AIS vessel identity comprises the MMSI, call sign, vessel name and IMO number. These elements are configured data rather than real-time measurements made by a receiving station. AIS static identity information also includes vessel dimensions and ship type.
Because these fields are manually entered, they require amendment after any change in identity or ownership to maintain accuracy. This configuration allows a bridge team to identify and track an equipped target, associating a name, call sign, ship type and navigational status with it.
Invalid or duplicate MMSIs can produce misleading target association. Such errors may result in a display that appears to show one vessel jumping between positions. Not every vessel has or transmits an IMO number, name, call sign or complete identity record in every AIS message.
