Multipath Mitigation Using Weight Suppression for Equalization in Indoor Positioning Systems

Multipath is the dominant source of error in indoor positioning systems, since the reception of multipath can significantly distort the shape of the correlation function used for time-delay estimation. When a band-limited signal is used, the range resolution is often insufficient to decompose the overlapped received signals. This paper presents a multipath mitigation algorithm for ATSC DTV signal-based positioning systems. The algorithm combines sample interpolation with a multipath signal delay estimator based on an equalizer which periodically suppresses a specified number of the lowest-magnitude equalizer weights. The goal of the new equalizer is to more accurately predict the channel response. MATLAB simulations were carried out to demonstrate the proposed method and was confirmed with field-test data. The proposed approach can reduce the range estimation resolution by 60% compared to the Fourier limit.