Virtual radar imaging for sensor networks

Most approaches to sensor data collection in the literature are based on a multihop wireless relay between sensor nodes forming an ad hoc network to reach a remote data-processing destination. We propose an alternative virtual radar paradigm, which, in its most rudimentary form, is implementable with sensor nodes without networking capabilities. We introduce this concept for a simple setting in which each sensor only has one bit of information to send (e.g., indicating whether the level of a certain chemical has crossed a threshold). "Active" sensors (those which have one to send) respond to a beacon sent by the collector node, precisely timed with a trigger sequence in the beacon. The collector node uses a modified version of synthetic aperture radar processing to obtain an "image" of the activity in the sensor network.