NavCom SF-2040 Rev.F - Manual (Page 74)

SF-2040 User Guide – Rev. F
Infrastructure
The system utilizes the GPS satellite system, L-Band
communication satellites, and a worldwide network of
reference stations to deliver real-time high precision
positioning.
To provide this unique service, NavCom has built a
global network of dual-frequency reference stations,
which constantly receive signals from the GPS
satellites as they orbit the earth. Data from these
reference stations is fed to two USA processing
centers in Torrance, California and Moline, Illinois
where they are processed to generate the differential
corrections.
From the two processing centers, the correction data
is fed via redundant and independent communication
links to satellite uplink stations at Laurentides,
Canada; Perth, Australia; Burum, The Netherlands;
Santa Paula, California; Auckland, New Zealand; and
Southbury, Connecticut for rebroadcast via the geo-
stationary satellites.
The key to the accuracy and convenience of the
StarFire™ system is the source of SBAS corrections.
GPS satellites transmit navigation data on two
L-Band frequencies. The StarFire™ reference
stations are all equipped with geodetic-quality, dual-
frequency receivers. These reference receivers
decode GPS signals and send precise, high quality,
dual-frequency pseudorange and carrier phase
measurements back to the processing centers
together with the data messages, which all GPS
satellites broadcast.
At the processing centers, NavCom's proprietary
differential processing techniques used to generate
real time precise orbits and clock correction data for
each satellite in the GPS constellation. This
proprietary Wide Area DGPS (WADGPS) algorithm is
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