Raymarine GPS navigation - Manual (Page 19)

If the Differential Beacon Receiver is connected and tracking the beacon
signal is indicated in the message window. The latitude/longitude
readouts will include the differential corrections for greater accuracy.
When the Loran-C mode is selected, the “LORAN” characters will be
illuminated along in the message window of the display and the L/L position
and ship’s course and speed data is then Loran-C derived.
When both GPS and Loran sensors are connected, the NAV
unit
always
selects the sensor that was “last used” when the power is turned ON. If its
the very first time the unit is used and both sensors are connected, the GPS
is always selected as the priority system.
3.4 Initializing Sensors
Although the 508 Loran and 108 GPS sensors are capable
of finding the latitude/longitude position once they have been powered up,
at the very first power-up following installation or after a Master Reset, the
position finding process may take up to 30 minutes or more. This startup time
can be reduced to some degree by entering initialization information into the
sensor’s memory. The process for initializing each sensor appears in the
following paragraphs.
The very first time the
NAV
unit is operated, or following
a Master reset of the unit, the
screen will prompt you to en-
ter your “estimated latitude”
coordinate followed by entry
of the “estimated longitude”
coordinate., Once you’ve en-
tered this information into the
sensors via the
NAV 398, the
sensors should be able to find
your location more rapidly.
The loran sensor only needs the initial L/L input and should typically lock-in
in 3 to 5 minutes. The GPS sensor also needs the initial L/L input and prefers
to have the Date and Time and Antenna height information as well for quick
acquisition and tracking.
OPERATION 3-5