NavCom SF-3050 Rev.B - Manual (Page 152)

SF-3050 User Guide – Rev B
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 are 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
optimized for a dual-frequency system such as
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