Precision Time Protocol

About: Precision Time Protocol is a research topic. Over the lifetime, 604 publications have been published within this topic receiving 6006 citations. The topic is also known as: PTP & IEEE 1588.

Application of Precision Time Protocol on Networked Control Systems

Abstract: In order to overcome the problem of the clock synchronization accuracy between scattered nodes was not high on traditional networked control systems, proposed a new method of using the IEEE 1588 standard for precision time protocol. First studied the principle and algorithm of precision time protocol, the best master clock algorithm and timestamp detection methods. Then presented the timestamp detection method with the use of software and hardware on networked control systems to improve clock synchronization accuracy, and analyzed the feasibility of the method in theory. Finally, tested accuracy of the clock synchronization, and the test results showed that synchronization accuracy can reach nanosecond, can meet the application requirements of the networked control systems.

High precision and robustness in network-based clock synchronization using IEEE 1588

Abstract: Network-based clock synchronization is an important prerequisite for many application areas and more and more required for the factory floor for network arbitration, control, and monitoring. Limitations of existing clock synchronization protocols are that they either support high redundancy and robustness or high precision. This paper presents an approach to integrate slave-side robustness into high precision clock synchronization. To achieve this goal, a system design facilitating the IEEE 1588 Precision Time Protocol (PTP) is proposed, which supports multiple masters in parallel and provides highly reliable and robust clock synchronization, while at the same time demanding no changes to the network and timing infrastructure. The slave-side robustness can be further enhanced to provide improved monitoring support for IEEE 1588. This makes the solution especially appealing for large-scale networks where retrofitting must be done efficiently and the network infrastructure is not under the control of the end device operator.

Time synchronization aid device, clock synchronization device, master communication station, and slave communication station

Abstract: PROBLEM TO BE SOLVED: To precisely synchronize clocks of a slave station of a wireless network enabling an IP access based on a PTP (high precision time protocol) synchronization protocol SOLUTION: The device (DA1) aids a clock synchronization device (DS1) by means of a master station (SM) in a wireless network when implementing a time synchronization procedure The master station includes a master clock (HM) represented as a value of a master counter (CM) and means (MG1) for generating wireless frames of IP packets containing particularly PTP messages of first and second types The aid device (DA1) includes detection means (MD1) and triggers sampling of a master clock value when a frame pulse received from the network is detected in a physical layer of the master station COPYRIGHT: (C)2008,JPO&INPIT

Clock calibration method based on PPT

Abstract: The invention belongs to the technical field of time synchronization. In order to solve the problem that if the time of a slave clock in a PTP (Precision Time Protocol) domain is deviated, the time of the slave clock is deviated again within a period of time after the time deviation of the slave clock is calibrated, and the time deviation of the slave clock affects time synchronization of a downstream slave clock relative to the slave clock, the invention provides a clock calibration method based on the PPT, comprising the steps as follows: (1) connecting a time tester with a calibration clock source; (2) connecting the time tester with a slave clock to be calibrated to test the time deviation value M between the slave clock and the calibration clock source; (3) measuring the time deviation value N between a downstream slave clock and the calibration clock source; and (4) calculating the calibration range value of the downstream slave clock according to the trend of the time deviation value M and the time deviation value N. By adopting the clock calibration method of the invention, the influence of time deviation of a slave clock to time synchronization of a downstream slave clock of the salve clock is reduced, and the precision and accuracy of time synchronization are improved.

TFR: A Novel Approach for Clock Synchronization Fault Recovery in Precision Time Protocol (PTP) Networks

Abstract: Accurate and precise clock synchronization is one of the fundamental requirements for various applications, such as telecommunication systems, measurement and control systems, and smart grid systems. Precision time protocol (PTP) was designed and specified in IEEE 1588 to meet that requirement. PTP provides a mechanism for synchronizing the clocks in a PTP system to a high degree of accuracy and precision based on exchange synchronization messages through a master–slave hierarchy. The best master clock (BMC) algorithm is currently used to establish the master–slave hierarchy for PTP. However, the BMC algorithm does not provide a fast recovery mechanism in case of master failures. The accuracy and precision of the PTP clocks could be deteriorated by the occurrence of failure in the network (link or node failure). These fault occurrences will affect network performance and reliability, and cause clock time drifting of the PTP nodes. In this paper, we present a novel approach, called timing fault recovery (TFR), to significantly reduce clock time drifting in PTP systems. TFR detects the fault occurrence in the network and recovers it by using a handshake mechanism with a short duration. Therefore, the TFR approach provides clock stability and constancy and increases the reliability and the availability of PTP systems. The performance of TFR has been analyzed and compared to that of the standard PTP. Various simulations were conducted to validate the performance analysis. The results show that, for our sample network, the TFR approach reduces clock drifting by 90% in comparison to the standard PTP, thus providing better clock firmness and synchronization accuracy for PTP clocks.