User's Manual

7
 Location of GPS antenna on the ship
 Dynamic data:
 Position of the vessel
 Course over ground (COG)
 Speed over ground (SOG)
 True heading
It receives also safety related messages (SRM) from other vessels or persons who are in
distress.
SOTDMA Class B AIS broadcasts ship´s static data every 6 minutes. Ship dynamic data
will be transmitted per following reporting interval:
Ship Speed
Nominal Reporting Interval
Increased reporting interval
>23 knots
Every 5 seconds
Every 15 seconds
between 14-23 knots
Every 15 seconds
Every 30 seconds
between 2-14 knots
Every 30 seconds
Every 30 seconds
≤ 2 knots or at anchored or
moored
Every 3 minutes
Every 3 minutes
The Class B “SO” AIS follows the rules set by ITU-R M.1371-5, and increases the
reporting interval to “Increased Reporting Interval” in accordance with Table above
when less than 50 % of the slots of each of the last four consecutive frames are free.
When more than 65 % of the slots of each of the last four consecutive frames are free,
the Class B “SO” AIS reports at the “Nominal Reporting Interval”.