Attack in U.S. would tax emergency tracking for cell phone users

Computerworld - If attacks similar to those that occurred earlier today in London happened in the U.S., most cell phone users would have trouble getting emergency crews to find them, according to experts.
Despite efforts after the Sept. 11, 2001, terrorist attacks to beef up mobile service so cell phones could be used to help track down people, "we"re in a sad state of affairs in the U.S.," said Jack Gold, an independent analyst at J. Gold Associates in Northboro, Mass. "If we faced a major disaster like London and had to locate injured people on cell phones today, maybe one or two could be located, but the system couldn't handle hundreds of calls.
"Location [tracking] is not an easy thing to do," he said.
At least 37 people were killed in the London blasts; hundreds were injured.
Part of the problem in using enhanced 911 (E911) wireless services would be too many people making calls at the same time, Gold said. Also, technical complexities and costs have slowed efforts by wireless carriers to implement automatic systems that could be used to locate cell phone callers, Gold and other experts said.
"It's a very difficult problem given the wireless infrastructure," Gold said. "Don't count on being rescued with your wireless phone unless you know exactly where you are" and can tell an emergency operator clearly.
Colleen Boothby, an attorney at Levine, Blaszak, Block & Boothby LLP in Washington who regularly appears before the Federal Communications Commission, said wireless E911 is "a lot better than it was five years ago," but she agrees that the service is not where public officials want it to be because of some "very technical issues."
There are two primary ways of finding a person using a cell phone who dials 911: network-based systems and handset-based systems, according to an FCC report to Congress on April 1. Another method relies on a combination of the two.
Network systems rely on equipment that captures the signal from a cell phone, including one approach called angle of arrival that involves calculating the direction of a signal at three cell sites and then using that data to calculate a user's location. Other methods rely on the timing of a signal's arrival at different towers or a comparison of its "signature" based on echoes from known buildings and landmarks.
A handset system requires that the cell phone be equipped with a Global Positioning System chip set to communicate with satellites that can transmit a user's location.
Both methods have technical limitations, Boothby