TYPES OF AUTOMATIC IDENTIFICATION SYSTEMS
ITU-R Recommendation M.1371-1 describes the following types
of AIS:
Class A
Shipborne mobile equipment intended for vessels meeting the
requirements of IMO AIS carriage requirement.
Class B
Shipborne mobile equipment provides facilities not necessarily
in full accord with IMO AIS carriage requirements. The Class
B is nearly identical to the Class A, except the Class B:
- Has a reporting rate less than a Class A (e.g. every
30 sec. when under 14 knots, as opposed to every 10 sec.
for Class A)
- Does not transmit the vessel’s IMO number
- Does not transmit ETA or destination
- Does not transmit navigational status
- Is only required to receive, not transmit, text safety
messages
- Is only required to receive, not transmit, application
identifiers (binary messages)
- Does not transmit rate of turn information
- Does not transmit maximum present static draught
U.S. Submission to the International Telecommunication Union:
Document
8B/234-E, "PERFORMANCE ASSESSMENT AND INTEROPERABILITY
OF PROPOSED CLASS B AIS WITH EXISTING CLASS A AIS SYSTEM USING
SIMULATION SOFTWARE" (2005).
See a comparison of
Class A and Class B/CS AIS.
Search and Rescue Aircraft
Aircraft mobile equipment, normally reporting every ten seconds.
Aids to Navigation
Shore-based or mobile station providing location and status
of an aid to navigation (ATON). Normally reports (message
21) every three minutes. These stations may also be programmed
to provide other navigation safety information, for example,
meteorological and hydrological data, via application specific
text or binary messages (i.e. messages 6, 8, 12, 14, or 25).
For more information read IALA
Recommendation A-126
on THE USE OF AIS IN MARINE AIDS TO NAVIGATION SERVICES and
Guideline 1062 on
THE ESTABLISHMENT OF AIS AS AN ATON.
Note: operation of an AIS Aton in the United
States requires prior approval from the Coast Guard and Federal
Communications Commission (FCC).
Air Base Station
Shore-based station providing text messages, time synchronization,
meteorological or hydrological information, navigation information,
or position of other vessels. Normally reports every
ten seconds.
AIS Messages >>
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