T6: Trustworthy Traceable Terrestrial Time Transfer Technology

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Innovate UK
Innovate UK
Innovate UK
Innovate UK
Innovate UK

£690,590

Nov. 1, 2022

Jan. 31, 2024

Modern technological living is dependent on infrastructures which have been developed over the past hundred years, such as electrical power, telecommunications, and transportation. These infrastructures go unnoticed, but they are at the heart of modern business, work, and services. One of the underlying technologies behind making these services work, is the capability to precisely synchronize time to an agreed standard.

Coordinated Universal Time (UTC) was established to allow for a single, precise standard which can be used anywhere in the world and, for some critical services, we need to maintain very close synchronisation to UTC.

A laptop or home computer has a simple clock technology that is only accurate to a few seconds every day. When it connects to the Internet, it synchronizes automatically to within a few hundredths or thousandths of a second (10-3), and this is accurate enough for most domestic and business users. In some industries, such as telecommunications and power, we need to be able to synchronize to millionths of a second (10-6). For example, for modern electricity, "Smart Grid" requires this sort of accuracy for some of its instrumentation and systems. This requires very specialist timing equipment. There are industrial and scientific applications which require accuracies of billionths of a second (10-9), such as navigation systems. To achieve 10-6 or better, we use expensive and complex atomic clocks. We must be able to synchronize these clocks, and for that purpose we use timing signals from navigation satellites, such as those used for GPS.

Unfortunately, over the past 30 years of satellite navigation, it has become obvious that satellite systems can be easily jammed, preventing their reception, causing a Denial of Service (DoS) attack on the critical infrastructure of a region. We could have a backup synchronisation system using conventional computer networks as we do on the Internet (10-3), but this would not provide sufficient accuracy. In this project, we will use conventional computer networks which will be adapted to transfer precision time. A clock will be established at Queen's University Belfast (QUB) with time which is traceable to UTC. Broadband NI Ltd. (BNI) have a comprehensive data communications network which will be configured to transfer precision time. BNI have many wind farm customers, one of which will be selected to pilot the service. Staff at QUB and the Atlantic Technological University (ATU) will contribute to measurement and management, to determine the efficacy of this project.

The proposed change to the scope of the project involves shifting from the originally planned use of the National Time Scale, UTC(NPL), to instead utilise UTC(NSAI) from the National Standards Authority of Ireland. WP1 was intended to establish a regional 'time node' at Queen's University Belfast and explore time transfer solutions that enable traceability of time to the UTC(NPL) without the need for a GNSS clock. As is detailed in the next section, challenges have been identified with regards getting the NPL time scale to QUB.

WP2 is not dependent on WP1, but a "whole system solution" without GNSS is preferred. A solution to achieve this has been found by using a fibre optic time signal already available at QUB which is traceable to NSAI. The knowledge gained in this process will be similar to the original plan, and will form the basis of follow on work after this project to yield a UTC(NPL) solution.