The ships often turn in circles and also turn over the banks. I think the reason is easy to explain:
MSFS processes the position and direction of the ship using a database available on the Internet, which in turn receives the GPS signal from the ship’s transponder. Since a GPS position always fluctuates by several meters and therefore new direction information is always given, MSFS evaluates this information as a moving ship. In fact, however, the ships are anchored and still have the transponder on. This deficiency can be observed in ports and at anchorages. Why the developer of the shipping traffic did not take this into account will probably always remain a mystery.
So the development team must build in a threshold value for the database or they take the ais information of the ship into accout:
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