Sperry Marine Visionmaster FT ECDIS, User Manual

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Navigation Tools ECDIS User Guide
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Dead Reckoning values
If valid position data for own ship is not received within a short period of
time from the sensor interface the system establishes a computed position
by dead reckoning from the last valid position received using own ship’s
direction and speed.
The timeout limit applied to valid dead reckoning values defaults to 30
seconds. The system considers position data to be invalid if the most
recent usable sample data received from a position sensor is older than the
timeout limit.
LOP Values
The geographic location of own ship, determined by using Lines of Position
(LOP), may be used as the active data source for the position sensor. For
information on LOPs, see Line Of Position in Chapter 5, NAV Tools.
CAUTION: LOP SENSOR
The amount of time that a LOP position sensor will be considered
usable is limited. Note that LOP position sensor data is dead
reckoned and this data will become degraded after a period of time.
To change the Position sensor source do the following:
1. Tick the button next to the source. Whenever the sensor source is
about to be changed a window prompts you to confirm the change.
2. To confirm click the Yes button, or to return to the previous sensor
source and value click the No button.
If no sensor source is currently available the user can enter manual sensor
data.
CAUTION: MANUAL SENSOR DATA
Using manual data is not the normal mode of operation. A sensor
device should be selected as soon as valid data is available.
Manual data cannot be entered if AIS input is enabled. Before
entering data turn off the AIS input, see AIS Display in Chapter 10
`Targets’
1. To enter manual sensor data click in the MAN field, the text
changes to green (editable). Move the trackball left or right to enter
the required value and left click to exit edit mode.
2. Click the MAN button to enter the value.