CN102710359A - Accurate clock frequency synchronizing method and device based on IEEE1588 (institute of electrical and electronics engineers) - Google Patents
Accurate clock frequency synchronizing method and device based on IEEE1588 (institute of electrical and electronics engineers) Download PDFInfo
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- CN102710359A CN102710359A CN2012102169532A CN201210216953A CN102710359A CN 102710359 A CN102710359 A CN 102710359A CN 2012102169532 A CN2012102169532 A CN 2012102169532A CN 201210216953 A CN201210216953 A CN 201210216953A CN 102710359 A CN102710359 A CN 102710359A
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Abstract
The invention provides an accurate clock frequency synchronizing method and device based on IEEE1588 (institute of electrical and electronics engineers), wherein the method comprises the following steps: receiving a clock synchronizing message sent from a master clock, parsing the clock synchronizing message so as to obtain a first frequency compensation value; calculating a second frequency compensation value according to the complete clock cycle count and incomplete clock cycle count of a local clock measured out by a plurality of detecting nodes, wherein the time space of adjacent detecting nodes is less than the clock cycle of the local clock; and synchronizing the frequency of the local clock according to the first frequency compensation value and the second frequency compensation value. The incomplete clock cycle is measured accurately by multiple detecting nodes and the measured results are reflected in the frequency compensation value, in this way, the accuracy of the frequency compensation value is enhanced so as to enhance the synchronizing precision of the node clock frequency.
Description
Technical field
The present invention relates to the EPA technical field, relate in particular to a kind of precision clock frequency synchronization method and device based on IEEE1588.
Background technology
Develop rapidly along with computer network; Increasing industrial circle is had higher requirement to clock synchronization; Especially be that the synchronous requirement to clock synchronization has reached the submicrosecond level in the dcs on basis with the EPA at great majority.Particularly in intelligent substation, dcs, consider real-time data acquisition, scheduling and control, just more strict to the requirement of time unification.
The IEEE1588 standard definition a kind of Precision Time Protocol (Precision Time Protocol; PTP), this agreement is that distributed observing and controlling application designs, and adds the thought of timestamp based on message flow; Adopt implementation soft, combination of hardware, be intended to realize the synchronization accuracy of submicrosecond level.The PTP agreement is the accurate clock synchronization protocol that proposes to the distributed network TT&C system; Can the independent clock of all kinds of different accuracy, resolution and stability on each node device that operates in the local area network (LAN) be synchronized on the unified time standard; Take minimum network and local computational resource, and guarantee the higher synchronous precision.The complete compatible ethernet technology of this agreement owing to its high synchronization accuracy, implemented with low cost, make things convenient for superiority such as I&M, has obtained in power supply management, Industry Control, test and fields such as measurement, network service using widely.
The Frequency Synchronization of clock is meant the difference on the frequency that produces according to reference clock source and local clock, the difference on the frequency that obtains with certain algorithm process, and, reached the synchronous purpose of nodal clock and master clock according to the output frequency of this difference on the frequency adjustment local clock.Wide the sending out that fixes on EPA along with the IEEE1588 standard used, and the Frequency Synchronization of carrying out clock as the clock source with IEEE 1588 messages just becomes means commonly used in the EPA.
But the conventional clock synchronizing method based on IEEE1588 is only revised the time of local clock, and the frequency of local clock is not revised.Yet nodal clock generally is to realize time measurement with a counter that is driven by the active or passive crystal oscillator of cheapness.Owing to reasons such as variations in temperature, electromagnetic interference, aging of oscillator and production debugging, can go out a deviation between the oscillator frequency of clock and the standard frequency.If these deviations are not revised through accumulating for a long time, will make clock time occur bigger drift at short notice.
Address the above problem so as to keep nodal clock well the method for timekeeping performance have two kinds, the one, adopt stable performance, the higher crystal oscillator of precision; But this can increase the cost of system, and in addition, the crystal oscillator problem of aging is still inevitable.The 2nd, adopt specific algorithm and circuit that crystal oscillator frequency is compensated dynamically; To eliminate of the influence of clock unsteadiness to synchronization accuracy; Yet the method for existing measurement master clock pulse per second (PPS) belongs to bigness scale, can only can't measure non-complete clock periodicity according to the complete clock periodicity of performance measurement in the unit interval of local crystal oscillator; This error will be very big under special situation; Therefore, the frequency compensation value that existing method is calculated is not accurate enough, thereby causes the synchronization accuracy of nodal clock frequency to can not get ensureing.
Summary of the invention
In view of this, the present invention provides a kind of precision clock frequency synchronization method and device based on IEEE1588, in order to solve in the prior art because frequency compensation value inaccuracy, and the low problem of nodal clock Frequency Synchronization precision that causes.
The invention provides a kind of precision clock frequency synchronization method based on IEEE1588, this method comprises:
Receive the clock synchronization message that clock equipment is sent, resolve said clock synchronization message, obtain the first frequency offset;
The complete clock periodicity and the non-complete clock periodicity of the local clock of measuring according to a plurality of detection node that are provided with calculate the second frequency offset, and wherein, the time interval of adjacent detection node is less than the clock cycle of local clock
According to said first frequency offset and said second frequency offset, the frequency of local clock is carried out synchronously.
The present invention also provides a kind of precision clock frequency synchronization device based on IEEE1588, and this device comprises:
Receiver module is used to receive the clock synchronization message that clock equipment is sent, and resolves said clock synchronization message, obtains the first frequency offset;
Computing module is used for complete clock periodicity and non-complete clock periodicity according to the local clock of a plurality of detection node measurements that are provided with, calculates the second frequency offset, and wherein, the time interval of adjacent detection node is less than the clock cycle of local clock;
Synchronization module is used for according to said first frequency offset and said second frequency offset the frequency of local clock being carried out synchronously.
The invention provides a kind of precision clock frequency synchronization method and device based on IEEE1588, this method is resolved said clock synchronization message through receiving the clock synchronization message that clock equipment is sent, and obtains the first frequency offset; The complete clock periodicity and the non-complete clock periodicity of the local clock of measuring according to a plurality of detection node that are provided with calculate the second frequency offset, and wherein, the time interval of adjacent detection node is less than the clock cycle of local clock; According to said first frequency offset and said second frequency offset, the frequency of local clock is carried out synchronously.Through a plurality of detection node are set the non-complete clock cycle is accurately measured in the present invention; And measurement result embodied in the frequency compensation value; Therefore, effectively raise the accuracy of frequency compensation value, thereby increased the synchronization accuracy of nodal clock frequency.
Description of drawings
Accompanying drawing described herein is used to provide further understanding of the present invention; Constitute a part of the present invention; Illustrative examples of the present invention and explanation thereof are used to explain the present invention; Do not constitute the circuit time delay of measuring before of the present invention is carried out clock alignment, simultaneously, node device is to main equipment forward delay interval request message and write down its corresponding transmitting time as delay measurements transmitting time stamp t
S2After [k], main equipment receive and resolve and be somebody's turn to do the request message of delaying time, and reply time-delay to node device and answer message, the time of reception of the slave unit time-delay request message that this message of record has after receiving the answer message of delaying time stabs t as the delay measurements time of reception
M2[k] and new line time delay value more.
S102: resolve said clock synchronization message, obtain the first frequency offset.
Concrete, node device is through four timestamps of record, side-play amount Offset computing time [k]=t
S1[k]-t
M1[k]-Delay_latest, and adopt frequency compensation formula calculated rate offset FreqCompValue [K]
Wherein, Δ u [k] is the variable quantity of frequency compensation value, the system time of pairing master clock when r [k] receives sync message the k time for slave unit, and node device estimates to its value that according to the circuit time delay value of measuring estimated value is: r [k]=t
M1[k]+Delay_latest; Y [k] for slave unit when receiving sync message the k time from the clock system time, y [k]=t
S1[k]; FreqCompValue [0]=2
q/ Ratio, CompPrecision≤1/ (T
SyncF
Norm), 2
q>=Ratio/CompPrecision, 2
r>=2
q/ Ratio, 2
p>=2
q, wherein: f
PLLBe the frequency of behind PLL, exporting from the crystal oscillator of clock module, f
NormBe the nominal frequency from clock and master clock system time, Ratio=f
PLL/ f
Norm, CompPrecision is the frequency compensation precision, T
SyncSend the cycle of sync message for main equipment.
S103: the complete clock periodicity and the non-complete clock periodicity of the local clock of measuring according to a plurality of detection node that are provided with, calculate the second frequency offset, wherein, the time interval of adjacent detection node is less than the clock cycle of local clock.
In addition, the present invention is to the measurement umber of pulse time, and said a plurality of detection node according to setting are measured non-complete clock periodicity and comprised:
Improper qualification.In the accompanying drawings:
Fig. 1 is the process sketch map of a kind of precision clock Frequency Synchronization based on IEEE1588 provided by the invention;
Fig. 2 is the structural representation of a kind of accurate measurement local clock periodicity provided by the invention;
Fig. 3 is the detailed process sketch map of a kind of precision clock Frequency Synchronization based on IEEE1588 provided by the invention;
Fig. 4 is the structural representation of a kind of precision clock frequency synchronization device based on IEEE1588 provided by the invention.
Embodiment
In order to make technical problem to be solved by this invention, technical scheme and beneficial effect clearer, clear,, the present invention is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
The embodiment of the invention is in order to solve in the prior art because frequency compensation value inaccuracy; And the low problem of nodal clock Frequency Synchronization precision that causes provides a kind of precision clock frequency synchronization method and device based on IEEE1588, thereby has effectively realized the non-complete clock cycle is accurately measured; And measurement result is increased in the frequency compensation value; Therefore, effectively raise the accuracy of frequency compensation value, thereby increased the synchronization accuracy of nodal clock frequency.
Below in conjunction with Figure of description, the present invention is elaborated.
Fig. 1 is the process sketch map of a kind of precision clock Frequency Synchronization based on IEEE1588 provided by the invention, and this process comprises following step:
S101: nodal clock equipment receives the clock synchronization message that clock equipment is sent.
Main equipment the multicast mode cycle send the sync message to each node device, node device receives this sync message, and write down this sync message time of reception stab t as time of reception
S1[k], main equipment sends and has sync message transmitting time stamp t then
M1[k] follows message, and node device is according to working as
Each detection node place before first complete clock period measurement; Detect and impulse hits whether occurs; When impulse hits occurring, the sequence number of the detection node of detected this impulse hits of record is according to the sequence number of this detection node; And the cycle that is provided with of detection node, confirm the first non-complete clock periodicity; Each detection node place after complete clock period measurement in the end; Detect and impulse hits whether occurs; When impulse hits occurring, the sequence number of the detection node of detected this impulse hits of record is according to the sequence number of this detection node; And the cycle that is provided with of detection node, confirm the second non-complete clock periodicity;
According to the first non-complete clock periodicity and the second non-complete clock periodicity, confirm non-complete clock periodicity.
S104:, the frequency of local clock is carried out synchronously according to said first frequency offset and said second frequency offset.
In addition; In the present invention in order further to improve certainty of measurement; The frequency compensation value that get rid of that master clock switches or link failure etc. causes is unusually to the influence of certainty of measurement, and node device is according to first frequency offset and second frequency offset, and the frequency of local clock is comprised synchronously:
First frequency offset and second frequency offset are added up, judge that frequency compensation value after said the adding up is whether greater than the threshold value of current saved;
When the frequency compensation value after confirming said adding up is not more than this threshold value, according to the frequency of the frequency compensation value correction local clock after said the adding up.
Frequency compensation value after confirming said adding up keeps the frequency of local clock constant during greater than this threshold value.
In addition; The present invention can be provided with being provided with of threshold value manually; Also can generate automatically according to the clock synchronization message of master clock and the performance of local crystal oscillator; In order to improve the filter capacity of threshold value, and get rid of because the aging influence that causes of local crystal oscillator threshold value to exception message, in the present invention when definite frequency compensation value after first frequency offset and second frequency offset are added up during greater than preset threshold; Adopt the frequency compensation value after said the adding up, this threshold value is adjusted through certain algorithm.
Node device calculates the first frequency offset except the clock synchronization message that sends according to main equipment in the present invention; Also measure and accurately measure non-integer umber of pulse in the umber of pulse through a plurality of detection node that are provided with; And said measurement result embodied through the second frequency offset; Thereby effectively raise the accuracy of the frequency compensation value between master clock and the nodal clock, thereby increased the synchronization accuracy of nodal clock frequency.
Fig. 2 is the structural representation of a kind of accurate measurement pulses per second provided by the invention, and in this sketch map, T0 is the clock cycle of a complete local clock; T1 and T2 are the non-complete clock cycle, and the complete clock periodicity that can only measure in the prior art in the 1S is pulse per second (PPS) PPS, still; Can not accurately measure for incomplete clock cycle T1 and T2, can only abandon or compensate basically, and the present invention is through inserting a plurality of monitoring points in the unit interval with an estimated value; Measure each detection node place before in first clock cycle, detect impulse hits whether occurs, when impulse hits occurring; The sequence number of the detection node of detected this impulse hits of record; According to the sequence number of this detection node, and the cycle that is provided with of detection node, confirm the first non-complete clock periodicity T1; In the end a clock cycle is measured each detection node place afterwards, detects impulse hits whether occurs, when impulse hits occurring; The sequence number of the detection node of detected this impulse hits of record, according to the sequence number of this detection node, and the cycle that is provided with of detection node; Confirm the second non-complete clock periodicity T2, wherein, the time interval of the adjacent detection node of insertion is less than the clock cycle of local clock; For example, the performance of local clock crystal oscillator is 10MPPS, and the time interval that adjacent detection node can be set according to the present invention is 100PS; Through inserting 1000 detection node, can effectively precision be controlled at nanosecond.
Fig. 3 is the detailed process sketch map of a kind of precision clock Frequency Synchronization based on LEEE1588 provided by the invention, and in this sketch map, detailed process comprises following several steps:
S301: nodal clock equipment receives the clock synchronization message that clock equipment is sent.
S302: resolve said clock synchronization message, obtain the first frequency offset.
S303: the complete clock periodicity and the non-complete clock periodicity of the local clock of measuring according to a plurality of detection node that are provided with, calculate the second frequency offset, wherein, the time interval of adjacent detection node is less than the clock cycle of local clock.
S304: first frequency offset and second frequency offset are added up, judge frequency compensation value after said the adding up whether greater than the threshold value of current saved, when result of determination when being, carry out step S306, otherwise, carry out step S305.
S305: according to the frequency of the frequency compensation value correction local clock after said the adding up.
S306: keep the frequency of local clock constant.
S307: adopt the frequency compensation value after said the adding up, threshold value is adjusted through certain algorithm.
Fig. 4 is the structural representation of a kind of precision clock frequency synchronization device based on IEEE1588 provided by the invention, and this device comprises:
This frequency synchronization device also comprises:
Said synchronization module 43; Specifically be used for first frequency offset and second frequency offset are added up; Judge that frequency compensation value after said the adding up is whether greater than the threshold value of current saved; When the frequency compensation value after confirming said adding up is not more than this threshold value, according to the frequency of the frequency compensation value correction local clock after said the adding up.
, said synchronization module 43, when specifically also being used for frequency compensation value after confirming said adding up greater than this threshold value, the frequency of maintenance local clock is constant.
This frequency synchronization device also comprises:
Threshold value adjusting module 45 is used for when the frequency compensation value after said the adding up during greater than this threshold value, adopts the frequency compensation value after said the adding up that this threshold value is adjusted.
The invention provides a kind of precision clock frequency synchronization method and device based on IEEE1588, this method is resolved said clock synchronization message through receiving the clock synchronization message that clock equipment is sent, and obtains the first frequency offset; The complete clock periodicity and the non-complete clock periodicity of the local clock of measuring according to a plurality of detection node that are provided with calculate the second frequency offset, and wherein, the time interval of adjacent detection node is less than the clock cycle of local clock; According to said first frequency offset and said second frequency offset, the frequency of local clock is carried out synchronously.Through a plurality of detection node are set the non-complete clock cycle is accurately measured in the present invention; And measurement result embodied in the frequency compensation value; Therefore, effectively raise the accuracy of frequency compensation value, thereby increased the synchronization accuracy of nodal clock frequency.
Above-mentioned explanation illustrates and has described the preferred embodiments of the present invention; But as previously mentioned; Be to be understood that the present invention is not limited to the form that this paper discloses, should do not regard eliminating as, and can be used for various other combinations, modification and environment other embodiment; And can in invention contemplated scope described herein, change through the technology or the knowledge of above-mentioned instruction or association area.And change that those skilled in the art carried out and variation do not break away from the spirit and scope of the present invention, then all should be in the protection range of accompanying claims of the present invention.
Claims (10)
1. precision clock frequency synchronization method based on IEEE1588 is characterized in that said method comprises:
Receive the clock synchronization message that clock equipment is sent, resolve said clock synchronization message, obtain the first frequency offset;
The complete clock periodicity and the non-complete clock periodicity of the local clock of measuring according to a plurality of detection node that are provided with calculate the second frequency offset, and wherein, the time interval of adjacent detection node is less than the clock cycle of local clock;
According to said first frequency offset and said second frequency offset, the frequency of local clock is carried out synchronously.
2. the method for claim 1 is characterized in that, the integer clock periodicity and the non-integer clock periodicity of the said local clock of measuring according to a plurality of detection node that are provided with comprise:
Each detection node place before first complete clock period measurement detects impulse hits whether occurs;
When impulse hits occurring, the sequence number of the detection node of detected this impulse hits of record;
According to the sequence number of this detection node, and the cycle that is provided with of detection node, confirm the first non-complete clock periodicity;
In the end complete clock period measurement each detection node place afterwards detects impulse hits whether occurs;
When impulse hits occurring, the sequence number of the detection node of detected this impulse hits of record;
According to the sequence number of this detection node, and the cycle that is provided with of detection node, confirm the second non-complete clock periodicity;
According to the first non-complete clock periodicity and the second non-complete clock periodicity, confirm non-complete clock periodicity.
3. the method for claim 1 is characterized in that, and is said according to said first frequency offset and said second frequency offset, and the frequency of local clock is comprised synchronously:
First frequency offset and second frequency offset are added up, judge that frequency compensation value after said the adding up is whether greater than the threshold value of current saved;
When the frequency compensation value after confirming said adding up is not more than this threshold value, according to the frequency of the frequency compensation value correction local clock after said the adding up.
4. method as claimed in claim 3 is characterized in that, the frequency compensation value after confirming said adding up keeps the frequency of local clock constant during greater than this threshold value.
5. method as claimed in claim 4 is characterized in that, said method also comprises:
When the frequency compensation value after said the adding up during, adopt the frequency compensation value after said the adding up that this threshold value is adjusted greater than this threshold value.
6. precision clock frequency synchronization device based on IEEE1588 is characterized in that said device comprises:
Receiver module is used to receive the clock synchronization message that clock equipment is sent, and resolves said clock synchronization message, obtains the first frequency offset;
Computing module is used for complete clock periodicity and non-complete clock periodicity according to the local clock of a plurality of detection node measurements that are provided with, calculates the second frequency offset, and wherein, the time interval of adjacent detection node is less than the clock cycle of local clock;
Synchronization module is used for according to said first frequency offset and said second frequency offset the frequency of local clock being carried out synchronously.
7. device as claimed in claim 6 is characterized in that, said device also comprises:
Measurement module; Be used for each the detection node place before first complete clock period measurement, detect impulse hits whether occurs, when impulse hits occurring; The sequence number of the detection node of detected this impulse hits of record; According to the sequence number of this detection node, and the cycle that is provided with of detection node, confirm the first non-complete clock periodicity; Each detection node place after complete clock period measurement in the end; Detect and impulse hits whether occurs; When impulse hits occurring, the sequence number of the detection node of detected this impulse hits of record is according to the sequence number of this detection node; And the cycle that is provided with of detection node, confirm the second non-complete clock periodicity; According to the first non-complete clock periodicity and the second non-complete clock periodicity, confirm non-complete clock periodicity.
8. device as claimed in claim 6; It is characterized in that; Said synchronization module specifically is used for first frequency offset and second frequency offset are added up; Judge that frequency compensation value after said the adding up is whether greater than the threshold value of current saved, when the frequency compensation value after confirming said adding up is not more than this threshold value, according to the frequency of the frequency compensation value correction local clock after said the adding up.
9. device as claimed in claim 8 is characterized in that, when said synchronization module specifically also is used for frequency compensation value after confirming said adding up greater than this threshold value, keeps the frequency of local clock constant.
10. device as claimed in claim 9 is characterized in that, said device also comprises:
The threshold value adjusting module is used for when the frequency compensation value after said the adding up during greater than this threshold value, adopts the frequency compensation value after said the adding up that this threshold value is adjusted.
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CN104505934A (en) * | 2014-12-01 | 2015-04-08 | 国电南瑞科技股份有限公司 | Clock synchronizing and monitoring system |
US10421074B2 (en) | 2013-12-13 | 2019-09-24 | Ge Healthcare Bio-Sciences Ab | Foldable microplate |
CN110995540A (en) * | 2019-12-13 | 2020-04-10 | 中国电子科技集团公司第五十四研究所 | PTP network time on-line monitoring module |
CN113483650A (en) * | 2021-06-26 | 2021-10-08 | 山东航天电子技术研究所 | Novel eddy current sensor measuring method |
CN113691339A (en) * | 2021-08-18 | 2021-11-23 | 北京车和家信息技术有限公司 | Clock synchronization method, device, equipment and storage medium |
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US10421074B2 (en) | 2013-12-13 | 2019-09-24 | Ge Healthcare Bio-Sciences Ab | Foldable microplate |
CN104505934A (en) * | 2014-12-01 | 2015-04-08 | 国电南瑞科技股份有限公司 | Clock synchronizing and monitoring system |
CN104505934B (en) * | 2014-12-01 | 2017-02-22 | 国电南瑞科技股份有限公司 | Clock synchronizing and monitoring system |
CN110995540A (en) * | 2019-12-13 | 2020-04-10 | 中国电子科技集团公司第五十四研究所 | PTP network time on-line monitoring module |
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CN113691339A (en) * | 2021-08-18 | 2021-11-23 | 北京车和家信息技术有限公司 | Clock synchronization method, device, equipment and storage medium |
CN113691339B (en) * | 2021-08-18 | 2023-09-29 | 北京车和家信息技术有限公司 | Clock synchronization method, device, equipment and storage medium |
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