AVIGA

Accuracy, Visibility, Integrity, Geometry & Availability (of Satellite Navigation Systems)

DOP

Dilution Of Precision

EGNOS

European Geostationary Navigation Overlay Service

GALILEA

Galileo Local Elements Augmentation

Galileo

Galileo will be Europe's own global navigation satellite system, providing highly accurate, guaranteed global positioning services under civilian control. It will be interoperable with GPS and GLONASS, the other two global satellite navigation systes. Further information is available from the European GNSS Supervisory Authority (GSA), the European Space Agency (ESA) and the European Union (EU).

GalTeC

Galileo Technology Center

GBAS

Ground Based Augmentation System

GLONASS

GLObal NAvigation Satellite System - the Russian counterpart to the US GPS system

GNSS

Global Navigation Satellite System

GPS

Global Positioning System

IGM

Independent GBAS Monitor

Integrity

Integrity can be defined as a measure of the trust that can be placed in the correctness of the information supplied by the system. Integrity includes the ability of the navigation system to provide users with timely and valid warnings (alerts) when the system must not be used for the intended operation. The integrity performance is usually specified by means of three parameters:

• Alarm Limit

• Time To Alarm

• Integrity Risk

IR

Integrity Risk

MSAS

Multi-functional Satellite Augmentation System, the Japanese SBAS system

RAIM

Receiver Autonomous Integrity Monitoring

SBAS

Space Based Augmentation System

SIS

Signal In Space

WAAS

Wide Area Augmentation System, the US SBAS system