Zero Velocity Detector for Foot-mounted Inertial Navigation System Assisted by a Dynamic Vision Sensor

Abstract

In this paper, we proposed a novel zero velocity detector, the Dynamic-Vision-Sensor (DVS)-aided Stance Phase Optimal dEtection (SHOE) detector, for Zero-velocity-UPdaTe (ZUPT)-aided Inertial Navigation Systems (INS) augmented by a foot-mounted event-based camera DVS128. We observed that the firing rate of the DVS consistently increased during the swing phase and decreased during the stance phase in indoor walking experiments. We experimentally determined that the optimal placement configuration for zero-velocity detection is to mount the DVS next to an Inertial Measurement Unit (IMU) and face the sensor outward. The DVS-SHOE detector was derived in a General Likelihood Ratio Test (GLRT) framework, combining statistics of the conventional SHOE detector and the DVS firing rate. This paper used two methods to evaluate the proposed DVS-SHOE detector. First, we compared the detection performances of the SHOE detector and the DVS-SHOE detector. The experimental results showed that the DVS-SHOE detector achieved a lower false alarm rate than the SHOE detector. Second, we compared the navigation performance of the ZUPT-aided INS using the SHOE detector and the DVS detector. The experimental results showed that the Circular Error Probable (CEP) of the case using DVS-SHOE was reduced by around 25 % from 1.2 m to 0.9 m, as compared to the case of the SHOE detector.