Robust Localization of a Wireless Device by a Network of Unsynchronized Anchors

The infrastructure available to the mobile phones is too costly to deploy for localizing small wireless devices in an Internet of Things (IoT) framework. Among available RF solutions, those based on the time of arrival measurements at a network of unsynchronized anchors suit quite well to this application. In this paper, we consider a wireless device moving at a pedestrian speed within such a network of unsynchronized anchors and track its position using time of flight measurements that are processed through an Extended Kaiman Filter (EKF). The system dynamics here come from the uniform speed of the device as well as the skew of the clocks involved. The purpose is to compare the results with Time Difference of Arrival (TDoA) and Differential Time Difference of Arrival (DTDoA) measurements that act as a lower and upper bound for this system, respectively.