AutoGait: A Mobile Platform that Accurately Estimates the Distance Walked

AutoGait is a mobile platform that accurately estimates the distance walked by leveraging Global Positioning System (GPS) in off-the-shelf mobile devices and pressure sensors in the SmartShoe platform. Noisy GPS readings are used to estimate the stride length, and SmartShoes force sensor measures the step frequency. The system takes advantage of the fact that a linear relationship exists between the step frequency and stride length. Subsequent calibrations that are invisible to the user allow the system to maintain a highlevel of accuracy under changing conditions. The main contribution of this paper is two-fold: (1) we propose an autocalibration method that effectively filters noisy GPS readings and trains the linear model, and (2) we build the AutoGait system and validate its performance via extensive experiments. Our results show that the system can estimate the distance traveled with 98.5% accuracy.