Raymarine Dragonfly-4 DV Installation And Operation Instructions Manual page 92

represent an error of approximately 15 m. Please
remember that even a very low HDOP figure is
NO guarantee that your receiver is providing an
accurate position. If in doubt, check the displayed
vessel position in the Chart application against
your actual proximity to a known charted object.
• Estimated Horizontal Position Error (EHPE)
— EHPE is a measure of the estimated error of
a position fix in the horizontal plane. The value
displayed indicates that your position is within a
circle radius of the stated size 50% of the time.
• Fix status — indicates the actual mode the
receiver is reporting:
– Fix — Satellite fix has been acquired.
– No Fix — No satellite fix can be acquired.
– D Fix — A differential beacon fix has been
acquired.
– SD Fix — A differential satellite fix has been
acquired.
• Position — Displays the latitude and longitude
position of your receiver.
• Date / Time — Displays the current date and time
generated by the position fix in UTC format .
• Mode — Identifies wether the receiver is working
in differential mode or non-differential mode.
• Datum — The receiver's datum setting affects
the accuracy of the vessel position information
displayed in the Chart application. In order for your
receiver and MFD to correlate accurately with your
paper charts, they must be using the same datum.
COG/SOG Filter
The COG/SOG filter averages the velocity vectors to
compensate for the oscillating motion of the vessel,
giving a clearer indication of the vessel's course and
speed.
The filter does not affect the calculation of your
receiver's reported position. The velocity vectors
calculated from the signal provide an instantaneous
measure of speed and direction of the receiver. The
COG and SOG can therefor seem erratic under
certain conditions. For example, when a vessel is
moving slowly through rough seas, the receiver
moves from side to side as well as in the direction
of travel.
Slow moving vessels, or vessels sailing in rough
seas will benefit from a high setting, whereas a
power boat that can quickly change speed and
direction will benefit from a low setting.
Tools & Settings
Sonar Set-up menu
The Sonar Set-up menu provides the following
options.
Depth Offset represents
Offset: the depth of the
transducer relative to:
• Waterline = 0.0 ft
and above.
• Keel = 0.1 ft and
below.
Sonar Reset Restore all settings
on the sonar module
to factory default.
When performing a
Sonar Reset, it is
normal to briefly lose
connection with the
sonar module.
• –9.8 to +9.8 feet —
or equivalent units
• Yes
• No
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