Can a Cell Phone Be Tracked by GPS?
A cell phone CAN be tracked by GPS.
Not only can a cell phone be tracked by GPS, via satellite or cell tower triangulation, but as of November, 2011, there is no federal law requiring that the government issue a warrant before doing so.
Conflicting Court Rulings
The matter is going both ways in court, depending on the judge. In August, 2011, a federal judge in New York ruled that police needed a warrant to track a particular individual via cell phone GPS. But just a few months later, in October, another judge in Washington D.C. Decreed that a warrant was not needed to track an armed robbery suspect. Then yet another judge in Houston, Texas in November 2011 pronounced that a warrant was needed.
Elements of the Patriot Act that were recently extended conflict with circuit court rulings against the use of GPS cell phone tracking. Another case involving a DC drug trafficking suspect who was tracked long past his warrant period has been kicked all the way up to the Supreme Court, with that ruling expected to further clarify or complicate matters.
U.S. regulations that require cell phone providers to locate subscriber equipment in the event of an emergency were instituted in 1996. This is one of the reasons a 911 operator will ask someone calling in to stay on the line, so that they can triangulate the caller and confirm their location.
Today, most Smartphones have GPS built in, making it that much easier to track them. What's more, many users of these devices happily use this information to notify their social media followers of when and where they have just "checked in," via 4Square and other applications.
GPS is more accurate than cell tower triangulation, however the latter can pinpoint someone down to a building or specific room if enough micro-towers are present in an urban area. It is now estimated that federal courts issue 20,000 to 30,000 cell phone tracking orders annually, while the count is even higher at the state level.