Data
Receiver
(receive)
Trans-
ceiver
(transmit)
Trans-
ceiver (re-
ceive)
Destina-
tion
Yes
No
Yes
ETA
Yes
No
Yes
Time
Yes
Yes
Yes
Ship's
position
Yes
Yes
Yes
COG
Yes
Yes
Yes
SOG
Yes
Yes
Yes
Gyro
heading
Yes
Yes*
Yes
Rate of
turn
Yes
No
Yes
Naviga-
tional sta-
tus
Yes
No
Yes
Safety
message
Yes
No
Yes
*Class B transceivers do not transmit a Gyro heading
unless the transceiver is receiving an NMEA HDT
sentence from an external source.
Data reporting intervals
AIS information is classed as either static or dynamic.
Static information is broadcast, when data has been
amended, or upon request, or by default, every 6
minutes.
The reporting rates for dynamic information depend
on speed and course change, and are given in the
following tables.
Note:
The reporting rates shown here are for
reference and may not be the rate at which
information is actually received by your AIS
transceiver. This is dependent on a number of
factors, including but not limited to antenna height,
gain and signal interference.
Class A systems
Ships Dynamic
Conditions
Reporting rate
Not changing
course
Changing
course
At anchor
or moored,
moving less
than 3 knots
3 Minutes
3 Minutes
At anchor
or moored,
moving greater
than 3 knots
10 Seconds
10 Seconds
0-14 knots
10 Seconds
3 1/3 Seconds
14-23 knots
6 Seconds
2 Seconds
Faster than 23
knots
2 Seconds
2 Seconds
Class B systems
Ships Dynamic
Conditions
Reporting rate (nominal)
SOTMDA – 0 to 2 knots
3 Minutes
SOTMDA – 2 to 14 knots
30 Seconds
SOTMDA – 14 to 23
knots
15 Seconds
SOTMDA – Greater than
23 knots
5 Seconds
Ships Dynamic
Conditions
Reporting rate (nominal)
CSTMDA – 0 to 2 knots
3 Minutes
CSTMDA – Greater than
2 knots
30 Seconds
Other AIS sources
Source
Reporting rate
Search and Rescue
(SAR) aircraft
10 Seconds
Aids to navigation (AToN)
3 Minutes
AIS base station
10 Seconds or 3.33
Seconds, depending on
operating parameters
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