The DGPS service was established in Norway at the end of the 1990s as an additional system to GPS for maritime users. The Norwegian Coastal Administration did this to meet the need for a more accurate GPS position signal for civilian users. The service in Norway consists of 12 stations along the coast that measure the GPS signals, broadcast corrections to the GPS signals and warn of deviations using their own signals to ships.
Why discontinue?
The DGPS service was modernized in 2012, but now has poor operational reliability and has reached its technical lifespan. If the service were to be continued, it would require extensive technical renewal of the infrastructure. Several other countries have discontinued DGPS in recent years, and there is no requirement to use DGPS on ships. Until the planned decommissioning, the service will be operated with the aim of as good an uptime as possible.
The Norwegian Coastal Administration considers that the improvement in position accuracy that DGPS provides, compared to the use of GPS alone, is so small that it has no significance in practical navigation. DGPS is not an independent backup system to GPS, and if the signals from the GPS satellites are blocked, e.g. in case of so-called jamming, DGPS will not be able to calculate and broadcast correction signals or alerts to DGPS users. In such cases, GPS receivers themselves, without the use of DGPS, will report that it cannot calculate the position.
During 2023, the Norwegian Coastal Administration conducted a user survey aimed at navigators who sail in Norwegian waters, and an open consultation regarding discontinuation of the DGPS service. Both the user survey and the consultation support the Norwegian Coastal Administration's recommendation to discontinue the service.
Better GPS
Since the DGPS service came into operation some 25 years ago, the GPS receivers on ships have improved. Reliability verification of the GPS signals (Receiver Autonomous Integrity Monitor) has been included in new GPS receivers approved for use on ships since 2003. The satellite-based service European Geostationary Navigation Overlay System (EGNOS) came into operation in 2009 and has since been included in most new GPS receivers for ships. EGNOS delivers GPS corrections in a similar way as the DGPS service. EGNOS has recently also launched the EGNOS Safety of Life Assisted Service for Maritime, which will notify of any unreliability in the GPS signals. The new service is expected to be included in new GPS receivers for ships in the future. In the coming years, the European satellite navigation system Galileo will also be able to be used on ships.
Adjustment period
The DGPS-service will remain in normal operation until January 2026. The Coastal Administration recommends shipping companies, having ships sailing in Norwegian waters and using the DGPS service, to assess whether the discontinuation of the service in Norway creates any need for adjustments.