A Novel Suppression Method of Height Drift for Pedestrian Navigation With a Circular Hypotheses on Terrain Slope

The inertial navigation system (INS) based on zero velocity update (ZUPT) is a traditional method for pedestrian positioning. The height information of INS will drift over time. A common solution is to use external height information, such as barometer output, to compensate the drift. However, this method is easily affected by air temperature, wind speed, etc. A new geometric model method is proposed in this study to suppress the height drift. The inertial sensor is mounted at the shoe. The natural terrain with continuous slope changing is assumed to be circular arc-shaped every single step. A geometric model of three-dimensional step length is established using the horizontal step length and the pitch angle of the shoe. Four experiments were designed on flat, sloped, and natural terrains, respectively. The experimental results show that the accuracy of the proposed method is improved by more than 90% and 70% compared to the classical INS method and the INS method incorporating a barometer, respectively. The proposed method needs no external signal and is not influenced by the external environment. Furthermore, lightweight calculations make it appropriate for real-time applications.