The document discusses different formulations for wireless sensor network object tracking including push-based, poll-based, and guided formulations. Push-based formulation has nodes periodically notifying a sink node of a target's position using a cluster structure. Poll-based formulation allows low-cost querying as nodes poll for a target's presence. Guided formulation defines a trajectory for a tracker to follow to intercept a target. Object tracking involves target detection, energy management, position computing, prediction, node cooperation, and recovery.