NavCom Technology GPS Products, User Manual

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SF-2050 User Guide - Rev. E
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 in
Canada, Goonhilly in England and Auckland in New
Zealand for uplink to 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 optimized for a
dual-frequency system such as StarFire
™
in which dual-
frequency
ionospheric measurements are available at
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