Freedom and Security: The Dilemma of Vessel Tracking

Improved vessel automated identification systems can help avoid collisions, prevent attacks

However, GPS provides such accurate positioning that ships are trying to get on to the waypoint and with a number of vessels aiming for the same point a number of near misses have been reported.

However, this is forgetting the primary reason AIS was introduced in the first place to aid security, making it easier for ships, ports and other authorities to identify approaching targets.

Today this AIS data is easily accessible by anyone with a receiver, and now ports and other industries are able to watch and use it in conjunction with their VTS systems, which again highlights how AIS can be a great help when used alongside radar-based tracking.

Ports such as Rotterdam and London, case studies at the vessel tracking conference, have successfully implemented their AIS systems, making their data more dynamic and accessible.

The global collection of this data is a commodity that services such as Seasearcher are using to good effect. A service from Lloyd's Marine Intelligence Unit, this provides optional real time data to subscribers who have an interest in knowing when certain ships are in port, close to ports and where they are bound.

Clearly the knowledge that a ship is coming into port over the next few hours is useful to many different kinds of person. LMIU has rolled out an AIS network to complement the Lloyd's agents around the world. They are assured that they do everything to prevent this data reaching the wrong hands.

But the threat of an attack does not just come from large ships. The threat from small vessels was proven when the Limburg and the USS Cole were attacked. It is for this reason that one of the largest ports and busiest stretches of water is pursuing a system to track every small vessel in its waters.

Singapore sees thousands of vessels pass through the straits every year, many calling for bunkers, provisions or cargo operations. They are serviced by thousands of small craft, which according to Kum Chee Meng of Singapore Technologies Electronics are vital to the smooth operation of maritime services

'These smaller vessels remains a constant major security concern,' he says. 'They are important, but the danger continues to lurk. Six years ago terrorists used small boats to attack the USS Cole in Aden and again the tanker Limburg off Yemen in 2000. The aim was to cause as much disruption as possible.'

That is why Singapore Technologies Electronics and the country's Maritime and Port Authority have been working on a system where smaller craft can also be tracked. That means that in the waters off Singapore about 5,000 craft will have to be monitored daily.

The new proposal is for an AIS B systems which is a cheaper, less robust version of the existing system. The proposal is that it transmits less data but can at least allow a small vessel's identity to be seen as well as other key data, allowing the Singapore port authority to identify radar targets swiftly and accurately eliminate the craft as a risk.

However, Hakan Lans, the inventor of the key functional technology that became AIS Sotdma, or Self-Organising Time Division Multiple Access, which prevents transmissions overlapping thinks that using a new AIS system, AIS-B, will cause huge problems

'It is strange that there is a proposal to increase the number of boats using the new class B AIS system and changing to a technology which some see has a hugely reduced capacity,' he says. 'AIS-A uses a technology that allows sharing of transmission slots, which AIS-B will not. These systems are not compatible.'

But the opportunity for a port to monitor and identify rapidly all its traffic is a benefit that many will see as outweighing any problems, and if this goes ahead the right solutions will be found.

But spare a thought for Southampton Water in Cowes week and imagine what even the most detailed AIS integrated radar picture will look like.

The next debate being raised is how to introduce global tracking. AIS is VHF-based and limited in range. Long Range tracking is a proposed total satellite based tracking system.

In its simplicity this is nothing new. Shipping companies have been requiring the masters of their vessels to report noon positions through Inmarsat for many years. Many companies even pass this information on to search and rescue services such as Amver (Automated Mutual Vessel Emergency Response).