Global Maritime Distress and Safety System (GMDSS) (GMDSS)

The international maritime communications framework for distress alerting, search-and-rescue coordination and the dissemination of maritime safety information.

GMDSS combines terrestrial and satellite services and equipment that can include VHF, MF and HF digital selective calling, recognised mobile satellite services, NAVTEX or enhanced group calling, emergency position-indicating radio beacons, radar or AIS search-and-rescue transponders and portable radios.

The equipment legally required aboard a vessel depends on its regulatory status, voyage and operating sea area. SOLAS requirements principally apply to specified passenger ships and cargo ships on international voyages; other craft may carry selected GMDSS equipment voluntarily or under national rules, so the acronym does not describe one universal equipment package.