The anonymous drone operator was part of a team that sought out high value targets in Yemen, Somalia, Afghanistan and elsewhere. These targets were said to be high ranking terrorists. But instead of confirming the identities of these targets using personnel on the ground, the drone crew relied on the cell phones used by the targets, tracking the phones' activities and locations. NSA whistle blower Edward Snowden has confirmed this as has Brandon Bryant, a former drone sensor operator with the USAF.
One method employed by the military is based on the NSA using its equipment to geolocate a specific SIM card or a mobile handset used by a suspected terrorist. One this information is known, it is passed along to the military or the CIA. A night strike or drone attack is then used to capture or kill the targeted individual. While the former drone operator says that terrorists have been captured or killed using the cellular data and metadata, innocent people have also been killed during drone strikes. This has happened because the Taliban would take the SIM cards out of their phones, put them in a bag, shake them up, and redistribute them. Sometimes, a targeted phone would be randomly passed along to another person who was not an intended target. That person ends up killed for using the wrong phone at the wrong time.
Some of the drones used by the U.S. military are equipped with a "virtual base-tower transceiver" that can trick a cell phone on the ground into thinking that it is a cell tower. This locks the phone onto the drone giving the military the ability to track the handset to within 30 feet of its location. At that point, it is like killing fish in a barrel.
But if the former drone operator is correct, and the military is targeting phones, not people, the success of the entire program could be overstated. As the anonymous source said during his interview, "I don’t know whether or not President Obama would be comfortable approving the drone strikes if he knew the potential for mistakes that are there. All he knows is what he’s told." That also applies to the American people.
source: TheIntercept via Gizmodo