Maritime Safety Systems

The Customer

Thomson-CSF Systems, part of the Thales group of companies, is one of Canada's leading command, control and communications systems integrators. Tait and Thomson CSF collaborated to install Global Marine Distress and Safety Systems (GMDSS) in Egypt and Trinidad and Tobago.

The Challenge

GMDSS has been introduced by the International Maritime Organisation - the United Nations Agency responsible for the safety of ships at sea.Individual countries and ship owners are required to install a GDMSS in accordance with the International Convention for the Safety of Life at Sea.GMDSS provides an emergency number for ships. In an emergency, an automatic distress message and locating signal is transmitted to shore-based authorities and nearby ships.

The Solution

GMDSS systems are typically installed by coastguard authorities which use them in emergencies, and telephone companies who use them to generate commercial ship-to-shore telephone revenue. GMDSS comes in four different range categories:

• A1 - VHF basically with line of sight range of about 50 to 70 kilometers,
• A2 - MF ground-wave systems operating at 2.175 MHz with a range of up to 240 kilometers, and
• A3 and A4 - skywave or satellite communications systems covering the globe.

Thomson CSF chose Tait VHF base stations for the Egyptian and Caribbean systems, and digital selective calling sub-systems provide automated radio watch-keeping on distress and calling channels.

The Tait base station was chosen because of its reputation for reliability. It provides the client with the lowest possible broadband noise and has the best receiver desensitisation characteristics. The base station includes a changeover panel which detects the first signal from a ship and then checks it against a second signal to ensure the message is received.

The system also allows direct dialling into the local telephone network after checking with the ship is a paid-up subscriber. If so it connects the parties through another channel.

The Egyptian system is the larger of the two with three control centres and 22 sites while the Caribbean system has one control centre and fi ve sites. Tait has also provided base stations for a GMDSS system supplied from a Russian dealer - Radioma - for operation in the Black Sea.