Inland ECDIS applications can clearly display the actual position of the own vessel on a chart. This position is generated with satellite based positioning systems (e.g. NAVSTAR GPS, GLONASS). However, as this application is currently not precise enough, the skippers have to be provided with augmentation signals, the so-called differential signals (dGPS).

The ongoing monitoring of the GPS satellite and dGPS stations offers another crucial advantage. This way, information about the quality of digital navigation can be continuously provided within the dGPS reference area. Users can be informed immediately about occurring errors or significant deterioration of the positioning accuracy. This service parameter is also called integrity.

Since the availability of EGNOS and Eurofix systems is unknown up to now, the GIS Forum Danube decided to use the IALA based dGPS as a common standard. The D4D project shall ensure a single and harmonized implementation of IALA beacons in the whole Danube area and thus provide the inland navigation and surveying with an accurate and reliable positioning system.


As IALA beacons are already used in many countries over the world, the system compatibility can also be reached between inland and maritime navigation. Currently many coastal areas in Northern and Western Europe are already covered with IALA based signals.

Locations of beacons to cover the Danube waterway

In course of project development, a network plan with possible positions of beacons was worked out based on German experiences. The Danube river can be completely covered with only six beacons. The coordination within D4D shall ensure a low cost implementation of a dGPS service.

Parallel to the implementation of this concept, first experiences with IALA beacons shall be gained in Germany and Austria. As next steps, the test beacons shall provide the basis for up-coming national and international research and development projects and especially verify their usability for River Information Services.