Haicom HI-204III, User Manual

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8
SECTION 2
RECEIVER OPERATION
Upon power up, after initial self-test has completed, the
HI-204
III
-USB will begin satellite acquisition and tracking
process. Under normal open-sky condition, position-fix
can be achieved within approximately 35 seconds (within
10 seconds if valid ephemeris data is already collected
from recent use). After receiver position has been
calculated, valid position, velocity and time information
are transmitted through the on board serial interface.
The receiver uses the latest stored position, satellite data,
and current RTC time to achieve rapid GPS signal
acquisition and fast TTFF. If the receiver is transported over
a large distance across the globe, cold-start automatic-
locate sequence is invoked. The first position fix may take
up to 50 sec searching the sky for the GPS signal. The
acquisition performance can be improved significantly if the
host initializes the receiver with a rough estimate of time
and user position.