Magellan NAV 5000 User Manual

6-7
FIXES VARY A LOT The position accuracy of the NAV
5000 is affected by several variables,
the most important of which is the GQ
(geometric quality). Therefore, the
specified accuracy of 15 meters RMS
in 2D is statistical, not absolute. Also,
it is assumed that GQ is greater than
7 and SQ is at least 7. Even under
good conditions, then, not all fixes will
be within 15 meters of the true
position.
A good rule of thumb is that
approximately two-thirds of the fixes
will be within 15 meters of the true
position and about 95% of the fixes
will be within 25 meters under good
conditions. This assumes that the
government is not "adjusting" the
satellites. (The government may
periodically degrade the accuracy of
the system.)
Since 20 meters is approximately 0.01
minute of latitude (and 0.01 minute of
longitude at the equator), it is normal
to see variations as large as +/-0.03
minutes of latitude/longitude from fix
to fix when conditions are good. Under
less favorable conditions, larger
variations are normal.
If the unit is being operated near the
poles, small changes in position may
cause great variations in position and
velocity-related data. Refer to Using
the Unit Near the Poles in
OPERATING TIPS.

Magellan NAV 5000 Specifications

General

Brand	Magellan
Model	NAV 5000
Category	GPS
Language	English