NorthStar Navigation Explorer 538i - Manual (Page 43)

Northstar Explorer 538i/538 Installation and Operation Manual 43
Press once or more until the Setup menu
is displayed, then select GPS:
GPS Source
• Internal: Use the internal GPS antenna
(Explorer 538i) or the external GPS antenna
supplied (Explorer 538) (see section 15-5).
• NMEA: Use an external GPS or DGPS source
connected via NMEA (see section 15-9).
• NavBus: Use an external GPS or DGPS
source connected via NavBus (see section
15-8).
DGPS Source
Enables or disables the satellite based DGPS
correction (see section 7). The options are
None
or WAAS/EGNOS . Do not enable WAAS/EGNOS
outside their coverage areas or the accuracy of
the position might be degraded.
WAAS covers all of the USA and most of Canada.
To use WAAS, the GPS antenna must have a clear
view of the sky towards the equator. EGNOS will
cover most of Western Europe when it becomes
operational.
Restart GPS
Restarts the internal GPS receiver for servicing
or troubleshooting. The GPS receiver takes up
to three minutes to restart. The satellite display
shows the status of the GPS receiver (see section
7). Restart the GPS if the receiver has not been
used for some time and is taking a long time to
get a GPS fix.
14-3 Setup > GPS
Static Navigation
When the boat stops or moves very slowly, the
calculated GPS speed and course become erratic.
Static navigation is a number, and the options are:
• 0.01 to 99.9: If the boat speed is slower
than this, the speed is displayed as zero and
the course stays unchanged.
• 0(Off): The calculated speed and course
are always used.
Speed and Course Filter
Waves and wind cause the boat speed and
course to fluctuate slightly. To give stable
readings, the Explorer calculates these values
by taking several measurements and averaging
them.
A lower value averages measurements over
a shorter period of time. This gives the most
accurate value but has the most fluctuations.
A higher value averages measurements over
a longer period of time. This gives the most
stable value but will ignore some true speed
changes.
Set the Speed and Course filters to the lowest
values which give stable readings. The range of
each filter is 1 to 60 seconds or Off (0).