iLight: Indoor device-free passive tracking using wireless sensor networks

Target tracking is a main application of wireless sensor networks (WSNs), and has been studied widely [4], [10]. In this work, we study indoor passive tracking problem using WSNs, in which we assume no equipment is carried by the target and the tracking procedure is passive. We propose to use light to track a moving target in WSNs. To our best knowledge, this is the first work which tracks a moving object by using light sensors and general light sources. We design a novel probabilistic protocol (system) iLight to track a moving target and several efficient methods to compute the target's moving patterns (like height, etc.) at the same time. We implement and evaluate our tracking system iLight in a testbed consisting of 40 sensor nodes, 10 general light sources and one base station. Through extensive experiments, we show that iLight can track a moving target efficiently and accurately.