PPZTEM: An efficient approximate trajectory extraction method with error bound constraint for wireless sensor networks

Trajectory extraction has been studied in many research areas, including traditional spatio-temporal databases, advanced vehicle information systems, and military surveillance. In wireless sensor networks, several factors make it difficult to acquire an object's trajectory, including imprecise and stream-oriented localized locations, limited sensor storage, and limited bandwidth. This paper proposes the Possible Presence Zone Trajectory Extraction Method (PPZTEM) with an error bound control mechanism to extract the approximate object trajectory from imprecise localized locations. PPZTEM constructs a trajectory that describes the most probable path of an object in wireless sensor networks. The constructed trajectory of PPZTEM satisfies the given error bound constraint and requires only a small amount of data. Experiments on a broad variety of synthetic and real-world object trajectories reveal that PPZTEM significantly reduces the data size of the trajectory by fusing the localized locations. At the same time PPZTEM achieves user-specified error constraints on the estimated locations.