NOAA: Rescues rising with satellite beacons
- By Susan M. Menke
- Feb 20, 2004
Satellite beacons have already led rescuers to save the lives of 34 people in life-threatening situations this year, the National Oceanic and Atmospheric Administration said today. Last year, NOAA helped rescue 224 people who activated beacons on land, sea or in the air.
The Federal Communications Commission last July approved public use of pocket-sized personal locator beacons, or PLBs. People who buy them either new or used must by law register them in the National 406-MHz Beacon Registration Database
, said SARSAT program manager Ajay Mehta.
Delays caused by unregistered signals 'may be the difference between life and death,' Mehta said. NOAA also requires registration updates every two years, or whenever the data changes.
'I'm happy to report that more than 20 percent of our beacon database transactions are online,' Mehta said. 'Our goal is 100 percent online, so we can use more of our resources to keep the database current.' He said NOAA has registered 1,789 PLBs.
When activated by someone in distress, a beacon sends its location to rescue authorities via NOAA satellites and the Search and Rescue Satellite Aid Tracking System, SARSAT.
NOAA's geostationary and polar-orbiting operational environmental satellites receive the 406-MHz signals from three types of beacons:Emergency position-indicating radio beacons, or EPIRBs, for maritime rescueEmergency locator transmitters, or ELTs, for aviation usePLBs for land use.
The Coast Guard requires EPIRBs on ships weighing 30 tons or more, commercial fishing vessels and those that transport six or more persons for hire. Requirements for monthly battery inspection and testing with a single signal burst have caused many anomalous alerts, however.
The SARSAT site advises, 'Only you can prevent false alarms.'
The smaller, cheaper PLBs cost around $500 and must be capable of transmitting a signal for 24 hours. When a POES satellite picks up the digital signal, it calculates the location to within about two miles by Doppler sound shift. Experts say most persons in distress can expect SARSAT to have their locations within about a half-hour.
Some PLBs send a separate, 121.5-MHz homing signal to guide rescuers to the spot. Newer ones also have a Global Positioning System chip or work with a GPS receiver to pinpoint location to a few hundred feet. With GPS, 'we'll know who you are and where you are within a matter of minutes,' Mehta said.