Multipath Triangulation

Decimeter-level localization has become a reality, in part due to the ability to eliminate the effects of multipath interference. In this paper, we demonstrate the ability to use multipath reflections to enhance localization rather than throwing them away. We present Multipath Triangulation, a new localization technique that uses multipath reflections to localize a target device with a single receiver that does not require any form of coordination with any other devices. In this paper, we leverage multipath triangulation to build the first decimeter-level WiFi localization system, called MonoLoco, that requires only a single access point (AP) and a single channel, and does not impose any overhead, data sharing, or coordination protocols beyond standard WiFi communication. As a bonus, it also determines the orientation of the target relative to the AP. We implemented MonoLoco using Intel 5300 commodity WiFi cards and deploy it in four environments with different multipath propagation. Results indicate median localization error of 0.5m and median orientation error of 6.6 degrees, which are comparable to the best performing prior systems, all of which require multiple APs and/or multiple frequency channels. High accuracy can be achieved with only a handful of packets.