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EGNOS Performances

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Title EGNOS Performances
Edited by GMV
Level Basic
Year of Publication 2011
Logo GMV.png

EGNOS (European Geostationary Navigation Overlay Service) is the European satellite-based augmentation service (SBAS) that complements the existing satellite navigation services provided by the US Global Positioning System (GPS). EGNOS performances are usually described in terms of accuracy, integrity, availability and continuity.

EGNOS Performances Requirements

EGNOS has been designed to meet SBAS performance requirements:[1][2]

Service Service Coverage Accuracy (95%) Integrity Continuity Availability
Lateral Vertical HAL VAL TTA Integrity Risk
Open Service EU25 States (plus Norway and Switzerland) land masses 3m 4m - - - - - 99%
SoL En-route and NPA Flight Information Regions (FIRs) of ECAC 96 220m - 556m - 10s 1e-7/hour 1e-5/hour 99.9%
SoL APV-I Land Masses of ECAC 96 16m 20m 40m 50m 6s 2e-7/150s 8e-6/15s 99%

Typical Performances

The typical performances provided by EGNOS are presented in the next figures. For the computation, the day 7th February 2011, considered to be a representative day, has bee selected. The actual EGNOS messages have been taken from the EGNOS Message Server. The images have been generated with the eclayr tool.

Monitoring of EGNOS Performances

EGNOS performances are being monitored continuously by several entities, such as ESSP[3] and ESA.[4]

The EGNOS performance monitoring done by ESSP[3] includes figures on achieved availability, continuity and integrity. In addition, it forecasts the performances in terms of availability and integrity.

The monitoring done by ESA[4] is twofold. On the one hand, the messages, as broadcast by the EGNOS satellites, are analyzed to determine the status of several parameters, such as the GPS satellites which are augmented by EGNOS, the level of monitoring of the ionosphere over Europe or the achieved protection levels. On the other hand, ESA monitoring environment allows to select different reference stations and depicts the accuracy and integrity obtained for those sites.