We’ve discussed marine traffic tracking technologies and AIS data regarding gathering vessel insights to create maritime solutions. This is crucial to situational awareness, bringing rich information to port monitoring and vessel route optimization.

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But, we thought we’d provide a breakdown and complete guide to this kind of data, so you know exactly what’s involved and more.

Perhaps your organization is looking to complement ship detection satellite analysis with AIS ship identification, leading you to wonder: what exactly is marine tracking and AIS data? How does it work and how do satellites play a role?

Let’s delve deeper and explore.

Understanding Marine Traffic

Marine traffic refers to all ships at sea, including tankers, naval ships, container ships, fishing boats, and passenger ships. Ships are classified based on their purpose, size, and cargo type.

A vessel traffic service (VTS) monitors marine traffic similarly to how air traffic control oversees aircraft. VTSs are established by harbor or port authorities and are designed to enhance the safety and efficiency of vessel movements and protect the environment.

Defining Maritime Tracking

Think of maritime tracking as your eyes on the seas. It’s the ideal method to monitor the waves, knowing what, where, when, and how fast ships travel.

Maritime tracking offers real-time information about ships' movements and current locations in harbors and ports.

A 2018 UNCTAD review reported 50,732 active ships worldwide, including those at sea and in port.

There are numerous ways to track all this traffic. AIS tracking websites like MarineTraffic operate over 2000 automatic identification system (AIS) stations across more than 165 countries.

Maritime tracking services provide global real-time ocean coverage and predictive services, offering detailed vessel information, including name, country of origin, speed, heading, status, and position.

Not all ships have the necessary technical equipment for maritime tracking. However, since 2004, all vessels over 300 GT on international voyages must have AIS equipment on board, as required by the International Maritime Organization (IMO) under SOLAS Regulation V/19.2.4.

Exploring AIS Data

AIS (automatic identification system) is an automated tracking system displaying other nearby vessels. It tracks larger vessels worldwide, offering real-time information.

AIS uses ship transponders to track and trace vessels, enabling automatic electronic data exchange between ships and shore installations.

Ships with AIS transmit and receive information periodically from other AIS-equipped vessels. This data is categorized into three types:

Static Information (transmitted every 6 minutes)

• Identity
• IMO number
• Length and beam
• Type of vessel
• Position-fixing antenna location

Dynamic Information (dependent on speed and course alteration)

• Position
• Speed over ground
• Course over ground
• Navigational status
• Rate of turn

Voyage Information (transmitted every 6 minutes)

• Type of cargo
• Destination
• Estimated Time of Arrival (ETA)
• Route plan
• Safety-related information

The Significance of AIS

The AIS tracking system was initially developed by the IMO as a collision avoidance tool for large vessels beyond shore-based systems' range. AIS enhances situational awareness among seafarers and enables ships to 'see' each other more clearly.

AIS shore stations and other nearby AIS-equipped ships receive AIS data transmissions. Consequently, automatically recognizing, identifying, and tracking vessels is possible, regardless of location—in high seas, inland waterways, or coastal waters.

This data can be displayed on a screen or an information system, presenting the bearing and distance of nearby vessels in a radar-like format. It allows seafarers to be aware of other vessels long before visual contact is possible, facilitating time-sensitive decisions.

AIS vessel tracking has been the most significant navigation safety development since the introduction of radar.

AIS does not replace navigation services like radar and VTS but supports them. AIS’s strength lies in its ability to detect and track other AIS-fitted vessels. AIS and radar complement each other due to their different features.

AIS data makes collision avoidance more accurate and safety at sea paramount.

IMO regulations mandate that AIS devices:

• Provide information on the ship’s identity, type, position, course, speed, and navigational status
• Receive such information automatically from nearby AIS-equipped ships
• Exchange data with shore-based facilities

Applications of AIS Data

Originally designed solely for collision avoidance, AIS has expanded into various maritime applications:

Collision Avoidance

• At sea, knowledge of the movements and identities of nearby ships is crucial for navigators to avoid collisions with other ships or objects.

Marine Protection

• The world's oceans are deteriorating in condition and seeing declining flora, fauna, and aquatic species populations. Using AIS data, vessel tracks and positions can be monitored for protected areas, geo-fence breaches can be alerted, and culprits identified.

Maritime Security

• AIS enables authorities to identify specific vessels and their activities within or near a nation's Exclusive Economic Zone (a sea zone over which a sovereign state has special rights).

Navigation Aids

• The AIS aids to navigation (AtoN) product standard was developed to transmit the positions and names of non-vessel objects, including navigational aids and dynamic environmental data like lighthouse locations or climate conditions.

Search and Rescue

• AIS data provides crucial information for coordinating maritime search and rescue (SAR) operations. The position and navigation status of other nearby ships enhance SAR teams' situational awareness.

Accident Investigation

• AIS data is essential for reconstructing timelines during accident investigations. It offers accurate historical data on time, identity, compass heading, GPS-based position, and speed, compared to radar's less accurate information.

Fleet and Cargo Tracking

• AIS tracking websites allow fleet or ship managers to track their ships' global locations, enabling cargo owners to monitor transit progress and predict port arrival times.

Insight into the Technologies

How AIS Operates

AIS is a broadcast transponder system operating in the very high frequency (VHF) mobile maritime band.

An AIS system includes a VHF transmitter, a VHF DSC receiver, two VHF TDMA receivers, and a standard marine electronic communications link to shipboard display and sensor systems.

AIS Data Information

Position and timing data typically come from an integrated or external GPS receiver. Additional information broadcast by AIS is electronically extracted from shipboard equipment through standard marine data connections.

AIS must be switched on at all times unless turned off for security or other reasons.

If a ship does not have AIS or it is not switched on, there is no information exchange between ships via AIS. Generally, AIS operates autonomously and continuously. Hence, if a vessel has AIS, it will be displayed on the screens of other nearby vessels.

AIS Frequencies

Although only one channel is necessary, each station alternately transmits and receives over two radio channels to avoid interference:

• AIS 1: 161.975 MHz (Channel 87B, Simplex, ship-ship)
• AIS 2: 162.025 MHz (Channel 88B, Duplex, ship-shore)

Data Transfer

Signals are received by AIS transceivers fitted on other ships or land-based systems, such as vessel traffic systems (VTS).

Data is transmitted using a self-organized time-division multiple access (SOTDMA) datalink designed by Swedish inventor Håkan Lans.

'Self-organized' refers to how time slots are assigned to users. With the SOTDMA method, only the first free slot available for transmission must be found, and the next five slots are automatically reserved.

For more details, visit HUAZHONG, Marine Aids to Navigation Solutions.