Pinpointing a WiFi-enabled device in 3D using Multipoint Triangulation

Abstract

WiFi has emerged as one of the essential technologies to provide location-based services indoors owing to the rapid proliferation of wireless access points in metropolitan areas and the rising use of smartphones.WiFi-basedpositioningappearstobeapotentialoption because itdoes notneedacomplicatedlocalinfrastructure,inaddition,userdevices(suchasmobilephones)can already analyse WiFi signals, and WiFi signals are widespread and powerful.This work proposes using triangulation of anglemeasurements from WiFi routers based on router access points. Theproposed algorithm has littleestimationnoiseandenablesforthe measurementof angle-of-arrivalandangle-of-departure.Multipath propagationcanbecalculatedusing the MUSIC technique.The generalised algorithm is not too complicated.Simple triangulation algorithm output measures Time ofArrival (ToA) and Time of Flight (ToF), and considersthesignal strengthofalltheaccesspoints hence increasestheaccess pointsrequired. Hence, we use Multipath Triangulationto buildthefirstdecimeter-levelWiFilocalizationsystem,whichutilisesa single access point and a single channel, and does not impose any overhead, data sharing, or complex coordination protocols. The results obtained indicate that Multipath Triangulation provides the capacity to improve localisation by using multipath reflections rather than discarding them. Furthermore, we use decimeter-level localization because it is possible to overcome the negative consequences of multipath interference.