Improving ranging accuracy of active and passive anchors in the presence of clock imperfection

When active anchors and agents conduct two-way time-of-arrival (TW-ToA) ranging, passive anchors can help active anchors to improve their localization accuracy. However, the range estimation at both active and passive anchors suffers from error due to clock imperfection. In this paper, we propose a new ranging protocol called two-way time-of-arrival with correction (TW-ToA-C), which can effectively suppress the range estimation error induced by clock imperfection at both active and passive anchors at a cost of transmitting one extra packet at agents.