The most common way to track cell phones is through global positioning systems (GPS) that come built into many cell phone models. Cell phone providers also use a process called triangulation to track phones, though this process does not return as accurate of a location as GPS tracking. Customers, cell phone service providers, emergency services and even some government agencies use both of these procedures to track cell phones for various purposes, including keeping track of children, locating the service tower from which a phone is pulling a signal, locating an individual who contacts an emergency service and preventing crime and fraudulent activities.
GPS tracking devices are the most accurate way to track cell phones and are the technology most used by emergency medical services and customers. In many countries, when an individual calls an emergency service, such as the police, fire department or ambulance service, the cell phone sends a signal that displays the location of the cell phone to the emergency responder. This enables the service to respond quickly and locate the individual, even if he or she does not know his or her location or cannot tell the operator where he or she is.
Cell phone customers use GPS to track phones on their accounts in some instances. Some cell phone providers offer services that enable customers to pinpoint the exact location mobile phones on their accounts via other phones or the Internet. These services are often marketed to parents who wish to keep track of their children.
Government agencies and police forces are able to track cell phones in many locations. They might employ these techniques in efforts to locate a missing person, track a suspect of a crime or determine an individual's whereabouts at a specific time. There is much debate about the legality of government agencies tracking cell phones and the level of privacy that a customer should be able to expect when it comes to tracking his or her location. The practice is legal in many jurisdictions, however.
Applications that a customer can choose to install might use the phone's GPS devices to track the customer's location and provide a service. For example, a customer might choose to install an application that accesses his or her location information to find nearby gas stations, restaurants or hospitals. Other applications include a social component where customers can allow friends and family members to view their locations.
Triangulation is a method often employed by cell phone service providers to track cell phones for technical support reasons. To triangulate a cell phone, the service provider locates the positions of the three closest cell phone towers. The provider then uses software to map out the coverage radius of each tower to get an approximate location of the cell phone where the areas covered by all three towers intersect.