
108 - Assessment of Time Transfer Techniques for Resilient Regional (Transnational) UTC Infrastructure
DESCRIPTION
Timing is a highly important use case of GNSS, as many sectors such as telecommunications, emergency services, transport and finance depend on precise time to operate correctly. Therefore, there is a need to provide Critical National Infrastructure (CNI) with accessible, resilient sources of precise reference time using time transfer techniques which are complementary to GNSS. The time reference should always be traceable to UTC (Coordinated Universal Time), the global time standard.
Local realisations of UTC(k) are operated at National Metrology Institutes (NMIs) in many countries, providing a real time UTC traceable reference source. An assessment of the feasibility of time transfer complementary to GNSS for comparison of UTC(k) clocks at geographically separate locations, ideally in different countries, will pave the way for a more resilient, certifiable timing infrastructure to protect CNI on a wider scale.
There are many techniques complementary to GNSS which can transfer precise time, for example using satellites, terrestrial broadcast, optical fibres or line of sight links, all of which are in scope for this activity. This activity may address the use of optical fibre-based time transfer techniques such as White Rabbit and Electronically Stabilised fibre optic system (ELSTAB), over long distance or transnational links, assessing technical and regulatory challenges.
The objective of this activity is to perform a detailed assessment of the use of a time transfer technique, complementary to GNSS, for precise comparison of UTC(k) clocks at geographically separate locations, ideally between different countries. It is envisioned that this Proof-of-Concept (PoC) activity will lay the foundation for a future NAVISP activity to implement this time transfer technique transnationally to support CNI.
The tasks to be performed shall include:
- review state-of-the-art time transfer techniques which are complementary to GNSS. A selected time transfer technique will be assessed, including a PoC, with the aim of increasing the transnational robustness of UTC(k) timing infrastructure for the future benefit of CNI. This time transfer technique will be used to compare two or more clocks at geographically separate locations. The technical and regulatory challenges, achievable stability and accuracy to UTC of the selected technique will be investigated
- define a roadmap towards wider implementation of the selected time transfer technique between countries and the interfaces with CNI.
The main outputs of the activity will consist of:
- Report of state-of-the-art time transfer techniques which are complementary to GNSS
- Feasibility study and PoC of the selected technique, including an assessment of any transnational issues, regulations and standards relating to the use of the selected time transfer technique between two or more UTC(k) realizations in different countries
- Roadmap for future implementation between countries and potential interfaces with CNI, including a cost/benefit analysis per country to inform potential future activities, both in Element 2 and Element 3. To ensure the activity’s capability to inform follow up Element 2 and Element 3 activities, it will be conducted in Phases, conditioned by a go/no-go check point.