Ad hoc indoor peer-to-peer tracking using relative location estimation

We consider an ad hoc indoor device tracking problem where a user device has no knowledge of map and infrastructure. Since it does not have any information of reference points, the user device finds relative location of its target device. In fact, relative location, which can be described by direction and distance, is sufficient for the user device to track and approach the target device. However, indoor multipath environment and a single antenna of the device are obstacles to measuring direction using direction-of-arrival (DOA). Instead, if the user or the target device is moving, then, by fusing distance measurements and sensor information, the user device can estimate direction and thus calculate the relative location of the target. We show that the relative location can be calculated by trilateration in some cases. As a flexible and adaptable method, we also employ a simultaneous localization and mapping (SLAM)-based method using a particle filter (PF).We evaluate the ad hoc device tracking in some environments by simulation.