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:
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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)
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Does not transmit the vessel's IMO number
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Does not transmit ETA or destination
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Does not transmit navigational status
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Is only required to receive, not transmit, text safety messages
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Is only required to receive, not transmit, application identifiers (binary messages)
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Does not transmit rate of turn information
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Does not transmit maximum present static draught
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; 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)
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
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 described under SOLAS V. Note that applications should be submitted to Commandant (CG-521), the new routing code replacing G-MSE and G-PSE.
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