Poster: Combinatorics, algorithms and systems for sensor deployment with line-of-sight constraints

In this paper we investigate sensor deployment and coverage algorithms for using infrared signals in indoor applications. Infrared signals are directional and reliable signals that have little interference with other electromagnetic signals that are commonly found in the deployment domain such as visible light and wireless radio waves. Since the angle of arrival is used, and line of sight is the main constraint for IR signals, we investigate the problem called robust guarding, i.e., placing emitters to ensure that all points of the domain are robustly covered by two emitters that are from sufficiently different directions. We prove combinatorial upper and lower bounds for the number of emitters needed and prove that finding the minimum number of guards is NP-hard. We show that n/2 guards are always sufficient and sometimes necessary for rectilinear polygons and we provide practical algorithms in general. We also developed a testbed with low cost off-the-shelf infrared (IR) emitters and sensors for indoor device-free localization. We tested the algorithms for using infrared sensors for indoor localization and our system achieves an average accuracy of 11.7 cm in a typical office setting.