Improved Step Detection and Step Length Estimation Based on Pedestrian Dead Reckoning

In the indoor environment, the Global Positioning System (GPS) cannot provide accurate location information due to the complexity of the internal structure of buildings and the interference of indoor equipments. Pedestrian Dead Reckoning (PDR) is an indoor positioning method that relies on smartphone carrying sensors (such as accelerometer, gyroscope, and magnetometer) without requiring additional equipments. The intense electromagnetic interferences caused by indoor electronic equipments have serious influences on the accuracies of indoor location. This paper presents an improved step detection and counting method based on PDR. There is continuity in the walking process. In order to make full use of this feature, this paper firstly filters and differential processes the acceleration data obtained from the smartphone, then uses the improved peak detection algorithm to detect and count the steps. This paper compares two algorithms of step length estimation, and presents an improved step length estimation algorithm based on differential acceleration data. As a result, this paper improves the accuracies of both step number detection and step length estimation.