JP2007178363A - Clocking system, time service providing device and time service providing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent output of wrong time information from a clocking system. <P>SOLUTION: An atomic clock checking part 12 determines whether the frequency of a pulse generated from an atomic clock 2 is normal or not by using an internal clock generated from an internal timepiece 11 and a pulse generated from an atomic clock 3. A timepiece selection part 13 selects the atomic clock 3 when the atomic clock 2 is determined to be abnormal based on a determination result by the atomic clock checking part 12, and imparts the pulse generated from the atomic clock 3 to a clocking part 14. A label selection part 15 selects either of each time information imparted from GPS time servers 4, 5, and imparts the selected time information to the clocking part. The clocking part 14 counts the number of pulses imparted from the timepiece selection part 13, and takes the time information selected by the label selection part 15 when reaching a prescribed value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a timing system, a time service providing apparatus, and a time service providing system.

Japanese Patent Application Laid-Open Publication No. 2004-228561 discloses time calibration means for performing time calibration on a time stamp server or an application server that performs time audit.
JP 2003-242278 A

  The time calibrating means of Patent Document 1 includes a cesium atomic clock as a time source and a time distribution server, provides time information to a time stamp server or an application server, and measures the time measured by the time stamp server or the application server. I calibrate regularly.

  In the time stamp server and application server of Patent Document 1 described above, the time stamp is calibrated by the time information measured by the time calibrating means. However, when the cesium atomic clock of the time calibrating means outputs an abnormal time, the time stamp server And the time information of the application server will be crazy.

  The present invention has been made in view of such a situation, and it is an object of the present invention to prevent erroneous time information from being provided to lower-level devices such as a time stamp server and an application server.

In order to achieve the above objective, a timing system according to the first aspect of the present invention provides:
A determination means for determining whether or not the frequency of a pulse generated by each of the plurality of atomic clocks is normal;
A timepiece selection means for selecting an atomic clock having a normal frequency of the generated pulse among the plurality of atomic clocks based on a determination result of the determination means;
Counting means for counting pulses applied from the atomic clock selected by the clock selection means;
Time information acquisition means for acquiring time information from an information source;
Means for updating the obtained time information in synchronization with the counting means counting pulses and measuring the time, and outputting the current time;
It is characterized by providing.

One of the plurality of atomic clocks is a master atomic clock that is preferentially selected by the clock selection means when the frequency of a pulse generated by itself is normal,
In addition, when the frequency of the pulse generated by itself is normal and the frequency of the pulse generated by the master atomic clock is abnormal, a backup atomic clock selected by the clock selecting means may be used.

  In addition, when the determination unit determines that all the frequencies of pulses generated by the plurality of atomic clocks are abnormal, an atomic clock abnormality warning unit that outputs information indicating abnormality may be provided.

It also has an internal clock with an oscillator that generates periodic clock pulses,
The determination means may determine whether or not the frequency of the pulses generated by the plurality of atomic clocks is normal based on the frequency of the clock pulse generated by the oscillator.

  In this case, the determination means determines the determination based on the frequency of the clock pulse generated by the oscillator and the frequency of the pulse generated by an atomic clock different from the determination target atomic clock among the plurality of atomic clocks. It may be determined whether the frequency of the pulse generated by the target atomic clock is normal.

Further, the internal clock has means for creating internal time information by measuring time synchronized with the clock pulse,
further,
Time information determination means for determining whether or not the time information acquired from the information generation source is normal by comparing the internal time information created by the internal clock with the time information acquired from the information generation source,
When the time information determination unit determines that the time information acquired from the information generation source is not normal, the time information may be acquired from another information generation source different from the information generation source thereafter.

In order to achieve the above object, a time service providing apparatus according to a second aspect of the present invention includes a timekeeping system according to the first aspect of the present invention,
Service providing means for providing a service based on the time information output by the timing system to a lower-level device;
It is characterized by providing.

  In this case, the service providing means may audit the time counted by the lower-level device based on the time information output by the timing system.

In order to achieve the above object, a time service providing system according to a third aspect of the present invention includes a plurality of time service providing apparatuses according to the second aspect of the present invention,
A plurality of atomic clocks shared by the respective time service providing devices and applying periodic pulses to the determination means and the time selection means of the respective time service providing devices;
An information generation source that is shared by the time service providing devices and gives the time information to the time service providing devices,
The plurality of time service providing devices, as a pair with other time service providing devices, each of the atomic clocks serving as a master atomic clock preferentially selected by the counterpart clock selecting means, A backup atomic clock selected by the clock selection means when the frequency of a pulse generated by the clock is abnormal is used, and the other backup atomic clock is used as the master atomic clock.

  According to the present invention, it is possible to reduce the risk of giving wrong time information to a lower-level device or providing a service based on the wrong time information.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a configuration diagram showing a time service providing system according to the first embodiment of the present invention.

  This time service providing system includes a time inspection device 1 which is a time service providing device, for example, two atomic clocks 2 and 3 and, for example, two GPS time servers 4 and 5.

  Each of the atomic clocks 2 and 3 is made of cesium or rubidium, generates a periodic pulse, and gives it to the time audit device 1. As the periodic pulse, a 1-second period pulse called a 1PPS signal is used. Each GPS time server 4, 5 is constituted by a receiver or the like, receives time information on Coordinated Universal Time from GPS (Global Positioning System), and gives it to the time audit device 1.

The time auditing apparatus 1 incorporates a timekeeping system 10 that counts time and includes a time auditing unit 20. The time audit system 1 uses the time audit unit 20 to audit time information with respect to a time stamp server (TSS) 30 of a lower-level device connected via the network N. An NTP (Network Time Protocol) server 40 that provides time information is also connected to the network N.
The time audit unit 20 and the measurement system 10 may be housed in a common housing, or may be housed in individual housings.

  The timekeeping system 10 is a system that measures time as a reference for time auditing, and includes an internal clock 11 incorporating a crystal oscillator, an atomic clock check unit 12, a clock selection unit 13, a time measurement unit 14, and a label selection. A unit 15 and a label check unit 16 are provided. The atomic clock check unit 12, clock selection unit 13, timing unit 14, label selection unit 15, and label check unit 16 may be configured by individual circuits, but may be configured by the CPU together with the time audit unit 20. Good.

  The internal clock 11 has a built-in crystal oscillator and outputs a clock pulse synchronized with the oscillation frequency of the crystal oscillator. That is, an internal clock is output. The internal clock 11 measures time in synchronization with the internal clock, and generates and outputs time information. The output side of the internal clock 11 is connected to the atomic clock check unit 12 and the label check unit 16.

  The atomic clock check unit 12 is a determination unit that determines whether or not the frequency of pulses generated by the atomic clocks 2 and 3 is normal. The internal clock is input from the internal clock 11, and the determination result is input to the clock selection unit 13. And the time auditing unit 20.

  The clock selection unit 13 is means for selecting a pulse supplied from the atomic clock 2 or the atomic clock 3 and supplying the pulse to the clock unit 14, and an output side of the clock selector 13 is connected to the clock unit 14.

  The timekeeping unit 14 includes a counter and a memory (not shown), measures the time by using these, and holds and outputs the latest time information. The output side of the timer unit 14 is connected to the time audit unit 20 and to the label check unit 16.

  The label selection unit 15 is a time information acquisition unit, selects time information given from the GPS time server 4 or the GPS time server 5, and gives it to the time measuring unit 14.

  The label check unit 16 is time information determination means for determining whether or not the time information provided from the GPS time server 4 or the GPS time server 5 is normal. The label check unit 16 is held in the time measuring unit 14. Current time information and time information generated by the internal clock 11 are input. The output side of the label check unit 16 is connected to the label selection unit 15 and the time audit unit 20. The label check unit 16 may be connected to the GPS time server 4 and the GPS time server 5 so as to input time information from the GPS time server 4 and the GPS time server 5.

Next, the operation of the time service providing system in FIG. 1 will be described.
First, the operation of the timing system 10 will be described with reference to FIGS.
2 and 3 are flowcharts showing the timing operation.

  The atomic clocks 2 and 3 generate periodic pulses. The clock selection unit 13 uses the atomic clock 2 as a master (master atomic clock) and the atomic clock 3 as a backup (backup atomic clock). At the first stage where both the atomic clocks 2 and 3 are considered to be normal, the atomic clock 2 And the pulse output from the selected atomic clock 2 is supplied to the timer unit 14.

  The GPS time servers 4 and 5 sequentially receive time information from the GPS and give the time information to the label selection unit 15. For example, the label selection unit 15 uses the GPS time server 4 as a master, the GPS time server 5 as a backup, and selects both the GPS time servers 4 and 5 at the initial stage where the GPS time servers 4 and 5 are considered to be normal. The time information given from the selected GPS time server 4 is given to the timer unit 14. The time information is information indicating year, month, day, hour, minute, and second.

  The time measuring unit 14 measures time in the circulation loop of Step S1 to Step S3. In other words, the time measuring unit 14 stores the time information given from the label selecting unit 15 in step S1 in the memory as a reference value, and resets the counter. After the time information is stored in step S1, the timer 14 updates the master atomic clock pulse given from the clock selector 13 every time it is counted using a counter, and measures the time. (Step S2).

  When the counted number of pulses reaches a predetermined value (step S3: YES), the time measuring unit 14 stores the time information given from the label selecting unit 15 at that time in the memory, and takes in the time information. (Step S1).

  On the other hand, the internal clock 11 also generates an internal clock synchronized with the oscillation frequency of the built-in crystal oscillator, measures the time synchronized with the internal clock, and outputs time information. The internal clock generated by the internal clock 11 is given to the atomic clock check unit 12. The time information output from the internal clock 11 is given to the label check unit 16.

The atomic clock check unit 12 is provided with an atomic clock check timing for periodically checking whether or not the frequency of pulses given from the atomic clocks 2 and 3 is normal.
At the atomic clock check timing, the atomic clock check unit 12 compares the frequency of the pulse generated by the atomic clock 2 with the frequency of the internal clock, and further generates the frequency of the pulse generated by the atomic clock 2 and the atomic clock 3. The frequency of the pulse is compared, and from these comparison results, it is determined whether or not the frequency of the pulse generated by the atomic clock 2 is normal. Similarly, the atomic clock check unit 12 compares the frequency of the pulse generated by the atomic clock 3 with the frequency of the internal clock, and further, the frequency of the pulse generated by the atomic clock 3 and the frequency of the pulse generated by the atomic clock 2. From these comparison results, it is determined whether or not the frequency of the pulse generated by the atomic clock 3 is normal.

  At the timing when the pulse counted by the time measuring unit 14 does not reach the predetermined value (step S3: NO), when the atomic clock check timing comes (step S4), the atomic clock check unit 12 turns the atomic clock 2 into the clock selection unit. If it is selected in step 13 (step S5: YES), it is determined whether or not the frequency of the pulse generated by the atomic clock 2 is normal (step S6).

  If the frequency of the pulse generated by the atomic clock 2 is not normal (step S6: NO), it is determined whether or not the frequency of the pulse generated by the atomic clock 3 is normal (step S7). When the frequency of the pulse generated by the atomic clock 3 is normal (step S7: YES), the atomic clock check unit 12 instructs the clock selection unit 13 to select the atomic clock 3. That is, the selection switching of the atomic clocks 2 and 3 is performed (step S8).

  When the frequency of the pulse generated by the atomic clock 3 is not normal (step S7: NO), the timekeeping unit 14 is not reliable, so information indicating abnormality is given to the time auditing unit 20 to stop providing the service. (Step S9a). At this time, a warning may be issued to the administrator.

  On the other hand, when the atomic clock 3 is selected by the clock selection unit 13 in step S5 (step S5: NO), it is determined whether the frequency of the pulse generated by the atomic clock 3 is normal. In this case, since the frequency of the pulse generated by the atomic clock 2 is not normal, whether the pulse generated by the atomic clock 3 is normal is determined by comparing the frequency of the pulse generated by the atomic clock 3 with the internal clock. Judge with. When the atomic clock check unit 12 determines that the frequency of the pulse generated by the atomic clock 3 is not normal (step S11: NO), the timekeeping unit 14 is not reliable, so information indicating abnormality is displayed as a time audit unit. 20 to stop providing the service (step S9b). At this time, a warning may be issued to the administrator.

  The atomic clock check unit 12 has an atomic clock check timing in order to make a determination on the pulses generated by the atomic clocks 2 and 3, whereas the label check unit 16 makes a determination on the time information output from the time measuring unit 14. Has time information check timing.

  If it is not the check timing of the atomic clock (step S4: NO) and it is determined in step S6 that the frequency of the pulse generated by the atomic clock 2 is normal (step S6: YES), the generation of the atomic clock 3 is performed in step S11. When it is determined that the frequency of the pulse to be transmitted is normal (step S11: YES), or when the time information check timing comes after the selection by the clock selection unit 15 is switched in step S8 (step S12 in FIG. 3). YES), the label check unit 16 compares the time information generated by the internal clock 11 with the time information stored in the memory of the time measuring unit 14 at that time, and the difference between the two time information is larger than the previous comparison. It is detected whether it is doing.

  Here, when the increase in the difference between both time information exceeds a predetermined value (step S13: YES), the label check unit 16 confirms whether or not the label selection unit 15 has selected the GPS time server 4. When the label selection unit 15 has selected the GPS time server 4 (step S14: YES), the label selection unit 15 is instructed to select the GPS time server 5 (step S15). That is, selection switching is performed. When the label selection unit 15 selects the GPS time server 5 (step S14: NO), it is considered that the time information given from both the GPS time servers 4 and 5 is abnormal. The auditing unit 20 is given to stop providing the service (step S9c).

  When the time information check timing is not reached (step S12: NO), when the increase in the time information difference is equal to or less than a predetermined value (step S13: NO), and when the GPS time server selection is switched (step S15). After that, the process proceeds to step S2, and the time measurement is continued.

  In response to a request from the time stamp server (TSS) 30 of the client connected via the network N, the time auditing unit 20 is stored in the memory of the time measuring unit 14 for the timing system 10 that performs the above operation. The time information is read out, compared with the time counted by the time stamp server 30, and the difference is obtained and transmitted to the time stamp server 30. When the client is an NTP (Network Time Protocol) server 40, the time audit unit 20 sequentially transmits time information updated and held by the time measuring unit 14.

As described above, the time auditing apparatus 1 according to the present embodiment includes the timekeeping system 10 and performs time auditing based on the time information output from the timekeeping system 10.
Here, the timekeeping system 10 includes two atomic clocks, atomic clocks 2 and 3, and can switch to the atomic clock 3 even when an abnormality occurs in the atomic clock 2, for example, and the time information is accurately updated. be able to. Also, regarding the GPS time servers 4 and 5 as information sources of time information, since the GPS time server 4 and the GPS time server 5 are selected by switching, accurate time information can be held in the time measuring unit 14.

[Second Embodiment]
FIG. 4 is a block diagram showing a time service providing system according to the second embodiment of the present invention.

  In the first embodiment described above, the time service providing system in the case where there is one time auditing device 1 is shown, but in this embodiment, a time service providing system including a plurality of time auditing devices is shown.

The time service providing system shown in FIG. 4 includes two atomic clocks 2 and 3, two GPS time servers 4 and 5, and two time inspection devices 6 and 7.
The two time inspection devices 6 and 7 share the atomic clocks 2 and 3 and the GPS time servers 4 and 5. Each of the time audit devices 6 and 7 has the same configuration as that of the time audit device 1 of the first embodiment, but the time audit devices 6 and 7 update the time information being timed by the timekeeping units 10 of each other. It has a function of aligning the timing with the timing of fetching time information from the GPS time servers 4 and 5 that are information sources. For example, the time audit devices 6 and 7 can add one of the atomic clocks to the other time audit devices 7 and 6 or synchronize the internal clocks used by the time audit devices 6 and 7. This can be realized by adding one of the GPS time servers 4 and 5 which are information sources of time information to the other time inspection devices 7 and 6. In particular, the time auditing devices 6 and 7 use the other master atomic clock as its own backup atomic clock and the other backup atomic clock as its own master atomic clock. For this reason, even if an abnormality occurs in the pulse cycle of one master atomic clock of the time auditing devices 6 and 7, the other of the time auditing devices 6 and 7 keeps the time with the pulse cycle of the normal master atomic clock. Can always provide time information with atomic clock accuracy. For example, when an abnormality occurs in the pulse period of one of the master atomic clocks of the time audit devices 6 and 7, if the client is notified of one of the time audit devices 6 and 7, the client is notified of the time audit device 6. 7 without waiting for the time required for switching between the master atomic clock and the backup atomic clock as described above, that is, without waiting for the generation of a pulse from the atomic clock newly switched to the master atomic clock, It becomes possible to request a service from the other of the time audit devices 6 and 7.

  As described above, in the time service providing system having the two time inspection devices 6 and 7, even if an abnormality occurs in one of the atomic clocks 2 and 3 as in the first embodiment, Even when an abnormality occurs in one of the time servers 4 and 5, an accurate time can be measured. In addition, by sharing the timing for updating the time information to be measured and the timing for updating the time information in the time audit devices 6 and 7, the same service can be provided to the client.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.
For example, the number of atomic clocks 2 and 3 may be three or more, and a normal atomic clock may be selected therefrom.

  Alternatively, three or more GPS time servers 4 and 5 as information sources of time information may be provided, and time information may be input from a GPS time server selected from them.

  Further, the GPS time servers 4 and 5 may not be provided, and the time information given from the external NTP device 40 may be stored in the memory of the timer unit 14.

It is a block diagram which shows the time service provision system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows a time measuring operation | movement. It is a flowchart which shows a time measuring operation | movement. It is a block diagram which shows the time service provision system which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,6,7 Time inspection apparatus 2,3 Atomic clock 4,5 GPS time server 10 Timekeeping system 11 Internal clock 12 Atomic clock check part 13 Clock selection part 14 Time measurement part 15 Label selection part 16 Label check part 20 Time inspection part 30 Time stamp server 40 NTP server

Claims (9)

A determination means for determining whether or not the frequency of a pulse generated by each of the plurality of atomic clocks is normal;
A timepiece selection means for selecting an atomic clock having a normal frequency of the generated pulse among the plurality of atomic clocks based on a determination result of the determination means;
Counting means for counting pulses applied from the atomic clock selected by the clock selection means;
Time information acquisition means for acquiring time information from an information source;
Means for updating the obtained time information in synchronization with the counting means counting pulses and measuring the time, and outputting the current time;
A timekeeping system comprising: One of the plurality of atomic clocks is a master atomic clock that is preferentially selected by the clock selection means when the frequency of a pulse generated by itself is normal,
The other is a backup atomic clock selected by the clock selection means when the frequency of the pulse generated by itself is normal and the frequency of the pulse generated by the master atomic clock is abnormal.
The timekeeping system according to claim 1.   3. An atomic clock abnormality warning unit that outputs information indicating abnormality when the determination unit determines that all of the frequencies of pulses generated by the plurality of atomic clocks are abnormal. Timekeeping system described in Comprising an internal clock having an oscillator for generating periodic clock pulses;
4. The determination unit according to claim 1, wherein the determination unit determines whether or not the frequency of the pulses generated by the plurality of atomic clocks is normal based on the frequency of the clock pulse generated by the oscillator. The timekeeping system according to item 1.   The determination means is configured to determine the determination target atom based on the frequency of the clock pulse generated by the oscillator and the frequency of the pulse generated by an atomic clock different from the determination target atomic clock among the plurality of atomic clocks. 5. The time measuring system according to claim 4, wherein it is determined whether or not a frequency of a pulse generated by the timepiece is normal. The internal clock has means for creating internal time information by measuring time synchronized with the clock pulse,
further,
Time information determination means for determining whether the time information acquired from the information generation source is normal by comparing the internal time information created by the internal clock with the time information acquired from the information generation source,
When the time information determination means determines that the time information acquired from the information generation source is not normal, the time information is acquired from another information generation source different from the information generation source thereafter. The timekeeping system according to claim 4 or 5. A timekeeping system according to any one of claims 1 to 6,
Service providing means for providing a service based on the time information output by the timing system to a lower-level device;
A time service providing apparatus comprising:   8. The time service providing apparatus according to claim 7, wherein the service providing unit audits a time measured by the lower-order apparatus based on time information output from the time measuring system. A plurality of time service providing devices according to claim 7 or 8,
A plurality of atomic clocks that are shared by the time service providing devices and that apply periodic pulses to the determination means and time selection means of the time service providing devices;
An information generation source that is shared by the time service providing devices and gives the time information to the time service providing devices,
The plurality of time service providing devices, as a pair with another time service providing device, each of the atomic clocks serving as a master atomic clock that is preferentially selected by the other clock selection means, Providing a time service characterized in that when the frequency of a pulse generated by a clock is abnormal, the backup atomic clock is selected by the clock selecting means of the clock, and the backup atomic clock of the counterpart is the master atomic clock of the clock. system.

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