Cospas-Sarsat is enhanced with new meosar satellites

摘要

The electronic position indicating radio beacon (epirb) has for many years been a life saver for seafarers. The international Cospas-Sarsat system that detects distress beacons operating at 406 MHz provides distress alert and location information to search and rescue (SAR) services throughout the world for maritime, aviation and land users in distress. The system comprises satellites in low-altitude Earth orbit (leosar) and geostationary orbit (geosar) that process and relay signals transmitted by distress beacons. There are ground receiving stations, known as local user terminals (LUTs), which process the satellite signals to locate the beacon, and mission control centres that distribute the distress alert information to SAR authorities. There can be an alert delay of up to 45 minutes depending on when the satellites come into view on the horizon. The satellite can determine the position of the epirb to within 5km and the coded message that is transmitted identifies the exact vessel to which the epirb is registered. This information allows the rescue services to eliminate false alerts and launch an appropriate rescue. GPS-enabled epirbs have a built-in transmitter which will typically alert the rescue services within three minutes and to a positional accuracy of +/- 50m (updated every 20 minutes), given a clear view skywards.