Question 35E4

The COSPAS-SARSAT system is a satellite-based international program dedicated solely to humanitarian search and rescue, detecting and locating distress beacons. **B) May be used to transmit public correspondence.** This statement is NOT true. The COSPAS-SARSAT system is specifically designed for distress alerting and locating. It does not have the capacity, design, or purpose to transmit public correspondence, which refers to general, non-emergency communications. **A) EPIRBs are satellite beacons used as alerting/locating devices.** This is true. EPIRBs (Emergency Position-Indicating Radio Beacons) are specifically designed to transmit distress signals to the COSPAS-SARSAT system for alerting rescue authorities and providing location data. **C) Locates Distress beacons transmitting on 406 MHz.** This is true. The primary frequency for modern COSPAS-SARSAT distress beacons (EPIRBs, ELTs, PLBs) is 406 MHz. This signal carries a digital message with identification information and, often, GPS coordinates. **D) Doppler shift is used to locate the beacons.** This is true. Even if a beacon doesn't transmit GPS data, the COSPAS-SARSAT satellites can determine its location by measuring the Doppler shift of the 406 MHz signal as the satellite passes overhead. This change in frequency allows for the calculation of the beacon's position.