Position Messages

AIS position (also sometimes referred to as dynamic) messages mostly broadcast information about a vessel's physical location and motion. This includes a vessel's MMSI number, longitude, latitude, rate of turn, speed, true heading, and other parameters. 

Spire offers the following position messages to customers:

  • Messages 1, 2, and 3 from Class A vessels
  • Message 4 from base stations
  • Message 18 from Class B vessels
  • Message 27 from Class A or B vessels (for long-range applications)

Nominal Reporting Interval

  • Anchored/Moored Class A/B vessels broadcast position messages every 3 minutes.
  • Class A and Class B traveling at most 3 knots and 2 knots respectively broadcast position messages every 3 minutes.

Static Messages

AIS static messages mostly broadcast information about vessel characteristics that should remain (relatively) static over the during of their voyage. This includes a vessel's MMSI number, AIS version number, IMO number, call sign, name, type of ship/cargo, ship dimensions, destination, and other parameters.

Spire offers the following static messages to customers:

  • Message 5 from Class A vessels
  • Message 24 from Class B vessels

Nominal Reporting Interval

Both Class A/B vessels broadcast static messages every 6 minutes, when an information change has been made, or upon request.

Other Messages

Message 19

Spire offers Message 19 from Class B vessels, which contains some parameters from Messages 18, 24A, and 24B.

Additional Encoded Available AIS Messages

We also offer the following AIS messages in an encoded fashion along with their MMSI and flag or origin:

  • Message 6: Addressed binary message
  • Message 7: Binary acknowledge
  • Message 8: Binary broadcast message
  • Message 9: Standard search and rescue aircraft position report
  • Message 10: Coordinated universal time and date inquiry
  • Message 11: Coordinated universal time/date response
  • Message 12: Addressed safety related mesaage
  • Message 14: Safety related broadcast message
  • Message 15: Interrogation
  • Message 16: Assigned mode command
  • Message 17: Global navigation-satellite system broadcast binary message
  • Message 20: Data link management message
  • Message 21: Aids-to-navigation report

References & Other Resources

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