Adaptive Threshold for Zero-Velocity Detector in ZUPT-Aided Pedestrian Inertial Navigation

We present a study on the adaptive threshold of the zero-velocity detector, which enables the detector to adjust to gait patterns with different speeds, from as low as walking with 80 steps per minute to as high as running with 160 steps per minute, without any tuning of design parameters during the navigation. This approach enables the zero-velocity update (ZUPT)-aided navigation algorithm to work properly with time-varying speed in a single navigation process. A Bayesian-based approach was applied to determine the adaptive threshold in the likelihood ratio test with a uniform prior information and time-varying cost function. The position error in a velocity-changing navigation scenario was demonstrated to be reduced by 12 times after applying the adaptive threshold instead of a fixed threshold.