Automatic Identification System

Automatic Identification System (AIS) is a digital maritime radio system that lets vessels broadcast identity, position, course and speed to other ships and shore stations.

Automatic Identification System (AIS) is a digital maritime radio system that lets vessels broadcast identity, position, course and speed to other ships and shore stations. It is used to improve situational awareness, reduce collision risk, and support vessel traffic services, search and rescue, and maritime monitoring.

What it is

AIS is an automated system that broadcasts vessel data over VHF radio so nearby ships and shore-based systems can identify and track traffic. It is widely used in commercial shipping and is also found on many smaller vessels.

Why it matters

AIS improves maritime safety by helping vessels avoid collisions and stay aware of their surroundings. It is mandatory on large SOLAS-covered ships, including passenger and cargo vessels, and supports search and rescue, traffic management, and monitoring in Canadian waters.

Key details

AIS uses VHF radio and self-organizing time division multiple access to transmit updates as often as every two seconds. Class A is the higher-power, SOLAS-required version for large ships; Class B is lower power for smaller craft. Range is typically 10–20 nautical miles for direct VHF reception, but can extend via satellite or favourable conditions.