AIS dynamic data has key limitations for navigation.
It includes position with accuracy and integrity indications, UTC position timestamp, course over ground, speed over ground, heading, navigational status and rate of turn where available. Most dynamic fields are updated automatically from connected ship sensors, but navigational status is entered and updated manually by the officer of the watch.
A missing sensor may cause AIS to transmit a not-available value, while an inaccurate connected sensor may supply plausible but incorrect data that the built-in integrity test does not validate. Dynamic reporting intervals vary with equipment class and the ship's movement or course-changing state; there is no single reporting interval for every AIS unit.
AIS information should be corroborated through systematic visual and radar observation and must not replace lookout, radar plotting or use of all available means.
