What is WAAS?
- WAAS is the acronym for the Wide Area Augmentation System developed by the FAA and the DOT to give aircraft the ability to rely on GPS for all phases of flight by improving GPS accuracy, integrity, and availability.
How does WAAS work?
- A network of ground based wide area reference stations (WRS) monitor GPS satellite signals for variations caused by atmospheric disturbances, clock drift, and satellite orbit errors.
- The WRS relay these errors to wide area master stations (WMS) where the deviation correction (DC) information is computed, and updated correction messages are transmitted to geosynchronous satellites via a ground uplink system (GUS) every five seconds or better.
- These geosynchronous satellites then broadcast the correction data back to Earth where any WAAS enabled receiver can use the information to improve reported position accuracy.
WAAS Service Area
- WAAS service currently extends to portions of North America, Alaska, and Hawaii.
WAAS Satellite Map
| Satellite Name | PRN | NMEA | Location |
| SES-15 | 133 | 46 | 129°W |
| Galaxy 30 | 135 | 48 | 125°W |
| Eutelsat 117 West B | 131 | 44 | 117°W |
- 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 WAAS?
- Unless you will be piloting an aircraft over the U.S. any time soon, probably not. However, if your Garmin GPSr is WAAS enabled, you can still use WAAS 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?
