Global Maritime Distress Safety System (GMDSS)

The Global Maritime Distress Safety System (GMDSS) is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships, boats and aircraft. GMDSS consists of several systems, some of which are new, but many of which have been in operation for many years. The system is intended to perform distress alerting, search and rescue coordination, locating (homing), maritime safety information broadcasts, general communications, and bridge-to-bridge communications. Specific radio carriage requirements depend upon the ship's area of operation, rather than its tonnage. The system also provides redundant means of distress alerting, and emergency sources of power. Redundancy is achieved by requiring more than one of several independent methods for performing each communication function. GMDSS communications functions are accomplished using several independent communication systems: satellite and MF, HF and VHF terrestrial radio services. Each of these communication systems is required to meet certain performance standards and to be available in certain sea areas.