Asynchronous Distance Measurement for Smartphone-Based Localization Exploiting Chirp Signals

Abstract

In this paper, we present an new asynchronous, accurate, and real time distance measurement method using chirp signals, which is capable of accurately locating and tracking, thus forming an ad-hoc network among smartphones in an indoor (e.g., smart meeting room) environment. Also we propose a distance measurement which can overcome limitations of previous representative distance measurements of Received Signal Strength Indicator (RSSI) and Time of Arrival (TOA). It operates in spontaneous, smartphone-based ad-hoc networks (SAN), sensory-based context inference, and device-to-device context extraction systems without requiring well–organized infrastructures. We then implement our proposed method on two Samsung Galaxy S5, one of Commercial Off-The-Shelf (COTS) smartphones. Without modifying their hardware or OS kernel. Our experimental results demonstrate that it takes < 1 second to conduct network-wide distance measurements and the measurement error is <10 cm, which is treated as an allowable error, in at least 87% of the experiments. ⓒ 2016 DGIST