CSI Wireless SBX-3, Reference Manual

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SBX-3 Reference Manual
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3.6 SBX-3 Operating Modes
The SBX-3 may be operated in either Automatic or Manual Tune mode.
In Automatic Beacon Search (ABS) Mode, the receiver will identify and
tune to the station providing the strongest DGPS signal using two
receiver channels. In Manual Mode, you specify the frequency to which
the receiver will tune. In Manual Mode, only the primary receiver
channel is used.
Refer to Section 5.6.1 to switch between Automatic and Manual Tune
modes using the standard $GPMSK NMEA command.
3.6.1 Automatic Beacon Search (ABS) Mode
The SBX-3 beacon receiver operates in Automatic Beacon Search
(ABS) mode by default, selecting and tuning to the most appropriate
beacon without operator intervention. The SBX-3 uses its two
independent channels to identify and lock to the best DGPS beacon.
ABS mode is ideal for navigation applications over considerable areas
with various beacon stations available, eliminating the need for operator
intervention when traveling from one beacon coverage zone to another.
3.6.1.1 ABS Global Search
When powered for the first time in ABS mode, the SBX-3 initiates a
Global Search (GS), examining each available DGPS beacon
frequency, and recording Signal Strength (SS) measurements in units
of dB
µ
V to the Global Search Table. The receiver uses these measured
values to compute an average SS, and noise floor, and to sort the
frequencies in descending order of SS.