RFID based Gait Speed Measurement using Doppler Shift

In recent years, gait speed measurement can play an important role in addressing the issue of elderly health monitoring. In this paper we present a technique of RFID gait speed measurement based on an analytical model of the Doppler Effect. Due to the relative motion between reader antenna and the tag on the subject’s clothing, it is possible to estimate subject’s gait speed from the Doppler frequency by using our geometric model. Based on experimental analysis, we demonstrate that gait speed measurement based on Doppler shift is a technique with high accuracy and low cost for elderly health monitoring. In the slide experiment, the relative error is about 4%. In addition, this technique does not require the elderly to carry extra equipment, just a tag on the clothes can measure the pace. This is very friendly for elderly people with mobility problems.