Vessel Inspecting and Recording via AIS System

       The automatic identification system (AIS) or called Universal Automatic Identification System (USIS) is an automatic tracking system that allows maritime authorities to track and monitor vessel movements and is widely used by vessel traffic services both inland and international routes. The plan for using AIS requires the vessels over 300GT on international voyages and the vessels over 500GT on domestic voyages to install AIS device under IMO (International Maritime Organization) regulation. The signal from a marine modified from VHF will be tuned to AIS frequencies automatically and converted into a digital format that the computer can read while transmitting information and the location about the vessel itself to other AIS receivers fixed on the vessels or from shore base station nearby. The main purpose of AIS is to help identify vessel between itself and other ones; between itself and base stations located along coast lines, exchange and provide additional information, strengthen more safety awareness for the vessel voyages, and enhance the effectiveness of inspection on Vessel Traffic Control System (VTS).ม

       AIS device operates in the VHF maritime band, works as a shipboard broadcast system and is capable of communicating ship to ship as well as ship to base stations. The signals are time multiplexed using a technology called self-organized time-division multiple access (SOTDMA). The information provided by AIS device are position (latitude/longitude), marine compass, length, width, type of ship/cargo, ship’s draught, on board dangerous goods information, etc. AIS functions primarily by acquiring Global Positioning System (GPS) coordinate to transmit data of geographic location (Lat/Long) including of ship information to AIS base station nearby or to other ships. The capacity for sending data can be 1,000 times per minute and is automically updated. Data will be displayed on Electronic Chart Systems (ECS) or an Electronic Chart Display and Information System (ECDIS) which is a geographic information system used for nautical navigation. The displayed signals on ECS provide data sending to all vessels which sail within a range of VHF to capture the location and information of the other vessels fitted with AIS tranceivers.
(Source from http://www.port.co.th/cs/internet/internetsystem_AIS.html) Transmission of data both sending and receiving in AIS system will be listed below:


  • IMO Number (International Maritime Organization)
  • Vessel Name and Voyage Number
  • Vessel Name
  • Vessel Type
  • Dimension)
  • LAT/LONG
  • Course
  • Speed
  • RoT – Rate of Turn
  • Heading
  • Draught
  • Cargo Type
  • Destination
  • ETA


       As mentioned above, after getting the vessel location and other information that will be transmitted into analog radio signal (VFH). Later, the system will send the signal decoded from analog to be displayed as digital map on the computer or on Electronic Chart Systems (ECS) or on Electronic Chart Display and Information System (ECDIS). The process of signal decoding must be matched with the terms of data transmission in the standard for interfacing marine electronic devices as identified from National Marine Electronics Association (NMEA) which is developed to permit ready and satisfactory data communication between electronic marine instruments, navigation equipment and communications equipment when interconnected via an appropriate interface. It is currently used for tracking and monitoring the vessels

Example NMEA Data Transaction

       From the information as abovementioned including with my experiences with AIS system and Radar system in Thailand, I think that this task is still not utilized in full capacity.
  • To assist in collision avoidance when operating in the ship-to-ship mode.
  • Warning when the ship entered in the unauthorized territorial.
  • Warning when the ship is disappeared from tracking.
  • Alerts will be provided when the speed exceeded the speed limits.
  • Alerts will be provided when ships entering Thai waters in the case of ships come from the territories outside Thailand.
  • Warning when ships entering Thai waters without any legal authorization.
  • Warning when ship is locked from wreck condition but the owner still uses it.
  • Alerts will be provided when special monitored vessels entering into the identified area.
       I may conclude that various organizations spend more resources to generate this task. Not only AIS system is installed, but also VTS system is also required. On VTS displays, we find numerous locations of vessels that need more staffs to monitor and track all vessels. In my opinion “Is it better if AI system should replace humans? AI can help analyze and alert for the urgent event that may be occurred as from the conditions and regulations have been set up.” As a matter of fact, the conditions and regulations will be changed depending upon either the current situation or the country law. Moreover, it will be better because any wrongdoers must be taken penalty. For example, if anyone takes the speed exceed the speed limits or enters into the restricted area, the system will send warning message to all relevant person’s mobile phones. Later, penalty documents are issued and all information are automatically sent to the related systems.
   In case of regular task such as the vessel arrives at or departs from the port, data will be automatically sent to Port In/Out system and stored in history record for making the statistic report. This will be useful for the effective consideration. Whatever we can do after decoding signal from NMEA that all vessels data displayed on the map. The system can assist to identify policy and regulations as fixed with our requirement. The most important role of the system is being developed by Thai staffs, helps from trade deficit, be able to be tuned and suited with the country policy better than purchasing the system from the foreigner. In case the information is confidential, data must be encoded and kept safe and secure.