Abstract: Due to the low angular resolution of angle of arrival (AoA), it is challenging for the AoA localization algorithm based on channel state information (CSI) to achieve sub-meter level localization accuracy. To improve the localization accuracy, a precise indoor Wi-Fi localization method based on carrier phase difference is proposed. First, the center frequency carrier phase of CSI and time of flight in line of sight path are extracted, and the carrier phase difference localization model is constructed with virtual reference point, thus achieving the initial target localization.Then, combining the initial localization result of the target, the integer ambiguity solution is realized by using the virtual baseline constraint. Finally, the carrier phase localization optimization algorithm based on the extended Kalman filter is proposed to obtain the precise location of the target. Experimental results for straight lines and arbitrary paths show that the median localization error of the proposed method is within 0.25 m, which is more accurate and reliable than the baseline method.

Key words: indoor localization, carrier phase information, Wi-Fi, virtual baseline constraint, integer ambiguity