Use of RSSI and time-of-flight wireless signal characteristics for location tracking

Abstract

Wireless networking is a common component in assistive environment designs. In addition to allowing the deployment of multiple sensors that are not physically connected, wireless networking carries an additional benefit - the characteristics and interactions between the wireless mobile node and the wireless base can be examined to determine the otherwise unknown location of the mobile node. Determining the location of the mobile node is the topic of this paper. In particular, this paper explores the relationship between Received Signal Strength Indicator (RSSI) and the error in the computed Time-of-Flight (TOF) data. This relationship is exploited to associate probabilities with location readings which are subsequently used to apply particle filtering techniques to reduce the inaccuracy in the location computation. We show that by using RSSI and particle filtering, the wireless node's location can be tracked far more accurately than by accepting TOF as provided.