NavCom SF-3050 Rev.E - Manual (Page 180)

SF-3050 Product User Guide
– Rev E
C-154
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 several
L-Band frequencies
1
. The StarFire reference stations
are all equipped with geodetic-quality, multi-frequency
receivers. These reference receivers decode GPS
signals and send precise, high quality, multi-
frequency pseudorange and carrier phase
measurements back to the processing centers
together with the data messages, which all GPS
satellites broadcast.
1
A single-frequency operation mode is available for
the SF-3050A. See the Sapphire Technical
Reference Manual and the StarUtil 3000 User Guide
for details on using this feature. Single-frequency is a
receiver mode that uses only the L1 GPS signal.
There is no compensation for ionospheric effects.