Personal Location Beacons Usage Grows

By Beth Bacheldor

Jan. 31, 2008—McMurdo, a maker of emergency position indicating radio beacons (EPIRBs), personal location beacons (PLBs), search-and-rescue transponders (SARTs) and other search-and-rescue devices, has announced its two latest PLBs designed to further aid in locating individuals during an emergency. This news comes on the heels of a search-and-rescue operation in which a sailor's life was saved after he activated his McMurdo PBL during a storm off the African coast.

PLBs are pocket-sized active RFID transponders that boaters, pilots, hikers and others can utilize in the event that they become lost or incapacitated. Although there are a variety of PLBs on the market, Cospas-Sarsat—an international search-and-rescue organization that operates a satellite system to detect and locate the signals of distress beacons—supports only those operating at 406 MHz or 121.5 MHz (processing of 121.5 MHz beacons will terminate on Feb. 1, 2009).

McMurdo's FastFind MAX G personal location beacons (PLB) is a pocket-sized active RFID transponder that boaters, pilots, hikers and others can utilize in the event that they become lost or incapacitated.

When activated, typically by a user pressing a button on the unit, a PLB transmits a unique ID number. In a registration document owned and managed by Cospas-Sarsat, each ID number is correlated to information about the PLB's owner. Typically, a PLB's location is determined by the three nearest satellites that take a position fix using what's known as the Doppler location process, according to Jeremy Harrison, sales and marketing director of McMurdo, a subsidiary of RFID and GPS products manufacturer Digital Angel Corp., based in St. Paul, Minn.

"This will take, typically, 45 minutes from the time a PLB is activated," Harrison says, "and will give a position accuracy of a three-nautical-mile radius [28 square miles]." The satellite closest to the determined location of the PLB then relays information to the nearest base station, more than 20 of which are scattered around the world. The base station reviews the data and, if the alert has not come from a military entity, passes that information along to the governing agency, such as the Maritime & Coastguard Agency (MCA) in the United Kingdom. From there, decisions are made regarding search-and-rescue operations.