As concerns over GNSS vulnerability mount, Dutch technology company Syntony is drawing increased attention for its work on terrestrial-based positioning and timing services designed to complement satellite-based navigation, particularly in the maritime domain.
Over the past several months, the company has accelerated development and trials of its ranging mode (R-Mode)-based PNT solutions, aimed at providing robust backup navigation and timing when GNSS signals are degraded or unavailable.
In 2026, international bodies such as the IMO and national transport authorities are set to continue to assess potential GNSS backup systems for maritime navigation. Meanwhile, Europe’s ongoing emphasis on PNT resilience and infrastructure protection has created renewed interest in solutions that reuse existing assets rather than relying solely on new constellations or sensors.
Syntony’s approach involves exploiting existing maritime radio infrastructure, including medium frequency (MF) and very high frequency (VHF) transmitters, providing signals that can be used for positioning and timing independent of satellites. Using advanced signal processing and synchronization techniques, R-Mode enables vessels to derive position fixes from terrestrial MF and VHF broadcasts originally intended for communication or navigation aids. While R-Mode has been discussed in research circles for years, Syntony has been among the few companies pushing it toward operational service readiness.
Staying on track
Syntony sees R-Mode as a true complementary PNT layer. Rather than augmenting GNSS accuracy, the company’s solution is designed to maintain continuity of navigation and timing during outages caused by interference, spoofing or local signal blockage – risks faced, especially now, by Northern European maritime authorities and port operators, but also by similar actors worldwide. Timing integrity, in particular, is a growing concern as digital maritime procedures depend on synchronized systems for communications, traffic management and safety services.
Recent trials conducted in cooperation with European maritime stakeholders have demonstrated meter-level positioning performance and stable timing outputs suitable for navigation support and system synchronization. These results suggest that terrestrial PNT can move beyond theoretical resilience concepts into deployable operational tools, especially in coastal waters, ports and busy sea lanes where GNSS disruptions are most likely to have economic and safety consequences.
In a sector where GNSS has long been taken for granted, Syntony’s work highlights a pragmatic shift. By pursuing resilience through diversity, using both terrestrial radio and satellite signals, the company is helping build a layered PNT architecture to better cope with today’s interference-prone environment.
