Tracking target using sensor networks: target detection and route activation under energy constraints

In this paper we consider tracking a target moving in a 2D plane using a network of sensors, each of which is capable of detecting presence of the target in its vicinity and communicating data to a central ldquotrackerrdquo. Information collated by the central tracker is presented in the from of a sub-set Sigma^tk of sensors in whose vicinity the target is estimated to be present at time t^k.Given that available energy in sensors is at a premium, we have proposed protocols for target detection and route activation that require sensors to conserve energy by switching between ´inactive´ and ´active´ modes of operations, while waking-up frequently in inactive mode to evaluate the need to become active. These protocols have been evaluated from the viewpoint of delay in target detection (or delay in route activation) and duty cycle, the fraction of the time for which a sensor is awake in inactive mode. Using simulation results we argue that this approach allows one to track a moving object with reasonable accuracy, provided the density of sensors is adequately large.