Robust Device-Free Localisation with Few Anchors

Radio-Frequency based device-free localisation systems are able to pinpoint people's location in a given area without their cooperation. They work by analysing the perturbations that the presence of a person causes on the communications exchanged by a high number of radio devices installed around the area. Typical numbers are some tens of devices for an area the size of a single-family house, with an accuracy around one meter and a high sensitivity to even the slightest movement. The literature about device-free localisation systems typically concentrates on improving sensitivity, accuracy and discriminating power, without worrying too much about the number of involved radio devices. In this paper, for the first time, we demonstrate that device-free localisation can work with reduced performance with as low as four anchors in an environment composed by two wide rooms. Being able to use so few anchors opens the possibility of several use cases where installing tens of devices is not desirable.