EGNOS Services

EGNOS is delivering its services on a long term basis (beyond 20 years from today). The free Open Service is being delivered since 2009 and a Safety-of-Life service for civil aviation since March 2011

Service Characteristics Service Status
Open Service Accuracy ~1m. The service is provided free of charge without any guarantee or resulting liability. It is open for use to anyone with an EGNOS-enabled satellite navigation receiver. This can be any receiver compatible with satellite-based augmentation systems. Read the announcement here Available since October 2009
Safety of Life Service Accuracy ~1m, compliant to aviation standards. EGNOS provides a valuable integrity message warning the user of any malfunction of the GPS signal within six seconds. This integrity message is essential when satellite navigation is used for applications where lives are at stake. Available since March 2011
EGNOS Data Access Service (EDAS) Accuracy less than 1m. EGNOS provides a terrestrial commercial data service called the EGNOS Data Access Service (EDAS). EDAS disseminates EGNOS data in real time and is the single point of access for the data collected and generated by the EGNOS infrastructure. experimental service since 2008; official service to be made available in 2012

EGNOS provides enhanced performances over GPS according to four parameters: accuracy, availability, continuity and integrity. Although the concept of position accuracy is easy to understand, the other three notions are frequently misunderstood. They are defined as follows by the system requirements:

Integrity
Integrity relates to the trust which can be placed in the correctness of the information supplied by the Navigation System, it includes the ability of the system to provide timely warnings to the user when the system or data provided by the system should not be used for navigation.

Continuity
Continuity of Navigation service is defined as the probability that the accuracy and integrity requirements will be supported by the Navigation System throughout a flight operation or flight hour given that they are supported at the beginning of the flight phase and that the flight operation is initiated and predicated to be supported all along the flight phase. Satellite outages predicted at least 48 hours in advance of the outage do not contribute to a loss of continuity.

Availability
Availability of the Navigation Service is the probability that the Positioning service and the Integrity monitoring service are available and provide the required accuracy, integrity and continuity performances. Availability is computed, at any point within the service volume, as the percentage of the time during which the service is available over the lifetime of the system, taking into account all the outages whatever their origins. The service will be declared available when accuracy, integrity and continuity requirements are estimated to be met.

Civil aviation was one of the first sectors to recognize the importance of EGNOS benefits, which include

  • Allows for IFR-like operation in non ILS-equipped airports
  • Increase in airports capacity
  • Increase in safety

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