Rescue workers worldwide have another way to search for missing persons via a cell-phone location solution from Icelandic technology integrator Rögg that does not utilize GPS, according to officials for Range Networks, which developed the supporting hardware and open-source software platform.

Known as the Norris Position System, the Rögg location solution triangulates the cell-phone location of lost hikers from radio-equipped helicopters that act as aerial base stations, performing calculations based on the GSM timing advance value and mapping the results on iPad tablets.

“What’s very unique about the Rögg application is that it relies completely on GSM, without requiring any GPS at all,” Jeff Stern, Range Networks’ general manager for field operations, said during an interview with IWCE’s Urgent Communications. “So, if people have their GPS turned off or it’s not working, this is a great application.”

To ensure that the correct person is found, responders need to get the missing person’s international mobile subscriber identity (IMSI) from a carrier. When that IMSI signal is detected—the cell phone only needs to be turned on and have battery power—the location is triangulated, so search-and-rescue workers know where to look.

“Once you find his IMSI, you can now do a timing advance calculation on the system—the Rögg application—based upon how long it takes signals to get back and forth from the phone,” Stern said. “Based on that, you can use this phone as a beacon essentially and bring your aircraft to him.”

The Icelandic Coast Guard conducted 15 tests of the Rögg offering and has used the technology during four search-and-rescue efforts to date, some of which have been “massive operations” involving 500 people, according to John Callon, Range Networks’ director of marketing and business development.

“When you consider the manpower involved and the risk to life and limb of the searchers—not just the search target—it’s sort of a no-brainer as an additional tool to be able to shorten these searches,” Callon said during an interview with IWCE’s Urgent Communications.