On 1 January 2021, the UK’s Brexit transition period ended and it left the EU after years of negotiations between London and Brussels. The effects of the country’s “divorce” from the Union have been felt everywhere, in economic and socio-political terms.

As for shipping, Brexit was felt not only by UK ports with regards to fishing rights but it will also impact navigation systems.

As per Brexit accords, the UK is no longer participating in European satellite-based navigation systems such as Galileo and EGNOS and, from 25 June, will not receive access to EGNOS Safety of Life services when it’s rolled out, meaning mariners will not receive a signal whenever positioning, navigation and timing (PNT) systems suffer degradation.

According to George Shaw, principal development engineer at the UK General Lighthouse Authorities, this could cause problems both for mariners and ships. “We’re getting into more complex sea spaces, particularly around the UK, and the need for integrity is fundamental,” he says.

“The EGNOS system is one of the components that helped provide integrity for positioning.”


What is EGNOS?

EGNOS is a global navigation satellite system (GNSS) that improves the GPS signal, making it suitable for applications such as aviation and shipping.

Developed by European agencies such as the European Space Agency, the European Commission and Eurocontrol in 1998, EGNOS functions through a system of three geostationary satellites. Linked to a network of stations, EGNOS transmits a signal that contains information on the reliability of the information sent by the GPS, allowing for more accurate positioning.

EGNOS can determine an object’s position with an accuracy of 3m, compared with just 17m for GPS.

Problems may arise if GNSS systems provide unreliable information. “We need warnings to be reliable,” explains Shaw. “It’s a bit like crying wolf; if you cry wolf too often falsely, then you start to disbelieve the warnings. Integrity is like that you need to be able to trust that the warnings are real.”


Potential dangers to mariners and ships

In crowded sea spaces, false positioning could become a big issue, for mariners and vessels alike.

“With UK shipping passages getting rapidly busier and more constrained due to increases in traffic, ship size, offshore installations, environmentally sensitive areas, and blue economy uses such as aquaculture, ships will need more trustworthy and reliable PNT to enable high-precision navigation,” he adds.

“With seaborne trade set to double by 2030, the precision of position and timing data will become even more pivotal to the speed and efficiency of trade flows and help avoid widespread slowdown and disruption to our trade.

Even though they are aware of the threat to the availability of GNSS and other PNT systems, mariners  are usually less aware of the threat to the integrity of GNSS, which could hinder their safety.

“The guarantees that the EGNOS Safety of Life services provide give that confidence to mariners in being able to use the system,” he says. “We’re talking about potentially small errors in crowded sea spaces that can provide risks to navigation and take the vessel closer to danger.”

“Having precise systems like GPS is creating a temptation for mariners to sail safely but more closely to danger and therefore having an understanding of the likely uncertainties of positioning is becoming increasingly important.”


Post-Brexit future

What will change for British ships after 25 June is that even though will still be able to receive EGNOS signals, they will no access to assurances provided by the EGNOS Safety of Life Services.

“Integrity needs to be assured at the user level as well as the system level,” says Shaw. “This includes the system being able to detect and provide timely warnings to the user when it must not be used for the intended purpose.”

“Users must also be warned in a timely manner about any errors in the data incurred locally that impact its use for the intended purpose.”

To ensure that positioning systems are correct, Shaw says there are a few solutions.

“The UK now recognises the need for a ‘backstop’ to augment GNSS data and warn mariners when GNSS data is erroneous,” he concludes. “The key is a mix of space-based and terrestrial solutions that not only provide round-the-clock availability of PNT data but also ensure that users can trust the correctness of that data, and act on it with confidence, by ensuring they have integrity at their core.”