7
Operational Characteristics
2.1 Initialization Setup
After the initial self-test is complete, the Z
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III will begin the process
of satellite acquisition and tracking. The acquisition process is fully automatic
and, under normal circumstances, will take approximately 48 seconds to achieve
a position fix (38 seconds if ephemeris data is known). After calculating a
position fix, valid position and time information will be transmitted over the
output channel(s).
The Z
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utilizes initial data such as last stored position, data and time as
well as satellite orbital data to achieve maximum acquisition performance. If
significant inaccuracy exists in the initial data, or if the orbital data is obsolete, it
may take a long time to achieve a navigation solution. The Z
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TAR
Auto-locate
feature is capable of automatically determining a navigation solution without
intervention from the host system. However, to improve acquisition
performance, initialize the Z
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TAR
with the host system if one or more of the
following events occurs: 1) The GPS receiver is not in use for more than 3
months or transportation over distances further than 500 kilometers. 2) Failure of
the external memory battery without system standby power.
Z
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III
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