area, does not exist on the orbit 9. Figure 5 shows an example of the installation of a base station 3 in which it is permissible for the communication discontinuity area, which is a communication unstable area, to exist on the orbit 9. Note that Figures 4 and 5 show the degree of overlap of the wireless area 30, focusing on the two base stations 3.

[0058] As shown in Figure 4, if base stations 3 are installed adjacent to each other at intervals where their communication stable areas overlap, the entire area on the orbit 9 will be within the communication stable area of ​​any one of the base stations 3. This makes it possible to install base stations 3 in a way that eliminates any areas on the orbit 9 where communication may be discontinuous. In other words, by installing base stations 3 at the intervals shown in Figure 4, wireless communication between the vehicle and the ground is reliably continuous throughout the entire area on the orbit 9. Conversely, in order for wireless communication to be reliably continuous throughout the entire area on the orbit 9, the installation intervals of each base station 3 must be close together, as shown in Figure 4.

[0059] In contrast, as shown in Figure 5, if two base stations 3 are installed adjacent to each other with overlapping communication unstable areas but no overlapping communication stable areas, a communication unstable area 95 will exist on the orbit 9. Within this communication unstable area 95, depending on the conditions of the wireless areas 30 of the two corresponding base stations 3, a state may occur where communication with either base station 3 is impossible. When this state actually occurs, the area 95 becomes a communication discontinuity area. In other words, if base stations 3 are installed at the intervals shown in Figure 5, a communication discontinuity area may exist on the orbit 9.

[0060] However, since this is a communication unstable area, the received signal strength based on long-term fluctuations, excluding the effects of short-term fluctuations, should be above the standard level. Therefore, even if communication with any of the base stations 3 becomes impossible when train T is located within range 95, it is possible that communication will be reconnected as train T moves and its position changes slightly, eliminating or reducing the effects of short-term fluctuations. Even if communication is not reconnected immediately, it will be reconnected once train T moves out of range 95.

[0061] Furthermore, with the base station 3 installation shown in Figure 5, it is possible to widen the installation interval of the base stations 3 compared to the installation interval in Figure 4 by the distance (distance along the track 9) of the communication instability area range 95 that may exist as a communication discontinuity area. Even when the base stations 3 are installed at the installation interval in Figure 5 and the train T is traveling on the track 9 where a communication discontinuity area may exist, the onboard equipment 40 of the train T can perform the same processing as in the above embodiment, thereby achieving the same effects as in the above embodiment.

[0062] In other words, each time the onboard device 40 detects a communication interruption with the base station 3, it decides whether to allow the train to travel based on the detection result of the obstacle detection unit 5. Upon receiving the decision to allow travel, the onboard device 40 performs slow-speed travel control, allowing the train T to travel at a predetermined slow speed. Furthermore, if communication with the base station 3 is reconnected while the train travels a predetermined permissible distance under slow-speed travel control, the onboard device 40 continues slow-speed travel control; otherwise, it performs a forced stop control to stop the train T. The permissible distance can be set, for example, based on the distance of the communication unstable area 95.

[0063] [Differentiation 2] Furthermore, in the above embodiment, an example was described in which the obstacle detection unit 5 detects obstacles in the direction of travel and determines whether or not to allow travel based on the detection result. In contrast, it is also possible to accept input from the crew indicating that they have confirmed that there are no obstacles, and determine whether or not to allow travel depending on whether or not such input is received. This can be achieved by configuring the determination unit 430 to have a confirmation input unit as shown in Figure 2.

[0064] For example, whenever the confirmation input unit detects a communication interruption with the base station 3, it displays a confirmation screen on the display unit 45 (see Figure 2) with a confirmation button, along with a message prompting the driver to visually check for obstacles ahead in the direction of travel. The unit then accepts the operation of the confirmation button as a confirmation operation by the crew. Of course, a dedicated input device for confirmation operations could also be provided in an appropriate location to accept confirmation operations.

[0065] Alternatively, the decision unit 430 may be configured to control the reception of permission notifications from the control center by using a communication means separate from the communication with the ground equipment 20 via the onboard radio 41. In this case, the decision unit 430 may transmit an image taken of the area in front of the train T in the direction of travel to the control center via the communication means. In this case, the control center can determine whether or not there are obstacles in front of the train in the direction of travel based on the transmitted image and decide whether or not to allow the train to travel. Then, when the decision unit 430 receives an instruction from the control center to allow the train to travel, it makes a decision to allow the train to travel.

[0066] [Difference 3] The antenna of base station 3 may be a directional antenna, and its orientation may be set to face either the uphill or downhill direction along the orbit 9. The above embodiment can be applied similarly even when a directional antenna is used. [Explanation of symbols]

[0067] 1 Ground radio system, 20 Ground equipment, 3 Base station, 30 Radio area, 40 Onboard equipment, 41 Onboard radio, 43 Operation input unit, 45 Display unit, 400 Onboard control unit, 410 Position and speed calculation unit, 420 Communication control unit, 421 Interruption detection unit, 430 Determination unit, 440 Driving control unit, 441 Driving control unit during communication interruption, 443 Forced stop control unit, 470 Memory unit, 473 Calculated position and speed information, 5 Obstacle detection unit, 80 Management device, 9 Track, 91 Control section, 93 Communication discontinuity area, 95 Range of communication unstable area, T Train

Claims

1. An onboard device for a train traveling on a track that communicates with a base station installed along the track, The base stations are installed along the track at intervals where there may be communication discontinuities where communication with the on-board equipment is interrupted. A disruption detection unit for detecting a communication interruption with the base station, In response to the detection of a communication interruption by the interruption detection unit, a decision unit determines whether or not to allow the train to travel based on the presence or absence of an obstacle in the direction of travel ahead of the train, A communication interruption-induced running control unit controls the running of the train according to the determination of the aforementioned determination unit, A forced stop control unit that stops the train if, under the control of the aforementioned communication interruption running control unit, communication with the base station is not re-established while the train is traveling a predetermined permissible distance, An on-board device equipped with the following features.

2. Obstacle detection unit for detecting the aforementioned obstacle, Furthermore, The determination unit determines whether or not to allow driving based on the detection result of the obstacle detection unit. The on-board device according to claim 1.

3. The determination unit has a confirmation input unit that receives a predetermined operation input from the crew indicating that they have confirmed the absence of the obstacle, and when the communication interruption is detected, it determines whether or not to allow driving depending on whether or not such operation input was received. The on-board device according to claim 1.

4. The aforementioned communication interruption-induced running control unit, when permitted to run by the decision unit, performs slow-speed running control to run the train at a predetermined slow speed. The on-board device according to claim 1.

5. The wireless area for each base station is divided into two areas: a communication unstable area where the received signal strength based on the long-term fluctuations reaches a predetermined reference level but may not reach it due to the superposition of the short-term fluctuations, and a communication stable area where the signal strength maintains above the reference level, using a radio wave propagation model based on predetermined long-term fluctuations and predetermined short-term fluctuations based on distance attenuation from the base station. The aforementioned communication discontinuity area is the aforementioned communication unstable area. The on-board device according to any one of claims 1 to 4.

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