The NASA Global Differential GPS (GDGPS) System is a complete, highly accurate, and extremely robust real-time GPS monitoring and augmentation system.

Employing a large ground network of real-time reference receivers, innovative network architecture, and award-winning real-time data processing software, the GDGPS System provides decimeter (10 cm) positioning accuracy and sub-nanosecond time transfer accuracy anywhere in the world, on the ground, in the air, and in space, independent of local infrastructure.

A complete array of real-time GPS state information, environmental data, and ancillary products are available in support of the most demanding GPS Augmentation operations, Assisted GPS (A-GPS) services, situational assessment, and environmental monitoring - globally, uniformly, accurately, and reliably.