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APPENDIX 4 WHAT IS SBAS?
A satellite based augmentation system, or SBAS (Satellite Based Augmentation System), is an
augmentation system that uses additional messages from satellite broadcasts to support regional
and wide area augmentation. SBAS provides GPS signal corrections to SBAS users, for even bet-
ter position accuracy, through the GPS error corrections that are widely broadcasted from the geo-
stationary satellite.
SBAS is used in America, Europe, Japan and India.
• America: WAAS (Wide Area Augmentation System)
• Europe: EGNOS (Euro Geostationary Navigation Overlay Service)
• Japan: MSAS (Multi-Functional Satellite Augmentation System)
• India: GAGAN (GPS And GEO Augmented Navigation)
These four systems have interoperability. The illustration below shows the coverage area for each
provider. This manual uses "SBAS" for these four providers generically.
As of March 6th, 2014
Provider
Satellite type
Longitude
Satellite No.
WAAS
Intelsat Galaxy XV
133°W
135
TeleSat Anik F1R
107.3°W
138
Inmarsat-4-F3
98°W
133
EGNOS
Inmarsat-3-F2/AOR-E
15.5°W
120
Inmarsat-4-F2
25°E
126
SES-5
5°E
136
MSAS
MTSAT-1R
140°E
129
MTSAT-2
145°E
137
GAGAN
GSAT-8
55°E
127
GSAT-10
83°E
128
WAAS
MSAS
EGNOS
GAGAN