The first of the IMO regulations came into force on 1st July.

The main benefits of the MDS system include precise and reliable tracking and positioning of vessels, data interchange between any mobile installation, the VTS centre and any wide area network; short message services and telemetry control for the remote control of navigation aids such as lighthouses and buoys.

Trinity House, together with ABP Southampton, Red Funel Ferries, Condor Marine, MDS and Tideland Signal have recently organised a pilot scheme tracking vessels in the Solent. A UAIS base station was integrated into Southampton's VTS centre and several UAIS transponders installed on vessels using the port.

The principal objectives of the test were to evaluate the impact of the system on the end user and to demonstrate the interoperability of UAIS, but perhaps its most interesting feature was the use of weather monitoring buoys.

Weather and hydrological data transmitted from the buoys to the VTS centre was re-transmitted as a UAIS message from the base station, thus making this useful information automaticaly available to all UAIS-equipped vessels within VHF range.

AIMS MIII uses VHF radio transponder transmission to provide accurate information on a ship's identification, position, speed and course. In adition to tracking, data interchange and telemetry application for the remote control of navaids, it will significantly reduce the use of VHF channels and operator workload by automatically transferring the ship's own data and standard information.

The design of the system is based on 4S broadcast transponder techniques, with co-channel operation supported by global and regional frequency management. With an AIMS MIII linked to a GNSS receiver with differential correction capability, positional accuracy of better than 3m can be achieved.

If a GPS system is not available, other navigation systems such as GLONASS, Loran-C or Chayka can be used as back-up.

The system has two general operating modes, autonomous and assigned. Autonomous is mainly for vessels in the open sea and is primarly intended for collision avoidance. Each vessel within the VHF range is tracked and can be displayed on board, so enhancing radar surveillance. As vessels approach the land they are automatically switched to the assigned mode by an AIMS base station.

MJ Information No: 17300