2GMDSS COSPAS (russiske) SARSAT (US/CA/FR) I alt 5 satelliter. NORD-SYD over polerne.Ca km over jorden.406 MHz, position ved doppler.INMARSAT, 4 SATELITTERGeostationære ved ækvator.Ca km.1,5/1,6 GHz.
3EPIRB - Emergency Position-Indicating Radio Beacon EPIRB is used to alert search and rescue services in the event of an emergency. It does this by transmitting a coded message on the 406MHz distress frequency, which is relayed via satellite and earth stations to the nearest rescue coordination centre. Marine EPIRBs work with the COSPAS-SARSAT polar orbiting satellite network which provides true global coverage, and can determine the casualty's position by triangulation to within 3 Nm (doppler) - or just a few metres if fitted with a built-in GPS (Global Positioning System). Most units also have a secondary distress transmitter, which operates on the old 121.5MHz and is used for homing purposes.