The StarFire™ global subscription service provides real-time accuracy typically better than 10cm (4 inches). Its globally corrected signal is available
virtually anywhere on the Earth's surface on land or sea, from 76ºN to 76ºS latitude.

To accomplish this, StarFire™ utilizes a network of more than 60 GPS reference stations around the world to compute GPS satellite orbit and clock
corrections. Two completely redundant processing centers and multiple communication links ensure the continuous availability of StarFire™ GPS
corrections. These corrections are broadcast via three geostationary satellites, providing worldwide coverage and enabling precise real-time
navigation without the need for local ground base stations.

Methodology
The StarFire™ Network is a major advance from earlier ground-based augmentation systems because it considers each of the GPS satellite signal
error sources independently. GPS satellite orbit and clock corrections are calculated from a global tracking network of dual-frequency receivers;
these corrections are transmitted via Inmarsat satellite links directly to StarFire™ receivers, resulting in worldwide operation and minimal data
latency. All StarFire™ dual-frequency GPS receivers measure the ionospheric delay for each satellite; tropospheric zenith delays are calculated from
a multi-state time and position model aided by redundant satellite observables.

Reliability
Redundant data links, geographically separated processing hubs, and dual satellite uplink equipment ensure continuous reliable positioning. The
system is inherently robust, with the ability to calculate a full set of corrections even if multiple reference stations were to become unavailable. With
an uptime of 99.999%, customers can be confident of the global availability and accuracy of the system.