GMDSS (Global Maritime Distress and Safety System)

The Global Maritime Distress and Safety System is the SOLAS communications framework, fully in force since 1999, that automates distress alerting and the delivery of maritime safety information using satellite and terrestrial radio. Carriage requirements depend on the sea area (A1 to A4) a ship operates in, defined by the coverage of VHF, MF, HF, and satellite services. The 2024 modernization recognized new mobile-satellite providers such as Iridium alongside the longstanding Inmarsat services.