Missing or incorrect AIS vessel identity weakens target association and can cause misleading displays on navigation systems. When static data such as the MMSI, call sign, name, or IMO number is unavailable or wrong, the system cannot reliably link radar contacts to specific vessels. This discrepancy often manifests as a display that appears to show one vessel jumping between positions.
AIS static identity information includes the MMSI, call sign, vessel name, IMO number, dimensions, and ship type. These are configured data points rather than real-time measurements made by a receiving station. Consequently, relevant fields need amendment after any changes to the vessel's identity or ownership to ensure accuracy.
To verify what is being transmitted, another vessel or shore station can check the own-ship’s identity. The USCG describes a verification service that highlights certain static-data or encoding discrepancies within its coverage area. Invalid or duplicate MMSIs can produce misleading target association, which such checks help reveal.
