Government Technology

Wireless Safety Net

May 1, 2002 By

Karla Gutierrez was in trouble. She lost control of her car, left the Florida Turnpike and plunged into a canal. Gutierrez got on her cell phone and informed a 911 operator that she was sinking, but she couldn't provide her exact location. By the time she was found, it was too late.

The scenario may have turned out differently if the center she called had wireless enhanced 911 location technology.

Nearly half of all Americans use wireless telephones, and in many jurisdictions, 50 percent or more of 911 calls are made from wireless phones. In those cases, 911 operators are entirely dependant on information from the caller to determine their exact location.

In 1999, the FCC mandated that Public Safety Answering Points (PSAPs) implement Automatic Location Identification (ALI) technology, which transmits the location of a cellular phone caller as the call is received at the PSAP.

So far, just three jurisdictions, Rhode Island, Lake County, Ind., and St. Clair, Ill., have begun implementing ALI.

Phase Two

The FCC mandate was to be met in two phases. The first phase required that PSAPs be able to identify wireless callers by phone number and location of the cell tower that transmitted the call. That gives the PSAP a general location, the south side of town, for example.

The second phase includes the implementation of ALI, which will transmit location data from the caller to the PSAP with either a handset-based GPS system or a network-based system. This technology can pinpoint the location of a caller within a few feet in some instances.

But implementation could take some time. The deadline for carriers to begin offering ALI to PSAPs was October 1, 2001. The FCC waived the deadline, however, at the behest of several wireless carriers who were behind in producing the new equipment.

Rhode Island was the first state to begin offering ALI to its citizens with Sprint PCS wireless phones. The phones contain a GPS chip and are capable of locating callers within three to five feet in about six seconds, according to Raymond LaBelle, executive director of Rhode Island's emergency telephone system.

Rhode Island will eventually include GIS mapping in its implementation, which will provide 911 dispatchers a picture of where the caller is located.

Which Technology is Better?

Which technology is superior, the handset-based or the network-based, has been a point of debate.

"At one point we heard that network would be more accurate and the handset would be too expensive, then it flip flopped," said Chris Ternet of Lake County, Ind., where they've begun to implement a network-based system with Verizon Wireless.

The FCC standards are stricter for the handset-based technology. They require that handset-based systems track 67 percent of callers to within 50 meters and 95 percent of callers to within 150 meters. The network-based technology must track 67 percent of callers to within 100 meters and 95 percent of callers to within 300 meters.

The location system determines the location coordinates of 911 callers by cell towers then forwards that information to a mobile positioning center (MPC). The advantage of the network-based system is that customers don't have to replace their old handsets. Still, the FCC wants older handsets replaced by more modern phones that contain the GPS chip. Some familiar with the technology advise jurisdictions implement both systems.

In Rhode Island, LaBelle expects the rest of the carriers will hurry to catch up to Sprint and offer the technology within the next few months. Sprint and Rhode Island were both at the fore of making implementation of this concept a reality; Sprint because it dedicated time and money to the project, and Rhode Island because it upgraded its facilities a couple of years ago and then took a hands-on approach to implementing the new technology.

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