Design and Implementation of a Sensor Network Based Location Determination Service for use in Home Networks

Location determination is a fundamental component enabling context aware home applications. Ultrasound, floor sensors and computer vision, among others, have been proposed for location determination, each with its own benefits and limitations. In this paper we discuss the design, implementation and evaluation of a location determination system based on sensor networks. Our implementation includes three components: the location determination system which adapts and extends Motetrack for in-home use, a location storage system, and a middleware interface to allow home applications to access both current and historical location information. Our system uses Crossbow Mica2 and Mica2Dot sensors to provide 28th, 50th, 85th and 97th percentile location errors of under 1,1.5,2 and 3 meters, respectively. This will support most home services which typically require only "room level" accuracy. Using sensor nodes in our location determination scheme provides a low cost solution and eliminates dependence on the availability of existing, in-home equipment to perform the location determination computations