Doppler Shift Mitigation In Acoustic Positioning Based On Pedestrian Dead Reckoning For Smartphone

Acoustic localization is a viable solution for high-precision indoor positioning with current built-in smartphone sensors. However, the Doppler shift produces an additional error in the time difference of arrival (TDOA) estimation when the smartphone is in motion, resulting in degradation in the acoustic localization performance. In this article, we present an indoor localization system for smartphones that overcomes the effects of the Doppler shift by combining inertial and acoustic sensors data. First, we establish an error correction model related to the current position and velocity of the smartphone, which can estimate and mitigate the errors caused by the Doppler shift in the TDOA measurements. Second, a uniform acceleration dynamic model and an improved pedestrian dead reckoning (PDR) algorithm are designed to obtain the model parameter. Experiments show that the two proposed algorithms reduce the positioning error by 49.1% and 71.9% under continuous acoustic signal conditions and by 33.3% and 69.8% under occasional abnormal signal conditions. The presented system can achieve a positioning accuracy of about 0.2 m (RMS).