NTOL NPL Timing Over Loran

The "NTOL -- NPL Time Over eLoran" project will aim to demonstrate the broadcast of the UK NPL managed national resilient time-base across the UK by using the eLoran transmitter based at Anthorn in Cumbria.

NTOL will synchronise the Anthorn eLoran transmitter directly to the NPL time-base and demonstrate accurate UTC time transfer by deploying eLoran receivers at various Critical National Infrastructure (CNI) locations across the UK.

Currently, CNI sectors typically utilise GNSS as the method of receiving UTC but are often aware of the vulnerabilities to GNSS signal reception due to jamming, interference, spoofing and space weather. eLoran is a high-power terrestrial broadcast signal and therefore immune to the effects of these GNSS vulnerabilities, so the use of eLoran broadcast signals provides significant advantages in terms of resiliency and robustness.

In addition, the broadcast of the NPL time-base provides a method of delivering UTC to CNI applications that is entirely under direct UK sovereign control, compared to GNSS whose constellations are operated by foreign countries and territories.