WO2022244154A1 - 測定器、測定方法および時刻同期システム - Google Patents
測定器、測定方法および時刻同期システム Download PDFInfo
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- 230000005540 biological transmission Effects 0.000 claims abstract description 159
- 238000004364 calculation method Methods 0.000 claims abstract description 134
- 238000012545 processing Methods 0.000 claims abstract description 134
- 238000000034 method Methods 0.000 claims description 26
- 230000004044 response Effects 0.000 claims description 8
- 230000006870 function Effects 0.000 description 29
- 238000005259 measurement Methods 0.000 description 22
- 238000010586 diagram Methods 0.000 description 11
- 230000001360 synchronised effect Effects 0.000 description 6
- 238000004891 communication Methods 0.000 description 5
- 238000009434 installation Methods 0.000 description 5
- 238000012423 maintenance Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- ADTDNFFHPRZSOT-PVFUSPOPSA-N ram-330 Chemical compound C([C@H]1N(CC2)C)C3=CC=C(OC)C(OC)=C3[C@]32[C@@]1(O)CC[C@@H](OC(=O)OCC)C3 ADTDNFFHPRZSOT-PVFUSPOPSA-N 0.000 description 2
- 108700009949 PTP protocol Proteins 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
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- 238000006467 substitution reaction Methods 0.000 description 1
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- G04—HOROLOGY
- G04G—ELECTRONIC TIME-PIECES
- G04G5/00—Setting, i.e. correcting or changing, the time-indication
Definitions
- the present disclosure relates to measuring instruments, measuring methods, and time synchronization systems.
- the PTP Precision Time Protocol
- the IEEE-1588 standard is a protocol that synchronizes the time (device time) of computers on a LAN (Local Area Network) with high accuracy (see Non-Patent Document 1).
- FIG. 10 is a diagram showing a configuration example of a conventional time synchronization system 1a that synchronizes the times of devices on a network using the PTP protocol.
- the time synchronization system 1a shown in FIG. 10 includes a Grand Master Clock 100, a client device 200, and a measuring device 300.
- Grand Master Clock 100 and client device 200 can communicate via a network 2 such as a LAN.
- the Grand Master Clock 100 includes a GNSS antenna that receives signals (GNSS signals) from satellites of a global navigation satellite system (GNSS) such as GPS (Global Positioning System).
- GNSS global navigation satellite system
- the Grand Master Clock 100 receives GNSS signals via a GNSS antenna and obtains Universal Time Coordinated (UTC) from the received GNSS signals.
- UTC Universal Time Coordinated
- the Grand Master Clock 100 has a master function that distributes the acquired UTC as a reference time via the network 2 .
- the client device 200 has a slave function that synchronizes the internal time of the device with the time delivered from the device with the master function.
- the Grand Master Clock 100 is a device having a master function
- the client device 200 synchronizes the device internal time with the time delivered from the Grand Master Clock 100.
- FIG. The client device 200 is, for example, a base station device in a mobile phone network.
- FIG. 1 As a measurement method for measuring the accuracy of the internal time of the client device 200, as shown in FIG. There is a method of comparing the signal quality of a timing reference signal such as a 1PPS (Pulse Per Second) signal output by the device 200 and the time delivered by GNSS (see, for example, Non-Patent Document 2).
- the 1PPS signal is a signal that outputs one pulse per second.
- the 1PPS signal is input from the client device 200 to the measuring device 300 by connecting the client device 200 and the measuring device 300 with a coaxial cable, for example. Therefore, the client device 200 and the measuring device 300 need to be installed within a range where they can be connected by a coaxial cable, for example, within the same building.
- IEEE Std 1588TM-2019 “IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems”
- ITU-T G.8273/Y.1368 “Framework of phase and time clocks”
- the conventional measurement method explained with reference to FIG. There is a constraint that the instrument 300 must be transported to the measurement site and the measurement performed before it is out of sync. Therefore, the conventional measurement method has the problem that prior preparation of the environment and a large amount of human labor are required in order to measure the accuracy of the time in the device. In addition, there is a problem that the measurement may be difficult due to the restriction that a GNSS antenna is required or the restriction that measurement must be performed before the measuring device 300 is out of synchronization.
- the object of the present disclosure which has been made in view of the above problems, is to relax the above-mentioned restrictions and to more easily measure the accuracy of the time in the device, the measurement method, and the time synchronization system. is to provide
- the measuring instrument synchronizes the device internal time with a reference time, and transmits and receives a packet to and from a first device that distributes the device internal time, thereby synchronizing the device internal time with the first device time.
- a measuring device for measuring the accuracy of the internal time of the second device with respect to the reference time in the second device synchronized with the device of , a second acquisition unit for acquiring time information related to the device internal time of the first device; based on the reference time acquired by the first acquisition unit and the time information acquired by the second acquisition unit; , a first calculation processing unit that calculates a first offset, which is a difference between the reference time and an internal time of the first device, and transmission and reception between the first device and the second device and obtains a copy of the packet to be sent, and based on the obtained packet and the transmission delay between the first device and the second device, the internal device time of the first device and the second device a second calculation processing unit that calculates a second offset that is the difference between the internal time of the device and the second device relative to the reference time based on the first offset and the second offset and a third calculation processing unit that measures the accuracy of the internal time of the device.
- the measurement method synchronizes the device internal time with a reference time, transmits and receives packets to and from a first device that distributes the device internal time, and synchronizes the device internal time with the reference time.
- calculating a first offset obtaining a copy of the packet sent and received between the first device and the second device; calculating a second offset, which is the difference between the internal device time of the first device and the internal device time of the second device, based on the transmission delay between the first device and the second device; measuring the accuracy of the internal time of the second device with respect to the reference time based on the offset of and the second offset.
- the time synchronization system synchronizes the device internal time with a reference time, and transmits packets between a first device that distributes the device internal time and the first device.
- a second device that synchronizes the internal time of the device with the first device by transmission and reception;
- a measuring device that measures the accuracy of the internal time of the second device with respect to the reference time in the second device; wherein the measuring device includes a first acquisition unit that acquires the reference time from a satellite signal, and a second acquisition unit that acquires time information related to the internal device time of the first device and, based on the reference time acquired by the first acquisition unit and the time information acquired by the second acquisition unit, a first and a copy of the packet transmitted and received between the first device and the second device, the obtained packet and the first device calculating a second offset, which is the difference between the internal device time of the first device and the internal device time of the second device, based on the transmission delay between the device and the second device a calculation processing unit;
- the measuring instrument measuring method, and time synchronization system according to the present disclosure, it is possible to more easily measure the accuracy of the device internal time.
- FIG. 4 is a diagram for explaining an outline of the operation of the measuring device according to the present disclosure
- FIG. 1 is a diagram illustrating a configuration example of a time synchronization system according to an embodiment of the present disclosure
- FIG. 3 is a flow chart showing an example of the operation of the measuring instrument shown in FIG. 2
- 3 is a diagram for explaining calculation of a second offset by the BC-client offset calculation processing unit shown in FIG. 2
- FIG. 3 is a diagram for explaining transmission delay calculation by a transmission delay calculation processing unit shown in FIG. 2
- FIG. It is a figure showing the example of composition of the time synchronous system concerning another one embodiment of this indication.
- FIG. 11 is a diagram showing a configuration example of a time synchronization system according to yet another embodiment of the present disclosure
- FIG. 11 is a diagram showing a configuration example of a time synchronization system according to yet another embodiment of the present disclosure
- FIG. 11 is a diagram showing a configuration example of a time synchronization system according to yet another embodiment of the
- FIG. 8 is a diagram for explaining calculation of a second offset by the BC-client offset calculation processing unit shown in FIG. 7; It is a figure which shows an example of the hardware configuration of the measuring device which concerns on this indication. It is a figure which shows the structural example of the conventional time synchronous system.
- the measuring instrument 30 synchronizes the internal time of the device with the first device 3 by transmitting and receiving PTP packets to and from the first device 3.
- This is a device that measures the accuracy of internal time.
- the first device 3 is a device having a master function of synchronizing the internal time with a reference time (UTC or time distributed from another device) and distributing the internal time.
- the other device is a device provided above the first device 3 and having a master function.
- the second device 4 is a device having a slave function for synchronizing the internal time with the time delivered from the first device 3 having a master function.
- the measuring instrument 30 obtains a copy of the PTP packets transmitted and received between the first device 3 and the second device 4 . Therefore, in this embodiment, in order to copy the mutual communication (both upstream and downstream communication) between the first device 3 and the second device 4, the first device 3 and the second device 4 A copy point is provided between and to copy the PTP packet.
- the measuring device 30 obtains a copy of the PTP packet via that copy point. In the following, the acquisition of a copy of a PTP packet by the meter 30 via a copypoint may simply be referred to as "obtaining a PTP packet.”
- the measuring instrument 30 acquires time information regarding the internal time of the first device 3 .
- the measuring device 30 acquires the GNSS signal from the GNSS antenna and acquires the reference time (UTC) from the acquired GNSS signal.
- the measuring device 30 measures the accuracy of the internal time of the second device 4 with respect to the reference time based on the acquired PTP packet, reference time, and time information.
- the measuring device 30 obtains a copy of the PTP packet, and uses the obtained PTP packet to measure the accuracy of the internal time of the second device 4 with respect to the reference time. It becomes unnecessary to carry the device 4 of 2 to the installation place. In addition, it is possible to alleviate restrictions such as the installation location of the GNSS antenna and bringing in the measuring instrument 300 synchronized with the reference time, as in the conventional time synchronization system 1a. Therefore, according to the measuring instrument 30 according to the present disclosure, it is possible to more easily measure the accuracy of the internal time. In addition, according to the measuring instrument 30 according to the present disclosure, it is possible to remotely measure the accuracy of the internal time of the second device 4, so that it is possible to quickly perform maintenance when a time error occurs. can.
- the first device 3 having the master function and the second device 4 having the slave function only need to be able to transmit and receive PTP packets. Therefore, there is no restriction that the first device 3 and the second device 4 are installed in the same building.
- restrictions on the installation positions of the first device 3 and the measuring device 30 differ depending on the method of acquiring the time information.
- the measuring device 30 acquires time information from a 1PPS signal output from the first device 3, which will be described later, it is necessary to connect the first device 3 and the measuring device 30 with a coaxial cable. Therefore, it is necessary to install the first device 3 and the measuring device 30 within a range where the first device 3 and the measuring device 30 can be connected by a coaxial cable, for example, within several tens of meters.
- the measuring device 30 acquires time information from a PTP packet output from the first device 3, which will be described later, the first device 3 and the measuring device 30 need only be able to transmit and receive PTP packets. Therefore, there is no restriction that the first device 3 and the measuring device 30 are installed in the same building.
- the measuring device 30 only needs to be able to copy and acquire the PTP packets transmitted and received between the first device 3 and the second device 4 . Therefore, there is no restriction that the second device 4 and the measuring device 30 are installed in the same building.
- the time synchronization system 1 includes a Boundary Clock 10, a client device 20, and a measuring device 30.
- the Boundary Clock 10 functions as a device with a slave function with respect to a higher-level device with a master function, and functions as a device with a master function with respect to a lower-level device with a slave function.
- the Boundary Clock 10 functions as a device having a slave function to the Grand Master Clock 100 and functions as a device having a master function to the client device 20 . Therefore, the Boundary Clock 10 synchronizes the internal time of the Boundary Clock 10 with the time (reference time) distributed from the Grand Master Clock 100 by sending and receiving PTP packets with the Grand Master Clock 100 .
- the Boundary Clock 10 distributes the internal device time to the client device 20 by sending and receiving PTP packets with the client device 20 .
- the Boundary Clock 10 outputs a pulse signal (1PPS signal) at 1PPS to the measuring device 30 in synchronization with the internal time of the Boundary Clock 10 as time information related to the internal time of the Boundary Clock 10 .
- the Boundary Clock 10 also calculates the packet transmission delay between the client device 20 and outputs the calculation result of the transmission delay to the measuring device 30 .
- the client device 20 synchronizes the internal time of the device with the time delivered from the Boundary Clock 10 by sending and receiving PTP packets to and from the Boundary Clock 10 . Therefore, in the time synchronization system shown in FIG. 2, the Boundary Clock 10 corresponds to the first device 3 having the master function, and the client device 20 corresponds to the second device 4 having the slave function.
- the measuring device 30 measures the accuracy of the device internal time with respect to the reference time in the client device 20 as the second device 4 .
- the measuring device 30 obtains a copy of the PTP packets transmitted and received between the Boundary Clock 10 and the client device 20.
- FIG. Based on the obtained PTP packet, 1PPS signal, and transmission delay between the Boundary Clock 10 and the client device 20, the measuring device 30 measures the accuracy error of the internal time in the client device 20 with respect to the reference time.
- the Boundary Clock 10 includes packet transmitter/receivers 11 and 12, a time synchronization processor 13, a 1PPS transmitter 14, a transmission delay measuring packet transmitter/receiver 15, and a transmission delay calculation processor 16. Prepare.
- the packet transmission/reception unit 11 transmits/receives PTP packets to/from the Grand Master Clock 100 .
- the packet transmission/reception unit 12 transmits/receives PTP packets to/from the client device 20 .
- the time synchronization processing unit 13 acquires the time delivered by the Grand Master Clock 100 from the PTP packets acquired from the Grand Master Clock 100 via the packet transmission/reception unit 11, and synchronizes the internal time of the Boundary Clock 10 with the acquired time.
- the 1PPS transmission section 14 outputs a pulse signal (1PPS signal) to the measuring instrument 30 at 1PPS in synchronization with the device internal time of the Boundary Clock 10 .
- the transmission delay measurement packet transmission/reception unit 15 transmits and receives packets (transmission delay measurement packets) for measuring the transmission delay between the Boundary Clock 10 and the client device 20 with the client device 20 .
- the transmission delay calculation processing unit 16 calculates the transmission delay between the Boundary Clock 10 and the client device 20 from the transmission delay measurement packet transmitted and received by the transmission delay measurement packet transmission/reception unit 15 .
- the transmission delay calculation processing unit 16 outputs the calculation result of the transmission delay to the measuring device 30 .
- the client device 20 includes a packet transmission/reception section 21, a time synchronization processing section 22, a transmission delay measurement packet transmission/reception section 23, and a transmission delay calculation processing section 24.
- the packet transmission/reception unit 21 transmits/receives PTP packets to/from the Boundary Clock 10 .
- the time synchronization processing unit 22 acquires the time delivered by the Boundary Clock 10 from the PTP packets received from the Boundary Clock 10 via the packet transmission/reception unit 21, and synchronizes the internal time of the client device 20 with the acquired time.
- the transmission delay measuring packet transmitting/receiving unit 23 transmits/receives the transmission delay measuring packet to/from the Boundary Clock 10 .
- the transmission delay between the Boundary Clock 10 and the client device 20 is calculated from the transmission delay measurement packet transmitted and received by the transmission delay calculation processing unit 24 and the transmission delay measurement packet transmission/reception unit 23 .
- the measuring device 30 includes a UTC acquisition unit 31, a BC time acquisition unit 32, a UTC-BC offset calculation processing unit 33, a BC-client offset calculation processing unit 34, and a time accuracy calculation processing unit. 35.
- the UTC acquisition unit 31 as a first acquisition unit receives GNSS signals, which are satellite signals transmitted from GNSS satellites, via GNSS antennas.
- the UTC acquisition unit 31 acquires the reference time (UTC) from the received GNSS signal, and synchronizes the internal time of the measuring device 30 with the acquired time.
- the UTC acquisition unit 31 outputs the acquired time to the UTC-BC offset calculation processing unit 33 .
- the BC time acquisition unit 32 as a second acquisition unit acquires time information regarding the internal time of the Boundary Clock 10 .
- the BC time acquisition unit 32 acquires a 1PPS signal, which is a pulse signal output from the Boundary Clock 10 at 1PPS in synchronization with the internal time of the Boundary Clock 10, and obtains the Boundary Clock 10 from the acquired 1PPS signal. Get the time information related to the internal time of the device.
- the BC time acquisition unit 32 outputs the acquired internal time of the Boundary Clock 10 to the UTC-BC offset calculation processing unit 33 .
- the UTC-BC offset calculation processing unit 33 as a first calculation processing unit is based on the reference time (UTC) acquired by the UTC acquisition unit 31 and the internal time of the Boundary Clock 10 acquired by the BC time acquisition unit 32, A first offset, which is the difference between UTC and the internal time of the Boundary Clock 10, is calculated.
- the UTC-BC offset calculation processing section 33 outputs the calculated first offset to the time accuracy calculation processing section 35 .
- the BC-client offset calculation processing unit 34 as a second calculation processing unit obtains a copy of the PTP packet transmitted and received between the Boundary Clock 10 and the client device 20. Based on the obtained PTP packet and the transmission delay between the Boundary Clock 10 and the client device 20, the BC-client offset calculation processing unit 34 calculates the difference between the device internal time of the Boundary Clock 10 and the client device 20. Calculate some second offset. The BC-client offset calculation processing unit 34 outputs the calculated second offset to the time accuracy calculation processing unit 35 .
- the time accuracy calculation processing unit 35 as a third calculation processing unit calculates the first offset calculated by the UTC-BC offset calculation processing unit 33 and the second offset calculated by the BC-client offset calculation processing unit 34. , the accuracy of the device internal time of the client device 20 with respect to the reference time (UTC) is measured.
- the measuring device 30 acquires the PTP packet, and uses the acquired PTP packet to measure the accuracy of the internal time of the client device 20 with respect to the reference time. No need to carry it to a place. In addition, it is possible to alleviate restrictions such as the installation location of the GNSS antenna and bringing in the measuring instrument 300 synchronized with the reference time, as in the conventional time synchronization system 1a. Therefore, according to the measuring instrument 30 according to the present disclosure, it is possible to more easily measure the accuracy of the internal time. In addition, according to the measuring device 30 according to the present disclosure, it is possible to remotely measure the accuracy of the internal time of the client device 20, so maintenance can be quickly performed when a time error occurs.
- the present disclosure is not limited to this.
- the Grand Master Clock 100 with the master function is the first device 3
- the Boundary Clock 10 with the slave function is the second device 4
- the measuring device 30 measures the accuracy of the internal time of the Boundary Clock 10. good.
- FIG. 3 is a flowchart showing an example of the operation of the measuring device 30 according to this embodiment, and is a diagram for explaining the measuring method by the measuring device 30.
- FIG. 3 is a flowchart showing an example of the operation of the measuring device 30 according to this embodiment, and is a diagram for explaining the measuring method by the measuring device 30.
- the UTC acquisition unit 31 acquires the reference time (UTC) from the GNSS signal received from the satellite via the GNSS antenna (step S11).
- the BC time acquisition unit 32 acquires time information regarding the internal time of the Boundary Clock 10 as the first device 3 (step S12). In the time synchronization system 1 shown in FIG. 2 , the BC time acquisition unit 32 acquires time information from the 1PPS signal output from the Boundary Clock 10 .
- the UTC-BC offset calculation processing unit 33 calculates the difference between the reference time (UTC) obtained by the UTC obtaining unit 31 and the time information obtained by the BC time obtaining unit 32, and the internal time of the Boundary Clock 10.
- a first offset is calculated (step S13). In the following it is assumed that the first offset is X seconds.
- the BC-client offset calculation processing unit 34 obtains a copy of the PTP packet transmitted and received between the Boundary Clock 10 and the client device 20. Based on the obtained PTP packet and the transmission delay between the Boundary Clock 10 and the client device 20, the BC-client offset calculation processing unit 34 calculates the difference between the device internal time of the Boundary Clock 10 and the client device 20. A certain second offset is calculated (step S14). In the following it is assumed that the second offset is Y seconds. Details of the calculation of the second offset will be described later.
- step S11 to step S13 and the processing of step S14 are described as branching, but actually these processings are not branched. , are executed sequentially.
- the time accuracy calculation processing unit 35 calculates the client device 20 with respect to the reference time based on the first offset calculated by the UTC-BC offset calculation processing unit 33 and the second offset calculated by the BC-client offset calculation processing unit 34. device time accuracy is measured (step S15). For example, the time accuracy calculation processing unit 35 calculates the difference (offset) between the reference time and the internal time of the client device 20 as the accuracy of the internal time of the client device 20 with respect to the reference time. Specifically, the time accuracy calculation processing unit 35 calculates the difference between the reference time and the internal time of the client device 20 by the sum (X+Y) of the first offset (X seconds) and the second offset (Y seconds). Calculate the offset.
- a message sent and received between the Boundary Clock 10 and the client device 20 consists of one or more PTP packets.
- the Boundary Clock 10 first sends a Sync message to the client device 20 (step S21).
- the Boundary Clock 10 transmits the Sync message to the client device 20, including a time stamp indicating time T1 (first time), which is the transmission time of the Sync message.
- the client device 20 When the client device 20 receives the Sync message transmitted from the Boundary Clock 10 at time T2 (second time), it transmits a Delay_Req message to the Boundary Clock 10 at time T3 in response to the Sync message (step S22). .
- the client device 20 transmits to the Boundary Clock 10 the Delay_Req message including a time stamp indicating time T3 (third time), which is the transmission time of the Delay_Req message.
- the Boundary Clock 10 When the Boundary Clock 10 receives the Delay_Req message sent from the client device 20 at time T4, it sends a Delay_Resp message to the client device 20 in response to the Delay_Req message (step S23). The Boundary Clock 10 transmits a Delay_Resp message to the client device 20 including a time stamp indicating time T4 (fourth time) at which the Delay_Req message was received.
- the BC-client offset calculation processing unit 34 acquires a PTP packet in which a message sent and received between the Boundary Clock 10 and the client device 20 is copied at a copy point between the Boundary Clock 10 and the client device 20.
- the BC-client offset calculation processing unit 34 acquires the PTP packet P1 (first packet) that is a copy of the PTP packet forming the Sync message.
- the PTP packet P1 is a packet transmitted from the Boundary Clock 10 as the first device 3 to the client device 20 as the second device 4, and the time T1 (first time) that is the transmission time of the packet is is a packet containing
- the BC-client offset calculation processing unit 34 acquires the PTP packet P2 (second packet) that constitutes the Delay_Req message.
- the PTP packet P2 is a packet transmitted from the client device 20 as the second device 4 to the Boundary Clock 10 as the first device 3, and the time T3 (third time), which is the transmission time of the packet, is is a packet containing
- the BC-client offset calculation processing unit 34 acquires the PTP packet P3 (third packet) that constitutes the Delay_Resp message.
- the PTP packet P3 is a packet transmitted from the Boundary Clock 10 as the first device 3 to the client device 20 as the second device 4, and is the reception of the PTP packet P2 (second packet) that constitutes the Delay_Req message. It is a packet containing time T4 (fourth time).
- the BC-client offset calculation processing unit 34 acquires the time T1 from the acquired PTP packet P1. Also, the BC-client offset calculation processing unit 34 obtains the time T3 from the obtained PTP packet P2. Also, the BC-client offset calculation processing unit 34 obtains the time T4 from the obtained PTP packet P3.
- the BC-client offset calculation processing unit 34 can receive times T1, T3, and T4 from the obtained copy of the PTP packet.
- the time T2 which is the reception time of the Sync message by the client device 20
- the BC-client offset calculation processing unit 34 needs to obtain the time T2 separately.
- As a method of obtaining the time T2 there is a method of using the transmission delay between the Boundary Clock 10 and the client device 20.
- FIG. The transmission delay between the Boundary Clock 10 and the client device 20 is calculated by the transmission delay calculation processor 16 by transmitting and receiving transmission delay measurement packets between the Boundary Clock 10 and the client device 20 . Calculation of the transmission delay by the transmission delay calculation processing unit 16 will be described below with reference to FIG.
- ETH-DM is a delay measurement method specified in JT-Y1731 OAM functions and mechanisms for Ethernet based networks.
- ETH-DM There are two types of ETH-DM, 1WAY ETH-DM and 2WYA ETH-DM, but the case of using 2WAY ETH-DM will be described below as an example.
- the transmission delay measuring packet transmitting/receiving section 15 of the Boundary Clock 10 transmits the DMM frame to the client device 20 (step S31).
- the transmission delay measuring packet transmitter/receiver 23 of the client device 20 transmits the DMR frame to the Boundary Clock 10 (step S32).
- the transmission time of the DMM frame by the Boundary Clock 10 is defined as Tx Time stampf
- the reception time of the DMM frame by the client device 20 is defined as Rx Time stampf.
- TxTimestampb be the transmission time of the DMR frame by the client device 20
- RxTimestampb be the reception time of the DMR frame by the Boundary Clock 10.
- the client device 20 includes the reception time Rx Time stampf of the DMM frame and the transmission time Tx Time stampb of the DMR frame in the DMR frame and transmits it to the Boundary Clock 10 .
- the frame delay of ETH-DM (time required for round trip between Boundary Clock 10 and client device 20) can be calculated by the following equation (2).
- Frame delay (Rx Time stampb - Tx Time stampf) - (Tx Time stampb - Rx Time stampf) ... formula (2)
- the transmission delay calculation processing unit 16 acquires Rx Time stampf and Tx Time stampb from the DMR frame received from the client device 20.
- the transmission delay calculation processing unit 16 can acquire Tx Time stampf and Rx Time stampb from transmission of DMM frames and reception of DMR frames by the transmission delay measuring packet transmission/reception unit 15 . Therefore, the transmission delay calculation processing unit 16 can calculate the frame delay using equation (2).
- the transmission delay calculation processing unit 16 outputs the transmission result of the transmission delay (frame delay) to the measuring device 30 .
- the transmission delay calculation method described with reference to FIG. 5 is merely an example, and any method may be used as long as the transmission delay can be obtained.
- FIG. 6 is a diagram showing a configuration example of a time synchronization system 1A according to another embodiment of the present disclosure.
- the same components as in FIG. 2 are denoted by the same reference numerals, and descriptions thereof are omitted.
- the time synchronization system 1A includes a Boundary Clock 10A, a client device 20, and a measuring device 30A.
- the time synchronization system 1A shown in FIG. 6 differs from the time synchronization system 1 shown in FIG. 2 in that the Boundary Clock 10 and the measuring device 30 are changed to a Boundary Clock 10A and a measuring device 30A, respectively.
- the Boundary Clock 10A includes packet transmitting/receiving units 11, 12, and 17, a time synchronization processing unit 13, a transmission delay measuring packet transmitting/receiving unit 15, and a transmission delay calculation processing unit 16.
- Boundary Clock 10A shown in FIG. 6 differs from Boundary Clock 10 shown in FIG.
- the packet transmitting/receiving section 17 transmits/receives PTP packets to/from the measuring instrument 30A.
- the measuring device 30A includes a UTC acquisition unit 31, a BC time acquisition unit 32A, a UTC-BC offset calculation processing unit 33, a BC-client offset calculation processing unit 34, a time accuracy calculation processing unit 35, and a packet transmission/reception unit 36. and
- a measuring instrument 30A shown in FIG. 6 differs from the measuring instrument 30 shown in FIG. 2 in that a packet transmitting/receiving section 36 is added and the BC time acquiring section 32 is changed to a BC time acquiring section 32A.
- the packet transmission/reception unit 36 transmits/receives PTP packets to/from the Boundary Clock 10A, and outputs the received PTP packets to the BC time acquisition unit 32A.
- the BC time acquisition unit 32A acquires time information from the PTP packet output from the packet transmission/reception unit 36. That is, the BC time acquisition unit 32A as a second acquisition unit acquires a PTP packet containing time information about the internal time of the Boundary Clock 10 as the first device 3 from the Boundary Clock 10, and obtains the time information from the acquired PTP packet. to get
- the BC time acquisition unit 32A acquires time information from the PTP packet transmitted from the Boundary Clock 10.
- the BC time acquisition unit 32 acquires time information from the 1PPS signal. Therefore, in the time synchronization system 1, it is necessary to connect the measuring device 30 and the client device 20 with a coaxial cable for transmitting the 1PPS signal, and the installation location of the measuring device 30 is restricted. On the other hand, in the time synchronization system 1A shown in FIG. 6, it is only necessary to be able to transmit and receive PTP packets between the Boundary Clock 10A and the measuring device 30A. measurements can be made
- time synchronization system 1A shown in FIG. 6 The rest of the configuration and operation of the time synchronization system 1A shown in FIG. 6 are the same as those of the time synchronization system 1 shown in FIG. 2, so descriptions thereof will be omitted.
- a time synchronization system 1B shown in FIG. 7 includes a Boundary Clock 10A, a client device 20, a measuring device 30B, and a Transparent Clock 40.
- a time synchronization system 1B shown in FIG. 7 differs from the time synchronization system 1A shown in FIG.
- Transparent Clock 40 as a third device is provided between Boundary Clock 10A as first device 3 and client device 20 as second device 4, and relays PTP packets between Boundary Clock 10 and client device 20. do.
- the transparent clock 40 includes packet transmitter/receivers 41 and 42, an intra-device relay delay processor 43, transmission delay measuring packet transmitter/receivers 44 and 45, and a transmission delay calculation processor 46, as shown in FIG.
- the packet transmission/reception unit 41 transmits/receives PTP packets to/from the Boundary Clock 10A.
- the packet transmission/reception unit 42 transmits/receives packets to/from the client device 20 .
- the in-device relay delay processing unit 43 measures the time required for the PTP packet relay processing in the Transparent Clock 40 and notifies the delivery destination of the PTP packet.
- the transmission delay measuring packet transmitting/receiving unit 44 transmits/receives the transmission delay measuring packet to/from the Boundary Clock 10 .
- the transmission delay measuring packet transmitting/receiving unit 45 transmits/receives a transmission delay measuring packet to/from the client device 20 .
- the transmission delay calculation processing unit 46 calculates the transmission delay between the Boundary Clock 10A and the Transparent Clock 40 based on the transmission delay measurement packet transmitted/received between the Boundary Clock 10A and the Boundary Clock 10A by the transmission delay measurement packet transmission/reception unit 44. Further, the transmission delay calculation processing unit 46 calculates the transmission delay between the client device 20 and the transparent clock 40 based on the transmission delay measurement packet transmitted/received between the client device 20 by the transmission delay measurement packet transmission/reception unit 45. calculate.
- the transmission delay calculation processing unit 46 calculates the transmission delay between the Boundary Clock 10A as the first device 3 and the Transparent Clock 40 (third device) and the transmission delay between the client device 20 as the second device 4 and the Transparent Clock 40. Calculate the transmission delay between The transmission delay calculation processing unit 46 outputs the calculation result of the transmission delay to the measuring device 30B.
- the measuring device 30B includes a UTC acquisition unit 31, a BC time acquisition unit 32A, a UTC-BC offset calculation processing unit 33, a BC-client offset calculation processing unit 34B, a time accuracy calculation processing unit 35, and a packet transmission/reception unit 36. and
- the measuring device 30B shown in FIG. 7 differs from the measuring device 30A shown in FIG. 6 in that the BC-client offset calculation processing section 34 is changed to a BC-client offset calculation processing section 34B.
- the BC-client offset calculation processing unit 34B as a second calculation processing unit calculates the transmission delay between the Boundary Clock 10A and the transparent clock 40 and the transmission delay between the client device 20 and the transparent clock 40 by the transmission delay calculation processing unit 46. Get the calculation result of Also, the BC-client offset calculation processing unit 34B obtains a copy of the PTP packet transmitted/received between the transparent clock 40 and the client device 20. FIG. The BC-client offset calculation processing unit 34B calculates a second offset based on the obtained transmission delay calculation result and (a copy of) the PTP packet.
- Boundary Clock 10A first transmits a Sync message to client device 20 (step S21).
- the Boundary Clock 10A transmits a sync message including a time stamp indicating the time T1 (first time) to the client device 20 .
- Sync message is sent to the client device 20 via the Transparent Clock 40 .
- the client device 20 When the client device 20 receives the Sync message at time T2 (second time), it transmits a Delay_Req message to the Boundary Clock 10A at time T3 in response to the Sync message (step S22).
- the client device 20 includes a time stamp indicating time T3 (third time), which is the transmission time of the Delay_Req message, in the Delay_Req message and transmits the Delay_Req message to the Boundary Clock 10A.
- Delay_Req message is sent to Boundary Clock 10A via Transparent Clock 40.
- the Boundary Clock 10A When the Boundary Clock 10A receives the Delay_Req message at time T4, it transmits a Delay_Resp message to the client device 20 in response to the Delay_Req message (step S23). The Boundary Clock 10A transmits a Delay_Resp message containing a timestamp indicating time T4 (fourth time) to the client device 20 .
- the Sync message reception time by the Transparent Clock 40 is dt1
- the Sync message transmission time is dt2.
- dt3 be the reception time of the Delay_Req message by the Transparent Clock 40
- dt4 be the transmission time of the Delay_Req message.
- the BC-client offset calculation processing unit 34B acquires the time T1 and the relay delay time dt2-dt1 from the PTP packet P1 that is a copy of the PTP packet that constitutes the sync message.
- the BC-client offset calculation processing unit 34B acquires the time T3 from the PTP packet P2, which is a copy of the PTP packet forming the Delay_Req message.
- the BC-client offset calculation processing unit 34B acquires the time T4 from the PTP packet P3, which is a copy of the PTP packet forming the Delay_Resp message. Also, the BC-client offset calculation processing unit 34B acquires the relay delay time dt4-dt3 of the Delay_Req message within the transparent clock 40 from the PTP packet P3.
- the BC-client offset calculation processing unit 34B calculates a second offset by the following equation (5) based on times T1 to T4, relay delay time dt2-dt1 and relay delay time dt4-dt3.
- second offset ((T2-T1)-(T4-T3)- (dt2-dt1)-(dt4-dt3))/2 Expression (5)
- the method of calculating the second offset by the BC-client offset calculation processing unit 34B is not limited to the method using Equation (5) described above. Another method of calculating the second offset by the BC-client offset calculation processing unit 34B will be described.
- the transmission delay time between the Boundary Clock 10A and the Transparent Clock 40 is pt1
- the transmission delay time between the Transparent Clock 40 and the client device 20 is pt2.
- the BC-client offset calculation processing unit 34B acquires the time T1, the relay delay time dt2-dt1 and the transmission delay time pt1 from the PTP packet P1.
- the transmission delay time pt1 can be measured by, for example, a P2P (Peer-to-Peer Mechanism) method.
- the P2P method is a method of measuring transmission delay time between devices physically connected by a cable.
- the BC-client offset calculation processing unit 34B cannot obtain the time T2 and the transmission delay time pt2 from the PTP packet. Therefore, the BC-client offset calculation processing unit 34B needs to separately acquire the time T2 when using the formula (5). Also, when using equation (6), the BC-client offset calculation processing unit 34B needs to separately acquire the time T2 and the transmission delay time pt2.
- the transmission delay calculation processing unit 46 of the transparent clock 40 calculates the frame delay between the transparent clock 40 and the client device 20 (time required for the DMM frame to make a round trip between the transparent clock 40 and the client device 20 ) can be calculated.
- the BC-client offset calculation processing section 34B can calculate the time T2 based on the frame delay calculated by the transmission delay calculation processing section 46.
- times T1, T3, T4, relay delay time dt2-dt1 and relay delay time dt4-dt3 can be obtained from the PTP packet.
- the round-trip transmission delay can be calculated by ETH-DM. Therefore, the BC-client offset calculation processing unit 34B calculates the times T1, T3, and T4 obtained from the PTP packet, the relay delay time dt2-dt1 and the relay delay time dt4-dt3, and the round-trip transmission delay calculated by ETH-DM. can be used to calculate time T2 based on equation (7).
- T1 and dt2-dt1 can be obtained from the PTP packet. Also, the round-trip transmission delay can be calculated by ETH-DM. Therefore, the BC-client offset calculation processing unit 34B uses T1 and dt2-dt1 obtained from the PTP packet and the round-trip transmission delay calculated by ETH-DM to calculate time T2 based on equation (8). can do.
- the hardware configuration of the measuring instrument 30 will be described.
- the measuring device 30 will be described below as an example, the same applies to the measuring devices 30A and 30B.
- FIG. 9 is a diagram showing an example hardware configuration of the measuring instrument 30 according to an embodiment of the present disclosure.
- FIG. 9 shows an example of the hardware configuration of measuring instrument 30 when measuring instrument 30 is configured by a computer capable of executing program instructions.
- the computer may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal computer), an electronic notepad, or the like.
- Program instructions may be program code, code segments, etc. for performing the required tasks.
- the measuring instrument 30 includes a processor 310, a ROM (Read Only Memory) 320, a RAM (Random Access Memory) 330, a storage 340, an input section 350, a display section 360 and a communication interface (I/F) 370.
- the processor 310 is specifically a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), etc. may be configured by a plurality of processors of
- the processor 310 is a controller that controls each component and executes various arithmetic processing. That is, processor 310 reads a program from ROM 320 or storage 340 and executes the program using RAM 330 as a work area. The processor 310 performs control of each configuration and various arithmetic processing according to programs stored in the ROM 320 or the storage 340 . In this embodiment, the ROM 120 or the storage 140 stores a program for causing a computer to function as the measuring instrument 30 according to the present disclosure.
- each configuration of the measuring instrument 30, that is, the UTC acquisition unit 31, the BC time acquisition unit 32, the UTC-BC offset calculation processing unit 33, the BC-client offset calculation A processing unit 34 and a time accuracy calculation processing unit 35 are realized.
- Programs are stored in non-transitory storage media such as CD-ROM (Compact Disk Read Only Memory), DVD-ROM (Digital Versatile Disk Read Only Memory), USB (Universal Serial Bus) memory, etc. may be provided in Also, the program may be downloaded from an external device via a network.
- CD-ROM Compact Disk Read Only Memory
- DVD-ROM Digital Versatile Disk Read Only Memory
- USB Universal Serial Bus
- the ROM 320 stores various programs and various data.
- RAM 330 temporarily stores programs or data as a work area.
- the storage 340 is configured by a HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs including an operating system and various data.
- the input unit 350 includes a pointing device such as a mouse and a keyboard, and is used for various inputs.
- the display unit 360 is, for example, a liquid crystal display, and displays various information.
- the display unit 360 may employ a touch panel method and function as the input unit 350 .
- the communication interface 370 is an interface for communicating with other devices such as external devices (not shown), and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark), for example.
- a computer can be preferably used to function as each part of the measuring instrument 30 described above.
- Such a computer is realized by storing a program describing the processing details for realizing the function of each part of the measuring instrument 30 in the memory of the computer, and reading and executing the program by the processor of the computer. be able to. That is, the program can cause the computer to function as the measuring instrument 30 described above. It is also possible to record the program on a non-temporary recording medium. It is also possible to provide the program via a network.
- a second device that synchronizes the internal time with the reference time and transmits and receives a packet to and from the first device that distributes the internal time
- the second device synchronizes the internal time with the first device, with respect to the reference time
- a measuring instrument for measuring the accuracy of the internal time of the second device with a processor
- the processor obtaining the reference time from a satellite signal; Acquiring time information related to the internal device time of the first device; calculating a first offset, which is a difference between the reference time and the device internal time of the first device, based on the obtained reference time and the obtained time information; obtaining a copy of the packet transmitted and received between the first device and the second device, and obtaining a copy of the packet and a transmission delay between the obtained packet and the first device and the second device; calculating a second offset, which is the difference between the internal device time of the first device and the internal device time of the second device, based on A measuring device that measures the accuracy of the internal time of the second device with respect to the reference time
- the processor in response to a first packet transmitted from the first device to the second device, the first packet including a first time that is a transmission time of the packet, the first packet , a packet transmitted from the second device to the first device, the second packet including a third time that is the transmission time of the packet, and in response to the second packet, Obtaining a copy of a third packet sent from the first device to the second device, the packet including a fourth time of reception of the second packet by the first device.
- the second device A meter that calculates a second time that is a reception time and that calculates the second offset based on the first time, the second time, the third time and the fourth time.
- a third device that relays the packet is provided between the first device and the second device, the third device calculates a transmission delay between the first device and the third device and a transmission delay between the second device and the third device;
- a measuring method using a measuring device for measuring the accuracy of the internal time of the second device, obtaining the reference time from a satellite signal; Acquiring time information related to the internal device time of the first device; calculating a first offset, which is a difference between the reference time and the device internal time of the first device, based on the acquired reference time and time information; obtaining a copy of the packet transmitted and received between the first device and the second device, and obtaining a copy of the packet and a transmission delay between the obtained packet and the first device and the second device; calculating a second offset, which is the difference between the internal device time of the first device and the internal device time of the second device, based on A measuring method, comprising measuring accuracy of an internal time of the second device with respect to the reference time based
- a time synchronization system comprising a measuring device for measuring the accuracy of the internal time of the second device with respect to the reference time in the second device, The measuring instrument with a processor The processor obtaining the reference time from a satellite signal; Acquiring time information related to the internal device time of the first device; calculating a first offset, which is a difference between the reference time and the device internal time of the first device, based on the obtained reference time and the obtained time information; obtaining a copy of the packet transmitted and received between the first device and the second device, and obtaining a copy of the packet and a transmission delay between the obtained packet and the first device and the second device; calculating a second offset, which is the difference between the internal device time of the first device and the internal device time of the second device, based on A time
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Abstract
Description
第2のオフセット=((T2-T1)-(T4-T3))/2 ・・・式(1)
フレーム遅延
=(Rx Time stampb-Tx Time stampf)-(Tx Time stampb-Rx Time stampf)
・・・式(2)
往復の伝送遅延=(T2-T1)+(T4-T3) ・・・式(3)
第2のオフセット=((T2-T1)-(T4-T3))/2 ・・・式(4)
第2のオフセット=((T2-T1)-(T4-T3)-
(dt2-dt1)-(dt4-dt3))/2 ・・・式(5)
第2のオフセット=(T2-T1)-pt1-pt2-(dt2-dt1)
・・・式(6)
往復の伝送遅延=(T2-T1)+(T4-T3)
-(dt2-dt1)-(dt4-dt3) ・・・式(7)
往復の伝送遅延=((T2-T1)-(dt2-dt1))*2 ・・・式(8)
基準時刻に装置内時刻を同期させ、前記装置内時刻を配信する第1の装置とのパケットの送受信により、装置内時刻を前記第1の装置と同期させる第2の装置における、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する測定器であって、
プロセッサを備え、
前記プロセッサは、
衛星信号から前記基準時刻を取得し、
前記第1の装置の装置内時刻に関する時刻情報を取得し、
前記取得した基準時刻と、前記取得した時刻情報とに基づき、前記基準時刻と前記第1の装置の装置内時刻との差である第1のオフセットを計算し、
前記第1の装置と前記第2の装置との間で送受信される前記パケットのコピーを取得し、前記取得したパケットと、前記第1の装置と前記第2の装置との間の伝送遅延とに基づき、前記第1の装置の装置内時刻と前記第2の装置の装置内時刻との差である第2のオフセットを計算し、
前記第1のオフセットと前記第2のオフセットとに基づき、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する、測定器。
付記項1に記載の測定器において、
前記プロセッサは、前記第1の装置から前記第2の装置に送信されるパケットであって、該パケットの送信時刻である第1の時刻を含む第1のパケット、前記第1のパケットに応じて、前記第2の装置から前記第1の装置に送信されるパケットであって、該パケットの送信時刻である第3の時刻を含む第2のパケット、および、前記第2のパケットに応じて、前記第1の装置から前記第2の装置に送信されるパケットであって、前記第1の装置による前記第2のパケットの受信時刻である第4の時刻を含む第3のパケットのコピーを取得し、前記第1から第3のパケットに含まれる前記第1の時刻、前記第3の時刻および第4の時刻と、前記伝送遅延とに基づき、前記第2の装置による前記第1のパケットの受信時刻である第2の時刻を計算し、前記第1の時刻、前記第2の時刻、前記第3の時刻および前記第4の時刻に基づき、前記第2のオフセットを計算する、測定器。
付記項1に記載の測定器において、
前記プロセッサは、前記第1の装置の装置内時刻に同期して1PPSで前記第1の装置から出力されるパルス信号に基づき、前記時刻情報を取得する、測定器。
付記項1に記載の測定器において、
前記プロセッサは、前記第1の装置の装置内時刻に関する時刻情報を含むパケットを前記第1の装置から取得し、該取得したパケットから前記時刻情報を取得する、測定器。
付記項1に記載の測定器において、
前記第1の装置と前記第2の装置との間に、前記パケットを中継する第3の装置が設けられ、
前記第3の装置は、前記第1の装置と前記第3の装置との間の伝送遅延および前記第2の装置と前記第3の装置との間の伝送遅延を計算し、
前記プロセッサは、前記第3の装置の計算結果に基づき、前記第2のオフセットを計算する、測定器。
基準時刻に装置内時刻を同期させ、前記装置内時刻を配信する第1の装置とのパケットの送受信により、装置内時刻を前記第1の装置と同期させる第2の装置における、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する測定器による測定方法であって、
衛星信号から前記基準時刻を取得し、
前記第1の装置の装置内時刻に関する時刻情報を取得し、
前記取得した基準時刻と時刻情報とに基づき、前記基準時刻と前記第1の装置の装置内時刻との差である第1のオフセットを計算し、
前記第1の装置と前記第2の装置との間で送受信される前記パケットのコピーを取得し、前記取得したパケットと、前記第1の装置と前記第2の装置との間の伝送遅延とに基づき、前記第1の装置の装置内時刻と前記第2の装置の装置内時刻との差である第2のオフセットを計算し、
前記第1のオフセットと前記第2のオフセットとに基づき、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する、測定方法。
基準時刻に装置内時刻を同期させ、前記装置内時刻を配信する第1の装置と、
前記第1の装置とのパケットの送受信により、装置内時刻を前記第1の装置と同期させる第2の装置と、
前記第2の装置における、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する測定器と、を備える時刻同期システムであって、
前記測定器は、
プロセッサを備え、
前記プロセッサは、
衛星信号から前記基準時刻を取得し、
前記第1の装置の装置内時刻に関する時刻情報を取得し、
前記取得した基準時刻と、前記取得した時刻情報とに基づき、前記基準時刻と前記第1の装置の装置内時刻との差である第1のオフセットを計算し、
前記第1の装置と前記第2の装置との間で送受信される前記パケットのコピーを取得し、前記取得したパケットと、前記第1の装置と前記第2の装置との間の伝送遅延とに基づき、前記第1の装置の装置内時刻と前記第2の装置の装置内時刻との差である第2のオフセットを計算し、
前記第1のオフセットと前記第2のオフセットとに基づき、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する、時刻同期システム。
2 ネットワーク
3 第1の装置
4 第2の装置
10,10A Boundary Clock
11,12,17 パケット送受信部
13 時刻同期処理部
14 1PPS送信部
15 伝送遅延測定用パケット送受信部
16 伝送遅延計算処理部
20 クライアント装置
21 パケット送受信部
22 時刻同期処理部
23 伝送遅延測定用パケット送受信部
24 伝送遅延計算処理部
30,30A,30B 計測器
31 UTC取得部(第1の取得部)
32 BC時刻取得部(第2の取得部)
33 UTC-BCオフセット計算処理部(第1の計算処理部)
34 BC-クライアントオフセット計算処理部(第2の計算処理部)
35 時刻精度計算処理部(第3の計算処理部)
36 パケット送受信部
40 Transparent Clock
41,42 パケット送受信部
43 装置内中継遅延処理部
44,45 伝送遅延測定用パケット送受信部
46 伝送遅延計算処理部
100 Grand Master Clock
310 プロセッサ
320 ROM
330 RAM
340 ストレージ
350 入力部
360 表示部
370 通信I/F
390 パス
Claims (7)
- 基準時刻に装置内時刻を同期させ、前記装置内時刻を配信する第1の装置とのパケットの送受信により、装置内時刻を前記第1の装置と同期させる第2の装置における、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する測定器であって、
衛星信号から前記基準時刻を取得する第1の取得部と、
前記第1の装置の装置内時刻に関する時刻情報を取得する第2の取得部と、
前記第1の取得部が取得した基準時刻と、前記第2の取得部が取得した時刻情報とに基づき、前記基準時刻と前記第1の装置の装置内時刻との差である第1のオフセットを計算する第1の計算処理部と、
前記第1の装置と前記第2の装置との間で送受信される前記パケットのコピーを取得し、前記取得したパケットと、前記第1の装置と前記第2の装置との間の伝送遅延とに基づき、前記第1の装置の装置内時刻と前記第2の装置の装置内時刻との差である第2のオフセットを計算する第2の計算処理部と、
前記第1のオフセットと前記第2のオフセットとに基づき、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する第3の計算処理部と、を備える測定器。 - 請求項1に記載の測定器において、
前記第2の計算処理部は、前記第1の装置から前記第2の装置に送信されるパケットであって、該パケットの送信時刻である第1の時刻を含む第1のパケット、前記第1のパケットに応じて、前記第2の装置から前記第1の装置に送信されるパケットであって、該パケットの送信時刻である第3の時刻を含む第2のパケット、および、前記第2のパケットに応じて、前記第1の装置から前記第2の装置に送信されるパケットであって、前記第1の装置による前記第2のパケットの受信時刻である第4の時刻を含む第3のパケットのコピーを取得し、前記第1から第3のパケットに含まれる前記第1の時刻、前記第3の時刻および第4の時刻と、前記伝送遅延とに基づき、前記第2の装置による前記第1のパケットの受信時刻である第2の時刻を計算し、前記第1の時刻、前記第2の時刻、前記第3の時刻および前記第4の時刻に基づき、前記第2のオフセットを計算する、測定器。 - 請求項1または2に記載の測定器において、
前記第2の取得部は、前記第1の装置の装置内時刻に同期して1PPSで前記第1の装置から出力されるパルス信号に基づき、前記時刻情報を取得する、測定器。 - 請求項1または2に記載の測定器において、
前記第2の取得部は、前記第1の装置の装置内時刻に関する時刻情報を含むパケットを前記第1の装置から取得し、該取得したパケットから前記時刻情報を取得する、測定器。 - 請求項1から4のいずれか一項に記載の測定器において、
前記第1の装置と前記第2の装置との間に、前記パケットを中継する第3の装置が設けられ、
前記第3の装置は、前記第1の装置と前記第3の装置との間の伝送遅延および前記第2の装置と前記第3の装置との間の伝送遅延を計算し、
前記第2の計算処理部は、前記第3の装置の計算結果に基づき、前記第2のオフセットを計算する、測定器。 - 基準時刻に装置内時刻を同期させ、前記装置内時刻を配信する第1の装置とのパケットの送受信により、装置内時刻を前記第1の装置と同期させる第2の装置における、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する測定器による測定方法であって、
衛星信号から前記基準時刻を取得するステップと、
前記第1の装置の装置内時刻に関する時刻情報を取得するステップと、
前記取得した基準時刻と時刻情報とに基づき、前記基準時刻と前記第1の装置の装置内時刻との差である第1のオフセットを計算するステップと、
前記第1の装置と前記第2の装置との間で送受信される前記パケットのコピーを取得し、前記取得したパケットと、前記第1の装置と前記第2の装置との間の伝送遅延とに基づき、前記第1の装置の装置内時刻と前記第2の装置の装置内時刻との差である第2のオフセットを計算するステップと、
前記第1のオフセットと前記第2のオフセットとに基づき、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定するステップと、を含む測定方法。 - 基準時刻に装置内時刻を同期させ、前記装置内時刻を配信する第1の装置と、
前記第1の装置とのパケットの送受信により、装置内時刻を前記第1の装置と同期させる第2の装置と、
前記第2の装置における、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する測定器と、を備える時刻同期システムであって、
前記測定器は、
衛星信号から前記基準時刻を取得する第1の取得部と、
前記第1の装置の装置内時刻に関する時刻情報を取得する第2の取得部と、
前記第1の取得部が取得した基準時刻と、前記第2の取得部が取得した時刻情報とに基づき、前記基準時刻と前記第1の装置の装置内時刻との差である第1のオフセットを計算する第1の計算処理部と、
前記第1の装置と前記第2の装置との間で送受信される前記パケットのコピーを取得し、前記取得したパケットと、前記第1の装置と前記第2の装置との間の伝送遅延とに基づき、前記第1の装置の装置内時刻と前記第2の装置の装置内時刻との差である第2のオフセットを計算する第2の計算処理部と、
前記第1のオフセットと前記第2のオフセットとに基づき、前記基準時刻に対する前記第2の装置の装置内時刻の精度を測定する第3の計算処理部と、を備える時刻同期システム。
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