How the NSA verifies a target's location

This is an excerpt from a transcript of National Security Agency training videos that describe how to verify the location of a targeted device. It explains how the NSA monitors different types of mobile signaling information known as HLR and VLR registrations in order to locate individuals. It also makes clear that the agency is able to use location tracking to ascertain whether a target is in the United States. NSA tracking cellphone locations worldwide, Snowden documents show