NavCom SF-3040 Rev.F - Manual (Page 154)

SF-3040 Product User Guide
– Rev. F
C-152
optimized for a dual-frequency system such as
StarFire™ in which dual-frequency ionospheric
measurements are available at both the reference
receivers and the user receivers. It is the use of dual-
frequency receivers at both the reference stations
and the user equipment together with the advanced
processing algorithms, which makes the exceptional
accuracy of the
StarFire™ system possible.
Creating the corrections is just the first part. From our
two processing centers, the differential corrections
are then sent to the Land Earth Station (LES) for
uplink to L-Band communications satellites. The
uplink sites for the network are equipped with
NavCom-built modulation equipment, which
interfaces to the satellite system transmitter and
uplinks the correction data stream to the satellite that
broadcasts it over the coverage area. Each L-Band
satellite covers more than a third of the earth.
Users equipped with a
StarFire™ precision GPS
receiver actually have two receivers in a single
package, a GPS receiver and an L-Band
communications receiver, both designed by NavCom
for this system. The GPS receiver tracks all the
satellites in view and makes pseudorange
measurements to the GPS satellites. Simultaneously,
the L-Band receiver receives the correction
messages broadcast via the L-Band satellite. When
the corrections are applied to the GPS
measurements, a position measurement of
unprecedented real time accuracy is produced.