What data does AIS transmit?

AIS transmits several types of data essential for navigation and safety at sea.

Dynamic data: updated frequently (every 2 to 10 seconds for moving vessels, and less frequently for stationary vessels). They include :

• GPS position,
• Course (COG - Course Over Ground),
• Speed (SOG - Speed Over Ground),
• Time to Closest Point of Approach (TCPA),
• Closest Point of Approach (CPA).

Static data, less frequently updated, includes :

• Boat name,
• MMSI number (unique ship identifier),
• Vessel type,
• Draught,
• Port of departure and arrival,
• Nature of cargo.

With the introduction of S-AIS, this surveillance now extends to all regions, including dense areas, or the high seas, beyond the range of land-based stations.