|
Cell Phone 911 Calls Are Hard To Locate
(Tampa Tribune (FL) Via Acquire Media NewsEdge) Nov. 22--UPDATED: 53 MIN. AGO
TAMPA -- In an ideal situation, when you dial 911 on a cell phone the police should be able to pinpoint your location down to just a few dozen yards, based on wireless signals from your phone.
It's supposed to work automatically, every time, in just a few seconds by pushing the buttons "9,1,1, Send."
Unfortunately, despite vast progress, there are still a lot of glitches that can prevent the police from finding someone using a cell phone to call for help. Half of U.S. 911 call centers can't accurately track a caller's location.
Even in modern cities, one glitch can mean the police will only know you are in an area several miles wide.
A glitch of some sort appears to have happened in the case of Jennifer Johnson, the 31-year-old mother found slain in a vacant house in Lakeland this week. Authorities confirmed Thursday that she was kidnapped and called 911 from the trunk of a car Saturday. They say she only got out two words, "Help me."
Authorities sent police to the general location where cell phone towers indicated she might be, but didn't find her in time. So far, Plant City officials are releasing few other details of the call.
For police to locate you in an emergency, a lot of things need to work perfectly.
To start, it helps to have a relatively new cell phone, bought in roughly the past two years. All new phones must be capable of communicating their location in an emergency. Generally, Verizon Wireless, Sprint and Alltel use GPS chips in their phones. AT&T and T-Mobile use several cellular towers to triangulate your position.
That's where the breakdowns can start.
If your phone can't "see" the orbiting GPS satellites or can't get good reception from multiple towers, such as in rural areas, the phone will only have a vague idea where it is. That means someone in an obstructed area -- such as a car trunk, parking garage or basement -- might not get good enough reception for the phone to locate itself. GPS data can also take 15 to 30 seconds to appear, so with very short calls the information to locate a person may not go through in time.
Next, cellular carriers who connect calls then send the best location information they have to the nearest 911 call center.
Unfortunately, about half the 911 call centers in the United States haven't yet upgraded their computer systems to receive that location data, according to CTIA, a trade group of cell phone carriers. In places without the upgrade, 911 operators could hear the call, but not locate the caller.
Plant City officials are still investigating, but said it appears that Johnson's phone was not GPS-capable.
"Usually we receive the phone number and approximate location" of the call's origin, Plant City Police Capt. Darrell Wilson said.
They also can't track calls from a moving car well because they might only receive location information from the first tower.
Hillsborough County officials said that despite its faults, the current system represents progress. Several years ago, 911 operators in Tampa might only be able to tell if a caller was near Lutz or Ruskin, for example.
"A lot of factors come into play," said Ira Pyles, operations manager for Hillsborough County 911 administration. It's still common for cellular calls to only reveal a vague area around Tampa Bay.
"Only if everyone lines up everything perfectly are we able to get exact location information," he said.
Tribune reporters Valerie Kalfrin and George Wilkens contributed to this report. Reporter Richard Mullins can be reached at (813) 259-7919.
To see more of the Tampa Tribune or to subscribe to the newspaper, go to http://www.tampatrib.com.
Copyright (c) 2008, Tampa Tribune, Fla.
Distributed by McClatchy-Tribune Information Services.
For reprints, email tmsreprints@permissionsgroup.com, call 800-374-7985 or 847-635-6550, send a fax to 847-635-6968, or write to The Permissions Group Inc., 1247 Milwaukee Ave., Suite 303, Glenview, IL 60025, USA.
[ Back To Smart Product Home's Homepage ]
|