Navigation systems monitoring

Ensuring Europe's navigation services are running smoothly

At EUROCONTROL we monitor the performance of ground and space-based navigation systems in support of the implementation and operation of navigation applications relevant for the execution of the network functions.

Ground-based navigation

We assess the coverage of the navigation services provided by ground-based navigation systems in support of RNAV and conventional en-route applications.

Our objective is to identify coverage gaps that could impact network operations.

In addition our function supports the planning process for the evolution of the ground navaids towards a Minimum Operational Network used mainly as GNSS backup. The service is enabled by the software tool designed for the assessment of the ground navigation infrastructure - DEMETER.

More about DEMETER

Learn all about our distance measuring equipment tracer


Our ground-based navigation monitoring includes an assessment of the coverage and redundancy of:

  • DME/DME service for RNAV applications, at:
    • 9.500 feet (FL 95) – usual minimum en-route altitude for existing RNAV ATS routes
    • 15.000 feet (FL150 – lower limit for RNAV 5 implementation
    • 31.000 feet (FL 310) – lower limit for Free Routes Airspace implementation
  • VOR/DME service for RNAV applications at same flight altitudes;
  • VOR/DME service for conventional navigation (supporting contingency operations), at same flight altitudes

Using reliable data, sourced via our European AIS Database (EAD) and Central register of European radio frequency assignments and the European frequency request coordination system (SAFIRE), we update the ground navigation systems database to ensure that our assessments are accurate.

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European AIS Database


Central register of European radio frequency assignments and the European frequency request coordination system

In our assessments, we also take into consideration the inputs made available by air navigation service providers.

Space-based navigation

In addition to assessing the coverage of the network of ground-based navigation systems, at EUROCONTROL, we monitor also the performance of the services provided by the space-based navigation systems.

By doing so, we support the implementation and operation of PBN and other CNS navigation applications based on GNSS, such as ADS-B.

The GNSS monitoring service provides three functions.

RAIM prediction

Our Receiver Autonomous Integrity Monitoring (RAIM) availability prediction service is made available to airspace users in order to satisfy related requirements set in AIR OPS for EU certified operators, and Regulation (EU) No 452/2014 for non EU operators. It is a web-based service accessible to operators for use during the flight planning process.

Support to the publication of GPS/RAIM NOTAMs

The predicted RAIM outages of more than 15 minutes are made available to ANSPs in a format that can be distributed to airspace users via NOTAM. This service is provided though EAD on request of ANSPs and is currently provided to several States.

Our space-based navigation monitoring is powered by our AUGUR tool.

Learn more about AUGUR

EUROCONTRO's pre-flight planning for GNSS operations.

In the future the service will be further enhanced on the basis of additional information to be provided by:

  • the Galileo Reference Centre (GRC) for the core constellations of the Global Navigation Satellite Systems (GNSS);
  • the European Geostationary Navigation Overlay Service (EGNOS) Service Provider for the EGNOS system.


Our support extends to the wider navigation community – we exchange information and include stakeholder inputs through a consultation process enabled by EUROCONTROL work arrangements (e.g. via work groups and teams).

Our exchange of information on ground-based systems includes the results of coverage assessments and the planned evolution of navigation infrastructure.

Regular updates are also provided on the performance and planned evolution of GNSS core constellations in general and EGNOS in particular. Additionally, we help detect, monitor and investigate GNSS unavailability.

The main findings from our monitoring service will be published in a yearly report made available through the navigation sub-group (NSG). Contact us if you have any questions.