Furuno FMD3100, Operator'S Manual

Page: 271 / 395

18. NAVIGATION SENSORS
18-5
18.3 Source of Position
The figure below shows how source for position is chosen. The position sensors have
either primary or secondary as input for their calculation. DGPS position sensors are
considered more accurate than other position sensors.
The latitude and longitude position is shown at the top-right position on the chart dis-
play, and in the example below the position source is DGPS. Other indications that
may be displayed in the position area are as follows:
• DR: Shown in yellow when position source is dead reckoning.
• DGPS, GPS: Name of position source.
If the system changes the source of position because of lost sensor data, the system
immediately generates the Alert 472 "Position Source Change".
Position sensor
selected as
high priority
Position sensor
selected as
low priority
Position
used by
this system
Valid data exists
Valid data exists
Selected
Backup
dead
reckoning
No valid data exists
No valid data exists