Automatic Identification System (AIS)
The Automatic Identification System (AIS) is a transponder system carried by ships that automatically broadcasts the vessel's identity, position, course, speed and other data over VHF radio to nearby ships and shore stations. Fitted with GPS, it lets vessels and coastal authorities see and identify each other in real time, greatly improving situational awareness and collision avoidance.
AIS is mandatory under SOLAS for most commercial ships above a certain size. Beyond collision avoidance, it feeds vessel traffic services (VTS), search and rescue, and the ship-tracking data behind the online vessel-tracking maps and analytics used across the industry for fleet visibility, port-call analysis and market intelligence. Because AIS data is public and global, it has become a foundational data source for maritime awareness — though it can be switched off or spoofed, which itself is monitored as a risk signal.
AIS turned ships from radar blips into identified, trackable objects — powering collision avoidance, VTS, and the global vessel-tracking data that now drives fleet visibility, port analytics and market intelligence. It is the single most important open data source in shipping, which is why gaps or spoofing in it are themselves watched closely.
What does AIS broadcast?
A ship's identity, position, course, speed and voyage data, automatically over VHF to nearby ships and shore stations.
Is AIS mandatory?
Yes — SOLAS requires it on most commercial ships above a certain size.