The Global Maritime Distress and Safety System (GMDSS) is the international radio safety system authorized by the International Maritime Organization (IMO) for ships at sea.
The Global Maritime Distress and Safety System (GMDSS) uses terrestrial and satellite technology and ship-board radio systems to ensure rapid, automated alerting of shore-based communication and rescue authorities in the event of an incident at sea. Ships engaged on international voyages must be equipped with radio equipment that conforms to international standards as set out in the system.
Search and rescue (SAR) authorities ashore and shipping in the immediate vicinity of the ship in distress, are rapidly alerted through satellite and terrestrial communications so that they can assist in a co-ordinated rescue operation with the minimum of delay.
GMDSS defines four sea areas based upon the location and capability of onshore-based communication facilities. The definition of the Sea Areas for GMDSS is outlined below.
Sea Area A1
Covered by VHF coast stations in which continuous alerting by Digital Selective Calling (DSC) is available.
Sea Area A2
Covered by MF coast stations in which continuous alerting by Digital Selective Calling is available.
Sea Area A3
The coverage of Inmarsat geostationary satellites and HF Coast Radio Stations.
Sea Area A4
Area outside A1, A2 and A3, mostly sea area around polar areas. Normally covered by HF Coast Radio Stations, which also can cover Sea Area A3, in which continuous alerting by Digital Selective Calling is available.
- VHF Radio Station
- MF/HF Radio Station
- NAVTEX Station
- Satellite Station
- Operation Centre
- Extended Warranty