Raytheon Pathfinder ECDIS Operator's Manual page 216

7.1.5 Position Offset
When displaying a signal from a navigational aid using the ARPA Radar Tracking
command, the target may not appear exactly over the navigational aid. When
this occurs, make sure your electronic charts have the most recent update. If this
is the case, the error may then be due to incorrect position information from your
navigational positioning device. You may adjust this situation using the Position
Offset command.
Ensure Radar Range and Bearings are correct before performing offset.
3655DOC020102
Operator Manual
NOTE
ECDIS display
Incorrect Ships Position
Correct Ships Position
Old ships position − dotted line
New ships position − solid line
Figure: 7−6 Example
7−10
ARPA Target
Step 3a
Navigational
Aid
Step 3a
ARPA Target
Navigational
Aid
Edition: 30.MAR.2007