EGNOS: add corrections and integrity to a regional service

The European Geostationary Navigation Overlay Service, EGNOS, is Europe’s satellite-based augmentation system — open definition. Galileo is a global navigation constellation; EGNOS adds information to an underlying navigation service. They belong to the same broader European space effort but have different technical functions and histories. Learning them as separate programs prevents a regional augmentation payload from being mistaken for a complete global constellation.

The European Commission took ownership of the EGNOS infrastructure on behalf of the EU in April 2009, and European civil-aviation certification followed in 2011. EUSPA’s program responsibilities include service exploitation. These milestones concern a coordinated system of ground facilities, satellite-hosted payloads, user equipment and service conditions, not simply the launch of one named spacecraft.

EGNOS ground stations observe navigation signals and send measurements for processing. The system produces corrections and integrity — open definition information that are distributed through geostationary satellite broadcasts. Corrections help reduce specified errors. Integrity information addresses whether the service can be relied upon within defined limits, including warnings when those conditions cannot be maintained.

Consider a fictional receiver whose position errors were usually small during a trial but which failed to warn users during one large error. Its average accuracy alone would not establish the integrity needed for an application that depends on timely warnings. Accuracy, availability, continuity and integrity describe related but different aspects of performance; a single attractive average cannot stand in for all of them.

EGNOS: evaluate more than one performance measure

In the EUSPA description reviewed on October 14, 2026, the existing EGNOS architecture augments GPS, while EGNOS V3 is described as under preparation to support both GPS and Galileo. A planned capability should not be silently transferred into a description of what the existing service already provides. Check the generation and date before comparing program specifications.

For a fictional mapping project, start with the required observation quality and identify a compatible receiver, the relevant service area and the applicable documentation. Then retain the evidence needed to assess the result. Comparing EGNOS with GAGAN shows a shared augmentation idea implemented through different regional infrastructure and service responsibilities, rather than one identical service available everywhere.