Physical Measurements

Abstract

It is absolutely infeasible to do localization without knowledge of the physical world. According to the capabilities of diverse hardware, we classify the measuring techniques into six categories (from fine grained to coarse grained): location, distance, angle, area, hop count, and neighborhood, as shown in Among them, the most powerful physical measurement is directly obtaining the position without any further computation. GPS is such a kind of infrastructure. Besides, the other five measurements are used in the scenarios of positioning an unknown node by giving some reference nodes. Distance and angle measurements are obtained by ranging techniques, while hop count and neighborhood are basically based on radio connectivity. In addition, area measurement relies on either ranging or connectivity depending on how the area constrains are formed.