Highly accurate synchronization has become a major requirement because of the rise of distributed applications, regulatory requests and position, navigation and timing backup needs. This fact has led to the development of new technologies which fulfill the new requirements in terms of accuracy and dependability. Nevertheless, some of these novel proposals have lacked determinism, robustness, interoperability, deployability, scalability or management tools preventing them to be extensively used in real industrial scenarios. Different segments require accurate timing information over a large number of nodes. Due to the high availability and low price of global satellite-based time references, many critical distributed facilities depend on them. However, the vulnerability to jamming or spoofing represents a well-known threat and backup systems need to be deployed to mitigate it. The recently approved draft standard IEEE 1588-2019 includes the High Accuracy Default Precision Time Protocol Profile which is intensively based on the White Rabbit protocol. White Rabbit is an extension of current IEEE 1588-2008 network synchronization protocol for sub-nanosecond synchronization. This approach has been validated and intensively used during the last years. This paper revises the pre-standard protocol to expose the challenges that the High Accuracy profile will find after its release and covers existing applications, promising deployments and the technological roadmap, providing hints and an overview of features to be studied. The authors review different issues that have prevented the industrial adoption of White Rabbit in the past and introduce the latest developments that will facilitate the next IEEE 1588 High Accuracy extensive adoption. INDEX TERMS GPS backup, high accuracy profile, IEEE 1588, time dissemination, precision time protocol, PTP, white rabbit.
Distributed data acquisition (DAQ) systems are in charge of converting different analog environment signals into digital values to perform control and monitor tasks. They require a computer network technology to share data between their different elements. One of their main issues is to match data with the specific events under study. A possible solution is to include an event synchronization technology such as Network Time Protocol (NTP), Precise Time Protocol (PTP), or White Rabbit (WR). This contribution proposes a high-performance distributed timing system based on the WR technology. We focus on the square kilometer array (SKA) project as an example of the distributed DAQ system. The SKA project has a strict timing requirements for its operation with a performance below 2 ns. This accuracy is not achievable by current standard synchronization technologies such as NTP or PTP. Under this context, the authors propose the WR zynq embedded node (WR-ZEN) platform as a candidate for the SKA's pulse per second (PPS) distribution system. It is a new design that integrates the WR technology, thus enabling the subnanosecond accuracy. Finally, the WR-ZEN has been evaluated in different scenarios to demonstrate its timing performance in dynamic environment conditions fulfilling the SKA telescope requirements for PPS distribution.
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