Without GPS: EU researchers develop satellite-independent navigation system

Since the end of 2023 at the latest, there has been a lot of talk about massive disruptions to satellite navigation systems such as GPS or Galileo in the Baltic Sea region. This has led to repeated disruptions to air and shipping traffic, especially around the Russian Kaliningrad Oblast (Königsberg), due to various jammers on the ground and on boats. The signal interference means, for example, that ship bridge systems display no or, in the worst case, incorrect position information. This is considered a high risk for groundings or collisions. However, with the terrestrial navigation system Ranging Mode (R-Mode), the German Aerospace Center (DLR) has already developed an alternative to satellite-based solutions together with European research institutions, authorities and industrial companies.

R-Mode uses existing infrastructures of national maritime facilities to provide radio services in the medium wave (MW) and ultra-short wave (VHF) range and thus offers "a cost-efficient supplementary navigation service", explains the DLR. According to the center, it has already prepared and built the world's first large-scale test field for the radio-based system with partners between 2017 and 2021. For DLR Chairwoman Anke Kaysser-Pyzalla, this first step towards a "maritime backup system" in the Baltic Sea has shown "that R-mode technology works in practice as an alternative terrestrial navigation system and makes it possible to position a ship even without satellite-based systems".

Over the past seven years, according to the DLR, a test field with eight R-Mode transmitters has been created with an extension of around 800 kilometers between Helgoland and Stockholm. The initiative was provided by the Federal Waterways and Shipping Administration (WSV). The Ormobass project, which was launched in 2023, is currently extending the test area to the Baltic Sea region between Sweden, Finland and Estonia. This is where the most disruptions to satellite navigation are currently reported.

R-mode standardization underway

In 2024, the scientists from the team analyzed the medium-wave radio signal stations there and developed the expansion concept together with the existing transmitters in the test area. This covers the basic functions of the system and is to be implemented by 2026. The aim is to design all the key functions of the R-mode system for MW and VHF by then and make them available to the relevant maritime authorities for operation. In addition to project management, DLR is also responsible for the development of the R-mode receiver technology, system design, system testing and standardization.

The project partners have deliberately chosen the path towards a standard. This is because suitable transmitters with a suitable uniform service must be available so that ships can use the R-Mode system on their journey between two ports, explains the DLR. Standardized receivers on board that are approved for ship navigation are also necessary. For the MW range of R-Mode, the participants were able to incorporate the results of Ormobass and previous projects into a relevant guideline of the IALA (International Organization for Marine Aids to Navigation). The IALA Guideline 1187 now available also incorporates experience from Canada and South Korea. The guidelines are now being implemented in the Baltic Sea region: the standardized signals are to be available via radio beacons in the area between Germany, Finland and Estonia from the beginning of 2026.

(wpl)