May 28, 2004
SEARCHING FOR CALLERS USING GPS
By: Kevin E. McCarthy, Principal Analyst
You asked (1) whether Connecticut, as part of its E 911 system, has the capacity to identify the location of people making calls from cell phones with global positioning systems (GPS); (2) if not, why not and what needs to be done to establish this capacity; and (3) which agency is responsible for ensuring that the state develop this capacity.
Connecticut will be one of the first states to have the capacity to locate a person using a cell phone who makes an E 911 call, according to George Pohorlak, director of the Office of Statewide Emergency Telecommunications. The locating system is largely in place now and should be in place statewide by the end of summer. The office is responsible for working with cell phone companies and public safety answering points (PSAPs, i.e., fire departments and other agencies that handle E 911 calls) to implement the system. The system can also be used, pursuant to a court order or in an emergency situation, to identify the location of callers making non- E 911 calls.
In 2001, the Federal Communications Commission (FCC) required cell phone companies to develop the capacity of automatically locating callers. The mandate has two phases. In the first phase, the companies were required to develop systems to identify the location of a caller based on the cell phone tower or antenna that first picked up the call. This allowed companies to locate the caller within an area that ranged from a few blocks in cities to one-mile circles in rural areas.
In the second phase, cell phone companies have two options for significantly improving the locating capacity. They can install GPS chips in their telephones. The chip determines the phone's location (in hours, minutes, and seconds of longitude and latitude) by receiving signals beamed down from an array of satellites. The chip determines the location based on different arrival times of these signals. Alternatively, a cell phone company can comply with the mandate by using information provided by its network. This approach uses towers and antennae in the carrier's network to measure the timing of signals emitted from the phone, and thus its location,
Under the FCC mandate, by the end of 2005, companies using the GPS approach must be able to place 95% of calls they handle within 150 meters (approximately 500 feet) of the actual location, and 67% of calls within 50 meters (approximately 165 feet). Companies that use the network option must be able to place 95% of calls within 300 meters and 67% within 100 meters. Further information about the mandate is available at http://www.fcc.gov/911/enhanced/.
According to Pohorlak, five of the six major cell phone companies serving the state have already deployed their systems. Nextel, Sprint, and Verizon have deployed the GPS option, while AT&T and Cingular have deployed the network option. T-Mobile originally chose the GPS option, but has decided to use the network option instead. Pohorlak anticipates that T-Mobile will complete the deployment of its system by this August. His office will test the accuracy of the systems.
Twenty of the state's 107 PSAPs have electronic maps that automatically display the location of a call using the information provided by cell phone companies. Pohorlak anticipates the remaining PSAPs will have this capacity by the end of June.