How Cell Phones are Traced and Tracked

  Business Phone Service

Each time your phone authenticates at a cell tower, this information is stored at the MTSO for billing purposes. From this record it is possible to place a cell user in a general area, because a tower may have a range of a couple of miles. Mobile carriers usually only release this data with a court order. In San Diego, prosecutors used this method to track the whereabouts of David Westerfield and to convict him of the murder of seven-year-old Danielle van Dam. His cell records revealed his movements in the days after Danielle disappeared.

Another way to track cellular users is through technology that calculates the time difference in arrival of a cellular signal among multiple towers, or the angle of arrival. These techniques can help locate a cellular customer within a much smaller area than by using MTSO records alone. This technology is used to locate people calling the 911 service from mobile phones, but it could just as easily be used in a criminal prosecution.

The most precise way to pinpoint the location of a mobile phone is through the use of the global positioning system {GPS). GPS satellites orbit the Earth and transmit coded signals at regular intervals. A GPS-enabled device calculates the difference in arrival time of three or more signals and calculates its location to within a few feet. As more handsets come equipped with GPS, the potential to accurately track mobile phone users will become more and more of a reality.

Note: Pagers may be receivers (one-way paging), or like cell phones, transceivers (two-way messaging and e-mail pagers). A pager network is arranged in a similar manner to a cell network. Instead of cell towers, paging networks use smaller remote terminal units (RTU). An RTU has a much weaker signal, so there are more of them in a given coverage area. RTUs are small and can be mounted on existing telephone poles or buildings. With the competition from low-cost mobile phone services, pager networks are in decline. Personal communication service (PCS) phones duplicate many of the functions of a pager.