Magellan NAV 5000, User Manual

Page: 42 / 153

3-9
DETERMINING THE QUALITY OF THE FIX
The quality of the fix is affected by the strength of the signals being
received from the satellites and the geometry of the satellite set used
to obtain the fix.
Signal Quality
The Signal quality (SQ) is an indication of the carrier-to-noise ratio of
the signal being received from a satellite. lt is displayed on the receiver
status screen and on the last screen of the position display.
Signal quality ranges from 0 to 9, with 9 being the best. When SQ is 4 or
greater, the signal is strong enough that the unit will not lose its lock on it.
SQ can sometimes be improved by moving the antenna; even a few inches
can improve SQ greatly.
The signal quality has almost no bearing on accuracy. lt is provided to alert
you to a condition that may affect the unit's ability to maintain a lock on
the satellites currently being used.
When this symbol appears
on the bottom right of the
display, the signal quality
of one or more satellites
used for the fix is 3 or less.
Geometric Quality
Geometric quality is a measurement of the geometry of the satellites
used to triangulate the position. The further apart the satellites are, the
better the geometry of the fix. Geometric quality ranges from 0 to 9,
with 9 being best. When the GQ is 7 or better, the geometry should
not affect accuracy.
When this symbol appears
on the display, the geom-
etry of the fix is 3 or less.
The accuracy of this fix is
extremely poor, and it
should not be used for
navigation.