GPS augmentation

Definition
A GPS augmentation is any system that aids GPS by providing accuracy, integrity, availability, or any other improvement to positioning, navigation, and timing that is not inherently part of GPS itself.

A wide range of different augmentation systems have been developed by both the public and private sectors. To meet specific requirements, the U.S. government has fielded a number of publicly available GPS augmentation systems, including (but not limited to) the following:


 * Continuously Operating Reference Stations (CORS)
 * Global Differential GPS (GDGPS)
 * International GNSS Service (IGS)
 * Nationwide Differential GPS System (NDGPS)
 * Wide Area Augmentation System (WAAS)