People see how FBI agents track the suspects in 24 hours, actually they are using GPS mobile phone tracking technology.
GPS, short for global positioning system, is a global radio navigation system set up by the US department of defense, it consists of 24 satellites and by connecting to at least three of them, any device that has a GPS receiver can determine its current location，and other factors like speed, time and distance.
In order to track your or others location, you need certain sever and clients. The sever which has a static IP receives and stores the clients locations so that people can keep track of them, this is very useful to track children, the old and fleets. The GPS compatible clients (like PDA and mobile phones) however, in order to be tracked, must have a built-in communication chip and certain software which send its current GPS coordinates to the sever via GSM/GPRS.
GPS cell phone tracking technology advances quickly, the accuracy increased a lot in the past few years so it can be used to track anyone with a GPS mobile phone.
Update, you can NOT track any cell phone as you wish unless you install mobile tracking apps first. Law enforcement can track down any cell phone easily via carrier’s cell phone sites across the country. But that’s web based, not GPS tracking.