What is EGNOS?
- The European Geostationary Navigation Overlay Service is a satellite based augmentation system (SBAS) developed by the European Space Agency, the European Commission, and EUROCONTROL to supplement GPS, GLONASS and GALILEO systems by reporting the reliability and accuracy of their signals.
How does EGNOS work?
- Similar to WAAS, the EGNOS system consists of three geostationary satellites and a network of ground stations.
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More than 40 ground stations are linked together to create the EGNOS network consisting of:
- 34 RIMS (Ranging and Integrity Monitoring Stations) - receiving signals from US GPS satellites,
- 4 MCC (Mission Control Centers) - data processing and differential corrections counting,
- 6 NLES (Navigation Land Earth Stations) - accuracy and reliability data sending to three geostationary satellite transponders to allow end-user devices to receive them.
EGNOS Service Area
- EGNOS currently broadcasts augmentation data only for the US GPS system.
- EGNOS is scheduled to begin broadcasting augmentation data for GALILEO satellites sometime in 2025.
- EGNOS service currently extends to parts of Europe and Africa.
EGNOS Satellite Map
| Satellite Name | PRN | NMEA | Location |
| SES-5 | 136 | 49 | 5.0°E |
| Astra 5B | 123 | 36 | 31.5°E |
| Inmarsat 4-F2 | 126 | 39 | 63.9°E |
- PRN is the satellites actual Psuedo-Random Noise code.
- NMEA is the satellite number referenced by most GPS receivers (NMEA = PRN - 87).
- View a list of available SBAS satellites.
Do I need EGNOS?
- Unless you will be piloting an aircraft over Europe any time soon, probably not. However, if your Garmin GPSr is EGNOS enabled, you can still use EGNOS to more accurately plot your position on Earth, so why not? Besides, you didn't buy a GPS receiver because you thought paper maps and a compass were 'close enough', now did you?
