Carrier-based ranging in IEEE 802.11 wireless local area networks

With the rise of Global Navigation Satellite Systems (GNSSes), accurate outdoor localization has become a widelyused service in our daily lives. Yet, most indoor localization systems are not able to deliver a similar performance due to typical multipath environments causing scattering and diffraction of the received signal. Depending on the amplitudes, phases, and delays of the multipath components, the measured range estimates are deteriorated by a significant ranging bias. This paper proposes a novel carrier phase locating method which improves the accuracy of time difference of arrival positioning systems in packet-based networks. The feasibility and practical applicability of the presented approach is demonstrated for a locating system based on IEEE 802.11 Wireless LAN. It is shown that the method is capable of reducing the ranging error to a few centimeters.