GPS disruptions in the Baltic Sea: New system to help ships navigate
News 2025-11-04
GPS disruptions have become increasingly common for vessels operating in the Baltic Sea. The Swedish Maritime Administration is now developing a system in collaboration with other countries to enable vessels to determine their position even when satellite signals are disrupted.
Today, almost all vessels use satellites to determine their position, course and speed. However, if satellite signals are disrupted or lost, navigation can become difficult and sometimes dangerous. An alternative system is now being developed through an EU project involving the Swedish Maritime Administration and other Baltic Sea countries.
“The system serves as a backup when satellite navigation is not functioning properly. It is based on land-based radio transmitters that send synchronised signals to vessels. An onboard receiver measures the signals and calculates the vessel’s position,” says Johnny Menard, Systems Engineer at the Swedish Maritime Administration.
A major advantage is that the system can make use of technology that is largely already in place, such as at coastal radio stations. This makes it cheaper and easier to implement, as it does not require new infrastructure. The Swedish Maritime Administration’s role in the project is to provide three land-based stations for this purpose and install the technology needed to enable implementation.
“Once the system is fully operational, we expect to achieve positioning accuracy of between 10 and 100 metres. This is sufficiently accurate for navigation on the open sea up to fairways where physical navigation marks are available, when satellite navigation is unavailable,” says Johnny Menard.
About the EU project
The ORMOBASS project (Operational Ranging Mode Baltic Sea System) is a joint initiative involving authorities and organisations in the Baltic Sea region. It has been carried out in three phases since 2014.
The aim is to establish a robust and reliable navigation system in the southern and central Baltic Sea that can support shipping even when satellite systems are disrupted. The project is led by the German Aerospace Center. Onboard trials will be conducted during 2026, and an operational system is expected to be developed by June 2027.
