An energy efficient tracking algorithm(EETA) was proposed
which reduced energy consumption in sensor network by introducing an event-driven sleep scheduling mechanism.EETA gave tradeoffs between real time and energy efficiency by letting a maximum number of sensor nodes outside tracing area stay asleep
and reduced the computation complexity to O(N) by formulating the location predication of an object as a state estimation problem of sensor node
in-stead of building a complex model of its trajectory.Meanwhile
EETA located the object by using adaptive weighted cen-troid algorithm with complexity of O(N).The method was evaluated with a network of 64 sensor nodes
as well as an analytical probabilistic model.The results demonstrate the effectiveness of the method.