How does WAAS function?

The correct answer highlights the essential operation of the Wide Area Augmentation System (WAAS). WAAS is designed to improve the accuracy, integrity, and availability of Global Positioning System (GPS) signals for aviation purposes. It achieves this through a network of ground stations that monitor the GPS signals. These ground stations detect any errors in the GPS signals received from the satellites and calculate correction information.

Once these corrections are calculated, they are transmitted back to the satellites, which then broadcast this corrected data to WAAS-equipped GPS receivers in aircraft. This process significantly improves the positional accuracy from typical GPS levels of about 10-15 meters to within 1-2 meters, enabling more precise navigation.

Understanding the operation of WAAS is crucial for pilots, especially when relying on GPS for approaches and landings in instrument flight conditions. While the other options presented may contain elements of truth about GPS or WAAS functionalities, they do not accurately reflect the primary mechanism by which WAAS enhances GPS signals.