WAAS is best described as which of the following?

• A. It provides only speed improvements
• B. correction signal from ground uplink station to geostationary satellite, then sent to WAAS receivers
• C. It disables GPS in degraded conditions
• D. It replaces GPS satellites

Answer: (B)

WAAS enhances GPS by providing differential corrections and integrity information, delivered to users via geostationary satellites. The system uses a network of ground reference stations that monitor GPS signals, sending data to a master station that computes corrections and monitors integrity. That information is uplinked to a geostationary satellite and broadcast to WAAS-enabled receivers. Receivers use the corrections to improve position accuracy and awareness of satellite health, which is why WAAS can significantly improve accuracy and reliability for IFR-type navigation. The description that the correction signal travels from ground uplink stations to a geostationary satellite and then to WAAS receivers is exactly how WAAS operates.

This is broader than just speed improvements, it does not disable GPS in degraded conditions, and it does not replace GPS satellites.