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AIS Data: History & Future


Dennis Bryant

The Automatic Identification System (AIS) was developed with the sole goal of improving maritime safety by allowing ships in proximity to one another to automatically exchange information regarding their name, course, speed, type, cargo, etc. The exchange of this information would allow conning officers on each ship to make better decisions regarding the possibility of close encounters and the need to change course and/or speed. It would also make it easier for one ship to contact the other by radio-telephone to hopefully remove any doubt. To that extent, AIS has largely worked as intended, although collisions continue to occur.

It did not take long, though, for governments to get involved. They started installing shore-based receivers to monitor AIS transmissions from approaching ships, out to a point just beyond the horizon. Those governments could also monitor ships in harbors and transiting off the coast or on inland waterways. The United States incorporated this data into its maritime security or maritime domain awareness programs. Governments also utilize the data to analyze marine casualties and to determine waterway usage. A large amount of AIS data is collected by governments around the world, which share much of that data amongst themselves. There are also commercial companies that collect AIS data, including several that utilize satellites to collect this data from ships on the high seas outside the range of land-based AIS receivers.

Governments are now using AIS in an innovative manner by creating virtual aids-to-navigation that provide an AIS signal to mark hazards to navigation in locations where a physical aid-to-navigation does not exist. The virtual aid appears on the electronic chart display and information system (ECDIS) of ships within range and they know (or should know) to avoid the location. By combining AIS data with other information, such as photos from surveillance aircraft or satellites, correlations can be made between individual vessels and pollution incidents. Use of AIS data from commercial services can allow traders and others to track vessels (and their cargoes) worldwide, making it difficult for vessels to arrive unexpectedly and influence a market.

As we learned in a recent report of the U.S. Committee on the Marine Transportation System (CMTS), three federal agencies generate terrestrial AIS-derived information. The U.S. Coast Guard focuses primarily on coastal areas, ports, and harbors. The U.S. Army Corps of Engineers (USACE) focuses on AIS products for inland waterways. The Saint Lawrence Seaway Development Corporation (SLSDC) focuses on the St. Lawrence Seaway and associated waters.

Numerous other federal agencies utilize AIS data in furtherance of their missions. The National Oceanic and Atmospheric Administration (NOAA) utilizes AIS data to monitor and analyze fishing activity; improve marine mammal protection; and prioritize charting and surveying based on measured traffic volumes. The Bureau of Ocean Energy Management (BOEM) uses AIS data to support its marine planning needs associated with offshore energy development.

The Maritime Safety and Security Information System (MSSIS) is a government-to-government data sharing network operated by the Department of Transportation. It combines AIS data from 74 participating nations into a single raw-AIS data stream that collects over 150 million vessel position reports per day from approximately 60,000 vessels. The combined data is available in several different formats to participating governments and federal agencies.

NOAA and BOEM jointly manage, a Geographic Information System (GIS)-based marine data viewer and repository that provides decision support tools for siting of offshore energy development, aquaculture, and other activities.

Because AIS data is stored on the Electronic Chart Display and Information System (ECIS) devices carried on most vessels engaged in international commerce, it has become the go-to location for marine casualty investigators and, in the event of litigation, for legal counsel. Almost every marine casualty report published by flag state or port state includes AIS data and an analysis of the movements of all vessels involved in the casualty based on that data. Interviews of crew members are still important, but actual ship movements as recorded in the AIS data tends to be the dominating factor in the analysis - and always prevails in the event of conflicts between different sources of information. The AIS data does not reveal why particular actions were taken, but it is almost always given full weight in determining what actions were.

AIS has expanded far beyond its original purpose and it is hard to imagine maritime operations in today's complex environment without it. It is not, though, a panacea. The Automatic Identification System is clearly an important tool, but must continue to be used with caution, recognizing its inherent limits, as well as future possibilities, including the increased prevalence of automated ships.

May 10, 2019


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