WRITE has presented its activities and early results through 5 paper submissions to international peer-reviewed journals (out of which 4 are now published), and 16 contributions at international conferences, such as the 2018 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS 2018, Geneva, Switzerland) and the Joint Conference of the IEEE International Frequency Control Symposium & European Frequency and Time Forum  (IFCS-EFTF 2019, Orlando, Florida).

The WRITE stakeholder workshop communicated the project results to 100 participants from science, industry, NMIs and European National Research and Education Networks (NRENs). Active workshop discussions facilitated the exchange of ideas between the consortium, stakeholders and users of PTP-WR, many of them experts in this field. The workshop was promoted at international conferences and on the project website, with the slides made available on the CERN repository https://ohwr.org/project/white-rabbit/wikis/Sep2020Meeting.

WRITE has presented the consortium activities to standardisation bodies, namely at EURAMET TC-TF and at BIPM, in the working group focused on Advanced Time and Frequency Transfer.

Impact on industrial and other user communities

WRITE realised new complete PTP-WR solutions (improved devices and performance, commercial network architecture compatibility, calibration procedures), addressing the needs of industrial manufacturers, service providers and end users. Improved reliability of secure time dissemination services is enabled as developments in the project tackle the distortion of GPS signals due to electromagnetic interference, and the vulnerability to spoofing or space weather. The project’s devices and methods offer reliable and high performing time transfer to users with performance and traceability beyond the current state-of the-art for stability and accuracy, but with the unique feature of being resilient and continuously calibrated with traceability to UTC.

The industrial partners collaborated in the knowledge transfer activity, regarding both methods and devices, and together with the NMIs were involved in the field realisations and the design of the fibre links.

INRIM extended the architecture developed in WRITE from LEONARDO to Fucino (central Italy), to transfer UTC (IT) to the premises of Telespazio, a company in charge of the operations for the ground segment of the Galileo Global Navigation Satellite System. In the future, the technologies and the methods developed within WRITE could be exploited by the European project Galileo. In Rome, a connection to another aerospace company, Thales Alenia Space Italia, was completed and Thales Alenia Space Italia is now receiving a timing signal traceable to UTC(IT) by PTP-WR dissemination. This dissemination is the extension from 230 km to 1000 km of the testbed developed in WRITE: a demonstration of the scalability of the techniques developed and implemented during the project.

INRIM has also started a collaboration for testing WR on the fibre infrastructure of the Italian National Research and Education Network, Consortium GARR.  An experimental set-up was implemented in Rome.

VSL started a collaboration with the European Space Agency (ESA) to test PTP-WR on 50 km for space applications.

OBSPARIS started to implement the PTP-WR technique on a large French network infrastructure for Time and Frequency dissemination over fibre, T-REFIMEVE, promoted in December 2020 by the Ministry of Higher Education, Research and Innovation (MESRI) and the General Secretariat for the Investment Plan (SGPI).

Impact on the metrology and scientific communities

The project’s outputs facilitated more accurate and efficient dissemination of the SI second, by enabling a traceable signal to be brought to the time and frequency users with unprecedented accuracy through an optical fibre network. Since fibre based PTP-WR time transfer to industries has been successfully demonstrated, complementary time links can be implemented to enable uninterrupted time transfer from all participating laboratories, even in cases when satellite signals are disturbed. In the long run, countries that do not possess primary frequency standards (optical or microwave) will be able to obtain easy access to accurate time and frequency signals available from the best clocks in Europe via the optical fibre networks. The collection of data for the realisation of International Atomic Time and the international reference timescale Coordinated Universal Time (UTC) would also benefit and indeed, PTP-WR will offer an outstanding method for clock comparisons, at least matching the performance of caesium clocks, as it outperforms satellite-based techniques and relies on common network traffic infrastructures. Many scientific users, for example atomic and molecular spectroscopy, very long baseline radio astronomy (VLBI), and the realisation of all other SI units, have more stringent requirements on timing stability and accuracy than most industrial users, and even scientific laboratories and academia that do not require the best-performing T/F solutions, would nonetheless benefit from improved solutions offered at a reasonable cost. WRITE provided all users with improved devices and techniques, highly reliable solutions and lower calibration uncertainties.

Impact on relevant standards

The partners also actively participated in the activities of the Storage Networking Industry Association (SNIA). The new high-performance time transfer technique developed by the project is beneficial for the activities of the BIPM, in particular the Working Group on Coordination of the Development of Advanced Time and Frequency Transfer Techniques (WG-ATFT). The EURAMET Technical Committee for Time and Frequency (TC-TF) was regularly updated with reports on the project activities. The radio astronomical community maintains its own technical standards concerning time transfer issues, and will also benefit from the project.

Longer-term economic, social and environmental impacts

From both the economic and the social point of view, WRITE has demonstrated a high-performance, scalable, cost-effective PTP-WR technique in industrial environments  that will be greatly beneficial for the implementation of smart grids and a broad range of applications described collectively as Internet of Things. The opportunity for synchronisation at the 10⁻¹⁶ level at two distant stations, such as the PTF (Precise Timing Facilities) of the GALILEO ground segment, will enable a test of the accuracy and stability of the GPS or GALILEO systems to be performed with significantly higher precision than with previously available techniques.

As for the telecommunications industry, the partners foresee an impact on wireless 5G telecommunications. All of these services will have a significant social impact, allowing new types of access to medical aid, information management and economic transactions. The opportunity for tight synchronisation of sensors will in turn generate a precise and distributed knowledge of control parameters on a variety of socially relevant infrastructures, such as car traffic in large urban areas, power distribution, geological and seismic surveys, and water distribution.

The wide adoption of PTP-WR on existing fibre networks will be beneficial to the environment for a number of reasons. Firstly, smart power grids will benefit from better timing of power distribution devices and their synchronisation will make power distribution more efficient, with a relevant impact on environment. Secondly, sensing for air pollution needs synchronisation and precise timing to reconstruct airflow modelling, hence PTP‑WR solutions developed in the project will help to generate an improved understanding of the environment, and to identify and act on pollution sources. Thirdly, a more long-term impact relates to water distribution, where new technologies, such as the smart water meters, Internet-of-Things devices and various sensors measuring hydraulic and quality parameters, will help monitoring and control in water distribution networks, including identification of leaks.