Sperry Marine VISIONMASTER FT ECDIS-E, User Manual, Page: 250 / 425

Sensor Management ECDIS-E User Guide
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Position Values
The Position folder shows geodetic position data
of own ship. The current position and sensor
source are also shown in the left corner of the
lower toolbar area, see Position.
The position displayed for CCRP is
accurate, providing that the correct
offsets for the position sensors are set
during commissioning.
The folder is divided into two areas; Sensors and
Position Offset.
Sensors
The Sensors area lists the available position
sensor data sources with the currently active
sensor source and its latitude/longitude values in
highlight.
The area also provides computed sensor data
that supplies geodetic position based on dead reckoning (DR) from the last
valid position received.
If position data becomes invalid the system will automatically switch to
water stabilised mode.
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.