CONDITION MONITORING DEVICE, WIRELESS FLOOR DEVICE, INTEGRATED WIRELESS DEVICE, FAILURE RISK DETERMINATION METHOD, CONTROL CIRCUIT AND STORAGE MEDIUM

Abstract

Condition monitoring device (400) that monitors the states of wireless ground devices (200, 210, 220, 230) and a wireless integrated device (300) that form a wireless train protection system that applies a time-division multiplexing scheme, wherein the condition monitoring device (400) comprises: a wired link unit (451) to acquire the result of a measurement of an error between a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) and a reference timing from the wireless ground device (200, 210, 220, 230); and a deterioration state determination unit (454) to determine a deterioration state of the wireless ground equipment (200, 210, 220, 230) based on the fault.

Description

AREA

[0001] The present disclosure relates to a condition monitoring device, a wireless ground device, a wireless integrated device, a failure risk determination method, a control circuit, and a storage medium, wherein the condition monitoring device monitors a condition of a wireless device in a wireless train control system that controls a train by using radio communication. background

[0002] A time-division multiplexing scheme is one of the multiplexing schemes in which a transmission path is used simultaneously by multiple wireless devices. A wireless communication system employing the time-division multiplexing scheme must synchronize the transmission / reception timing of all wireless devices in the system through time synchronization.

[0003] As an example of a wireless communication system that uses the time-division multiplexing scheme, a wireless communication system for a wireless train control system is known. In this wireless communication system, a mobile object equipped with a wireless integrated device continues communication within a communication area including a plurality of wireless ground devices, while performing a handover to switch the wireless ground device to be a connection destination with the movement of the moving object.In addition, this wireless communication system synchronizes the transmission / reception timings between the ground wireless devices and between the ground wireless device and the integrated wireless device to achieve switching of a frequency channel to be used for signal transmission and reception and to avoid communication interruption due to handover.

[0004] In the wireless train control system, the wireless ground equipment deployed along a railway line and the wireless integrated equipment installed on a train conduct wireless communication with each other, so that traffic operations and train speed are controlled based on the information transmitted through wireless communication. For the wireless train control system, no wireless communication scheme between the wireless ground equipment and the wireless integrated equipment is defined, but a system using radio in the 2.4 GHz band is common practice. In the wireless train control system using the 2.4 GHz band, the wireless ground equipment is deployed every few hundred meters along a railway line due to its radio characteristics.In addition, the wireless integrated devices are usually installed in carriages at both ends of the entire train composition, i.e. in a first carriage and a last carriage.

[0005] For the maintenance and replacement of these numerous ground wireless facilities and integrated wireless facilities, maintenance plans must be established and replacements ensured, so detecting the status changes of the wireless facilities is important. Furthermore, considering the differences between the installation environments of the wireless facilities and the additional installation or replacement of the wireless facilities during the operation of the facility, the wireless facilities have their own individual differences in the details of secular changes, namely the deterioration of components and the environmental changes caused by iron powder, wind pressure, etc., as well as the speed of secular changes from a long-term perspective.In recent years, condition-based maintenance, in which the timing of equipment maintenance is determined depending on a condition, has gained attention. For example, Patent Literature 1 discloses a system that collects signals indicating measurements from a variety of types of physical quantity detecting means provided in equipment in a transformation facility and determines a deteriorated condition of the equipment by using a residual value obtained by performing statistical processing on the collected measurements as an index. US 2019 / 0 028 214 A1 relates to a monitoring device that monitors communication quality in a wireless communication system. REFERENCE LISTPATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent No. JP 6474564 B2 SummaryTECHNICAL PROBLEM

[0007] The system disclosed in Patent Literature 1 determines the deteriorated condition of the facility by analyzing the temperature, pressure, electrical power, and ambient temperature of the facility. However, in the wireless train protection system, which requires time synchronization between wireless devices, only physical quantities obtained from a single facility, such as the temperature, pressure, electrical power, and ambient temperature of the facility, cannot determine the failure risk of a communication service of the entire system.

[0008] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a condition monitoring device capable of extracting a device requiring certain maintenance associated with a secular change in a wireless train protection system. SOLUTION TO THE PROBLEM

[0009] To address the above-mentioned problem and achieve the object, the present disclosure provides a condition monitoring device that monitors states of wireless ground equipment and a wireless integrated equipment constituting a wireless train protection system employing a time-division multiplexing scheme, the condition monitoring device comprising: a wired connection unit for acquiring a result of measuring an error between a transmission timing of a signal in the wireless ground equipment and a reference timing from the wireless ground equipment; a degraded condition determining unit for determining a degraded performance state of the wireless ground equipment based on the error. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0010] The condition monitoring device according to the present disclosure has the advantageous effect of being able to extract a device requiring maintenance associated with the secular change in the wireless train protection system. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram illustrating an example of a configuration of a wireless train protection system according to a first embodiment. Fig. 2 is a diagram showing an example of a functional configuration of a wireless ground device. Fig. 3 is a diagram showing an example of a hardware configuration of the wireless ground device. Fig. 4 is a diagram showing another example of the hardware configuration of the wireless ground device. Fig. 5 is a diagram showing an example of a functional configuration of an internal wireless device. Fig. 6 is a diagram showing an example of a hardware configuration of the wireless integrated device. Fig. 7 is a diagram showing another example of the hardware configuration of the wireless integrated device. Fig. 8 is a diagram showing an example of a functional configuration of a condition monitoring device. Fig. 9 is a diagram showing an example of a hardware configuration of the condition monitoring device. Fig. 10 is a diagram showing another example of the hardware configuration of the condition monitoring device. Fig. 11 is a flowchart showing an example of an operation that disables time correction of the wireless ground device and an operation that enables the time correction. Fig. 12 is a diagram showing an example of a setting result of a time correction function based on a traffic operation status in the wireless ground device. Fig. 13 is a diagram showing an example of a time correction operation performed by the ground wireless device. Fig. 14 is a flowchart showing an example of the overall operation of the wireless train protection system in a state where the time correction function of the wireless ground device is disabled. Fig. 15 is a table showing an example of path information retained by a condition monitor according to a second embodiment. Fig. 16 is a diagram illustrating an example of a reference timing correction operation performed by a wireless integrated device according to a third embodiment. DESCRIPTION OF THE EMBODIMENTS

[0011] Hereinafter, a condition monitoring device, a wireless ground device, a wireless integrated device, a failure risk determination method, a control circuit, and a storage medium according to embodiments of the present disclosure will be described in detail with reference to the drawings. First embodiment.

[0012] Fig. 1 is a diagram showing an example of a configuration of a wireless train protection system according to a first embodiment. As shown in Fig. 1, the wireless train control system according to the first embodiment includes wireless ground devices 200, 210, 220, and 230 deployed on the ground, a wireless integrated device 300 installed in a train 110, and a condition monitoring device 400. The wireless ground devices 200 and 210 are deployed along a railway line 100, and the wireless ground devices 220 and 230 are deployed along a railway line 101. The wireless ground devices 200, 210, 220, and 230 and the wireless integrated device 300 constitute a wireless communication system to which a time-division multiplexing scheme is applied.

[0013] In the Fig. 1, the wireless integrated device 300 installed in the train 110 moves on the track 100 while transmitting and receiving control information to and from one of the wireless ground devices 200, 210, 220, and 230. The wireless ground device for which the control information is transmitted and received by the wireless integrated device 300 is a wireless ground device located closest to an antenna-oriented surface on the same track. The antenna-oriented surface is oriented such that it points in a direction of movement of the train indicated by a bold arrow, and in the case of a Fig. 1, the wireless integrated device 300 transmits the control information to the wireless ground device 200 and receives the control information therefrom.

[0014] The condition monitoring device 400 is connected to each of the wireless ground devices 200, 210, 220, and 230 via a wired network 151 to facilitate the transmission of control information and monitor the states of the wireless integrated device 300 and the wireless ground devices 200, 210, 220, and 230. Note that in the drawings used in the following description, the same reference symbols denote the same or corresponding parts.

[0015] Fig. 2 is a diagram illustrating an example of a functional configuration of the wireless ground equipment 200. The wireless ground equipment 200 includes: a radio transmission / reception unit 251 that transmits a radio signal to and receives a radio signal from the wireless integrated equipment 300; a signal measurement unit 252 that measures radio signal timing; a radio control unit 253 that controls a radio line; a wired transmission / reception unit 254 that transmits a signal to and receives a signal from the condition monitoring equipment 400; a wired control unit 255 that controls a wired line; and a time management unit 256 that manages an internal time of the wireless ground equipment 200.The radio signal timing measured by the signal measuring unit 252 refers to the timing at which the wireless ground device 200 transmits a radio signal and the timing at which the other wireless ground devices, i.e., the wireless ground devices 210, 220, and 230, transmit their respective radio signals. The time management unit 256 has a function of correcting the managed internal time based on the information acquired from the outside. A functional configuration of each of the wireless ground devices 210, 220, and 230 is substantially the same as that of the wireless ground device 200.

[0016] Fig. 3 is a diagram showing an example of a hardware configuration of the wireless ground device 200. The wireless ground device 200 includes a transmit / receive antenna 201, a radio interface 202, a timing generation circuit 203, a wired interface 204, a memory 205, a processor 206, and a power supply circuit 207.

[0017] The radio interface 202 is a communication circuit connected to the transmitting / receiving antenna 201 and performs radio signal processing. The wired interface 204 is a circuit connected to the wired network 151 and performs communication processing with the condition monitor 400. The timing generation circuit 203 is a circuit that generates a timing at which each unit of the wireless ground device 200 should perform processing, and generates, for example, a clock signal. The working memory 205 corresponds, for example, to a non-volatile or volatile semiconductor memory such as a random access memory (RAM), a read-only memory (ROM), a flash memory, or a magnetic disk, or the like. The processor 206 is a central processing unit (CPU), a microprocessor, or the like.The power supply circuit 207 is a circuit that supplies power to the units of the wireless ground device 200. Note that the wireless ground devices 210, 220, and 230 each have a similar hardware configuration.

[0018] The Fig. The radio transmission / reception unit 251 shown in Figure 2 is implemented by the transmission / reception antenna 201 and the radio interface 202. Fig. The wired transmission / reception unit 254 shown in Figure 2 is implemented by the wired interface 204.

[0019] The Fig. The signal measuring unit 252 shown in Figure 2, the radio control unit 253, the wired control unit 255, and the time management unit 256 are implemented by the processor 206, which executes a program to perform the operations of these units. The functions of the signal measuring unit 252, the radio control unit 253, the wired control unit 255, and the time management unit 256 are described as a program and stored in the RAM 205. The processor 206 reads and executes the program stored in the RAM 205 to realize the functions of the signal measuring unit 252, the radio control unit 253, the wired control unit 255, and the time management unit 256. It can also be said that the program causes a computer to execute an operation or procedure for the signal measuring unit 252, the radio control unit 253, the wired control unit 255 and the time management unit 256.The memory 205 is also used as a temporary memory when the processor 206 performs various types of processing.

[0020] Although Fig. 3 shows the hardware configuration in the case where the wireless ground device 200 is implemented by using the processor 206 and the memory 205, which are general-purpose components, the wireless ground device 200 may also be implemented by using a dedicated processing circuit instead of the processor 206 and the memory 205.

[0021] Fig. 4 is a diagram showing another example of the hardware configuration of the wireless ground device 200. The Fig. 4 is replaced by the hardware shown in Fig. 3 and the processor 206 by a dedicated processing circuit 208. The processing circuit 208 is a single circuit, a composite circuit, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a circuit obtained from a combination thereof. In a case where the wireless ground device 200 is controlled by the Fig. 4, the signal measurement unit 252, the radio control unit 253, the wired control unit 255, and the time management unit 256 are implemented by the processing circuit 208. Although the wireless ground device 200 has been described, the wireless ground devices 210, 220, and 230 also have a similar hardware configuration.

[0022] It should be noted that part of the functions of the signal measuring unit 252, the radio control unit 253, the wired control unit 255 and the time management unit 256 can be implemented by a dedicated processing circuit similar to the one shown in Fig. 4, while the remaining part of it is implemented by a general-purpose memory and a processor corresponding to the processing circuit 208 shown in Fig. 3 shown main memory 205 and the processor 206.

[0023] Fig. 5 is a diagram showing an example of a functional configuration of the wireless integrated device 300. The wireless integrated device 300 includes a radio transmission / reception unit 351 that transmits and receives a radio signal to and from the ground wireless devices 200, 210, 220, and 230, a signal measurement unit 352 that measures a radio signal timing, a radio control unit 353 that controls a radio line, a wired transmission / reception unit 354 that transmits and receives a signal to and from another device (not shown) installed in the train 110, a wired control unit 355 that controls a wired line, and a time management unit 356 that manages an internal time of the internal wireless device 300.

[0024] Fig. 6 is a diagram showing an example of a hardware configuration of the internal wireless device 300. The ground wireless device 300 is composed of a transmitting / receiving antenna 301, a radio interface 302, a timing generation circuit 303, a wired interface 304, a memory 305, a processor 306, and a power supply circuit 307.

[0025] The radio interface 302 is a communication circuit connected to the transmitting / receiving antenna 301 and performs radio signal processing. The wired interface 304 is a circuit connected to a wired network installed in the train 110 and performs communication processing with each other or other devices in the train 110. The timing generation circuit 303 is a circuit that generates a timing at which each unit of the wireless ground equipment 300 performs processing, and generates, for example, a clock signal. The working memory 305 corresponds, for example, to a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, a magnetic disk, or the like. The processor 306 is a CPU, a microprocessor, or the like.The power supply circuit 307 is a circuit that supplies power to the units of the wireless ground device 300.

[0026] The Fig. The radio transmission / reception unit 351 shown in Figure 5 is implemented by the transmission / reception antenna 301 and the radio interface 302. Fig. The wired transmission / reception unit 354 shown in Figure 5 is implemented by the wired interface 304.

[0027] The Fig. The signal measuring unit 352, the radio control unit 353, the wired control unit 355, and the time management unit 356 shown in Figure 5 are implemented by the processor 306, which executes a program to operate these units. The functions of the signal measuring unit 352, the radio control unit 353, the wired control unit 355, and the time management unit 305 are described as a program, and the program is stored in the RAM 305. The processor 306 reads and executes the program stored in the RAM 305 to realize the functions of the signal measuring unit 352, the radio control unit 353, the wired control unit 355, and the time management unit 356. It can also be said that the program causes a computer to execute an operation or procedure for the signal measuring unit 352, the radio control unit 353, the wired control unit 355 and the time management unit 356.The memory 305 is also used as a temporary memory when the processor 306 performs various types of processing.

[0028] Although Fig. 6 shows the hardware configuration in the case where the wireless integrated device 300 is implemented by using the processor 306 and the memory 305, which are general-purpose components, the wireless integrated device 300 may also be implemented by using a dedicated processing circuit instead of the processor 306 and the memory 305.

[0029] Fig. Fig. 7 is a diagram showing another example of the hardware configuration of the wireless integrated device 300. The Fig. The hardware configuration shown in Figure 7 is achieved by Fig. 6, the memory 305 and the processor 306 can be replaced by a dedicated processing circuit 308. The processing circuit 308 is a single circuit, a composite circuit, an ASIC, an FPGA, or a circuit obtained from a combination thereof. In a case where the wireless integrated device 300 is implemented by the Fig. 7, the signal measuring unit 352, the radio control unit 353, the wired control unit 355 and the time management unit 356 are implemented by the processing circuit 308.

[0030] It should be noted that part of the functions of the signal measuring unit 352, the radio control unit 353, the wired control unit 355 and the time management unit 356 can be implemented by a dedicated processing circuit similar to that shown in Fig. 7, while the remaining part of it is implemented by a general-purpose memory and a processor corresponding to the processing circuit 308 shown in Fig. 6 correspond to the main memory 305 and the processor 306.

[0031] Fig. 8 is a diagram showing an example of a functional configuration of the condition monitoring device 400. The condition monitoring device 400 includes a wired connection unit 451, a determination unit 452 that determines states of the wireless ground devices 200, 210, 220, and 230, an output unit 455 that outputs a determination result of the determination unit 452, and a data retention unit 456. The determination unit 452 includes an operation instruction unit 453 that determines a traffic operation status of the train and outputs an operation instruction to the wireless ground devices 200, 210, 220, and 230, and a deteriorated state determination unit 454 that determines deteriorated states of the wireless ground devices 200, 210, 220, and 230.The data retention unit 456 retains a traffic operation information record 461 in which traffic operation information of the train is recorded, a path information record 462 in which a positional relationship of the ground wireless devices 200, 210, 220, and 230 is recorded, and a history information record 463 in which past measurement results are recorded. The measurement results recorded in the history information record 463 are measurement results obtained by the signal measurement unit 252 and acquired from the ground wireless devices 200, 210, 220, and 230.

[0032] Fig. 9 is a diagram showing an example of a hardware configuration of the condition monitor 400. The condition monitor 400 is composed of a wired interface 401, a memory 402, a processor 403, and a power supply circuit 404.

[0033] The wired interface 401 is a circuit connected to the wired network 151 and performs communication processing with the wireless ground devices 200, 210, 220, and 230. The memory 402 corresponds, for example, to a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, a magnetic disk, or the like. The processor 403 is a CPU, a microprocessor, or the like. The power supply circuit 404 is a circuit that supplies power to the units of the wireless ground device 400.

[0034] The Fig. The wired connection unit 451 shown in Figure 8 is implemented by the wired interface 401. The Fig. The destination unit 452 and the output unit 455 shown in Figure 8 are implemented by the processor 403, which executes a program to perform operations of these units. The functions of the destination unit 452 and the output unit 455 are described as a program, and the program is stored in the memory 402. The processor 403 implements the functions of the destination unit 452 and the output unit 455 by reading and executing the program stored in the memory 402. The program can also be said to cause a computer to perform an operation or method for the destination unit 452 and the output unit 455. The memory 402 is also used as a temporary storage when the processor 403 performs various types of processing.

[0035] Although Fig. 9 shows the hardware configuration in the case where the state monitor 400 is implemented by using the processor 403 and the memory 402, which are general-purpose components, the state monitor 400 may also be implemented by using a dedicated processing circuit instead of the processor 403 and the memory 402.

[0036] Fig. 10 is a diagram showing another example of the hardware configuration of the condition monitoring device 400. The Fig. 10 is achieved by replacing the memory 402 and the processor 403 as in Fig. 9, with a dedicated processing circuit 405. The processing circuit 405 is a single circuit, a composite circuit, an ASIC, an FPGA, or a circuit obtained from a combination of these. In a case where the condition monitoring device 400 is implemented by the Fig. 10, the determination unit 452 and the output unit 455 are implemented by the processing circuit 405.

[0037] It should be noted that part of the functions of the determination unit 452 and the output unit 455 may be implemented by a dedicated processing circuit, which is the one described in Fig. 10, while the remaining part of it is implemented by a general-purpose memory and a processor corresponding to the processing circuit 405 shown in Fig. 9 shown main memory 402 and processor 403.

[0038] Next, operations of the ground wireless devices 200, 210, 220, and 230, the wireless integrated device 300, and the condition monitoring device 400 according to the present embodiment will be described.

[0039] The wireless integrated device 300 is connected to the wireless ground device 200 to transmit and receive control information. The wireless integrated device 300 continues transmitting and receiving control information while switching the wireless ground device, which is a connection destination associated with the movement of the train 110. In the case of the time-division multiplexing scheme, not only the wireless integrated device 200 and the wireless ground device 300, but also all the wireless ground devices synchronize their internal timings, thereby enabling switching of the connection destination of the wireless ground device 300. The internal timings are used to determine the transmission / reception timings in the wireless ground devices 200, 210, 220, and 230 and the wireless integrated device 300.Therefore, if the internal times between the devices are not synchronized, a deviation in the transmission / reception timing of signals will occur, potentially leading to a communication failure. As a means of time synchronization, for example, time synchronization using absolute time obtained by a global positioning system (GPS) or the like, time synchronization based on relative time using a radio signal between the wireless ground device 200 and the wireless integrated device 300, or between the wireless ground device 200 and another wireless ground device, or a combination of these time synchronizations is employed.By performing time synchronization, the signal transmission timings of the ground wireless devices 200, 210, 220, and 230 and the wireless integrated device 300 can be synchronized, achieving highly reliable wireless communication. In the following description, time synchronization may be referred to as case-by-case time correction.

[0040] Furthermore, the signal measurement unit 252 of the wireless ground device 200 can monitor the transmission timing of the wireless ground device 210 by receiving a signal transmitted from the wireless ground device 210 via the radio transmission / reception unit 251. Similarly, the wireless ground devices 210, 220, and 230 can each monitor the transmission timing of a different one of the wireless ground devices located within an area where the wireless ground device can monitor a signal. Two or more wireless ground devices can be located within the area where a particular one of the wireless ground devices can monitor a signal.

[0041] To monitor a timing difference, i.e., a time gap, with a neighboring wireless ground device over an extended period of time, it is advantageous to temporarily stop a time correction function. Therefore, in the present embodiment, the time correction is deactivated during a period in which the train is out of service, e.g., at night, or during a period within the train's operating hours when the wireless integrated device is not within a coverage area of ​​each wireless ground device. The condition monitor 400 determines a failure risk due to a secular change of each wireless ground device based on the amount of a time gap measured by each of the wireless ground devices 200, 210, 220, and 230 during a period in which the time correction is deactivated.

[0042] A method for deactivating and enabling time correction of wireless ground devices 200, 210, 220, and 230 is described. Wireless ground devices 200, 210, 220, and 230 deactivate and enable time correction in accordance with an instruction from condition monitor 400. As an example, an operation of deactivating time correction of wireless ground device 200 and an operation of enabling time correction thereof are described.

[0043] Fig. 11 is a flowchart illustrating an example of the operation of disabling the time correction of the wireless ground device 200 and the operation of enabling the time correction thereof.

[0044] In the condition monitoring device 400, the operation instruction unit 453 of the determination unit 452 determines whether or not to disable the time correction of the wireless ground equipment 200 based on the traffic operation information set 461. That is, the operation instruction unit 453 refers to the traffic operation information 461 and monitors whether or not an operation status of the entire system has changed from an "in operation" status to another "out of operation" status. The "entire system operation status" is an operation status of a railway system, and is an "in operation" status in a case where the train is in operation, or in other words, in a case where at least one of the wireless ground equipment communicates with the wireless integrated equipment 300 in the wireless train control system.When it is detected that the operation status of the entire system has changed from the “in operation” status to the “out of operation” status, the operation instruction unit 453 transmits a time correction switching message to the integrated ground equipment 200 as shown in FIG. Fig. 11 (step S101). In this case, the time correction switching message contains the information indicating that time correction is deactivated.

[0045] Upon receiving the time correction switching message including information indicating that time correction is disabled, the wireless ground device 200 disables the time correction. Thereafter, the wireless ground device 200 continues monitoring the difference between the internal time managed by the time management unit 256 in the wireless ground device 200 and the time managed by the other of the wireless ground devices until a time correction switching message containing information indicating that time correction is enabled is received. The difference between the internal time and the time managed by the other wireless ground device is calculated based on the transmission timing of the other wireless ground device. The wireless ground devices 200, 210, 220, and 230 each transmit a control signal in predetermined cycles.Therefore, the signal measuring unit 252 of the wireless ground device 200 measures an error between the timing at which the wireless ground device 200 transmits the control signal and the timing at which the other wireless ground device, for example, the wireless ground device 210, transmits the control signal, and calculates the difference between the internal time managed by the time management unit 256 and the time managed by the other wireless ground device using the measured error.

[0046] Furthermore, the operation instruction unit 453 transmits a time correction switching message to the wireless ground equipment 200 when the wireless ground equipment 200 refers to the traffic operation information set 461 and detects that the operation status of the entire system has changed from a "non-operational" state to an "operational" state, to notify the wireless ground equipment 200 that the time correction function is enabled. That is, the operation instruction unit 453 transmits to the integrated ground equipment 200 the time correction switching message containing information indicating that time correction is enabled.

[0047] Even if the operating status of the entire system is "in operation," the operation instruction unit 453 transmits a time correction switching message containing information indicating that time correction is disabled to the wireless ground device 200 and disables the time correction function if it is determined from the traffic operation information set 461 that it is now a period in which a ground-to-vehicle communication function is not necessary in the wireless ground device 200. The ground-to-vehicle communication mentioned here refers to the communication between the wireless ground device 200 and the wireless integrated device 300.For example, if the entire system is in the operating state, but there is a period of time during which the train is not running in a section where the wireless ground equipment 200 is installed, the determination unit 452 of the condition monitoring device 400 determines that the ground-to-vehicle communication function is not required during this period. When the period during which the ground-to-vehicle communication function is not required ends, the operation instruction unit 453 transmits the time correction switching message including the information indicating that time correction is enabled, and then activates the time correction function of the wireless ground equipment 200.

[0048] Fig. 12 is a flowchart showing an example of the status of the time correction function of the wireless ground device 200 obtained by the above-explained process. As shown in Fig. As shown in Figure 12, the time correction function is enabled during periods when ground-to-vehicle communication is "ON." As just described, the operation instruction unit 453 of the condition monitoring device 400 instructs the wireless ground device 200 to disable the time correction function during the period when the wireless ground device 200 is not communicating with the wireless integrated device 300. Fig. 12 is a diagram showing an example of a setting result of a time correction function based on a service status in the wireless ground equipment 200.

[0049] Fig. 13 is a diagram illustrating an example of a time correction operation performed by the wireless ground device 200. As shown in Fig. 13, in a case where the time correction switching message received from the condition monitor 400 indicates that the time correction function is activated ((A) in Fig. 13), performs time correction with respect to a reference timing. The reference timing is an absolute time obtained using a GPS or the like, a timing generated based on the absolute time, a transmission timing of a control signal by the other of the wireless ground devices, or the like. In the time correction operation, the time management unit 256 of the wireless ground device 200 corrects the managed internal time to coincide with the absolute time, for example, in a case where the reference timing is the absolute time.In a case where the reference timing is the transmission timing of the control signal by the other of the wireless ground devices, the time management unit 256 of the wireless ground device 200 corrects the managed internal time so that the signal transmission timing generated based on the internal time within the wireless ground device 200 matches the reference timing. Note that the timer shown in FIG. Fig. 13 is a range in which the operation of the wireless communication system is guaranteed, and that the risk of a communication failure occurring increases when the time gap falls outside this range.

[0050] If the time correction switching message received from the condition monitoring device 400 indicates that the time correction function is deactivated ((B) in Fig. 13), the wireless ground device 200 measures the time gap. Specifically, the signal measuring unit 252 of the wireless ground device 200 measures the time gap based on a difference between the timing obtained by periodically monitoring the signal transmission timing of the other wireless ground device and the signal transmission timing of the radio transmission / reception unit 251 of the wireless ground device 200. The wireless ground device 200 transmits a result of the time gap measurement to the condition monitor 400. The signal measuring unit 252 of the wireless ground device 200 can measure the time gap with respect to each of the wireless ground devices by switching the wireless ground device subjected to measurement.

[0051] Next, an example of the overall operation of the wireless train protection system in a state where the time correction function of the wireless ground device is deactivated is described.

[0052] Fig. Figure 14 is a flowchart showing an example of the overall operation of the wireless train protection system in the state where the time correction function of the wireless ground equipment is deactivated. Although Fig. 14 only the wireless ground devices 200 and 210 are shown, it is assumed that the wireless ground devices 220 and 230 are also present.

[0053] In the case where the time correction function is deactivated, the wireless ground device 200 measures a difference between the signal transmission timing of each of the wireless ground devices 210, 220, and 230 and the signal transmission timing of the wireless ground device 200 (step S201). Next, the wireless ground device 200 notifies the condition monitor 400 of the measured timing difference as a measurement result notification (step S202). Note that the timing difference may be transmitted to the condition monitor 400 each time the measurement is performed, the differences may be transmitted thereto collectively after the measured timing differences have been accumulated for a certain period of time, or such a transmission may be performed when a change amount based on the differences reaches a certain value or more.Similarly, the wireless ground device 210 measures a difference between the signal transmission timing of each of the other wireless ground devices and the signal transmission timing of the wireless ground device 210 and notifies the condition monitor 400 of a measurement result (steps S203 and S204). Similarly, the wireless ground devices 220 and 230 each measure a difference between the signal transmission timing of each of the other wireless ground devices and the signal transmission timing of a corresponding one of the wireless ground devices 220 and 230 and each notifies the condition monitor 400 of a measurement result.

[0054] In response to a notification of the measurement results of the time gaps from the wireless ground devices 200, 210, 220, and 230, the condition monitor 400 calculates a risk value for each of the wireless ground devices 200, 210, 220, and 230 based on the time gaps obtained through the notification (step S205). Specifically, the deteriorated condition determination unit 454 of the determination unit 452 calculates a change amount per unit time, that is, a slope, from the measurement result acquired from the wireless ground device 200 and determines the calculated value as a risk value of the wireless ground device 200. The change amount per unit time of the measurement result acquired from the wireless ground device 200 is obtained using the measurement result acquired from the wireless ground device 200 in the past.Note that the acquired measurement result is retained as the history information set 463 in the data retention unit 456. The risk value increases according to the degree of performance degradation of the wireless ground device 200. That is, the risk value indicates a degraded performance state of the wireless ground device 200. The degraded state determination unit 454 calculates a risk value for each of the wireless ground devices 210, 220, and 230 in a similar process.

[0055] After calculating the risk values, the deteriorated state determination unit 454 compares the risk values ​​among the wireless ground devices 200, 210, 220, and 230 and extracts the wireless ground device with a high risk value as a wireless ground device whose performance has deteriorated and where a communication failure is highly likely to occur. For example, the deteriorated state determination unit 454 extracts a wireless ground device whose risk value is higher than that of the other wireless ground devices. Whether the risk value is higher than that of the other wireless ground devices is determined, for example, based on whether or not the difference from an average of the risk values ​​of all the wireless ground devices is greater than a predetermined threshold.The wireless ground device with the highest risk value may be extracted, or a specific number of wireless ground devices may be extracted, starting with a wireless ground device with the highest risk value. As a comparison method, the maximum values ​​of the risk values ​​of the wireless ground devices may be compared with each other, or the average values ​​of the risk values ​​may be compared with each other. Alternatively, the deteriorated condition determination unit 454 may compare the risk values ​​of the wireless ground devices with a predetermined threshold and extract a wireless ground device with a risk value above the threshold. The threshold may be a value that is the same for all wireless ground devices 200, 210, 220, and 230, or a value that is individually set for each wireless ground device.

[0056] The deteriorated condition determination unit 454 outputs information about a wireless ground device that has been extracted to the outside from the output unit 455 (step S206). An example of the operation of the output unit 455 includes an operation of outputting the information in the form of a screen displayed on a display unit (not shown) of the condition monitoring device 400. Furthermore, the information to be outputted by the output unit 455 may include, in addition to the identification information of the wireless ground device, information about a recommended maintenance timing of the wireless ground device or information about a replacement timing of the device. That is, the deteriorated condition determination unit 454 may derive the recommended maintenance timing or replacement timing of the extracted wireless ground device.The recommended maintenance time and replacement timing of the wireless ground equipment are derived, for example, by creating a correspondence table of the risk values ​​and recommended maintenance times in advance, and comparing the risk value calculated in step S205 with the correspondence table. When obtaining the replacement timing of the wireless ground equipment, the number of times maintenance work has been performed in the past can be taken into account. For example, when the number of times maintenance has reached a certain value, the deterioration determination unit 454 determines the replacement timing by comparing the risk value with the correspondence table.The deteriorated condition determination unit 454 records the measurement results and the like acquired in steps S202 and S204 in the history information set 463 and uses the measurement results to calculate a risk value when a new measurement result is acquired.

[0057] Next, the operation instruction unit 453 determines a cycle in which the wireless ground devices 200, 210, 220, and 230 should next perform measurement based on the risk values ​​calculated by the deterioration condition determination unit 454 in step S205 (step S207). The cycle described here is a cycle in which each wireless ground device measures a difference between the signal transmission timing of each of the other wireless ground devices and the signal transmission timing of its own wireless ground device. The operation instruction unit 453 determines the cycle individually for each wireless ground device. The operation instruction unit 453 lengthens the cycle for the integrated ground device with a small change in the risk value, but shortens the cycle for the wireless ground device with a large change in the risk value.

[0058] The operation instruction unit 453 notifies each wireless ground device of the determined cycle through a measurement cycle update message via the wired connection unit 451 (steps S208 and S209). The wireless ground devices, including the wireless ground devices 200 and 210, each measure a difference between the signal transmission timing of each of the other wireless ground devices and the signal transmission timing of their own wireless ground devices (steps S210 and S212) in a cycle obtained by the message, and each notifies the condition monitor 400 of a measurement result (steps S211 and S213).Note that a configuration may be adopted in which the operation instruction unit 453 does not notify a cycle to a wireless ground device whose cycle does not need to be changed, and each wireless ground device that has not received notification of a cycle continues to operate at a predetermined cycle or at the same cycle as last time.

[0059] As described above, in the wireless train protection system according to the first embodiment, the condition monitoring device 400 instructs the integrated ground equipment not provided for communication with the wireless integrated equipment 300 to disable the time correction, and determines the deteriorated state of each wireless ground equipment, that is, it calculates the risk value indicating the risk of occurrence of a communication failure in each wireless ground equipment based on differences in the signal transmission timing with respect to the other wireless ground equipment measured by the wireless ground equipment having a status in which the time correction is not performed.The condition monitor 400 specifies a period of time during which each wireless ground device does not conduct communication with the wireless integrated device 300 based on the train's traffic operation information set 461. The wireless train control system according to the present embodiment can ensure a long period of time during which each of the wireless ground devices 200, 210, 220, and 230 monitors the transmission timing of the other wireless ground devices, and can collect information for determining a failure risk due to a secular change. Furthermore, using the risk values ​​determined by the condition monitor 400 can reduce the workload for developing plans, securing replacements, and the like for on-site maintenance and device replacement of the wireless ground devices 200, 210, 220, and 230.

[0060] Note that in the present embodiment, each ground wireless device measures the difference between the transmission timing of its own ground wireless device and the transmission timing of each other ground wireless device and transmits the measurement result to the condition monitor 400. However, it may measure a difference between the internal time and the absolute time in a case where absolute time information can be acquired. The absolute time information can be acquired using the GPS described above or distributed from the condition monitor 400 to each ground wireless device, for example.Alternatively, a configuration may be adopted in which the condition monitor 400 generates a reference timing signal that is consistent throughout the system and distributes the reference timing signal to each wireless ground device, and each wireless ground device measures the amount of the gap in the internal time using the reference timing signal. In a case where the wireless ground device measures the amount of the gap in the internal time using the absolute time or the reference timing that is consistent throughout the system, the condition monitor 400 can determine the deteriorated condition of the wireless ground device with higher accuracy.

[0061] Furthermore, in the present embodiment, the risk value is calculated based on the measurement result in the state where the time synchronization function of the ground wireless device is disabled, but disabling the time synchronization function is not essential. Since the time gap per unit time increases with the performance deterioration of the device, the risk value described above can be calculated, for example, based on the time lag caused between the execution of the first time synchronization and the execution of the second time synchronization.

[0062] Moreover, in the present embodiment, the description is based on the assumption that the measured value reported from each ground wireless device to the condition monitor 400 is the timing difference information, but a similar effect can be obtained if the reception powers of the signals received from the other ground wireless devices are used instead of the timing difference. Second embodiment.

[0063] In the wireless train control system according to the first embodiment, the determination unit 452 of the condition monitor 400 compares the risk values ​​calculated from the measurement results acquired from the wireless ground devices 200, 210, 220, and 230 to extract a wireless ground device with a high probability of communication failure. On the other hand, in the present embodiment, a method for calculating risk values ​​by weighting measurement values ​​measured between the wireless ground devices on a movement path of the train 110 is described, thereby preferentially selecting a wireless ground device with a significant risk for switching the wireless ground device to which the wireless integrated device 300 is connected or for handover thereof.It should be noted that a configuration of the wireless train protection system is similar to that of the first embodiment (see ). Fig. 1). The functional configurations and hardware configurations of the wireless ground devices 200, 210, 220 and 230, the wireless integrated device 300 and the condition monitoring device 400 are also similar to those of the first embodiment (see Fig. 2 to 10).

[0064] The difference from the first embodiment lies in an operation in which the deteriorated condition determination unit 454 in the determination unit 452 of the condition monitoring device 400 calculates the risk values ​​of the ground wireless devices 200, 210, 220, and 230. Therefore, the present embodiment mainly describes the operation in which the deteriorated condition determination unit 454 calculates the risk values. Note that the operations of the ground wireless devices 200, 210, 220, and 230 and the wireless integrated device 300 are similar to those in the first embodiment.

[0065] Fig. 15 shows a configuration of the path information set 462 retained in the data retention unit 456 used by the condition monitor 400 according to a second embodiment. Fig. 15 is a table showing an example of the path information set 462 retained by the condition monitor 400 according to the second embodiment. In Fig. 15, a ground wireless facility identifier adjacent to a ground wireless facility indicated by a ground wireless facility identifier in the same row is registered in the “path information set”.

[0066] The wireless ground device 200 transmits information about a timing difference measured by the signal measurement unit 252 to the condition monitor 400 through a measurement result message. For example, the wireless ground device 200 sets d_200_210 as the timing difference measured with respect to the wireless ground device 210, d_200_220 as the timing difference measured with respect to the wireless ground device 220, and d_200_230 as the timing difference measured with respect to the wireless ground device 230, and transmits the set values ​​to the condition monitor 400.

[0067] In the determination unit 452 of the condition monitoring device 400, the deteriorated condition determination unit 454 refers to the path information set 462 from Fig. 15, when the risk values ​​are calculated from the change amounts of the timing differences d_200_210, d_200_220, and d_200_230 received from the wireless ground devices 200, 210, 220, and 230, respectively. From the path information set 462, it is understood that the wireless ground device 210 is located on the path of the wireless ground device 200, and that these two wireless ground devices are adjacent to each other on the same path and are used for the handover of the wireless integrated device 300. In this situation, a weight w1 represents the availability of path information between the wireless ground devices 200 and 210. That is, the degraded state determination unit 454 multiplies d_200_210 by w1. On the other hand, it can be determined that no handover is performed between the wireless ground facilities 200 and 220 and between the wireless ground facilities 200 and 230.Therefore, for these combined cases, the deteriorated state determination unit 454 uses a weight w2, which represents the unavailability of path information. That is, the deteriorated state determination unit 454 multiplies each of d_200_220 and d_200_230 by w2. In this example, the two weights used for weighting are in the relationship "w1>w2." The deteriorated state determination unit 454 calculates the risk values ​​using the weighted timing differences according to a method similar to the first embodiment. The deteriorated state determination unit 454 also records the weighted timing differences in the set history information 463 and uses the weighted timing differences to calculate the risk value when a new measurement result is acquired.

[0068] As described above, when calculating risk values ​​based on the change amounts of the timing differences measured by the wireless ground devices, the condition monitoring device 400 according to the second embodiment weights the measured values ​​(timing differences) between the wireless ground devices located on the train's movement path, making it possible to preferentially extract a wireless ground device with a significant risk of switching or handing over the wireless ground device to which the wireless integrated device 300 is connected. In this way, it is possible to save the labor required for planning, securing replacements, and the like for on-site maintenance and device replacement of the wireless ground devices, and to perform appropriate prioritization. Third embodiment.

[0069] In the first and second embodiments, the risk values ​​are calculated based on the measurement results measured between the wireless ground equipment. On the other hand, in the present embodiment, a method is described in which the condition monitoring device 400 calculates a risk value based on a difference between a signal transmission timing of the wireless ground equipment 200 measured by the wireless integrated equipment 300 and a timing generated by the radio transmission / reception unit 351 within the wireless integrated equipment 300. It should be noted that a configuration of the wireless train protection system is similar to that of the first embodiment (see Fig. 1). The functional configurations and hardware configurations of the wireless ground devices 200, 210, 220 and 230, the wireless integrated device 300 and the condition monitoring device 400 are also the same as those of the first embodiment (see Fig. 2 to 10).

[0070] In the present embodiment, the parts different from the first and second embodiments will be mainly described, particularly the operations of the wireless integrated device 300 and the condition monitoring device 400. Note that the operations of the wireless ground devices 200, 210, 220, and 230 are similar to those of the first embodiment.

[0071] The train 110 equipped with the wireless integrated device 300 travels along the track 100 toward the wireless ground device 200. To maintain communication with the wireless ground device 200, the wireless integrated device 300 monitors a signal from the wireless ground device 200 and corrects the internal time based on a signal transmission timing of the wireless ground device 200 to synchronize with the wireless ground device 200.

[0072] Within the communication coverage area of ​​the wireless ground equipment 200, the signal measurement unit 352 of the wireless integrated equipment 300 can receive a signal from the wireless ground equipment 200 and measure a timing difference with respect to the wireless integrated equipment 200. The signal measurement unit 352 of the wireless integrated equipment 300 transmits a timing difference d_300_200 with respect to the wireless ground equipment 200 as a result of the measurement of the wireless integrated equipment 300 to the condition monitoring equipment 400 via the wireless ground equipment 200. The transmission to the condition monitoring equipment 400 may be performed every time the measurement is performed, may be performed collectively after the timing differences have been accumulated over a certain period of time, or may be performed when the amount of change therein reaches a certain value or more.

[0073] After passing the wireless ground facility 200, the train 110 equipped with the wireless integrated device 300 performs a handover operation to switch the connection destination to the wireless ground facility 210. At the time of handover, as shown in Fig.As shown in Figure 16, the wireless integrated device 300 corrects a reference timing generated by the radio transmission / reception unit 351 of the wireless integrated device 300 to a reference timing of the wireless ground device 210 to which the handover is performed. The reference timing of the wireless ground device 210 can be determined by monitoring a control signal transmitted from the wireless ground device 210. The signal measurement unit 352 transmits a correction amount for correcting the reference timing at the time of handover as a timing difference d_300_200-210 between the wireless ground devices 200 and 210 to the condition monitoring device 400 via the wireless ground device 210.Similarly, a wireless integrated device installed in another train (not shown) transmits a timing difference obtained at the time of a handover operation between a wireless ground device from which the handover is initiated and a wireless ground device to which the handover is performed to the condition monitor 400.

[0074] The deteriorated condition determination unit 454 of the condition monitoring device 400 calculates risk values ​​based on the timing difference d_300_200 between the wireless integrated device 300 and the wireless ground device 200 and the timing difference d_300_200-210 between the wireless ground device 200 and the wireless ground device 210, each of which is acquired from the wireless integrated device 300. At this time, the risk values ​​calculated by the deteriorated condition determination unit 454 are a risk value for the combination of the wireless integrated device 300 and the wireless ground device 200, and a risk value for the combination of the wireless ground device 200 and the wireless ground device 210.For example, the deteriorated condition determination unit 454 calculates the change amount per unit time of the timing difference d_300_200 and a variation per unit time of the timing difference d_300_200-210, and sets each of these two change amounts as the risk value. Similarly, for a combination of another wireless integrated device (not shown) and a wireless ground device, the deteriorated condition determination unit 454 calculates a risk value based on an acquired timing difference.

[0075] The deteriorated state determination unit 454 compares the risk values ​​among the combinations of the wireless integrated devices and the wireless ground devices in the system, and extracts a combination with a high risk value as a combination of the wireless integrated device and the wireless ground device with a high probability of experiencing a communication failure. In the comparison method described in the first embodiment, the maximum values ​​of the risk values ​​for the combinations may be compared with each other, or the average values ​​of the risk values ​​for the combinations may be compared with each other. Alternatively, the risk values ​​(e.g.,Average values) for the combinations are compared with a given threshold, and a combination whose risk value is greater than the threshold can be extracted as a combination for which a communication failure is highly likely.

[0076] In addition, the deteriorated condition determining unit 454 stores the measurement results acquired from the wireless integrated devices in the history information set 463 and uses the measurement results to calculate the risk value when a measurement result is newly acquired.

[0077] Note that each ground wireless device performs the operation described in the first embodiment, and the condition monitor 400 performs the operation described in the first or second embodiment in addition to the operation described in the present embodiment to calculate the risk value for each ground wireless device, although this is not described.

[0078] As described above, the condition monitor 400 according to the third embodiment calculates the risk values ​​for the combinations of the wireless integrated device and two of the wireless ground devices that are connection targets before and after the handover, based on a timing difference with respect to the wireless ground device connected before the handover and a timing difference between the two wireless ground devices that are connection targets before and after the handover, the timing differences being measured by the wireless integrated device at the time of the handover.In this way, in addition to achieving an advantageous effect achieved by the first and second embodiments, it is possible to save labor for preparing plans, securing replacements, and the like for maintenance of the wireless integrated device and replacement of the wireless integrated device.

[0079] The configurations described in the above embodiments are merely examples, each of which can be combined with other well-known techniques, and the embodiments can be combined with each other. Furthermore, the configurations may be partially omitted and / or modified without departing from the scope of the present disclosure. List of reference symbols

[0080] 100, 101 track; 110 train; 151 wired network; 200, 210, 220, 230 wireless ground facility; 201, 301 transmitting / receiving antenna; 202, 302 radio interface; 203, 303 timing generation circuit; 204, 304, 401 wired interface; 205, 305, 402 memory; 206, 306, 403 processor; 207, 307, 404 power supply circuit; 208, 308, 405 processing circuit; 251, 351 radio transmitting / receiving unit; 252, 352 signal measuring unit; 253, 353 radio control unit; 254, 354 wired transmission / reception unit; 255, 355 wired control unit; 256, 356 time management unit; 300 wireless integrated device; 400 condition monitoring device; 451 wired connection unit; 452 determination unit; 453 operation instruction unit; 454 deteriorated condition determination unit; 455 output unit; 456 data retention unit; 461 traffic operation information set; 462 path information set; 463 history information set.

Claims

[1] A condition monitoring device (400) that monitors conditions of wireless ground devices (200, 210, 220, 230) and a wireless integrated device (300) that form a wireless train protection system using a time-division multiplexing scheme, the condition monitoring device (400) comprising: a wired connection unit (451) for acquiring a result of measuring an error between a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) and a reference timing from the wireless ground device (200, 210, 220, 230); and a degraded condition determining unit (454) for determining a degraded performance condition of the wireless ground device (200, 210, 220, 230) based on the error. [2] Condition monitoring device (400) according to claim 1, comprising: an operation instruction unit (453) for issuing, in a period in which the wireless ground device (200, 210, 220, 230) does not communicate with the wireless integrated device (300), an instruction to deactivate a time correction function in which the wireless ground device (200, 210, 220, 230) corrects an internal time to synchronize the transmission timing with the reference timing, wherein the degraded condition determining unit (454) determines the degraded performance condition based on the error measured by the wireless ground device (200, 210, 220, 230) having a status in which the time correction function is deactivated. [3] The condition monitoring device (400) according to claim 2, wherein the operation instruction unit (453) determines a cycle in which the wireless ground device (200, 210, 220, 230) next measures the error based on a result of the determination of the deteriorated performance state obtained by the deteriorated state determination unit (454), and notifies the wireless ground device (200, 210, 220, 230) of the determined cycle. [4] The condition monitoring device (400) according to any one of claims 1 to 3, wherein the deteriorated condition determining unit (454) extracts, based on the fault, a wireless ground device (200, 210, 220, 230) in which a communication failure is more likely to occur. [5] The condition monitoring device (400) according to claim 4, wherein the deteriorated condition determining unit (454) extracts a wireless ground device (200, 210, 220, 230) in which a change amount per unit time of the error is greater than a predetermined threshold. [6] The condition monitoring device (400) according to claim 4, wherein the deteriorated condition determining unit (454) compares change amounts per unit time of the error between the wireless ground devices (200, 210, 220, 230) and extracts a wireless ground device whose change amount is larger than that of the other wireless ground devices (200, 210, 220, 230). [7] The condition monitoring device (400) according to any one of claims 1 to 6, wherein the reference timing is a timing based on an absolute time. [8] The condition monitoring device (400) according to any one of claims 1 to 6, wherein an area is provided in which one of the wireless ground devices (200, 210, 220, 230) by which the error is measured can monitor a signal, and the reference timing is a signal transmission timing of the other wireless ground device (200, 210, 220, 230) located in the area. [9] The condition monitoring device (400) according to claim 8, wherein the degraded condition determining unit (454) weights the error based on a positional relationship between the ground wireless devices (200, 210, 220, 230) and determines the degraded performance condition using the weighted error. [10] The condition monitoring device (400) according to claim 9, wherein the deteriorated condition determining unit (454) performs weighting so that a weight of an error of the internal time between two wireless ground devices (200, 210) adjacent on a path (100) on which a train (110) moves is increased. [11] Condition monitoring device (400) according to one of claims 1 to 10, wherein the wired connection unit (451) acquires from the wireless integrated device (300) a result of measuring an error between a transmission timing of a signal in the wireless integrated device (300) and a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) that is in communication with the wireless integrated device (300), and a result of measuring an error when the wireless integrated device (300) performs a handover, between a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) that is a connection destination of the wireless integrated device (300) before the handover is performed and a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) that is a connection destination of the wireless integrated device (300) after the handover has been completed, and the degraded state determining unit (454) determines a state of degraded performance of the wireless integrated device (300) based on the error acquired by the wireless integrated device (300) through the wired connection unit (451). [12] A wireless ground device (200, 210, 220, 230) of a wireless train protection system, comprising: wireless ground devices (200, 210, 220, 230) and a wireless integrated device (300) which perform wireless communication using a time-division multiplexing scheme; and a condition monitoring device (400) for monitoring conditions of the wireless ground devices (200, 210, 220, 230) and the wireless integrated device (300), the wireless ground device (200, 210, 220, 230) comprising: a time management unit (256) for managing an internal time; a radio transmission / reception unit (251) for transmitting / receiving a signal at a timing based on the internal time; a signal measuring unit (252) for measuring an error between a transmission timing of a signal in the radio transmission / reception unit (251) and a reference timing; and a wired transmission / reception unit (254) for transmitting the error to the condition monitoring device (400). [13] Wireless ground device (200, 210, 220, 230) according to claim 12, wherein the time management unit (256) has a time correction function of correcting the internal time to synchronize the transmission timing with the reference timing, and the signal measuring unit (252) measures the error when the time management unit (256) is in a state in which the time correction function is deactivated according to an instruction from the condition monitoring device (400). [14] A wireless integrated device (300) of a wireless train protection system, comprising: wireless ground devices (200, 210, 220, 230) and the wireless integrated device (300) which perform wireless communication using a time-division multiplexing scheme; and a condition monitoring device (400) for monitoring conditions of the wireless ground devices (200, 210, 220, 230) and the wireless integrated device (300), the wireless integrated device (300) comprising: a time management unit (356) for managing an internal time; a radio transmission / reception unit (351) for transmitting / receiving a signal at a timing based on the internal time; a signal measuring unit (352) for measuring an error between a transmission timing of a signal in the radio transmission / reception unit (351) and a transmission timing of a signal in the wireless ground equipment (200, 210, 220, 230) that is in connection, and, in the case of a handover by which a connection destination is switched by the wireless ground equipment (200, 210, 220, 230) that is in connection with another of the wireless ground equipments (200, 210, 220, 230), an error between a transmission timing of a signal in the wireless ground equipment (200) that is a connection destination before the handover is performed and a transmission timing of a signal in the wireless ground equipment (200, 210, 220, 230) that is a connection destination after the handover is performed; and a wired transmission / reception unit (354) for transmitting the error measured by the signal measuring unit (352) to the condition monitoring device (400). [15] A failure risk determination method in a wireless train protection system, comprising: wireless ground equipment (200, 210, 220, 230) and a wireless integrated equipment (300) which perform wireless communication using a time-division multiplexing scheme; and a condition monitoring device (400) for monitoring conditions of the wireless ground equipment (200, 210, 220, 230) and the wireless integrated equipment (300), the failure risk determination method comprising: a step of the wireless ground device (200, 210, 220, 230) of measuring an error between a transmission timing of a signal based on an internal time and a reference timing; and a step of the condition monitoring device (400) of determining a state of degraded performance of the wireless ground device (200, 210, 220, 230) or the wireless integrated device (300) based on the error. [16] A control circuit for controlling a condition monitoring device (400) to monitor conditions of wireless ground devices (200, 210, 220, 230) and a wireless integrated device (300) forming a wireless train protection system to which a time-division multiplexing scheme is applied, the control circuit causing the condition monitoring device (400) to perform: a step of acquiring a result of measuring an error between a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) and a reference timing from the wireless ground device (200, 210, 220, 230); and a step of determining a degraded performance condition of the ground wireless device (200, 210, 220, 230) or the internal wireless device (300) based on the error. [17] A storage medium in which a program is stored, the program being designed to control a condition monitoring device (400) to monitor conditions of wireless ground devices (200, 210, 220, 230) and a wireless integrated device (300) constituting a wireless train protection system for which a time-division multiplexing scheme is used, the program causing the condition monitoring device (400) to execute: a step of acquiring a result of measuring an error between a transmission timing of a signal in the wireless ground device (200, 210, 220, 230) and a reference timing from the wireless ground device (200, 210, 220, 230); and a step of determining a degraded performance condition of the ground wireless device (200, 210, 220, 230) or the internal wireless device (300) based on the error.

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