Time calibration method and system for time synchronization network

Abstract

The invention discloses a time calibration method and system for a time synchronization network, and relates to the technical field of communication, and the method comprises the steps: installing a clock on each node in the network; time calibration of a master clock is realized by receiving signals of at least two navigation satellites and calculating a time difference between the satellites; message exchange is carried out between the master clock and the slave clock through a network; calculating network delay and clock offset between the master clock and the slave clock; constructing a transparent clock model, recording delay time passing through each node in a message, and performing compensation when network delay is calculated; dynamically selecting a path with lower network delay to perform message exchange between the master clock and the slave clock; and optimizing the clock skew between the master clock and the slave clock. The error calculation module and the error optimization module are arranged to eliminate the uncertainty of most of network delay and message exchange, so that the time synchronization precision is improved, and the long-term stability of synchronization is improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a time calibration method and system for a time synchronization network. Background Art

[0002] Time is the physical quantity with the highest measurement accuracy at present. Precision time not only has an important impact on basic scientific research fields such as the study of relativity and pulsar periods, but also plays a vital role in fields closely related to people's lives, such as aerospace, navigation and communication, and electronic measurement. With the rapid development of network technology and the widespread application of distributed systems, the system has higher and higher requirements for the accuracy of network time synchronization. In the fields of measurement and control, communication, industrial automation, and electric power, microsecond-level requirements have been put forward for time synchronization.

[0003] Traditional network time synchronization methods, such as NTP (Network Time Protocol), are limited by network delays and uncertainty in message exchange, making it difficult to achieve high-precision time synchronization. In particular, in scenarios where sub-microsecond or higher precision synchronization is required, the performance of NTP often fails to meet the requirements. The delay in the network changes dynamically, and the delays of different paths may vary greatly. Traditional network time synchronization methods do not take into account the instability of this delay, so large synchronization errors may occur in actual applications. Summary of the invention

[0004] In order to solve the above technical problems, a time calibration method and system for a time synchronization network are provided. This technical solution solves the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: A time calibration method for a time synchronization network, comprising: Install a clock on each node in the network, select the clock with the highest time accuracy as the master clock, and mark the rest as slave clocks; Based on the principle of continuous common view of navigation satellites, the time calibration of the master clock is achieved by receiving signals from at least two navigation satellites and calculating the time difference between the satellites. The master clock and the slave clock exchange messages through the network, periodically recording and sending time marks to each other; Based on the time stamp of the message exchange between the master clock and the slave clock, the network delay and clock offset between the master clock and the slave clock are calculated; By building a transparent clock model, the delay time of each node is recorded in the message and compensated when calculating the network delay; Adopt multi-path transmission technology to dynamically select the path with lower network delay to exchange messages between the master clock and the slave clock; The clock skew between the master and slave clocks is optimized by monitoring the frequency change of the slave clock and adjusting its frequency to keep consistent with the master clock.

[0006] Preferably, the time calibration of the master clock based on the principle of continuous common view of navigation satellites by receiving signals from at least two navigation satellites and calculating the time difference between the satellites specifically includes: The receiver where the master clock is located receives signals from at least two navigation satellites simultaneously; The signal from the navigation satellite contains the time stamp sent by the navigation satellite and the precise time information of the navigation satellite itself; The receiver where the master clock is located calculates the time difference between the signals received from two navigation satellites; Get the real-time position and speed of navigation satellites; The propagation time difference is corrected based on the real-time position and velocity parameters of the navigation satellite to obtain the time difference between the satellite clocks of the navigation satellites; The master clock calibrates the time of the master clock based on the calculated satellite clock time difference and the known deviation between the satellite clock and the master clock; The time calibration process involves adjusting the frequency and phase of the master clock.

[0007] Preferably, the master clock and the slave clock exchange messages via a network, and periodically record and send time marks to each other, specifically including: The master clock periodically sends synchronization messages to the slave clock and records the first time mark of sending; receiving a synchronization message from the clock and recording a second time mark of receiving; The slave clock periodically records the sending and receiving time of the synchronization message; The slave clock sends a delay message to the master clock and records the sending third time mark; The master clock receives the delayed message and records the receipt of the fourth time mark; The master clock periodically records the sending and receiving time of the delayed message.

[0008] Preferably, the calculating of the network delay and clock offset between the master and slave clocks based on the time mark of the message exchange between the master clock and the slave clock specifically includes: Get the time stamp of the message exchange between the master clock and the slave clock; Based on the time mark of the message exchange between the master clock and the slave clock, the network delay between the master clock and the slave clock is calculated using the network delay formula; Based on the time mark of the message exchange between the master clock and the slave clock, the clock offset between the master clock and the slave clock is calculated using the clock offset formula; The network delay formula is: , In the formula, The network delay between the master and slave clocks, , , , They are the first time mark, the second time mark, the third time mark and the fourth time mark; The clock offset formula is: , In the formula, The clock offset between the master and slave clocks.

[0009] Preferably, the step of constructing a transparent clock model, recording the delay time of each node in the message, and performing compensation when calculating the network delay specifically includes: Construct a point-to-point transparent clock model for the point delay mechanism; The transparent clock model automatically measures the average network transmission delay time between each port and the connected port; When an event message is sent from the master clock to the slave clock, the residence time of the message in the transparent clock is accumulated in the correction domain, and the link delay is accumulated in the correction domain.

[0010] Preferably, the adopting of multi-path transmission technology to dynamically select a path with lower network delay to exchange messages between the master clock and the slave clock specifically includes: Deploy at least one link in the network and set a monitoring node on each link to monitor the network status of the link in real time; Generate a real-time link performance table based on the real-time network status monitored by the monitoring node, wherein the link performance includes the bandwidth, delay and congestion rate of the link; Deploy a dynamic path selection algorithm on the network edge device. The dynamic path selection algorithm selects the transmission path with the lowest network delay based on the real-time link performance table. Splitting the message to be exchanged between the master clock and the slave clock into at least two sub-messages, and allocating the sub-messages according to the path determined by the dynamic path selection algorithm; The sub-messages are transmitted in parallel through at least one path. After reaching the slave clock, the slave clock reassembles these sub-messages to restore the original message; Continuously monitor the network status of each link; Determine whether the network delay increase rate of each link is greater than the preset threshold. If so, trigger the path switching mechanism. If not, no output is made. The path switching mechanism dynamically selects a new optimal path based on the real-time link performance table and quickly switches to the path.

[0011] Furthermore, a time calibration system for a time synchronization network is proposed, which is used to implement the time calibration method for a time synchronization network as described above, comprising: An error calculation module, wherein the error calculation module is used to install a clock on each node in the network, select the clock with the highest time accuracy as the master clock, mark the other clocks as slave clocks, receive signals from at least two navigation satellites based on the principle of continuous common view of navigation satellites, and calculate the time difference between the satellites to achieve time calibration of the master clock, exchange messages between the master clock and the slave clock through the network, periodically record and send time marks to each other, and calculate the network delay and clock offset between the master and slave clocks based on the time marks of the message exchange between the master clock and the slave clock; The error optimization module is used to construct a transparent clock model, record the delay time passing through each node in the message, compensate when calculating the network delay, adopt multi-path transmission technology, dynamically select the path with lower network delay to exchange messages between the master clock and the slave clock, and optimize the clock offset between the master and slave clocks by monitoring the frequency changes of the slave clock and adjusting its frequency to keep consistent with the master clock.

[0012] Optionally, the error calculation module specifically includes: A clock installation unit, which is used to install a clock on each node in the network, and select the clock with the highest time accuracy as the master clock, and mark the remaining clocks as slave clocks; A master clock calibration unit, the master clock calibration unit is used to achieve time calibration of the master clock by receiving signals from at least two navigation satellites and calculating the time difference between the satellites based on the principle of continuous common view of navigation satellites; A message exchange unit, the message exchange unit is used for exchanging messages between the master clock and the slave clock through the network, and periodically recording and sending time marks to each other; The error calculation unit is used to calculate the network delay and clock offset between the master clock and the slave clock based on the time mark of the message exchange between the master clock and the slave clock.

[0013] Optionally, the error optimization module specifically includes: A delay compensation unit, the delay compensation unit is used to record the delay time of each node in the message by building a transparent clock model, and compensate when calculating the network delay; A path selection unit, the path selection unit is used to adopt a multi-path transmission technology to dynamically select a path with a lower network delay to perform message exchange between the master clock and the slave clock; The offset compensation unit is used to optimize the clock offset between the master and slave clocks by monitoring the frequency change of the slave clock and adjusting its frequency to be consistent with the master clock.

[0014] Compared with the prior art, the present invention has the following beneficial effects: By setting up an error calculation module and an error optimization module, most of the network delays and uncertainties in message exchange are eliminated, thereby improving the accuracy of time synchronization and the long-term stability of synchronization. The delay time passing through each node is recorded in the message and compensated when calculating the network delay. This method can effectively eliminate the impact of network delay on time synchronization, dynamically select a path with lower network delay to exchange messages between the master clock and the slave clock, which can further reduce the impact of network delay on time synchronization and improve the stability and accuracy of synchronization. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of a time calibration method for a time synchronization network according to the present invention; Figure 2 A flow chart of a method for implementing time calibration of a master clock according to the present invention; Figure 3 A flow chart of a method for exchanging messages between a master clock and a slave clock via a network according to the present invention; Figure 4 A flow chart of a method for calculating network delay and clock offset between a master and a slave clock according to the present invention; Figure 5 This is a flow chart of the method for building a transparent clock model of the present invention; Figure 6 The present invention dynamically selects a path with lower network delay to perform a message exchange diagram between a master clock and a slave clock. DETAILED DESCRIPTION

[0016] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0017] Reference Figure 1 As shown, a time calibration method for a time synchronization network includes: Install a clock on each node in the network, select the clock with the highest time accuracy as the master clock, and mark the rest as slave clocks; Based on the principle of continuous common view of navigation satellites, the time calibration of the master clock is achieved by receiving signals from at least two navigation satellites and calculating the time difference between the satellites. The master clock and the slave clock exchange messages through the network, periodically recording and sending time marks to each other; Based on the time stamp of the message exchange between the master clock and the slave clock, the network delay and clock offset between the master clock and the slave clock are calculated; By building a transparent clock model, the delay time of each node is recorded in the message and compensated when calculating the network delay; Adopt multi-path transmission technology to dynamically select the path with lower network delay to exchange messages between the master clock and the slave clock; The clock skew between the master and slave clocks is optimized by monitoring the frequency change of the slave clock and adjusting its frequency to keep consistent with the master clock.

[0018] Reference Figure 2 As shown, based on the principle of continuous common view of navigation satellites, by receiving signals from at least two navigation satellites and calculating the time difference between the satellites, the time calibration of the master clock is realized, which specifically includes: The receiver where the master clock is located receives signals from at least two navigation satellites simultaneously; The signal from the navigation satellite contains the time stamp sent by the navigation satellite and the precise time information of the navigation satellite itself; The receiver where the master clock is located calculates the time difference between the two received navigation satellite signals; Get the real-time position and speed of navigation satellites; The propagation time difference is corrected based on the real-time position and velocity parameters of the navigation satellite to obtain the time difference between the satellite clocks of the navigation satellites; The master clock calibrates the time of the master clock based on the calculated satellite clock time difference and the known deviation between the satellite clock and the master clock; The time calibration process involves adjusting the frequency and phase of the master clock.

[0019] The common view principle means that when an event is observed to occur, if another observer observes the same event at the same time and place as the first observer, the first observer can be used to verify the time.

[0020] Reference Figure 3 As shown, the master clock and the slave clock exchange messages through the network, and periodically record and send time marks to each other, specifically including: The master clock periodically sends synchronization messages to the slave clock and records the first time mark of sending; receiving a synchronization message from the clock and recording a second time mark of receiving; The slave clock periodically records the sending and receiving time of the synchronization message; The slave clock sends a delay message to the master clock and records the sending third time mark; The master clock receives the delayed message and records the receipt of the fourth time mark; The master clock periodically records the sending and receiving time of the delayed message.

[0021] Determine the period of the master clock sending synchronization messages, once per second. The master clock sends synchronization messages to the slave clock through the network according to the set period; the synchronization message is mainly used to start the time synchronization process and measure the propagation delay from the master clock to the slave clock; the delay message is used to measure the propagation delay from the slave clock to the master clock and allow the slave clock to calculate the time offset.

[0022] Reference Figure 4 As shown, based on the time mark of the message exchange between the master clock and the slave clock, the network delay and clock offset between the master and slave clocks are calculated specifically including: Get the time stamp of the message exchange between the master clock and the slave clock; Based on the time mark of the message exchange between the master clock and the slave clock, the network delay between the master clock and the slave clock is calculated using the network delay formula; Based on the time mark of the message exchange between the master clock and the slave clock, the clock offset between the master clock and the slave clock is calculated using the clock offset formula; The network delay formula is: , In the formula, The network delay between the master and slave clocks, , , , They are the first time mark, the second time mark, the third time mark and the fourth time mark; The clock offset formula is: , In the formula, The clock offset between the master and slave clocks.

[0023] Since the time it takes for a message to be transmitted in the network is symmetrical (assuming the network conditions are stable), we only need to use the network delay formula to calculate the network delay for one-way transmission between the master and slave clocks to obtain the network delay for mutual transmission between the master and slave clocks.

[0024] Reference Figure 5 As shown in the figure, by building a transparent clock model, the delay time of each node is recorded in the message, and compensation is performed when calculating the network delay. Specifically, it includes: Construct a point-to-point transparent clock model for the point delay mechanism; The transparent clock model automatically measures the average network transmission delay time between each port and the connected port; When an event message is sent from the master clock to the slave clock, the residence time of the message in the transparent clock is accumulated in the correction domain, and the link delay is accumulated in the correction domain.

[0025] The transparent clock also records and accumulates the delay time of the synchronization message within it, and includes this delay time in a specific field of the message. When the slave device calculates the path delay, the delay time in this field is taken into account, thereby more accurately measuring and compensating for the delay on each link.

[0026] Reference Figure 6 As shown, multi-path transmission technology is used to dynamically select a path with lower network delay to exchange messages between the master clock and the slave clock. Specifically, the following steps are included: Deploy at least one link in the network and set a monitoring node on each link to monitor the network status of the link in real time; Generate a real-time link performance table based on the real-time network status monitored by the monitoring node, wherein the link performance includes the bandwidth, delay and congestion rate of the link; Deploy a dynamic path selection algorithm on the network edge device. The dynamic path selection algorithm selects the transmission path with the lowest network delay based on the real-time link performance table. Splitting the message to be exchanged between the master clock and the slave clock into at least two sub-messages, and allocating the sub-messages according to the path determined by the dynamic path selection algorithm; The sub-messages are transmitted in parallel through at least one path. After reaching the slave clock, the slave clock reassembles these sub-messages to restore the original message; Continuously monitor the network status of each link; Determine whether the network delay increase rate of each link is greater than the preset threshold. If so, trigger the path switching mechanism. If not, no output is made. The path switching mechanism dynamically selects a new optimal path based on the real-time link performance table and quickly switches to the path.

[0027] The core of multi-path transmission technology lies in path selection and data grouping. Path selection technology refers to selecting the optimal transmission path based on network load, bandwidth, delay and other indicators during data transmission. Data grouping technology divides data into small blocks and transmits them through different paths, and finally reassembles them at the destination. This technology can significantly improve bandwidth utilization and reduce network delay and transmission loss rate.

[0028] Further, based on the same inventive concept as the above-mentioned time calibration method for a time synchronization network, the present solution also proposes a time calibration system for a time synchronization network, comprising: An error calculation module, wherein the error calculation module is used to install a clock on each node in the network, select the clock with the highest time accuracy as the master clock, mark the other clocks as slave clocks, receive signals from at least two navigation satellites based on the principle of continuous common view of navigation satellites, and calculate the time difference between the satellites to achieve time calibration of the master clock, exchange messages between the master clock and the slave clock through the network, periodically record and send time marks to each other, and calculate the network delay and clock offset between the master and slave clocks based on the time marks of the message exchange between the master clock and the slave clock; The error optimization module is used to construct a transparent clock model, record the delay time passing through each node in the message, compensate when calculating the network delay, adopt multi-path transmission technology, dynamically select the path with lower network delay to exchange messages between the master clock and the slave clock, and optimize the clock offset between the master and slave clocks by monitoring the frequency changes of the slave clock and adjusting its frequency to keep consistent with the master clock.

[0029] The error calculation module specifically includes: A clock installation unit, which is used to install a clock on each node in the network, and select the clock with the highest time accuracy as the master clock, and mark the remaining clocks as slave clocks; A master clock calibration unit, the master clock calibration unit is used to achieve time calibration of the master clock by receiving signals from at least two navigation satellites and calculating the time difference between the satellites based on the principle of continuous common view of navigation satellites; A message exchange unit, the message exchange unit is used for exchanging messages between the master clock and the slave clock through the network, and periodically recording and sending time marks to each other; The error calculation unit is used to calculate the network delay and clock offset between the master clock and the slave clock based on the time mark of the message exchange between the master clock and the slave clock.

[0030] The error optimization module specifically includes: A delay compensation unit, the delay compensation unit is used to record the delay time of each node in the message by building a transparent clock model, and compensate when calculating the network delay; A path selection unit, the path selection unit is used to adopt a multi-path transmission technology to dynamically select a path with a lower network delay to perform message exchange between the master clock and the slave clock; The offset compensation unit is used to optimize the clock offset between the master and slave clocks by monitoring the frequency change of the slave clock and adjusting its frequency to be consistent with the master clock.

[0031] Furthermore, the present solution also proposes a computer-readable storage medium on which a computer-readable program is stored. When the computer-readable program is called, the time calibration method for a time synchronization network is executed.

[0032] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state drive (SSD).

[0033] In summary, the advantages of the present invention are: by setting an error calculation module and an error optimization module, most of the network delays and uncertainties in message exchange are eliminated, thereby improving the accuracy of time synchronization, improving the long-term stability of synchronization, recording the delay time passing through each node in the message, and compensating when calculating the network delay. This method can effectively eliminate the impact of network delay on time synchronization, dynamically select a path with lower network delay to exchange messages between the master clock and the slave clock, which can further reduce the impact of network delay on time synchronization and improve the stability and accuracy of synchronization.

[0034] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A time calibration method for a time synchronization network, characterized in that: include: Install a clock on each node in the network, select the clock with the highest time accuracy as the master clock, and mark the rest as slave clocks; Based on the principle of continuous common view of navigation satellites, the time calibration of the master clock is achieved by receiving signals from at least two navigation satellites and calculating the time difference between the satellites. The master clock and the slave clock exchange messages through the network, periodically recording and sending time marks to each other; Based on the time stamp of the message exchange between the master clock and the slave clock, the network delay and clock offset between the master clock and the slave clock are calculated; By building a transparent clock model, the delay time of each node is recorded in the message and compensated when calculating the network delay; Adopt multi-path transmission technology to dynamically select the path with lower network delay to exchange messages between the master clock and the slave clock; The clock skew between the master and slave clocks is optimized by monitoring the frequency change of the slave clock and adjusting its frequency to keep consistent with the master clock.

2. A time calibration method for a time synchronization network according to claim 1, characterized in that: The method of realizing time calibration of the master clock based on the principle of continuous common view of navigation satellites by receiving signals from at least two navigation satellites and calculating the time difference between the satellites specifically includes: The receiver where the master clock is located receives signals from at least two navigation satellites simultaneously; The signal from the navigation satellite contains the time stamp sent by the navigation satellite and the precise time information of the navigation satellite itself; The receiver where the master clock is located calculates the time difference between the two received navigation satellite signals; Get the real-time position and speed of navigation satellites; The propagation time difference is corrected based on the real-time position and velocity parameters of the navigation satellite to obtain the time difference between the satellite clocks of the navigation satellites; The master clock calibrates the time of the master clock based on the calculated satellite clock time difference and the known deviation between the satellite clock and the master clock; The time calibration process involves adjusting the frequency and phase of the master clock.

3. A time calibration method for a time synchronization network according to claim 2, characterized in that: The master clock and the slave clock exchange messages through the network, and periodically record and send time marks to each other, specifically including: The master clock periodically sends synchronization messages to the slave clock and records the first time mark of sending; receiving a synchronization message from the clock and recording a second time mark of receiving; The slave clock periodically records the sending and receiving time of the synchronization message; The slave clock sends a delay message to the master clock and records the sending third time mark; The master clock receives the delayed message and records the receipt of the fourth time mark; The master clock periodically records the sending and receiving time of the delayed message.

4. A time calibration method for a time synchronization network according to claim 3, characterized in that: The calculating of the network delay and clock offset between the master and slave clocks based on the time mark of the message exchange between the master clock and the slave clock specifically includes: Get the time stamp of the message exchange between the master clock and the slave clock; Based on the time mark of the message exchange between the master clock and the slave clock, the network delay between the master clock and the slave clock is calculated using the network delay formula; Based on the time mark of the message exchange between the master clock and the slave clock, the clock offset between the master clock and the slave clock is calculated using the clock offset formula; The network delay formula is: ， In the formula, The network delay between the master and slave clocks, , , , They are the first time mark, the second time mark, the third time mark and the fourth time mark; The clock offset formula is: ， In the formula, The clock offset between the master and slave clocks.

5. A time calibration method for a time synchronization network according to claim 4, characterized in that: The transparent clock model is constructed to record the delay time of each node in the message and compensate for it when calculating the network delay. Specifically, it includes: Construct a point-to-point transparent clock model for the point delay mechanism; The transparent clock model automatically measures the average network transmission delay time between each port and the connected port; When an event message is sent from the master clock to the slave clock, the residence time of the message in the transparent clock is accumulated in the correction domain, and the link delay is accumulated in the correction domain.

6. A time calibration method for a time synchronization network according to claim 5, characterized in that: The method of using multi-path transmission technology to dynamically select a path with lower network delay to exchange messages between the master clock and the slave clock specifically includes: Deploy at least one link in the network and set a monitoring node on each link to monitor the network status of the link in real time; Generate a real-time link performance table based on the real-time network status monitored by the monitoring node, wherein the link performance includes the bandwidth, delay and congestion rate of the link; Deploy a dynamic path selection algorithm on the network edge device. The dynamic path selection algorithm selects the transmission path with the lowest network delay based on the real-time link performance table. Splitting the message to be exchanged between the master clock and the slave clock into at least two sub-messages, and allocating the sub-messages according to the path determined by the dynamic path selection algorithm; The sub-messages are transmitted in parallel through at least one path. After reaching the slave clock, the slave clock reassembles these sub-messages to restore the original message; Continuously monitor the network status of each link; Determine whether the network delay increase rate of each link is greater than the preset threshold. If so, trigger the path switching mechanism. If not, no output is made. The path switching mechanism dynamically selects a new optimal path based on the real-time link performance table and quickly switches to the path.

7. A time calibration system for a time synchronization network, used to implement the time calibration method for a time synchronization network according to any one of claims 1 to 6, characterized in that: include: An error calculation module, wherein the error calculation module is used to install a clock on each node in the network, select the clock with the highest time accuracy as the master clock, mark the other clocks as slave clocks, receive signals from at least two navigation satellites based on the principle of continuous common view of navigation satellites, and calculate the time difference between the satellites to achieve time calibration of the master clock, exchange messages between the master clock and the slave clock through the network, periodically record and send time marks to each other, and calculate the network delay and clock offset between the master and slave clocks based on the time marks of the message exchange between the master clock and the slave clock; The error optimization module is used to construct a transparent clock model, record the delay time passing through each node in the message, compensate when calculating the network delay, adopt multi-path transmission technology, dynamically select the path with lower network delay to exchange messages between the master clock and the slave clock, and optimize the clock offset between the master and slave clocks by monitoring the frequency changes of the slave clock and adjusting its frequency to keep consistent with the master clock.

8. A time calibration system for a time synchronization network according to claim 7, characterized in that: The error calculation module specifically includes: A clock installation unit, which is used to install a clock on each node in the network, and select the clock with the highest time accuracy as the master clock, and mark the remaining clocks as slave clocks; A master clock calibration unit, the master clock calibration unit is used to achieve time calibration of the master clock by receiving signals from at least two navigation satellites and calculating the time difference between the satellites based on the principle of continuous common view of navigation satellites; A message exchange unit, the message exchange unit is used for exchanging messages between the master clock and the slave clock through the network, and periodically recording and sending time marks to each other; The error calculation unit is used to calculate the network delay and clock offset between the master clock and the slave clock based on the time mark of the message exchange between the master clock and the slave clock.

9. A time calibration system for a time synchronization network according to claim 8, characterized in that: The error optimization module specifically includes: A delay compensation unit, the delay compensation unit is used to record the delay time of each node in the message by building a transparent clock model, and compensate when calculating the network delay; A path selection unit, the path selection unit is used to adopt a multi-path transmission technology to dynamically select a path with a lower network delay to perform message exchange between the master clock and the slave clock; The offset compensation unit is used to optimize the clock offset between the master and slave clocks by monitoring the frequency change of the slave clock and adjusting its frequency to be consistent with the master clock.

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