Target Localization in NLOS Condition Using Beacons to Determine Reflector Orientation

Localization of a stationary target in Non-Line Of Sight (NLOS) condition, in which the target signal is received after a single reflection from a reflector, is a challenging problem. In this paper, we address this problem when the reflector position is available. To solve this localization problem, a new Beacon-Based Localization approach (BBL) is introduced in which a number of known beacons are used to localize the target and the reflector at the same time. We further specify the minimum number of beacons needed to localize a target in a given situation. Furthermore, we propose a procedure to determine the best location to place beacons in order to improve the localization process. To test the proposed approach, a mirror space is considered in which the reflectors are mirrors with no signal attenuation, i.e., the reflection is perfect. The receiver was a camera and the distance is calculated using the size constancy concept. Furthermore, the angle of arrival was calculated based on the orientation of the camera with respect to a global frame. The problem is solved for large reflectors first, and then for finite reflectors. The simulation results show the validity of the proposed approaches.