What is AIS Tracking and Why is it Important?

Posted by Chris Leslie

AIS Vessel Tracking Map
What is AIS Tracking?
AIS, short for Automatic Identification System, is an automatic ship tracking system used onboard ships as well as onshore VTS (Vessel Traffic Service) systems to monitor vessel movements around the world. An AIS signal is sent from a transponder onboard a vessel to a receiver located onshore or on another vessel. AIS was originally created to supplement marine radar tracking for collision avoidance and safety efforts on the waterway. However, since then, AIS data has evolved into a vital tool for a number of different maritime stakeholders, including: shipowners, cargo owners, vessel operators, cargo dispatchers, marine service providers, terminal operators, charters, traders, maritime law firms, and many more.
Benefits of AIS Tracking
Fleet and Cargo Tracking
Ship and cargo owners can use AIS systems to track their fleet of vessels on a global scale. This allows for more accurate arrival times and better transparency to all stakeholders.
Demurrage Validation
One very valuable benefit of AIS tracking is the ability to effectively manage your demurrage costs. AIS data gives you the exact location and time a vessel has arrived or departed the sea buoy or dock, which allows you to validate or contest the statement of facts. With demurrage costs continuing to rise, this can result in millions of dollars in savings.
Many AIS providers have been collecting and storing data since its inception. With terrestrial and satellite AIS data combined, there are tens of billions of vessel positions available for companies to use. This data can be uploaded and processed into a number of different systems, allowing for predictive analytics and forecasting of vessel traffic.
Collision Avoidance
As previously mentioned, AIS was originally created to promote safety and security on the water. By providing a real-time picture of vessel traffic, AIS helps vessel operators, the USCG, and other maritime stakeholders avoid dangerous collisions. AIS is able to provide accurate information when visual observation, audio exchanges, and radar detection fail.
Vessel Traffic Services
Due to the ever increasing vessel traffic and congestion at ports, harbors, and other waterways, a VTS is used to help manage and optimize vessel movements. AIS tracking provides traffic awareness and information about the configuration and movements of ships, even during times of low visibility.
Incident Response
Whether during an actual incident, or a response drill, AIS can help track and monitor all of the response vessels and equipment (barges, tugs, service boats, etc.) Additionally, historical AIS can provide post-mortem analysis and reporting.
Accident Investigation
After an accident has occurred, it is up to the VTS as well as the involved parties to figure out what happened. AIS, and more specifically, historical AIS, can provide the positional and navigational information of the vessels involved as well as those nearby. AIS data has been used in numerous legal cases, investigations, and negotiations.
Subsea pipelines, cables, and other marine assets are at risk from vessel movements every day. Marine infrastructure incidents can cost millions of dollars in damage and result in injury and even death. AIS systems have the ability to alert the user when a vessel is operating near your marine assets. Also, historical AIS data is used to create vessel heatmaps of highly trafficked areas that companies will use when planning construction on a new pipeline or other marine asset.
History of AIS Tracking
AIS was developed in the 1990s as a high intensity, short-range identification and tracking network. The United States began developing AIS in response to the Exxon Valdez oil spill in Alaska. Congress passed the Oil Pollution Act, which called for the USCG to “develop a vessel tracking system for tankers going to Alaska”. The new system had to be autonomous, continuous, and digital - something that could automatically communicate and portray a ship’s location to other ships and to shore-based Vessel Traffic Services without the risk of human error. The USCG decided to use VHF radio whiles, while simultaneously the British were testing a VHS-based tracking system. Shortly thereafter, in the mid 1990s, the IMO and ITU decided to work together on a single system that could be used worldwide.
In 2000, the IMO (International Maritime Organization) adopted a new requirement to Regulation 19 of SOLAS (Safety of Life at Sea) Chapter 5. This required all vessels of 300 gross tonnage and upwards engaged on international voyages, cargo ships of 500 gross tonnage and upwards not engaged in on international voyages and all passenger ships irrespective of size to carry AIS tracking transceivers onboard. In December 2004, it became a requirement for all ships, irrespective of size. Different countries have since adopted different rules, including the US. The USCG Navigation Center’s set of requirements can be viewed in full on their website.
Satellite AIS Vessel Tracking
In 2008, companies and government programs began deploying low orbit satellites with AIS receivers on them.  The combination of both terrestrial and satellite AIS has resulted in truly global AIS coverage.
How AIS Ship Tracking Works
AIS transceivers automatically broadcast positional data via VHF radio transmissions. The transceivers are connected to the ships navigational sensors, such as GNSS (global navigation satellite system) and a gyrocompass. This allows for nearly real-time updates of positional information including: Latitude/Longitude, Rate of Turn, Speed Over Ground (SOG), Course of Ground (COG), and True Heading. This positional data is sent out at regular intervals, between 2 and 10 seconds while underway and every 3 minutes while at anchor.
The second type of information sent via AIS messages are Static and Voyage Data. This information is sent out every 6 minutes and is manually entered and updated by the vessel operator. The additional set of data values are: IMO number, call sign, vessel name, vessel type, cargo type, activity, navigational status, ETA, destination, draught, length, beam, and country (flag). Instructions for inputting this data into the AIS device can be found on the USCG Navigation Center website.
The average AIS tracking unit has a range of about 20 nautical miles. However, this range can be increased by positioning the transceiver on a platform high in the air. With a high enough location, on a clear day, with no huge land mass in the way, the range can double to 40 nmi.
Thanks to dramatic improvements in technology, AIS transceivers have been placed on low-orbit satellites, allowing for AIS tracking in the middle of the ocean and remote areas around the world. If you would like to learn more about Satellite AIS, you can read our write-up here.
The final step in utilizing AIS information is plotting the positional data on an ECDIS (Electronic Chart Display and Information System) or visual mapping platform of choice. This allows for the various different maritime stakeholders to get a clear picture of what is happening on the waterway. Initially intended for use onboard the vessels and their shore-base facilities, AIS data is now available publicly online with the only requirement being an internet browser. Data aggregators combine both terrestrial AIS data and Satellite AIS to provide a global view of real-time and historical marine traffic.
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Posted on Jun 5, 2018 6:07:00 AM

Topics: Maritime, Satellite AIS, Demurrage, Vessel Tracking, AIS, Marine Assets