Novel method for the wireless synchronization of the anchors in the UWB localization system utilizing two reference nodes

Nowadays indoor localization is getting more and more attention as there is a considerable growth in the interest for the indoor location-based services (LBS). There are several different techniques that allow for the calculation of the position of objects and people inside the buildings. Methods utilizing measurements of the received signal strength (e.g. WiFi or BLE based) are most common but provide accuracy of roughly 2-3 meters. Recently, ultrawideband (UWB) technique is more often being considered for the indoor localization. It relies on the measurements of the time of arrival of received signals and allows for the calculation of the position with errors in the range of only dozens of centimeters. However, in order to work correctly, UWB-based systems require strict synchronization between the anchors that form the infrastructure. In the paper a novel method of wireless synchronization utilizing two reference nodes is presented. Synchronization method is described along with the explanation of the transmission scheme and discussion on the results of the performed experimental verification.