Faster distributed localization of large numbers of nodes using clustering

Chirp Spread Spectrum (CSS) based localization techniques are becoming more attractive as they provide improved localization accuracy and robustness compared to WiFi or ZigBee based approaches. However, a remaining problem is the necessary update frequency: In existing CSS based localization systems, the positions of the objects are determined one by one via unicast with nearby anchors instead of using broadcasts. We propose a faster distributed localization scheme for CSS based systems. A portion of nodes are considered cluster heads; they determine the locations of un-localized nodes by dynamically increasing the transmission power. Our novel scheme not only fully utilizes the spatial redundancy, which is crucial for speeding up the localization process. By also allowing to establish new anchors in a two-hop range, we can further increase speed without significantly influencing localization error. The performance of the proposed method is demonstrated through simulation.