T6: Trustworthy Traceable Terrestrial Time Transfer Technology

现代科技生活依赖于过去一百年来发展起来的基础设施，如电力、电信和交通。这些基础设施不为人注意，但它们是现代商业、工作和服务的核心。使这些服务工作的底层技术之一是将时间精确地同步到商定的标准的能力。协调世界时（UTC）的建立是为了允许一个单一的、精确的标准，可以在世界任何地方使用，对于一些关键的服务，我们需要与UTC保持非常密切的同步。笔记本电脑或家用电脑有一个简单的时钟技术，每天只能精确到几秒。当它连接到互联网时，它会自动同步到几百分之一或千分之一秒（10-3），这对大多数家庭和商业用户来说已经足够精确了。在某些行业，如电信和电力，我们需要能够同步到百万分之一秒（10-6）。例如，对于现代电力，“智能电网”要求其某些仪器和系统具有这种精度。这需要非常专业的计时设备。有些工业和科学应用需要十亿分之一秒（10-9）的精度，例如导航系统。为了达到10-6或更好，我们使用昂贵而复杂的原子钟。我们必须能够使这些时钟同步，为此，我们使用来自导航卫星的定时信号，例如用于GPS的卫星。不幸的是，在过去30年的卫星导航中，很明显，卫星系统很容易被阻塞，阻止它们的接收，导致对一个地区关键基础设施的拒绝服务（DoS）攻击。我们可以像在因特网上那样，使用传统的计算机网络建立一个备份同步系统，但这不能提供足够的准确性。在这个项目中，我们将使用传统的计算机网络来传输精确的时间。贝尔法斯特女王大学（QUB）将建立一个时钟，其时间可追溯到世界标准时间。宽带NI有限公司（BNI）拥有一个全面的数据通信网络，将被配置为传输精确的时间。BNI有许多风电场客户，其中一家将被选中进行这项服务的试点。昆士兰大学和大西洋科技大学（ATU）的工作人员将参与测量和管理，以确定该项目的有效性。对项目范围的拟议变更涉及从最初计划使用国家时间尺度UTC（NPL）转变为使用爱尔兰国家标准局的UTC（NSAI）。WP1的目的是在贝尔法斯特女王大学建立一个区域“时间节点”，并探索时间转移解决方案，使时间能够追溯到UTC(NPL)，而不需要GNSS时钟。正如下一节所详述的那样，在将NPL时间尺度确定为QUB方面已经确定了挑战。WP2不依赖于WP1，但首选不含GNSS的“整体系统解决方案”。实现这一目标的解决方案是使用QUB已经可用的光纤时间信号，该信号可追溯到NSAI。在这个过程中获得的知识将与最初的计划相似，并将在该项目之后形成后续工作的基础，以产生UTC（NPL）解决方案。

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.