The biggest challenge cellular mobile phones introduce for 911 is location accuracy—especially during an emergency call. The problem is a global one, inherited with any wireless technology. Getting the location wrong directly impacts the level of safety provided to citizens, as routing the call to the most appropriate Public Safety Answer Position (PSAP) specifically relies on this critical piece of data.
Can you find me now?
Many of us don't stop and think how our mobile devices determine where we are on the planet, and most of us will assume GPS plays a significant role in providing that answer. While GPS remains an important piece of the location puzzle, quite often it is not the answer by itself. Fundamentally, there are three sources for location information used by cellular phones.