CN112202523A - Double-fiber double-wave time transfer system and instantaneous clock error estimation method - Google Patents

Double-fiber double-wave time transfer system and instantaneous clock error estimation method Download PDF

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CN112202523A
CN112202523A CN202011078893.3A CN202011078893A CN112202523A CN 112202523 A CN112202523 A CN 112202523A CN 202011078893 A CN202011078893 A CN 202011078893A CN 112202523 A CN112202523 A CN 112202523A
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clock
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slave
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CN112202523B (en
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吴苗
陈丁
许江宁
李方能
梁益丰
谭小容
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Naval University of Engineering PLA
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0682—Clock or time synchronisation in a network by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging

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Abstract

The invention discloses a double-fiber double-wave time transmission system and an instantaneous clock error estimation method, wherein a master time service station and a slave time service station are connected through an optical fiber link, the master time service station and the slave time service station are respectively provided with a laser emitter, a wavelength division multiplexing module, a time difference measuring module, a light detector, a transmitting channel and a receiving channel, the master time service station is also provided with a time signal holding module, and the slave time service station is also provided with a clock and a time delay compensation module. The method can accurately measure and calculate the clock error of the master station and the slave station, realize real-time automatic compensation and improve the time transmission precision of the optical fiber.

Description

Double-fiber double-wave time transfer system and instantaneous clock error estimation method
Technical Field
The invention relates to the technical field of optical fiber time service synchronization, in particular to a double-fiber double-wave time transmission system and an instantaneous clock error estimation method.
Background
With the continuous breakthrough of the high-precision frequency standard technology, the precision of the atomic frequency standard with the highest precision at present reaches 10-16The second and day stability of light clock reach 10-16And 10-18In order of magnitude, time has become the physical quantity with the highest measurement accuracy among 7 international basic units. With the continuous improvement of the requirements on time synchronization precision and stability in the fields of scientific research, navigation positioning, aerospace, power transmission, military safety and the like, how to transmit high-precision time-frequency information to each user side becomes an important subject in the field.
Due to the unique advantages of low loss, high stability, large bandwidth and the like, the optical fiber time-frequency synchronization technology has become one of the highest-precision time service means in recent years. According to the actual condition of laying the optical cable network, the method has very important practical significance for researching the long-distance high-precision optical fiber time transmission method.
At present, the main methods for researching the optical fiber time transfer technology are as follows: 1) dual-fiber bidirectional same-wavelength transmission technology, 2) single-fiber bidirectional wavelength division multiplexing technology, 3) single-fiber bidirectional loopback method, 4) single-fiber bidirectional time division multiplexing technology and the like. Compared with the method in the 4, the dual-fiber bidirectional same-wavelength transmission has the problems that the lengths of optical fiber links are unequal, and the length of the existing network optical fiber cannot be accurately measured; the single-fiber bidirectional wavelength division multiplexing and loopback method has the defects that the round-trip wavelength and the refractive index are not equal, so that the round-trip delay is asymmetric, and a time service system lacks the tracking estimation of the change of the delay difference value influenced by the change of the environment temperature due to the difficulty in measuring the environment temperature; the single-fiber bidirectional time division technology has high cost and is difficult to be applied in a large range.
In an actual optical fiber link, the optical fiber link is inevitably influenced by environmental factors, such as pressure, temperature change and the like, wherein the temperature change can obviously influence the transmission delay value of the optical fiber link, and is a main factor influencing the transmission precision based on the single-fiber bidirectional wavelength division multiplexing and the loopback method. For the round trip delay in the WDM technology based loopback transmissionDifference τλ1-τλ1The calculation of (2) is mainly related to methods given by a time service center of a Chinese academy, namely 'an automatic compensation device and method for delay deviation in optical fiber time transmission' (application publication No. CN 109302258A, application No. 201811526157.2). The estimation method directly converts tauλ1And τλ2The relationship between the two is quantitatively analyzed (at normal temperature), and the delay variation under the temperature variation condition is not considered. Therefore, the method is only suitable for testing under the room temperature condition in a laboratory, and further analysis is needed for the actually laid optical fiber.
In summary, the problems of the prior art are as follows: the existing optical fiber time service method with the cost, the technical maturity and the precision suitable for large-scale networking is a loopback transfer method based on WDM technology, but the existing optical fiber transfer technology is usually only applied in a laboratory constant temperature environment, the time delay difference change under the temperature change condition is not considered, and meanwhile, a method for estimating the round-trip time delay difference under the temperature change environment is not adopted in the prior art, so that the time service precision of actually laying an optical cable network is influenced to a certain extent, and therefore the factor is urgently considered for the practicability of optical fiber time service.
Disclosure of Invention
The present invention is directed to a dual-fiber dual-wave time transfer system and an instantaneous clock error estimation method for solving the above problems.
The difficulty of solving the technical problems is as follows: if the real-time temperature of the fiber core can be always grasped, the round-trip delay can be directly calculated, and the delay difference can be accurately calculated. However, even if the temperature of the surface of the measuring fiber is simply maintained and the test data is transmitted to the delay difference calculating section, it is difficult to do so. Meanwhile, the error of estimating the fiber core temperature through the fiber surface temperature is large, and the fact that the temperature of the optical cable network, the optical fiber and the fiber core is different due to the fact that the temperature is often transmitted through the optical cable network in the actual environment is considered, and it is basically impossible to obtain required data through direct measurement, so that a better method is not provided at present.
The significance of solving the technical problems is as follows: under the condition of temperature change, the clock error of a master station and a slave station is solved by measuring the time delay values of 4 paths of time signals on two optical fibers and according to the ratio relation of time delays, so that the influence factors of the optical fiber length caused by the temperature change are eliminated in the algorithm, and the influence factors of the time delay values with different wavelengths along with the temperature change are eliminated.
The invention realizes the purpose through the following technical scheme:
the invention relates to a double-fiber double-wave time transmission system, which comprises a master time service station and a slave time service station, wherein the master time service station and the slave time service station are connected through an optical fiber link, the master time service station and the slave time service station are respectively provided with a laser transmitter, a wavelength division multiplexing module, a time difference measuring module, an optical detector, a transmitting channel and a receiving channel, the master time service station is also provided with a time signal holding module, the slave time service station is also provided with a clock and a time delay compensation module, and the laser transmitter is used for converting a time signal into an optical signal; the wavelength division multiplexing module is used for modulating a time signal to two different wavelengths and sending the two different wavelengths to an optical fiber link, the input end of a transmitting channel is connected with the output end of a laser transmitter, and the output end of the transmitting channel is used for being connected with the optical fiber link; the output end of a receiving channel of the wavelength division multiplexing module is connected with the input end of a receiver, and the input end of the receiving channel is used for being connected with an optical fiber link; the time difference measuring module is used for measuring the starting and stopping time of the sending or receiving signal and outputting the time difference value of the sending or receiving signal; the optical detector is used for receiving a time signal sent by the opposite station; and the time delay compensation module is used for compensating the time signal of the slave station clock to be disciplined according to the estimated clock difference value.
Furthermore, the optical fiber link is composed of two optical fibers, and the lengths of the optical fibers are L respectively1And L2The Clock A of the master time service station is used as a reference Clock source, the Clock B of the slave time service station is used as a Clock to be tamed, and the Clock difference between the Clock A and the Clock B is delta T; at the same time, the time signal of the Clock A of the master time service station is modulated and then has the wavelength lambda1And λ2Via optical fiber L1Sending the data to a slave station; the time signal of the slave time service station Clock B is modulated with the wavelength lambda1And λ2Via optical fiber L2And transmitting to the master station.
Further, the length of the main time service station is L1To the wavelength lambda transmitted from the time service station1The transmission time delay of the time signal in the optical fiber link is tau1(ii) a The length of the master time service station is L1Wavelength lambda of the optical fibre transmitting to the slave station2The transmission time delay of the time signal in the optical fiber link is tau2(ii) a The slave time service station has a length of L2Wavelength lambda of the optical fiber to the main time service station1The transmission time delay of the time signal in the optical fiber link is tau3(ii) a The slave time service station has a length of L1Wavelength lambda of the optical fiber to the main time service station2The transmission time delay of the time signal in the optical fiber link is tau4。
The invention discloses an instantaneous clock error estimation method of a double-fiber double-wave time transfer system, which comprises the following steps:
step 1: the value TIC is obtained by measuring through 4 time measuring modules1、TIC2、TIC3And TIC4；
Step 2: calculating the clock difference value delta T of the master station and the slave station according to the relational expression of the measured value, the time delay value and the clock difference obtained in the step 1 and by combining the time delay ratio relation;
and step 3: according to the clock difference value obtained in the step 2, a slave station clock is compensated through a slave station time delay compensation module, and time synchronization of a master station and a slave station is achieved;
and 4, step 4: and (4) repeating the step 1 to the step 3 to obtain the instantaneous clock error so as to realize the real-time synchronization of the master station and the slave station.
Further, two time interval counters TIC are installed on the main time service station1And TIC2，TIC1The time interval measuring device is used for measuring the time interval from the time when the master station Clock A sends a time signal to the time when the master time service station receives the time signal sent by the slave time service station Clock B, namely: TIC1＝τ3+ΔT；TIC2For measuring length L2On the optical fiber from the time service station to the master time service station1And λ2The delay difference of the time signal of (a), namely: TIC2＝τ3-τ4(ii) a Installing a time interval counter TIC from a time service station3And TIC4，TIC3For measuring length L1From the time service station to the master station1And λ2The time delay difference of the time signal is as follows: TIC3＝τ1-τ2；TIC4The time interval for measuring the time interval from the time when the time service station Clock B sends out the time signal to the time when the time service station receives the time signal sent by the master time service station Clock A, namely: TIC4＝τ2-ΔT。
Further, the optical fiber transmission time delay tau1、τ2、τ3、τ4The relationship with the fiber length, transmission wavelength and refractive index is:
Figure BDA0002717771650000041
Figure BDA0002717771650000042
wherein tau is optical fiber transmission time delay, L is optical fiber length, C is optical speed, n is refractive index, and lambda is wavelength;
so as to obtain the compound with the characteristics of,
Figure BDA0002717771650000051
thus, it is possible to obtain:
Figure BDA0002717771650000052
according to TIC1＝τ3+ΔT，TIC2＝τ3-τ4，TIC3＝τ1-τ2，TIC4＝τ2- Δ T and
Figure BDA0002717771650000053
the Clock difference Δ T of the master Clock a and the slave Clock B can be solved by five equations:
Figure BDA0002717771650000054
and sending the calculated Clock difference delta T to a time delay compensation module, and compensating a Clock B at the slave station.
The invention has the beneficial effects that:
the invention relates to a double-fiber double-wave time transmission system and an instantaneous clock difference estimation method, compared with the prior art, the invention can solve the technical problem that the environmental temperature change affects the optical fiber time synchronization precision, simultaneously solve the technical problems that the length of an optical fiber link cannot be measured and the fiber core temperature change affects the optical fiber length when being laid on the spot, and the like, can accurately measure and calculate the clock difference of a master station and a slave station by measuring the transmission time delay and the time delay difference of two wavelengths and four paths of time signals and eliminating the influence of the environmental temperature on the refractive index, the optical signal transmission group time delay, the optical fiber length and the like in an algorithm, can realize real-time automatic compensation, and can improve the optical fiber time transmission precision.
Drawings
FIG. 1 is a schematic diagram of the method of the present invention;
FIG. 2 is a timing diagram of the method of the present invention;
FIG. 3 is a TIC of the present invention1An actual measurement value;
FIG. 4 is a TIC of the present invention2An actual measurement value;
FIG. 5 is a TIC of the present invention3An actual measurement value;
FIG. 6 is a TIC of the present invention4An actual measurement value;
fig. 7 is a graph of the clock difference Δ T estimation accuracy of the present invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings in which:
the invention relates to a double-fiber double-wave time transmission system, which comprises a master time service station and a slave time service station, wherein the master time service station and the slave time service station are connected through an optical fiber link, the master time service station and the slave time service station are respectively provided with a laser transmitter, a wavelength division multiplexing module, a time difference measuring module, an optical detector, a transmitting channel and a receiving channel, the master time service station is also provided with a time signal holding module, the slave time service station is also provided with a clock and a time delay compensation module, and the laser transmitter is used for converting a time signal into an optical signal; the wavelength division multiplexing module is used for modulating a time signal to two different wavelengths and sending the two different wavelengths to an optical fiber link, the input end of a transmitting channel is connected with the output end of a laser transmitter, and the output end of the transmitting channel is used for being connected with the optical fiber link; the output end of a receiving channel of the wavelength division multiplexing module is connected with the input end of a receiver, and the input end of the receiving channel is used for being connected with an optical fiber link; the time difference measuring module is used for measuring the starting and stopping time of the sending or receiving signal and outputting the time difference value of the sending or receiving signal; the optical detector is used for receiving a time signal sent by the opposite station; and the time delay compensation module is used for compensating the time signal of the slave station clock to be disciplined according to the estimated clock difference value.
Furthermore, the optical fiber link is composed of two optical fibers, and the lengths of the optical fibers are L respectively1And L2The Clock A of the master time service station is used as a reference Clock source, the Clock B of the slave time service station is used as a Clock to be tamed, and the Clock difference between the Clock A and the Clock B is delta T; at the same time, the time signal of the Clock A of the master time service station is modulated and then has the wavelength lambda1And λ2Via optical fiber L1Sending the data to a slave station; the time signal of the slave time service station Clock B is modulated with the wavelength lambda1And λ2Via optical fiber L2And transmitting to the master station.
Further, the length of the main time service station is L1To the wavelength lambda transmitted from the time service station1The transmission time delay of the time signal in the optical fiber link is tau1(ii) a The length of the master time service station is L1Wavelength lambda of the optical fibre transmitting to the slave station2The transmission time delay of the time signal in the optical fiber link is tau2(ii) a The slave time service station has a length of L2Wavelength lambda of the optical fiber to the main time service station1The transmission time delay of the time signal in the optical fiber link is tau3(ii) a The slave time service station has a length of L1Wavelength lambda of the optical fiber to the main time service station2The transmission time delay of the time signal in the optical fiber link is tau4。
As shown in fig. 1: the invention discloses an instantaneous clock error estimation method of a double-fiber double-wave time transfer system, which comprises the following steps:
step 1: the value TIC is obtained by measuring through 4 time measuring modules1、TIC2、TIC3And TIC4；
Step 2: calculating the clock difference value delta T of the master station and the slave station according to the relational expression of the measured value, the time delay value and the clock difference obtained in the step 1 and by combining the time delay ratio relation;
and step 3: according to the clock difference value obtained in the step 2, a slave station clock is compensated through a slave station time delay compensation module, and time synchronization of a master station and a slave station is achieved;
and 4, step 4: and (4) repeating the step 1 to the step 3 to obtain the instantaneous clock error so as to realize the real-time synchronization of the master station and the slave station.
The sequence of the above method steps is as follows:
TIC3＝τ1-τ2 (1)
TIC2＝τ3-τ4 (2)
TIC1＝τ3+ΔT (3)
TIC4＝τ2-ΔT (4)
Figure BDA0002717771650000071
Figure BDA0002717771650000072
two time interval counters TIC are installed on main time service station1And TIC2，TIC1The time interval measuring device is used for measuring the time interval from the time when the master station Clock A sends a time signal to the time when the master time service station receives the time signal sent by the slave time service station Clock B, namely: TIC1＝τ3+ΔT；TIC2For measuring length L2On the optical fiber from the time service station to the master time service station1And λ2The delay difference of the time signal of (a), namely: TIC2＝τ3-τ4(ii) a Installing a time interval counter TIC from a time service station3And TIC4，TIC3For measuring length L1From the time service station to the master stationWavelength of transmission lambda1And λ2The time delay difference of the time signal is as follows: TIC3＝τ1-τ2；TIC4The time interval for measuring the time interval from the time when the time service station Clock B sends out the time signal to the time when the time service station receives the time signal sent by the master time service station Clock A, namely: TIC4＝τ2-ΔT。
Further, the optical fiber transmission time delay tau1、τ2、τ3、τ4The relationship with the fiber length, transmission wavelength and refractive index is:
Figure BDA0002717771650000081
Figure BDA0002717771650000082
wherein tau is optical fiber transmission time delay, L is optical fiber length, C is optical speed, n is refractive index, and lambda is wavelength;
so as to obtain the compound with the characteristics of,
Figure BDA0002717771650000083
thus, it is possible to obtain:
Figure BDA0002717771650000084
according to TIC1＝τ3+ΔT，TIC2＝τ3-τ4，TIC3＝τ1-τ2，TIC4＝τ2- Δ T and
Figure BDA0002717771650000085
the Clock difference Δ T of the master Clock a and the slave Clock B can be solved by five equations:
Figure BDA0002717771650000086
and sending the calculated Clock difference delta T to a time delay compensation module, and compensating a Clock B at the slave station.
And (3) experimental verification:
experiment setting parameter table
Parameter(s) Value of Parameter(s) Value of
Optical fiber model G.652 Initial temperature -20℃
Optical fiber L1Length of 100km Amplitude of temperature change 60℃
Optical fiber L2Length of 75km Period of temperature change 60min
Loss of optical fiber 0.187dB/km Wavelength lambda1 1310nm
TIC measurement accuracy 10ps Wavelength lambda2 1550nm
In order to increase the inconsistency of the length of the round-trip link, the master time service station and the slave time service station are connected through G.652 single-mode optical fibers of 100km and 75km to form a double-fiber link. In order to simulate adjacent round-trip optical fibers in the same optical cable in a field time service system and ensure the consistency of the temperature change of the optical fibers caused by the environmental temperature change, all the optical fibers are products with the same batch and the same specification and are placed in a programmable temperature control box. After the experiment starts to measure, the temperature of the optical fiber environment is raised from room temperature of-20 ℃ to 40 ℃ within 0min to 60min by using a constant temperature box, and then the temperature is kept unchanged, so that the delay fluctuation of the optical signal in the optical fiber is changed. All equipment and optical fiber links of the master time service site and the slave time service site are placed in the same laboratory for convenience of data measurement and performance evaluation. In order to reduce random fluctuation and measurement errors of optical fiber devices and measurement platform hardware caused by environment temperature fluctuation, the environment temperature of a laboratory is controlled to be about 23 ℃, so that optical signals with specific wavelengths emitted by two lasers are not easy to generate wavelength drift.
Four groups of time delay data need to be measured in the experiment, and are respectively measured by four time measuring chips with the resolution ratio of 10 ps.
TIC located at primary time service site1The time interval measuring device is used for measuring the time interval from the time when the master station Clock A sends a time signal to the time when the master time service station receives the time signal sent by the slave time service station Clock B, namely: TIC1＝τ3+ Δ T, the measurement results are shown in fig. 3.
TIC located at primary time service site2For measuring length L2On the optical fiber from the time service station to the master time service station1And λ2The delay difference of the time signal of (a), namely: TIC2＝τ3-τ4The measurement results are shown in fig. 4.
TIC located at slave time service site3For measuring length L1From the time service station to the master station1And λ2The time delay difference of the time signal is as follows: TIC3＝τ1-τ2The measurement results are shown in fig. 5.
TIC located at slave time service site4The time interval for measuring the time interval from the time when the time service station Clock B sends out the time signal to the time when the time service station receives the time signal sent by the master time service station Clock A, namely: TIC4＝τ2Δ T, the measurement results are shown in FIG. 6.
By passing
Figure BDA0002717771650000091
The calculated clock difference between the master time service station and the slave time service station is compared with the measured clock difference, and the clock difference estimation accuracy can be obtained as shown in fig. 7.
The invention provides a method for accurately estimating clock error of a master station and a slave station under the environment of temperature change, thereby greatly saving cost, improving time transmission precision of optical fibers and expanding the application environment of the method. The invention can reduce the time delay difference of the optical fiber changing within-20-40 ℃ by about 100ps when using 1490nm and 1550nm wavelength at two ends of 100km optical fiber, and if the conventional 1310nm/1550nm wavelength pair combination is adopted, the time service precision is improved by about 300 ps. The invention can help the optical cable network which is actually laid to greatly improve the time service precision, and has important practical significance and application value.
The foregoing shows and describes the general principles and features of the present invention, together with the advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (6)

1. A dual fiber dual wave time transfer system characterized by: the time delay line comprises a master time service site and a slave time service site, wherein the master time service site and the slave time service site are connected through an optical fiber link, the master time service site and the slave time service site are respectively provided with a laser transmitter, a wavelength division multiplexing module, a time difference measuring module, an optical detector, a transmitting channel and a receiving channel, the master time service site is also provided with a time signal holding module, the slave time service site is also provided with a clock and a time delay compensation module, and the laser transmitter is used for converting a time signal into an optical signal; the wavelength division multiplexing module is used for modulating a time signal to two different wavelengths and sending the two different wavelengths to an optical fiber link, the input end of a transmitting channel is connected with the output end of a laser transmitter, and the output end of the transmitting channel is used for being connected with the optical fiber link; the output end of a receiving channel of the wavelength division multiplexing module is connected with the input end of a receiver, and the input end of the receiving channel is used for being connected with an optical fiber link; the time difference measuring module is used for measuring the starting and stopping time of the sending or receiving signal and outputting the time difference value of the sending or receiving signal; the optical detector is used for receiving a time signal sent by the opposite station; and the time delay compensation module is used for compensating the time signal of the slave station clock to be disciplined according to the estimated clock difference value.
2. The dual fiber dual wave time transfer system of claim 1 wherein: the optical fiber link is composed of two optical fibers with respective lengths of L1And L2The Clock A of the master time service station is used as a reference Clock source, the Clock B of the slave time service station is used as a Clock to be tamed, and the Clock difference between the Clock A and the Clock B is delta T; at the same time, the time signal of the Clock A of the master time service station is modulated and then has the wavelength lambda1And λ2Via optical fiber L1Sending the data to a slave station; the time signal of the slave time service station Clock B is modulated with the wavelength lambda1And λ2Via optical fiber L2And transmitting to the master station.
3. The dual fiber dual wave time transfer system of claim 2 wherein: the length of the master time service station is L1To the wavelength lambda transmitted from the time service station1The transmission time delay of the time signal in the optical fiber link is tau1(ii) a The length of the master time service station is L1Wavelength lambda of the optical fibre transmitting to the slave station2Time signal in optical fiber chainPropagation delay in the path of tau2(ii) a The slave time service station has a length of L2Wavelength lambda of the optical fiber to the main time service station1The transmission time delay of the time signal in the optical fiber link is tau3(ii) a The slave time service station has a length of L1Wavelength lambda of the optical fiber to the main time service station2The transmission time delay of the time signal in the optical fiber link is tau4。
4. An instantaneous clock error estimation method of a double-fiber double-wave time transfer system is characterized by comprising the following steps: the method comprises the following steps:
step 1: the value TIC is obtained by measuring through 4 time measuring modules1、TIC2、TIC3And TIC4；
Step 2: calculating the clock difference value delta T of the master station and the slave station according to the relational expression of the measured value, the time delay value and the clock difference obtained in the step 1 and by combining the time delay ratio relation;
and step 3: according to the clock difference value obtained in the step 2, a slave station clock is compensated through a slave station time delay compensation module, and time synchronization of a master station and a slave station is achieved;
and 4, step 4: and (4) repeating the step 1 to the step 3 to obtain the instantaneous clock error so as to realize the real-time synchronization of the master station and the slave station.
5. The method of estimating an instantaneous clock error of a dual-fiber dual-wave time transfer system according to claim 3, characterized in that: two time interval counters TIC are installed on main time service station1And TIC2，TIC1The time interval measuring device is used for measuring the time interval from the time when the master station Clock A sends a time signal to the time when the master time service station receives the time signal sent by the slave time service station Clock B, namely: TIC1＝τ3+ΔT；TIC2For measuring length L2On the optical fiber from the time service station to the master time service station1And λ2The delay difference of the time signal of (a), namely: TIC2＝τ3-τ4(ii) a Installing a time interval counter TIC from a time service station3And TIC4，TIC3For measuring length L1On the optical fiberThe time station sends a wavelength lambda to the master station1And λ2The time delay difference of the time signal is as follows: TIC3＝τ1-τ2；TIC4The time interval for measuring the time interval from the time when the time service station Clock B sends out the time signal to the time when the time service station receives the time signal sent by the master time service station Clock A, namely: TIC4＝τ2-ΔT。
6. The method of estimating an instantaneous clock error of a dual-fiber dual-wave time transfer system according to claim 4, wherein: optical fibre transmission time delay tau1、τ2、τ3、τ4The relationship with the fiber length, transmission wavelength and refractive index is:
Figure RE-FDA0002773191500000021
Figure RE-FDA0002773191500000031
wherein tau is optical fiber transmission time delay, L is optical fiber length, C is optical speed, n is refractive index, and lambda is wavelength;
so as to obtain the compound with the characteristics of,
Figure RE-FDA0002773191500000032
thus, it is possible to obtain:
Figure RE-FDA0002773191500000033
according to TIC1＝τ3+ΔT，TIC2＝τ3-τ4，TIC3＝τ1-τ2，TIC4＝τ2- Δ T and
Figure RE-FDA0002773191500000034
the Clock difference Δ T of the master Clock a and the slave Clock B can be solved by five equations:
Figure RE-FDA0002773191500000035
and sending the calculated Clock difference delta T to a time delay compensation module, and compensating a Clock B at the slave station.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113252088A (en) * 2021-05-18 2021-08-13 电子科技大学 Multi-wavelength distributed optical fiber sensing system and method
CN114265093A (en) * 2021-12-06 2022-04-01 中国人民解放军海军工程大学 Satellite clock error forecasting method, system, medium, equipment and terminal
CN114427922A (en) * 2021-12-20 2022-05-03 九江学院 Method for measuring real-time temperature of optical fiber link
CN116599619A (en) * 2023-07-17 2023-08-15 成都通航科技有限公司 High-precision remote optical fiber synchronization system
CN117240393A (en) * 2023-11-13 2023-12-15 四川长虹新网科技有限责任公司 Multi-AP (access point) combination-oriented high-precision time-frequency synchronization method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130209096A1 (en) * 2010-09-20 2013-08-15 Michel Le Pallec Method for correcting a delay asymmetry
CN104954093A (en) * 2015-06-29 2015-09-30 北京无线电计量测试研究所 High-precision remote time transmission system and method based on optical fibers
CN105187275A (en) * 2015-08-28 2015-12-23 四川泰富地面北斗科技股份有限公司 Method and device for measuring optical fiber transmission link asymmetric time delay
CN105933085A (en) * 2016-04-27 2016-09-07 西南民族大学 Asymmetric fiber link transmission delay measuring method
CN109302258A (en) * 2018-12-13 2019-02-01 中国科学院国家授时中心 The autocompensation installation and method of time-delay deviation in a kind of transmitting of optical fiber time

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130209096A1 (en) * 2010-09-20 2013-08-15 Michel Le Pallec Method for correcting a delay asymmetry
CN104954093A (en) * 2015-06-29 2015-09-30 北京无线电计量测试研究所 High-precision remote time transmission system and method based on optical fibers
CN105187275A (en) * 2015-08-28 2015-12-23 四川泰富地面北斗科技股份有限公司 Method and device for measuring optical fiber transmission link asymmetric time delay
CN105933085A (en) * 2016-04-27 2016-09-07 西南民族大学 Asymmetric fiber link transmission delay measuring method
CN109302258A (en) * 2018-12-13 2019-02-01 中国科学院国家授时中心 The autocompensation installation and method of time-delay deviation in a kind of transmitting of optical fiber time

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113252088A (en) * 2021-05-18 2021-08-13 电子科技大学 Multi-wavelength distributed optical fiber sensing system and method
CN114265093A (en) * 2021-12-06 2022-04-01 中国人民解放军海军工程大学 Satellite clock error forecasting method, system, medium, equipment and terminal
CN114427922A (en) * 2021-12-20 2022-05-03 九江学院 Method for measuring real-time temperature of optical fiber link
CN116599619A (en) * 2023-07-17 2023-08-15 成都通航科技有限公司 High-precision remote optical fiber synchronization system
CN116599619B (en) * 2023-07-17 2023-09-22 成都通航科技有限公司 High-precision remote optical fiber synchronization system
CN117240393A (en) * 2023-11-13 2023-12-15 四川长虹新网科技有限责任公司 Multi-AP (access point) combination-oriented high-precision time-frequency synchronization method
CN117240393B (en) * 2023-11-13 2024-01-23 四川长虹新网科技有限责任公司 Multi-AP (access point) combination-oriented high-precision time-frequency synchronization method

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