Operators check an AIS vessel identity by comparing its configured static fields with independent sources. The Automatic Identification System transmits a set of static identity fields that serve as claims rather than independently measured facts. These fields include the Maritime Mobile Service Identity (MMSI), call sign, vessel name, and International Maritime Organization (IMO) number. Because this information is manually configured on board, it requires amendment whenever there are changes to the vessel's identity or ownership. Consequently, a receiving station cannot treat these transmitted details as conclusive proof of identity without corroboration.
To verify the accuracy of these claims, operators can compare the received data with information obtained from another nearby vessel or a shore-based monitoring station. Within the coverage area of the United States Coast Guard, a specific verification service is available to highlight discrepancies in static data or encoding errors. This official check helps identify potential mismatches between the transmitted identity and the registered records. Such cross-checking is essential for bridge teams to accurately associate a name, call sign, ship type, and navigational status with an equipped target.
