The Justice Department said Thursday it will require its law-enforcement agents to get a warrant before using technology that tracks the location of cellphone users by posing as cellphone towers.
The cellphone-tracking technology, which sweeps up identifying information from every mobile device within range in order to find a target device’s location, has been met with criticism from privacy advocates who have raised concerns about the widespread data collection it makes possible.
Sometimes called Stingrays after a popular model used by law enforcement, the cell-site simulators operate by mimicking a cellphone tower and establishing connections with nearby devices searching for a cell signal. When devices connect to the simulator, they transmit identifying information. Police can single out a device and use the direction and strength of the signal to acquire its location.
The Justice Department has historically remained highly secretive about the technology, often pushing state and local police to stay silent about their usage of the simulators.
Stingrays do not receive GPS information, and may not be used to intercept communication to and from mobile devices, or the data stored on them, according to the Justice Department.