Indoor Positioning Methods Based on Dual Feet-Mounted IMUs With Distance Constraints

The zero velocity update (ZUPT) offers an effective correction method for the sensor drift in indoor positioning systems using foot-mounted inertial measurement units (IMUs). However, the heading drift is still problematic in positioning systems using a single IMU. This paper studies methods for positioning using two foot-mounted IMUs. We propose two methods for this purpose, which are based on the use of a distance constraint and a spacing-vector constraint, respectively. Our methods are compared against other distance-constraint-based methods. The results reveal that our methods are able to achieve a better distribution concentration than the other methods, and they better control the separation between the trajectories of the feet.