Through-Wall Person Localization Using Transceivers in Motion

We develop novel methods for device-free localization (DFL) using transceivers in motion. Such localization technologies are useful in various cross-layer applications/protocols including those that are related to security situations where it is important to know the presence and position of an unauthorized person; in monitoring the daily activities of elderly or special needs individuals; or in emergency situations when police or firefighters can use the locations of people inside of a building in order to save lives. We propose that transceivers mounted on autonomous vehicles could be both quickly deployed and kept moving to ``sweep'' an area for changes in the channel that would indicate the location of moving people and objects. The challenge is that changes to channel measurements are introduced both by changes in the environment and from motion of the transceivers. In this paper, we demonstrate a method to detect human movement despite transceiver motion using ultra-wideband impulse radar (UWB-IR) transceivers. The measurements reliably detect a person's presence on a link line despite small-scale fading. We explore via multiple experiments the ability of mobile UWB-IR transceivers, moving outside of the walls of a room, to measure many lines crossing through the room and accurately locate a person inside within 0.25 m average error.