JP2001324584A - Time synchronizer, time synchronizing system, and method of controlling time synchronizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically correct times of plural devices connected to a network, and to precisely conduct time synchronization among the devices. SOLUTION: A GPS receiver 13 receives a time signal from a GPS satellite 11 via an antenna 12. The receiver 13 is connected to terminals 15-1-15-n via the network 14, a time data is transmitted to the terminals 15-1-15-n connected directly to the network 14 in the condition where the time data is received at the same time, based on the time signal received from the satellite 11, and the times in the terminals 15-1-15-n are synchronized highly precisely with respect to the present time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a time synchronization device, a time synchronization system, and a method for controlling a time synchronization device.
In particular, the present invention relates to a time synchronization device, a time synchronization system, and a control method of a time synchronization device for performing time synchronization with high accuracy between a plurality of devices connected via a network.

[0002]

2. Description of the Related Art In a computer system composed of a plurality of devices, it may be necessary to accurately synchronize the time between the devices according to the processing contents.
For example, simultaneous data recording / reproduction starting by a time event, log collection, and the like are processing contents that require time synchronization. Further, in such a computer system, the time of each device needs to be synchronized with the current time with high accuracy.

In order to perform such time synchronization, accurate time information is received from outside the computer system.
At least one time synchronization device for notifying time information to other devices constituting the computer system is required in the system.

[0004] As this time synchronization device, for example, FIG.
GPS (Global Positioning System)
A GPS receiver 61 that receives a time signal transmitted from the satellite 63 via the antenna 66 can be used.

[0005] By the way, a commercially available GPS receiver 6
1 mostly adopts an interface such as RS-232C or parallel for output of time information,
There was no configuration for connecting directly to the network.

On the other hand, in recent computer systems, the devices 65-1 to 65-n are interconnected by a network 64.

Therefore, in order to synchronize the time of the system using the GPS receiver 61, the GPS receiver 61 is required.
In order to receive time information from the PC through an interface 67 such as RS-232C or parallel, and to output the time information to the network 64, a time server device 62 constructed by a personal computer or the like is required.

[0008]

In the above-mentioned conventional computer system, the GPS receiver receives time information from the GPS receiver to transfer the time signal received from the satellite to another device connected to the network. In addition, a dedicated computer must be installed as a time server for outputting to a network.

Such a dedicated computer is, for example,
Japanese Patent Application Laid-Open No. 10-31083 discloses a system and method for automatically correcting a clock built in a computer.
The dedicated computer disclosed in this publication compares the time of a built-in clock with time information input from a GPS receiver, and determines that the time difference is greater than a preset allowable value. Then, the internal clock is corrected, and the time of the terminal on the network is set using this time as a reference time.

In order to perform such an operation, since the least significant digit of the clock device built in the computer is usually in the unit of second, unless an interrupt synchronized with one second is generated inside the computer. However, there is a problem that the time information transmitted to the network has an error of 1 second at the maximum.

In order to avoid this problem, even if the time data received from the GPS receiver is directly transmitted to the network without using the built-in clock of the dedicated computer as the reference time, the following new problems will occur. Can be

[0012] Such a dedicated computer is a UNIX computer.
Application software for time synchronization operates on various operating systems (hereinafter, referred to as “OS”) such as (registered trademark), and this application software performs acquisition of time information from a GPS receiver and transmission to a network. Is going.

By the way, in a general OS, application software cannot directly control various hardware (serial port, network port, etc.) mounted on a computer, and driver software dependent on each hardware is not available. And hardware control via the OS.

More specifically, when the time information is input from the GPS receiver, the dedicated computer
Receives the time data input from the serial port (hardware) via the serial port driver (software),
It has been transmitted to a network port (hardware) via a network protocol stack (software such as a TCP / IP protocol stack) and a network driver (software).

In such an operation, even if high-precision time information is received from the GPS receiver, processing of the OS and various driver software is interposed, and the accuracy of time data transmitted to the network is reduced. There is.

A highly versatile device such as a personal computer can be provided with various functions for general purposes. However, when only such dedicated functions are performed, a small size, simplification, and high precision are required. Considering this, it can be said that there is much waste.

Therefore, a main object of the present invention is to automatically correct the times of a plurality of devices connected to a network, and to perform time synchronization between the devices with high accuracy.
It is an object of the present invention to provide a time synchronization device, a time synchronization system, and a method of controlling the time synchronization device, which can reduce the size and simplification of a portion necessary for performing time synchronization.

[0018]

According to a first aspect of the present invention, there is provided a time synchronizing apparatus for synchronizing time between a plurality of devices connected via a network. In the synchronizer, a time signal corresponding to a second pulse and time data synchronized with a predetermined reference time is received from a GPS satellite, and the second pulse and the time data are generated and output. A time data transmitting unit for transmitting the time data at a synchronized timing using the predetermined protocol via the network in a state where the plurality of devices can simultaneously receive the time data.

According to the first aspect of the invention, the time signal receiving unit receives a time signal corresponding to the second pulse and the time data synchronized with the predetermined reference time from the GPS satellite, and receives the second pulse and the time data. Is generated and output to the time data sending unit.

The time data transmitting unit transmits the time data at a timing synchronized with the second pulse in a state where a plurality of devices can simultaneously receive the data via a network using a predetermined protocol.

According to a second aspect of the present invention, in the first aspect of the present invention, the predetermined reference time is UTC, and the second pulse is synchronized with the first second of the UTC. I do.

According to the second aspect of the invention, in addition to the operation of the first aspect, the predetermined reference time is UTC, and the second pulse is synchronized with the first second of UTC. , And time data can be transmitted at a timing synchronized with the first second of UTC.

According to a third aspect of the present invention, in the first aspect of the present invention, the predetermined protocol is a connectionless type protocol.

According to the third aspect of the present invention, in addition to the operation of the first aspect of the present invention, since the predetermined protocol is a connectionless type protocol, there is no overhead for establishing a connection and processing is performed at high speed. It can be performed.

According to a fourth aspect of the present invention, in the third aspect of the invention, the connectionless protocol is
It is characterized by the DP / IP protocol.

According to the fourth aspect of the invention, in addition to the operation of the third aspect of the present invention, the connectionless protocol is a UDP / IP protocol, so that the processing is simplified and the processing is performed at a high speed. be able to.

According to a fifth aspect of the present invention, in the first aspect of the present invention, there is provided a timekeeping unit which performs a timekeeping operation in synchronization with the reference time and generates an internal second pulse and internal time data. The sending unit, in the time signal receiving unit, when the time signal cannot be received, using the internal second pulse instead of the second pulse, sending the internal time data instead of the time data, I do.

According to the fifth aspect of the invention, in addition to the operation of the first aspect, the time data transmitting section uses the time measuring section when the time signal receiving section cannot receive the time signal. An internal second pulse is used instead of the second pulse, and internal time data is transmitted instead of the time data.

According to a sixth aspect of the present invention, a plurality of devices connected via a network and a time signal corresponding to a second pulse and time data synchronized with a predetermined reference time are transmitted by a GPS.
A time synchronization device that receives from a satellite and transmits the time data at a timing synchronized with the second pulse using the predetermined protocol via the network so that the plurality of devices can simultaneously receive the time data. Features.

According to the invention described in claim 6, the time synchronizing device receives the second pulse synchronized with the predetermined reference time and the time signal corresponding to the time data from the GPS satellite, and sets the time at the timing synchronized with the second pulse. A plurality of devices transmit data via a network using a predetermined protocol in a state where data can be received simultaneously.

The invention according to claim 7 is characterized in that, in the invention according to claim 6, the predetermined protocol is a connectionless type protocol.

According to the seventh aspect of the present invention, in addition to the operation of the sixth aspect of the present invention, since the predetermined protocol is a connectionless type protocol, there is no overhead for establishing a connection and processing is performed at high speed. It can be performed.

The invention according to claim 8 is a control method of a time synchronization device for synchronizing time between a plurality of devices connected via a network, wherein the second pulse and the time data synchronized with a predetermined reference time are converted to time data. GP corresponding time signal
A time signal receiving step of receiving from the S satellite, generating and outputting the second pulse and time data, and transmitting the time data at a timing synchronized with the second pulse through the network using a predetermined protocol using a predetermined protocol. A time data transmission step of transmitting the data in a state where the apparatus can receive the data at the same time.

According to the present invention, in the time signal receiving step, the time signal corresponding to the second pulse and the time data synchronized with the predetermined reference time is received from the GPS satellite to generate the second pulse and the time data. And output.

In the time data transmitting step, the time data is transmitted at a timing synchronized with the second pulse in a state where a plurality of devices can simultaneously receive the data via a network using a predetermined protocol.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, the predetermined reference time is UTC, the second pulse is synchronized with the first second of the UTC, and the time data The sending step is characterized in that the time data is sent by interruption processing by the second pulse.

According to the ninth aspect of the present invention, in addition to the operation of the eighth aspect, the second pulse is synchronized with the first second of the UTC, and the time data transmission process is performed by the interruption by the second pulse. Since the time data is transmitted in the processing, the processing can be performed at high speed.

[0038]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of a network system according to a first embodiment of the present invention. This network system 10 includes a GPS receiver 13 for receiving a time signal from a GPS satellite 11 via an antenna 12. And a plurality of terminal devices 15-1 to 15-n connected to the GPS receiver 13 via the network 14.

As shown in FIGS. 2 and 3, a GPS receiver 13 receives a time signal from a GPS satellite 11 via an antenna 12 and outputs a one-second pulse 35 and time data 36. , A common control unit 22 that controls the entire GPS receiver 13, and converts the time data 36 received from the common control unit 22 into a signal to be transmitted to a network, and transmits the signals to a plurality of terminal devices 15-1 to 15-1 through a network 14. 15-n.

The common control unit 22 includes a CPU 22a for controlling the entire common control unit 22, and a ROM storing an OS, an application program, and a network protocol.
RAM 22b for temporarily storing various data and the like
2c.

In this case, the one-second pulse 35 is input to the hardware interrupt input terminal of the CPU 22a of the common control unit 22, and when the time data 36 is received from the GPS module 21 every second, the common control unit 22 Starts the interrupt processing at the rise of the one-second pulse 35, and can immediately pass the time data to the LAN control unit 23.

The O used in the common control unit 22
S is an OS having excellent real-time performance, unlike a general-purpose OS for a general personal computer, and an application program operating on the OS can directly control the GPS module 21 and the LAN control unit 23. , Without software such as drivers in between,
Processing delay is reduced as compared with the case where an application program is operated on a general-purpose OS for personal computers.

Here, the one-second pulse 35 and the time data 3
6 will be described. The one-second pulse is a pulse synchronized with one second in UTC (Coordinated Universal Time). The time data 36 is data representing the date and the hour, minute, and second.
For example, in the serial format, "20000112083
020 ", year (4 digits) month (2 digits) day (2
(Digit) hour (two digits) minute (two digits) is transmitted in seconds (two digits).

The one-second pulse 35 and the time data 36
Are electrically TTL level signals and are configured to be used as they are in ordinary digital circuits.

FIG. 3 shows the output 1 of the GPS module 21.
A timing chart of the second pulse 35, the time data 36, and the time data output to the network 14 is shown.

The common control unit 22 includes a GPS module 21
When the reception of the time data 36 corresponding to the time t is completed before the time T before the time t via the time t, the time data 36 corresponding to the time t is synchronized with the rising edge of the one-second pulse 35 at the time t. Network 1 via control unit 23
4 is output.

Thereafter, similarly, when the reception of the time data 36 corresponding to the time t + 1 is completed by the time T before the time t + 1 via the GPS module 21, the time of the time t + 1 becomes 1
In synchronization with the rise of the second pulse 35, the time data 36 corresponding to the time t + 1 is output to the network 14 via the LAN control unit 23, and the time t + 2 before the time T + from the time t + 2 via the GPS module 21. When the reception of the corresponding time data 36 is completed, the time data 36 corresponding to the time t + 1 is output to the network 14 via the LAN control unit 23 in synchronization with the rise of the one-second pulse 35 at the time t + 2.

For sending time data to the network 14, UDP / IP (User Datagram Protocol / Internet P
rotocol). UDP / IP is TCP / I
P (Transmission Control Protocol / Internet Protoco
The difference from l) is that it is a best effort type and connectionless type communication system.

In TCP / IP, when transmitting data to a terminal having a certain IP address on a network, it is necessary to open a connection with the terminal of the transmission destination in advance. For this reason, it is conceivable that a delay occurs between the time when the connection is established and the time data is transmitted, and the accuracy of the time data deteriorates.

On the other hand, when UDP / IP is used,
There is no need to open a connection, and the time data received from the GPS module 21 is immediately transmitted to the network 1
4 can be sent. In addition, UDP / IP
Has a function called a multicast method that can collectively transmit data to a certain range of IP addresses on a network. Time data can be sent to the other terminals at the same time, and the time between the terminals can be accurately synchronized. This U
The DP / IP protocol is stored in the ROM 22 of the common controller 22.
b.

Next, the operation of the first embodiment will be described in detail with reference to the processing flowchart of FIG.

In FIG. 2, the GPS module 21
The time signal received from the GPS satellite 11 via the antenna 12 is output as a signal of a one-second pulse 35 and time data 36.

The one-second pulse 35 is a pulse synchronized with the first second of UTC (Coordinated Universal Time), and the time data 36 is basically transmitted every second as shown in FIG. However, the accuracy is not so high.

However, as shown in FIG. 3, the reception of the time data 36 in one-second units has been completed before the predetermined time T before the rising timing of the one-second pulse 35.

As described above, the one-second pulse 35 is connected to the hardware interrupt terminal of the CPU 22a of the common control unit 22, and upon detecting the rise of the one-second pulse 35, the CPU 33a starts the interrupt processing. More specifically, in this interrupt processing, the CPU 33a transmits the time data 36 corresponding to the time t at which the reception is completed before the time T before the time t via the LAN control unit 34 in synchronization with the rise of the one-second pulse 35. It will be sent to the network 14.

In the time data input process, first,
It is determined whether the reception of the time data 36 in the serial format from the GPS module 21 has been started (step S).
1). In this case, if the start-stop synchronization method is employed as the serial time data 36 output from the GPS module 21, the start-stop synchronization method determines whether or not a start bit indicating the start of data is detected. It is determined whether the reception of the time data 36 has been started.

If it is determined in step S1 that the reception of the time data 36 has not been started (step S1; No), the process directly enters the standby state.

If it is determined in step S1 that the start bit of the time data 36 is detected (step S1; Yes), the reception of the time data 36 is started. Time data 3
6 is saved (stored) in the RAM 22c (step S
2).

In the case of the above example, the time data 36
Is the year (4 digits) month (2 digits) day (2 digits) hour (2 digits) minutes (2
It is composed of a total of 14 bytes (digits) seconds (two digits). Here, the time data 36 saved in the RAM 33c is
At this point, the time accuracy is still poor, so if it is sent to the network as it is, time data 3 with poor time accuracy
6 will be transmitted.

That is, at the timing of the next rising edge of the one-second pulse 35 after receiving the time data 36, the time accuracy of the time data 36 is improved, and it is the time to save the data in the RAM 22c around the world.

In step S2, after saving the time data 36 in the RAM 22c, a flag indicating that new time data has been received is set (step S3).

This is to prevent erroneous transmission of old time data when new time data is not received in the one-second pulse interrupt process started thereafter.

After the flag indicating that new time data has been received is set, after a time T, a one-second pulse 35 synchronized with the first second of UTC activates a UTC first-second pulse interrupt process.

In the UTC 1-second pulse interrupt processing (time data output processing), first, a flag indicating that new time data has been received is checked (step S5).

If it is determined in step S5 that the flag indicating that data has been received is not set (step S5; No), no new time data has been received, so the process goes to step S8 without any operation and exits from the interrupt process. . This is to prevent old time data from being sent to the network even when the hardware interrupt processing by the UTC 1 second pulse is started at an unintended timing due to noise or the like generated at the terminal. It is.

If it is determined in step S5 that the new time data has been received (step S5; Y
es), the time data saved in the RAM 22c is transmitted to the network (step S6), the flag for receiving new time data is reset (step S7), and the process exits from the interrupt process (step S8).

As described above, in the first embodiment of the present invention, the GPS satellite 11 is equipped with an atomic clock, and the transmitted time signal has extremely high accuracy. The time data 36 and the one-second pulse 35 also have high accuracy.

The common control unit 22, unlike a general-purpose OS generally used in a personal computer or the like, runs an application program on an OS having excellent real-time properties, and delays processing by driver software and the like. Absent.

Further, the time data 36 received from the GPS module 11 is output to the network 14 via the LAN control unit 34 at high speed by an interrupt process using a pulse 35 synchronized with the first second of UTC. When outputting to the network 14, time data is sent to a plurality of terminals collectively using the UDP / IP protocol.

For this reason, the time data transmitted to the network 14 also has high accuracy. As a result, the times of the terminal devices 15-1 to 15-n are synchronized with the current time with high accuracy.

The GPS module 21 currently has three to three
Ultra-small ones measuring 4 cm square are commercially available and can be generally purchased, and the common control unit 22 and the LAN control unit 23 can be similarly miniaturized. These can be mounted on the same board, and can be integrated into one board like the GPS receiver control board 31. Therefore, the time data is received from the GPS receiver 61 as in the related art, and
The size and weight of the device can be reduced as compared with a case where a dedicated computer 62 for outputting to a computer is installed.

In the above description, the GPS receiver 13
Although time data is sent to the network 14 every second,
Terminal devices 15-1 to 15-n connected to the network 14
May receive the time data once an hour or about once a day, depending on the performance of the built-in clock device, and may not perform the reception processing at other times. . Alternatively, on the GPS receiver 13 side, the transmission interval of the time data may be set to such an extent that the time accuracy can be sufficiently maintained in consideration of the performance of the clock device of the entire system.

Next, a second embodiment of the present invention will be described.

The basic configuration of the second embodiment is the same as that of the first embodiment. However, the second embodiment is different from the first embodiment in that the second embodiment is different from the first embodiment in that a radio wave obstruction of a GPS satellite radio wave or the like causes a problem. The point is that a countermeasure is taken in the GPS receiver when the time signal cannot be received from the GPS satellite.

FIG. 5 is a block diagram of a second embodiment of the present invention, in which the same parts as those in the first embodiment of FIG. 2 are denoted by the same reference numerals.

In this embodiment, the GPS module 21
Is in a state where the GPS time signal cannot be received due to radio wave obstruction of the GPS satellites 11 or the like. In this case, G
The PS module 21 cannot transmit the one-second pulse 35 and the time data 36 to the common control unit 22 as well.

In the second embodiment, a clock IC 22 d is provided in the common control unit 22 in order to enable the GPS receiver 13 to transmit highly accurate time information to the network 14 even in this state.

The operation of the second embodiment will be described below.

While the time signal is normally transmitted from the GPS satellite 11, in the second embodiment,
As in the first embodiment, the common control unit 22 sends out the received time data 36 to the network 14 by a one-second pulse 35 in an interrupt process.

However, in the second embodiment, FIG.
In transmitting the time data 36 of the RAM 22c to the network 14 in the process of step S6 of FIG.
The time data 36 is also written in 22d.

As a result, the clock IC 22d, which is a clock device in the GPS receiver 13, operates in a state synchronized with the current time with high accuracy.

On the other hand, if the time data 36 or the one-second pulse 35 cannot be received from the GPS module 21 for a certain period of time or more, the common control unit 22 determines that the reception of the time signal from the GPS satellite 11 is abnormal, and thereafter, the network 14
The time data 36 is sent to the clock IC 22 in its own device.
The data of d is used as a reference time.

Normally, the least significant digit of the clock IC 22d is 1 second, and sending time data read from the clock IC 22d at an appropriate time to the network 14 causes an error of 1 second at the maximum.

Incidentally, a clock IC 22d capable of generating an interval timer can be used, and the interruption interval of the interval timer is 1
Seconds, 10 seconds, and 60 seconds.

Thus, by connecting the interval timer of the clock IC 22d to the hardware interrupt terminal of the CPU 22a, the CPU 22a receives the time data from the clock IC 22d during the interrupt processing by the interval timer of the clock IC, as in the first embodiment. The data can be read and transmitted to the network 14.

The clock IC 22d is originally synchronized with highly accurate time by the time data received from the GPS module 21, and the interval timer generated by the clock IC 22d and the time data read from the clock IC 22d are also highly accurate. . For this reason, the time data sent to the network 14 also has high accuracy.

According to the second embodiment, it is impossible to always output highly accurate time data to the network 14 as compared with a case where a time signal is always received from a GPS satellite. However, if it is about one day, sufficiently high-precision time data can be output to the network until the radio interference is restored.

As described above, in the second embodiment, in addition to the effects of the first embodiment, even when a time signal cannot be received from the GPS satellite 11 due to radio wave interference or the like, high accuracy can be obtained within a certain time. There is an effect that time data can be transmitted.

It should be noted that the present invention is not limited to the above embodiments, but can be appropriately modified within the scope of the technical idea of the present invention.

For example, in each of the above embodiments, the GP
Although the case has been described where the S receiver is independently incorporated in the network, a terminal device having a built-in GPS receiver may be configured to realize the same function.

Further, as the GPS module or the LAN control unit, a commercially available GPS module or LAN control unit can be used.

Further, in the above description, the UDP / IP protocol is used as the communication protocol.
Another communication protocol may be used as long as it is a high-speed communication protocol such as a connectionless type.

[0094]

As described above, according to the present invention,
Based on an extremely accurate time signal transmitted from a GPS satellite, time data can be transmitted to a network at a high speed in a state where it can be simultaneously received by a plurality of terminal devices connected to the network.

Further, since a dedicated computer for time synchronization is not required, the system configuration becomes easy, and the time synchronization device can be miniaturized and reduced in weight, and can be accurately connected between a plurality of devices on a network. Time synchronization can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a control system according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a GPS receiver of the control system of FIG. 1;

FIG. 3 is a timing chart for explaining a GPS receiver of the control system of FIG. 1;

FIG. 4 is an operation flowchart of a GPS receiver of the control system of FIG. 1;

FIG. 5 is a diagram illustrating a schematic configuration of GPS reception according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an example of a conventional control system.

[Explanation of symbols]

 Reference Signs List 10 network system 11 GPS satellite 12 antenna 13 GPS receiver 14 network 15 terminal device 21 GPS module 22 common control unit 22a CPU 22b ROM 22c RAM 22d clock IC 23 LAN control unit 31 GPS receiver control board 35 1 second pulse 36 time data

Claims (9)

[Claims] 1. A time synchronization device for performing time synchronization between a plurality of devices connected via a network, wherein a time signal corresponding to a second pulse and time data synchronized with a predetermined reference time is received from a GPS satellite. A time signal receiving unit that generates and outputs the second pulse and time data; and the plurality of devices simultaneously receive the time data at a timing synchronized with the second pulse via the network using a predetermined protocol. A time data transmitting unit for transmitting the data in a possible state. 2. The method according to claim 1, wherein the predetermined reference time is UTC,
2. The time synchronization device according to claim 1, wherein the second pulse is synchronized with the first second of the UTC. 3. The time synchronization apparatus according to claim 1, wherein the predetermined protocol is a connectionless type protocol. 4. The connectionless protocol according to claim 1,
The time synchronization device according to claim 3, wherein the time synchronization device is a UDP / IP protocol. 5. A time-measuring unit that performs a time-measuring operation in synchronization with the reference time and generates an internal second pulse and internal time data. 2. The time synchronization device according to claim 1, wherein, when a time signal cannot be received, the internal second pulse is used instead of the second pulse, and the internal time data is transmitted instead of the time data. 6. A plurality of devices connected via a network, a second pulse synchronized with a predetermined reference time and a time signal corresponding to time data are received from a GPS satellite, and at a timing synchronized with the second pulse, A time synchronization system comprising: a time synchronization device that transmits time data in a state where the plurality of devices can simultaneously receive the time data via the network using a predetermined protocol. 7. The time synchronization system according to claim 6, wherein the predetermined protocol is a connectionless type protocol. 8. A method for controlling a time synchronization device for performing time synchronization between a plurality of devices connected via a network, wherein a time signal corresponding to a second pulse and time data synchronized with a predetermined reference time is detected by a GPS. A time signal receiving step of receiving from a satellite, generating and outputting the second pulse and time data, and the plurality of devices through the network using a predetermined protocol at a timing synchronized with the second pulse using the time data. A time data transmitting step of transmitting the time data in a state in which the time data can be received at the same time. 9. The predetermined reference time is UTC,
9. The time synchronization device according to claim 8, wherein the second pulse is synchronized with the first second of the UTC, and the time data transmission step transmits the time data by an interruption process by the second pulse. .