CN115941549B - High-precision path delay measurement method suitable for time synchronization network - Google Patents
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Abstract
本发明公开了一种适用于时间同步网络的高精度路径延迟测量方法，主时钟将当前时刻封装到同步测量帧里，派发同步测量帧到网络中的从时钟；从时钟接收到同步测量帧，对该同步测量帧进行固化处理，然后提取当前派发时刻，在同步测量帧的固化时刻将自身的时钟的时间校正为同步测量帧的派发时刻与最大传输延迟的累加值；同时从时钟设置跟随同步测量帧的预期固化时刻；主时钟将跟随派发时刻封装到跟随同步测量帧中，并在跟随派发时刻派发跟随同步测量帧到网络中的从时钟；从时钟接收到跟随同步测量帧，对该跟随同步测量帧进行固化处理，得到跟随同步测量帧的固化时刻，将跟随同步测量帧的固化时刻与预期固化时刻进行比较，计算得到路径修正因子。
The present invention discloses a high-precision path delay measurement method suitable for a time synchronization network. The master clock encapsulates the current time into a synchronization measurement frame, and dispatches the synchronization measurement frame to a slave clock in the network; the slave clock receives the synchronization measurement frame, solidifies the synchronization measurement frame, and then extracts the current dispatch time, and corrects the time of its own clock to the cumulative value of the dispatch time of the synchronization measurement frame and the maximum transmission delay at the solidification time of the synchronization measurement frame; at the same time, the slave clock sets the expected solidification time of the follow-up synchronization measurement frame; the master clock encapsulates the follow-up dispatch time into the follow-up synchronization measurement frame, and dispatches the follow-up synchronization measurement frame to the slave clock in the network at the follow-up dispatch time; the slave clock receives the follow-up synchronization measurement frame, solidifies the follow-up synchronization measurement frame, obtains the solidification time of the follow-up synchronization measurement frame, compares the solidification time of the follow-up synchronization measurement frame with the expected solidification time, and calculates the path correction factor.
Description
Technical Field
The present invention relates to a method for measuring time delay, and more particularly, to a method for measuring path delay with high accuracy suitable for time synchronization network.
Background
The IEEE 1588 (IEEE 1588-2008) standard proposed by the american society of electrical and electronic engineers provides a master-slave time synchronization method for time deterministic networks. The master-slave time synchronization protocol is divided into two phases, namely a clock offset measurement phase and a path delay measurement phase. The first phase measures the time offset between the master and slave clocks, referred to as the clock offset measurement phase. The second phase of the synchronization process is a delay measurement phase, which measures the path transfer delay between the master and slave clocks. The master clock receives the delay request message, marks the accurate receiving time stamp, and writes the time stamp value into the delay response frame sent after. The slave clock calculates a network transmission delay between the slave clock and the master clock from the round-trip measurement frames. And introducing a transparent clock mechanism into the transmission process of the measurement frame, and accurately recording the transmission delay of the frame at each node.
The SAE AS6802 standard promulgated by the american society of automotive industries specifies a distributed Time synchronization protocol for Time triggered ethernet (Time-TRIGGED ETHERNET, TTE). The SAE AS6802 standard specifies 3 different synchronization roles, synchronization master (Synchronization Master, SM), synchronization client (Synchronization Client, SC) and compression master (Compression Master, CM), respectively. End systems are typically configured as SMs and SCs, and switches are typically configured as CMs. Synchronization nodes (SM, SC, and CM) of the same synchronization priority within the same synchronization domain form a cluster. The SAE AS6802 standard specifies a two-step time synchronization method. The method comprises a first step of sending protocol control frames (protocol control frame, PCF) to CM in the cluster at the starting time of the synchronization period to request synchronization, and a second step of sending compressed PCF to SM and SC after the CM extracts the transparent clock information of PCF frame. The SM, SC and CM introduce transparent clock mechanism in the process of transmitting PCF frame, and adopt solidifying algorithm to process PCF frame at receiving end, so receiving end can rebuild the sending sequence of PCF frame.
In IEEE 1588 networks, the averaging of the round-trip path delays introduces uncertainty in the path measurement, which in turn leads to a drop in clock accuracy, since the round-trip path delays are unequal. In TTE network, a solidifying mechanism is introduced in the process of PCF frame transmission, which is favorable for reconstructing PCF frame time sequence and improving time synchronization precision, but because the fixed delay brought by hardware such as PHY chip in the transmission process is based on off-line measurement, the fixed delay floats in a range, and after power-on, the actual value of the fixed delay is often inconsistent with the off-line measurement value due to the influence of environment, which can lead to the reduction of time synchronization precision. The existing TTE network transmission mechanism cannot eliminate the situation that the actual delay value is inconsistent with the offline measurement value.
Disclosure of Invention
In order to accurately measure the path delay in the time synchronization network, the invention aims to provide a method for accurately measuring the path delay in the time synchronization network, which can provide high-precision path delay measurement service for the time synchronization network.
The invention aims at realizing the following technical scheme:
a high-precision path delay measuring method suitable for a time synchronization network comprises the following steps:
After the network equipment is electrified, the master clock takes the current moment as the dispatch moment, encapsulates the current dispatch moment into a synchronous measurement frame, and dispatches the synchronous measurement frame to the slave clock in the network;
step two, the slave clock receives the synchronous measurement frame sent by the master clock, carries out solidification treatment on the synchronous measurement frame, then extracts the current dispatch time of the master clock in the synchronous measurement frame, corrects the time of the clock of the slave clock to be the accumulated value of the current dispatch time and the maximum transmission delay of the master clock at the solidification time of the synchronous measurement frame;
The master clock encapsulates the following dispatch time into a following synchronous measurement frame, and dispatches the following synchronous measurement frame to the slave clock in the network by taking the following dispatch time as a dispatch time point;
and step four, receiving a following synchronous measurement frame sent by the master clock from the clock, solidifying the following synchronous measurement frame to obtain the solidifying moment of the following synchronous measurement frame, comparing the solidifying moment of the following synchronous measurement frame with the expected solidifying moment, and calculating to obtain the path correction factor.
Preferably, the desired curing timeThe method comprises the following steps:
Wherein, The MD transmits the synchronization measurement frame to any other synchronization clock in the time synchronization network until the synchronization clock receiving the synchronization measurement frame completes the solidification operation of the synchronization measurement frame, and the transparent clock in the synchronization measurement frame accumulates to a maximum value.
Preferably, the following dispatch timeThe method comprises the following steps:
Wherein, The MD is the maximum value of the accumulation of transparent clocks in the synchronization measurement frame after the slave clock finishes the solidification operation of the synchronization measurement frame, which is the time when the synchronization measurement frame is dispatched for the master clock.
Preferably, the method for measuring the high-precision path delay suitable for the time synchronization network further comprises the steps that the slave clock uses the path correction factor to correct the current time of the local clock to finish time synchronization operation, or the slave clock stores the path correction factor, and in the subsequent time synchronization operation, the transparent clock value of the synchronization frame sent by the master clock is corrected, and then solidification operation is carried out to realize accurate measurement of the path delay.
The invention has the beneficial effects that:
(1) The invention fully considers the network time synchronization characteristic, and the provided path delay measuring method is suitable for the switched network connected by various topologies such as star, ring and the like.
(2) The method for measuring the path delay provided by the invention can realize high-precision unidirectional path delay measurement, avoid the introduction of unequal delay and uncertain fixed delay in the path transmission process of a synchronous measurement frame, and improve the precision of time synchronization.
(3) The invention considers the difference between the off-line measurement value and the on-line measurement value of the network hardware fixed delay, and proposes to measure the path delay in an on-line mode, thereby realizing accurate measurement of the path delay and improving the time precision.
(4) The path delay measurement method provided by the invention is based on the existing hardware equipment and software calculation operation, does not need to introduce an additional high-precision hardware clock and a measurement device, and reduces the cost of the hardware equipment required by path delay measurement.
(5) The path delay measuring method provided by the invention can be used in combination with the existing time synchronization method, can accurately measure the path delay on line, and can also be independently used as the time synchronization method to be applied to the time synchronization network.
Drawings
Fig. 1 is a network physical topology diagram of a time-synchronized network as illustrated in an embodiment.
Fig. 2 is a path measurement frame interaction process.
Fig. 3 is a flow chart of a high-precision path delay measurement method according to the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples.
In this embodiment, a time synchronization network is illustrated in fig. 1, and a high-precision clock source synchronization clock capable of time-synchronizing other clocks in the time synchronization network is referred to as a master clock for short. And a synchronous clock for receiving the synchronous frame from the master clock and performing time synchronization operation according to the time synchronization information of the master clock contained in the synchronous frame, which is called a slave clock.
The master clock measures the one-way path delay between the master clock and the slave clocks by sending a synchronization measurement frame and a follow synchronization measurement frame to all the slave clocks, wherein the synchronization measurement frame and the follow synchronization measurement frame both belong to the synchronization frame.
The timing accuracy of the master clock should be higher than the timing accuracy of the remaining slave clocks within the time synchronized network, typically the total number of master clocks is at least 2 or more.
In the physical topology of the time synchronization network, the time synchronization network comprises a plurality of master clocks and slave clocks, wherein the master clocks are denoted by SD＝{M1,M2,M3,...,Mn,S1,S2,S3,…,Sm},M1 in a collective form, M 2 is denoted by a second master clock in the SD, M 3 is denoted by a third master clock in the SD, M n is denoted by a last master clock in the SD, for convenience of explanation, the embodiment uses M p to denote any one of the master clocks in the SD, S 1 is denoted by a first slave clock in the SD, S 2 is denoted by a second slave clock in the SD, S 3 is denoted by a third slave clock in the SD, S q is denoted by a last slave clock in the SD, and for convenience of explanation, the embodiment uses S q to denote any one of the slave clocks in the SD.
With reference to SAE AS6802 standard protocol, dispatch timeRefers to the time at which a master clock dispatches a sync measurement frame to a slave clock.
The definition of the maximum transmission delay MD may refer to the maximum transmission delay of SAE AS6802 standard protocol. Any one of the synchronous clocks in the time synchronous network transmits the synchronous frame to any other synchronous clock until the synchronous clock receiving the synchronous frame completes the solidification operation of the synchronous frame, and the maximum value of the accumulation of the transparent clock in the synchronous frame is called maximum transmission delay MD.
Following the dispensing momentRefers to a master clock at the dispatch timeAfter that, the time with the length of MD is passed, and the time following the synchronization measurement frame is distributed to a slave clock. The following dispatch time
A synchronization node in the clock synchronization network may perform transparent clock mechanism operations on the synchronization frames with reference to SAE AS6802 standard protocol.
Synchronous measurement frame with reference to SAE AS6802 standard or IEEE 1588Refers to the time of dispatch including the time of dispatch sent from the master clock M p to the slave clock S q And a data frame of transparent clock information. Synchronous measurement frameThe upper corner mark in (a) represents the synchronous measurement frame, M p before the lower corner mark arrow represents the identity of the master clock of the sending end of the synchronous measurement frame, and S q after the lower corner mark arrow represents the identity of the slave clock of the receiving end of the synchronous measurement frame.
For example, the number of the cells to be processed,Representing the synchronization measurement frame sent by the master clock M 1 to the slave clock S 1.
With reference to SAE AS6802 standard or IEEE 1588, following a synchronization measurement frameRefers to the inclusion following dispatch time sent by the master clock M p to the slave clock S q And a data frame of transparent clock information. Synchronous measurement frameThe upper corner mark in (a) represents the identity of the master clock of the transmitting end of the synchronous measurement frame following the synchronous measurement frame, M p before the lower corner mark arrow, and S q after the lower corner mark arrow represents the identity of the slave clock of the receiving end of the synchronous measurement frame.
For example, the number of the cells to be processed,Representing a follow-up synchronization measurement frame sent by the master node M 1 to the slave clock S 1.
The slave clock S q measures the frame for synchronization from the master clock M p according to the SAE AS6802 standardSolidifying to obtain synchronous measurement frameThe curing time of (2) is recorded asCuring timeThe upper corner mark S in (a) represents a synchronous measurement frame, M p before the lower corner mark arrow represents the identity of the master clock of the sending end of the synchronous measurement frame, and S q after the lower corner mark arrow represents the identity of the slave clock of the receiving end of the synchronous measurement frame.
For example, the number of the cells to be processed,Representing a synchronization measurement frame transmitted from the slave clock S 1 to the master clock M 1 And (3) curing the obtained cured product.
The slave clock S q follows the synchronization measurement frame from the master clock M p according to the SAE AS6802 standardCuring to obtain following synchronous measurement frameThe curing time of (2) is recorded asCuring timeThe upper corner mark F in (a) represents the identity of the master clock of the transmitting end of the following synchronous measurement frame, the M p before the lower corner mark arrow represents the identity of the slave clock of the receiving end of the following synchronous measurement frame, and the S q after the lower corner mark arrow represents the identity of the slave clock of the receiving end of the following synchronous measurement frame.
For example, the number of the cells to be processed,Representing a follow-up synchronization measurement frame from the slave clock S 1 to the master clock M 1 And (3) curing the obtained cured product.
Transmitting the following synchronization measurement frame to the slave clock S q at the master clock M p The following synchronization measurement frameIs recorded as the expected curing time of (2)The expected curing time The upper corner mark F in (a) indicates that the synchronization measurement frame is followed.
For example, the number of the cells to be processed,Follow-up synchronization measurement frame representing transmission of master clock M 1 to slave clock S 1 Is used for the curing time.
Path correction factorRefers to the slave clock calculating the preset following synchronous measurement frameThe difference between the expected curing time and the curing time, i.ePath correction factorThe lower corner mark S q in (a) represents the identity of the slave clock of the receiving end, and the upper corner mark M p represents the identity of the master clock of the transmitting end.
Referring to fig. 3, a process of a high-precision path delay measurement method suitable for a time-synchronized network includes the steps of:
After the network equipment is electrified, the master clock takes the current time as the dispatch time, and encapsulates the current dispatch time into a synchronous measurement frame, and dispatches the synchronous measurement frame to the slave clock in the network.
In the present embodiment, after time synchronizing the network device, the master clock M p starts the path delay measurement, and distributes the synchronization measurement frameInto the slave clock S q. For example, the time synchronization network is composed of 4 synchronization clocks as shown in fig. 1, including 1 master clock and 3 slave clocks.
Referring to fig. 1 and 2, after power-up, the master clock M 1 takes the current time as the dispatch timeWill be at the current timeEncapsulation into synchronous measurement framesTransmitting a synchronization measurement frame to the slave clock S 1
Similarly, after power-up, the master clock M 1 takes the current time as the dispatch timeWill be at the current timeEncapsulation into synchronous measurement framesTransmitting a synchronization measurement frame to the slave clock S 2
Similarly, after power-up, the master clock M 1 takes the current time as the dispatch timeWill be at the current timeEncapsulation into synchronous measurement framesTransmitting a synchronization measurement frame to the slave clock S 3
And secondly, receiving a synchronous measurement frame sent by the master clock from the slave clock, solidifying the synchronous measurement frame, extracting the current dispatch time of the master clock in the synchronous measurement frame, correcting the time of the clock of the slave clock to be the accumulated value of the current dispatch time and the maximum transmission delay of the master clock at the solidification time of the synchronous measurement frame, and setting the expected solidification time following the synchronous measurement frame from the slave clock. The method can be concretely divided into the following steps:
Step 201, the slave clock receives the synchronous measurement frame sent by the master clock, and carries out solidification treatment on the synchronous measurement frame.
Specifically, the slave clock S q receives the synchronization measurement frame from the master clock M p Performing solidifying, i.e. extracting synchronous measurement frames from clock S q Transparent clock information carried in the data frame is processed according to a curing method in SAE AS6802 standard to obtain the synchronous measurement frameIs set at the curing time of (2)
For example, see fig. 1 and 2, the slave clock S 1 receives the synchronization measurement frame from the master clock M 1 For the synchronous measurement frameSolidifying to obtain synchronous measurement frameIs set at the curing time of (2)
Similarly, the slave clock S 2 receives the synchronous measurement frame from the master clock M 1 For the synchronous measurement frameSolidifying to obtain synchronous measurement frameIs set at the curing time of (2)
Similarly, the slave clock S 3 receives the synchronous measurement frame from the master clock M 1 For the synchronous measurement frameSolidifying to obtain synchronous measurement frameIs set at the curing time of (2)
Step 202, extracting the current dispatch time of the synchronous measurement frame sent by the master clock from the clock, and correcting the time of the clock of the slave clock to be the accumulated value of the current dispatch time and the maximum transmission delay of the master clock at the solidification time of the synchronous measurement frame.
Specifically, the slave clock S q receives the synchronization measurement frame from the master clock M p Extracting synchronization measurement framesThe current dispatch time in (3)At the solidification time of the synchronous measurement frameThe slave clock correcting the time of its own clock to the accumulated value of the current dispatch time of the master clock and the maximum transmission delay, i.e.
For example, see fig. 1 and 2, the slave clock S 1 receives the synchronization measurement frame from the master clock M 1 Extracting synchronization measurement framesThe current dispatch time in (3)At the solidification time of the synchronous measurement frameThe slave clock S 1 corrects the time of its own clock to the sum of the current dispatch time of the master clock and the maximum transmission delay, i.e
Similarly, the slave clock S 2 receives the synchronous measurement frame from the master clock M 1 Extracting synchronization measurement framesThe current dispatch time in (3)At the solidification time of the synchronous measurement frameThe slave clock S 2 corrects the time of its own clock to the sum of the current dispatch time of the master clock and the maximum transmission delay, i.e
Similarly, the slave clock S 3 receives the synchronous measurement frame from the master clock M 1 Extracting synchronization measurement framesThe current dispatch time in (3)At the solidification time of the synchronous measurement frameThe slave clock S 3 corrects the time of its own clock to the sum of the current dispatch time of the master clock and the maximum transmission delay, i.e
Step 203, setting the expected curing time following the synchronization measurement frame from the clock.
Specifically, the slave clock S q sets the current dispatch point of the master clock M p An accumulated value of 2 times of the maximum transmission delay is set to follow the expected solidification time of the synchronous measurement frameI.e.
For example, as shown in fig. 1 and 2, the slave clock S 1 transmits the current dispatch time of the master clock M 1 An accumulated value of 2 times of the maximum transmission delay is set to follow the expected solidification time of the synchronous measurement frameI.e.
Similarly, the slave clock S 2 sends the current dispatch point of the master clock M 1 An accumulated value of 2 times of the maximum transmission delay is set to follow the expected solidification time of the synchronous measurement frameI.e.
Similarly, the slave clock S 3 sends the current dispatch point of the master clock M 1 An accumulated value of 2 times of the maximum transmission delay is set to follow the expected solidification time of the synchronous measurement frameI.e.
And step three, the master clock packages the following dispatch time into the following synchronous measurement frame, and dispatches the following synchronous measurement frame to the slave clock in the network by taking the following dispatch time as the dispatch time point.
Specifically, in the present invention, the master clock M p will follow the dispatch timeEncapsulation to follow-up synchronization measurement frameIn order to follow the dispatch timeFor dispatch time points, dispatch follow-up synchronization measurement framesTo the slave clock S q.
For example, referring to FIGS. 1 and 2, the master clock M 1 will follow the dispatch timeEncapsulation to follow-up synchronization measurement frameIn order to follow the dispatch timeFor dispatch time points, dispatch follow-up synchronization measurement framesTo a slave clock S 1;
similarly, the master clock M 1 will follow the dispatch time Encapsulation to follow-up synchronization measurement frameIn order to follow the dispatch timeFor dispatch time points, dispatch follow-up synchronization measurement framesTo a slave clock S 2;
similarly, the master clock M 1 will follow the dispatch time Encapsulation to follow-up synchronization measurement frameIn order to follow the dispatch timeFor dispatch time points, dispatch follow-up synchronization measurement framesTo the slave clock S 3.
And step four, receiving a following synchronous measurement frame sent by the master clock from the clock, solidifying the following synchronous measurement frame to obtain the solidifying moment of the following synchronous measurement frame, comparing the solidifying moment of the following synchronous measurement frame with the expected solidifying moment, and calculating to obtain the path correction factor.
Specifically, the slave clock S q follows the synchronization measurement frame sent from the master clock M p Performing solidifying, i.e. extracting synchronous measurement frames from clock S q Transparent clock information carried in the data frame is processed according to a curing method in SAE AS6802 standard to obtain the following synchronous measurement frameIs set at the curing time of (2)And with the expected curing time preset by the selfComparing and calculating to obtain path correction factorI.e.The slave clock can use the path correction factor to correct the current time of the local clock to finish time synchronization operation, or can store the path correction factor, in the subsequent time synchronization operation, correct the transparent clock value of the synchronization frame sent by the master clock, then execute solidification operation, realize accurate measurement of path delay and improve time synchronization accuracy.
For example, see fig. 1 and 2, the slave clock S 1 transmits a following synchronization measurement frame to the master clock M 1 Curing to obtain the following synchronous measurement frameIs set at the curing time of (2)And with the expected curing time preset by the selfComparing and calculating to obtain path correction factorI.e.
Similarly, the slave clock S 2 transmits a following synchronous measurement frame to the master clock M 1 Curing to obtain the following synchronous measurement frameIs set at the curing time of (2)And with the expected curing time preset by the selfComparing and calculating to obtain path correction factorI.e.
Similarly, the slave clock S 3 transmits a following synchronous measurement frame to the master clock M 1 Curing to obtain the following synchronous measurement frameIs set at the curing time of (2)And with the expected curing time preset by the selfComparing and calculating to obtain path correction factorI.e.
In this embodiment, the paths between all the synchronous clocks of the time synchronization network in the first to fourth steps are measured, so that the path correction factor can be obtained finally, and the transparent clock value used for correcting the unidirectional path delay between the master clock and the slave clock in the subsequent time synchronization is used to improve the precision of the time synchronization.
The high-precision path delay measurement method suitable for the time synchronization network in the embodiment is used for accurately measuring the unidirectional path delay between a master clock and a slave clock. In a time-synchronized network, a measurement operation may be initiated by a master clock, with accurate measurements of the one-way path delay between the master clock and each slave clock within the network. In addition, the path delay measurement method provided by the embodiment is also suitable for precisely measuring the unidirectional path delay between the slave clock and the master clock, and the slave clock can initiate the measurement operation.
The high-precision path delay measuring method suitable for the time synchronization network can be used in combination with the existing time synchronization method, can accurately measure the path delay on line, and can also be independently used as the time synchronization method to be applied to the time synchronization network.
It will be understood that equivalents and modifications will occur to those skilled in the art in light of the present invention and their spirit, and all such modifications and substitutions are intended to be included within the scope of the present invention as defined in the following claims.
Claims (5)
1. The high-precision path delay measuring method suitable for the time synchronization network is characterized by comprising the following steps of:
After the network equipment is electrified, the master clock takes the current moment as the dispatch moment, encapsulates the current dispatch moment into a synchronous measurement frame, and dispatches the synchronous measurement frame to the slave clock in the network;
step two, the slave clock receives the synchronous measurement frame sent by the master clock, carries out solidification treatment on the synchronous measurement frame, then extracts the current dispatch time of the master clock in the synchronous measurement frame, corrects the time of the clock of the slave clock to be the accumulated value of the current dispatch time and the maximum transmission delay of the master clock at the solidification time of the synchronous measurement frame;
The master clock encapsulates the following dispatch time into a following synchronous measurement frame, and dispatches the following synchronous measurement frame to the slave clock in the network by taking the following dispatch time as a dispatch time point;
and step four, receiving a following synchronous measurement frame sent by the master clock from the clock, solidifying the following synchronous measurement frame to obtain the solidifying moment of the following synchronous measurement frame, comparing the solidifying moment of the following synchronous measurement frame with the expected solidifying moment, and calculating to obtain the path correction factor.
2. A method for high accuracy path delay measurement for time synchronized networks according to claim 1, characterized in that said expected solidification momentThe method comprises the following steps:
Wherein, The MD transmits the synchronous measurement frame to any other synchronous clock for any synchronous clock in the time synchronous network to start until the synchronous clock receiving the synchronous measurement frame finishes the solidifying operation of the synchronous measurement frame, the transparent clock in the synchronous measurement frame accumulates to the maximum value, and the solidifying time is expectedThe upper corner mark F in (a) represents the following synchronization measurement frame, M p before the lower corner mark arrow represents the identity of the master clock, and S q after the lower corner mark arrow represents the identity of the receiving end slave clock, that is, the expected solidification moment of the following synchronization measurement frame sent from the master clock to the slave clock.
3. A method for high accuracy path delay measurement for time synchronized networks according to claim 1, characterized in that said follow-up dispatch momentThe method comprises the following steps:
Wherein, The MD is the maximum value of the accumulation of transparent clocks in the synchronization measurement frame after the slave clock finishes the solidification operation of the synchronization measurement frame, which is the time when the synchronization measurement frame is dispatched for the master clock.
4. The method of claim 1, further comprising correcting the current time of the local clock by the slave clock using a path correction factor to complete the time synchronization operation.
5. The method for measuring path delay with high precision for time synchronization network as claimed in claim 1, further comprising storing path correction factors by the slave clock, correcting transparent clock values of synchronization frames transmitted from the master clock in subsequent time synchronization operation, and then performing curing operation to realize accurate measurement of path delay.
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| CN114337895A (en) * | 2021-12-31 | 2022-04-12 | 苏州联视泰电子信息技术有限公司 | Clock synchronization system based on linear daisy chain Ethernet topology |
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| CN110896339A (en) * | 2019-11-29 | 2020-03-20 | 南京航空航天大学 | A Clock Synchronization Compensation Method Based on Local Weighted Least Squares |
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