Trail: A Distance Sensitive WSN Service for Distributed Object Tracking

Distributed observation and control of mobile objects via static wireless sensors demands timely information in a distance sensitive manner: information about closer objects is required more often and more quickly than that of farther objects. In this paper, we present a wireless sensor network protocol, Trail, that supports distance sensitive tracking of mobile object by in-network subscribers upon demand. Trail achieves a find time that is linear in the distance from the subscriber to the object, via a distributed data structure that is updated only locally when objects move. Trail seeks to minimize the size of the data structure. Moreover, Trail is reliable, fault-tolerant and energy-efficient, despite the network dynamics that are typical of wireless sensor networks. We evaluate the performance of Trail by simulations in a 90-by-90 sensor network and report on 105 node experiments in the context of a pursuer-evader control application.