a system for tracking mobile subscribers , the system includes an aircraft having an on - board virtual bts that substitutes for a stationary bts . the virtual bts emulates a behavior of the stationary bts so as to be indistinguishable from the stationary bts to the mobile device , including emulation of communication protocols and billing operations the virtual bts communicate with the mobile devices . the virtual bts includes a processor running software defined radio and a signal amplifier , the sdr receiving identifiers of the mobile devices . the aircraft includes a high - gain antenna for determining directions of signals from the mobile devices . a camera on board the aircraft takes images or video of an area on the ground . the processor collects and processes the images or video , the directions of the signals and the identifiers of the mobile devices to locate a specific subscriber . the processor transmits the processed information to a server .