TYPES OF AUTOMATIC IDENTIFICATION SYSTEMS (PER ITU-R M.1371 AND IEC STANDARDS)
Class A (IEC 61993-2)
Shipborne mobile equipment intended to meet the performance standards and carriage requirements adopted by IMO. Class A stations report their position (message 1/2/3) autonomously every 2-10 seconds dependent on the vessel’s speed and/or course changes (every three minutes when at anchor or moored); and, the vessel’s static and voyage related information (message 5) every 6 minutes. Class A stations are also capable of text messaging safety related information (message 12/14) and AIS Application Specific Messages (message 6,8,25,26), such as meteorological and hydrological data, electronic Broadcast Notice to Mariners, and other marine safety information.
Class B (IEC 62287)
Shipborne mobile equipment which is interoperable with all other AIS stations, but, does not meet all the performance standards adopted by IMO. Similar to Class A stations, they report every three minutes when at anchor or moored, but, their position (message 18) is reported less often and at a lower power. Likewise, they report the vessel’s static data (message 18/24) every 6 minutes, but, not any voyage related information. They can receive safety related text and application specific messages, but, cannot transmit them. See this broader comparison of Class A and Class B AIS.
Search and Rescue Aircraft (IEC standards yet to be developed)
Aircraft mobile equipment, normally reporting every ten seconds.
Aids to Navigation (IEC 62320-2)
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; see IMO Safety of Navigation Circular 289, GUIDANCE ON THE USE OF AIS APPLICATION-SPECIFIC MESSAGES (ASM). For more information on AIS AtoN stations and their use see the following IALA references:
Note, current U.S. regulations (33 CFR §66.01-1) prohibit the authorization of electronic aids to navigation (ATON) as private aids--other than racons or radars. The Coast Guard is in the process of amending these regulations to permit the authorization and use of AIS ATON's as private aids to navigation; until this accomplished the Coast Guard will not be accepting or approving any private (i.e. non-Federal) USCG AIS Aton Approval Forms. Further, the Federal Communications Commission (FCC) will not grant licensing to an AIS ATON station without prior approval from the Coast Guard.
AIS Search and Rescue Transmitter (SART) (IEC 61097-14)
Mobile equipment to assist homing to itself (i.e. life boats, life raft). An AIS SART transmits a text broadcast (message 14) of either 'SART TEST' or 'ACTIVE SART'. When active the unit also transmits a position message (message 1 with a 'Navigation Status' = 14) in a burst of 8 messages once per minute.
AIS Base Station (IEC 62320-1)
Shore-based station providing text messages, time synchronization, meteorological or hydrological information, navigation information, or position of other vessels. Normally reports (message 4) every ten seconds. Note: private sale or operation of an AIS Base Station is prohibited in the United States (47 CFR 2.803, 80.371).
For a listing of U.S. certified AIS equipment visit the Coast Guard Maritime Information Exchange (CGMIX) (go to’ EQList Search’, select “Approval Series Name: Shipborne AIS”) or the FCC OET Equipment Authorization Search Form (select " Equipment Class: AIS”). Certification requirements for Class A AIS are described in 47 CFR 80.275, 47 CFR 80.1101(c)12 and in the Coast Guard's Navigational and Vessel Inspection Circular (NVIC) 8-01, as amended by Change 01, Approval of Navigation Equipment for Ships. NVIC 8-01 describes the certification process for AIS and other navigation equipment denoted in SOLAS V. For further information on the USCG type approval process email TypeApproval@uscg.mil.
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