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In summary, the Nationwide Automatic Identification System (NAIS) is a nationwide network of land-based VHF receivers and transmitters designed to increase Maritime Domain Awareness (MDA) in U.S. coastal and territorial waters. Numerous NAIS sites along the coast “listen” to transmitted maritime AIS activity; this data is then consolidated and disseminated to the Coast Guard and other government agencies. For more information, please visit our Nationwide AIS page section.

In comparison to NAIS, the Automatic Identification System (AIS) is a ship-to-ship collision avoidance system that allows for communication of position, speed, and other ship data via a VHF virtual data link (VDL) network. Mariners worldwide use AIS to ensure safety at sea. For more information, visit our AIS section.