The Automatic Identification System (AIS) is an automated tracking system which is extensively used in the maritime world. Thanks to it, static and dynamic vessel information can be electronically exchanged between (terrestrial or vessel) AIS-receiving stations.

Regulations for carriage of AIS

Regulation 19 of SOLAS Chapter V - Carriage requirements for shipborne navigational systems and equipment - sets out navigational equipment to be carried on board ships, according to ship type. In 2000, IMO adopted a new requirement (as part of a revised new chapter V) for all ships to carry automatic identification systems (AISs) capable of providing information about the ship to other ships and to coastal authorities automatically.

The regulation requires AIS to be fitted aboard all ships of 300 gross tonnage and upwards engaged on international voyages, cargo ships of 500 gross tonnage and upwards not engaged on international voyages and all passenger ships irrespective of size. The requirement became effective for all ships by 31 December 2004.

Ships fitted with AIS shall maintain AIS in operation at all times except where international agreements, rules or standards provide for the protection of navigational information.

A flag State may exempt ships from carrying AISs when ships will be taken permanently out of service within two years after the implementation date. Performance standards for AIS were adopted in 1998.

The regulation requires that AIS shall:

  • provide information - including the ship's identity, type, position, course, speed, navigational status and other safety-related information - automatically to appropriately equipped shore stations, other ships and aircraft;
  • receive automatically such information from similarly fitted ships; monitor and track ships;
  • exchange data with shore-based facilities.

The regulation applies to ships built on or after 1 July 2002 and to ships engaged on international voyages constructed before 1 July 2002, according to the following timetable:

  • passenger ships, not later than 1 July 2003;
  • tankers, not later than the first survey for safety equipment on or after 1 July 2003;
  • ships, other than passenger ships and tankers, of 50,000 gross tonnage and upwards, not later than 1 July 2004.

An amendment adopted by the Diplomatic Conference on Maritime Security in December 2002 states that, additionally, ships of 300 gross tonnage and upwards but less than 50,000 gross tonnage, are required to fit AIS not later than the first safety equipment survey after 1 July 2004 or by 31 December 2004, whichever occurs earlier. (The original regulation adopted in 2000 exempted these vessels.)

Automatic Identification System (AIS)

AIS transponders (on vessel stations) include a GPS (Global Positioning System) receiver which collects the subject vessel's position and movement details. Such (dynamic) details along with other static information provided by the vessel's crew are automatically broadcasted at regular intervals via a built-in VHF transmitter using 2 specific VHF channels (161.975 Mhz and 162.025 Mhz - 87 & 88 old VHF channels).

The periodic AIS-data broadcasted information can be received by other vessel or base stations (provided they are within range). Then, with the use of special software, it can be processed and depicted on chart plotters or on computers. AIS-data can also be received by satellites - in this case, the term S-AIS is used (Satellite AIS).

The availability of the AIS information to the public domain quickly led to a drastic change regarding the initial perception of its use. AIS was originally developed by IMO (International Maritime Organisation) as a standard which would help vessels to avoid collisions while assisting port authorities to control marine traffic with more efficiency. However, the fact that its capabilities could become applicable to a wider spectrum of maritime-related business fields, soon became clear!

Nowadays, AIS information is used to serve various purposes and facilitates the work of people in various occupations, such as (among others):

  • Port Authorities and Harbor Masters
  • Ship Owners, Managers and Builders
  • Ship Agents, Brokers and Charterers
  • Researchers and Data Analysts
  • Tug Operators and Pilots
  • Search and Rescue teams
  • Flag administrators and Classification Societies
  • Vessels' crews and their families' members
  • Coast Guard and Border Patrol
  • Hotels and Tour operators
  • Passengers or recreational sailors
  • Environmental Protection agents
  • Maritime Enthusiasts and Radio-amateurs

Vessel traffic online (MAP)

Cargo ships — Cargo ships
Passenger vessels — Passenger vessels
Tankers — Tankers
Tug, Pilot, etc. — Tug, Pilot, etc.
Yachts, etc. — Yachts, etc.
Uncertain — Uncertain
Anchored — Anchored

Updated positions of the vessels

The position of any vessel is automatically updated whenever new incoming AIS-data becomes available! The process of picking up, decoding and presenting this data is quick and effective.

The frequency of incoming data depends on the AIS-receiving source (terrestrial or satellite):

  • Vessels that sail within the range of the network of AIS-receiving stations get continuous updates in near real-time as they transmit their AIS signals in frequent intervals (every 2 to 10 seconds).
  • Vessels that sail in the open seas can be covered using Satellite AIS. The position updates provided by this service may vary from a few minutes up to several hours. On average, we get one position update per hour for ocean-going vessels, equipped with a Class-A AIS transponder.
AIS traffic - view from space

AIS traffic - view from space