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.

Design and Implementation of a Switching Controller for Transient Improvement in a Time Synchronization System

Abstract: Currently, many large and complex systems, such as telecommunication systems, power systems, and automated manufacture systems, require their distributed clocks to be synchronized to the master clock. This paper discusses implementation of a distributed embedded time-synchronized system, based on the IEEE 1588 standard. Two important requirements exist in time synchronization. One is that the clocks be synchronized at maximum speed. The other is that the clocks operate at optimum precision and accuracy over the long term. This paper proposes a switching controller, which combines a fuzzy control scheme and a traditional proportional integral (PI) control scheme to meet the aforementioned two requirements. The traditional PI control scheme was used in the steady state, whereas the fuzzy control scheme was adopted in the transient stage. The experimental results showed that in the fuzzy control scheme, transient time, which is the length of time in the transient state, was reduced to 50% of the transient time in the PI control scheme.

Wireless synchronization protocols for collaborative robotic and sensor environments

Abstract: In this paper we consider the problem of time synchronization in collaborative environments of robots and intelligent sensors. Due to its superior performance, the Precision Time Protocol (PTP) has been implemented and tested using various topologies of complex, multi-hop networks. Two distinct approaches have been studied. The first one uses boundary clocks, while the second uses a transparent clock for the intermediary nodes. A set of experiments and simulations have been conducted with the OMNeT++ environment. Finally, we propose and discuss a modified version of the PTP protocol, specifically designed to consider the particular problems of networks with mobile robotic nodes.

Adapter that converts enhanced long range navigation (eLORAN) to precision time protocol (PTP)

Abstract: A method and system are provided for converting an enhanced Long Range Navigational (eLORAN) signal to a Precision Time Protocol (PTP) signal. Network devices can be located within buildings and not have access to a GPS signal directly from a GPS satellite. Network devices may also be located in a line of sight of a GPS satellite but may lose the GPS signal. An adapter is provided that takes an eLORAN signal, when a GPS signal is lost or not available, and converts the signal into a PTP and other signals to act as timing, synchronization, and syntonization inputs into the network devices. In some cases, the network devices can have a PTP client to receive the PTP signal, one pulse per second signal, and a ten (10) megahertz frequency signal. In other cases, the network devices do not have a PTP client, but can receive a time of day message, one pulse per second signal, and the 10 megahertz frequency signal.

Distributed measurement system for the assesment of IEC 61850 transfer time in smart grid

Abstract: The rise of Smart Grids based on IEC61850 standard requires specialized measurement systems in order to characterize the main performance parameters. In this paper, a new distributed measurement system for the estimation of IEC61850 Transfer Time over Smart Grid communication infrastructure is introduced. The structure of a possible implementation, based on specialized sampling devices coordinated by a virtual instrument, is described in details. The synchronization uncertainty of the distributed system is below 30ns, (thanks to the use of IEE1588 Precision Time Protocol), while the measurement extended uncertainty is below 100ns. A test case is used to demonstrate the system feasibility and the effectiveness of the obtained results: the evaluation of sample IEC61850 devices highlighted their weak points, allowing for a correct classification of their Transfer Time Class (according to IEC61850).

Precise time protocol in Ethernet over SDH network

Abstract: This article deals with transmission of Precision Time Protocol (PTP) over SDH (Synchronous Digital Hierarchy) network. Precision Time Protocol described in standard IEEE 1588 — Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems — is a protocol for synchronization in packet networks. This article discusses the transmission of Ethernet synchronization messages over existing SDH networks. The introduction in this paper provides possibilities of synchronization in telecommunication networks and packet networks. Synchronous Ethernet and Precision Time Protocol are methods for synchronization in packet network. The second part of this article describes several measurements and comparisons of the accuracy of precision time distribution for different conditions in Ethernet over SDH network. These results are also commented here and several conclusions about the influence of transmission capacity are given in this article.