Pedestrian Tracking Solution Combining an Impulse Radio Handset Transmitter with an Ankle-Mounted Inertial Measurement Unit

摘要

We address the indoor tracking problem by combining anImpulse Radio-Ultra-Widebandhandset with an ankle-mountedInertial Measurement Unitembedding an accelerometer and a gyroscope. The latter unit makes possible the detection of the stance phases to overcome velocity drifts. Regarding radiolocation, atime-of-arrivalestimator adapted to energy-based receivers is applied to mitigate the effects of dense multipath profiles. A novel quality factor associated with this estimator is also provided as a function of the receivedsignal-to-noise ratio, enabling us to identify outliers corresponding to obstructed radio links and to scale the covariance matrix of radiolocation measurements. Finally, both radio and inertial subsystems are loosely-coupled into one single navigation solution relying on a specificextended Kalman filter. In the proposed fusion strategy, processed inertial data control the filter state prediction whereasCombined Time Differences Of Arrivalare formed as input observations. These combinations offer low computational complexity as well as a unique filter structure over time, even after removing outliers. Experimental results obtained in a representatively harsh indoor environment emphasize the complementarity of the two technologies and the relevance of the chosen fusion method while operating with low-cost, noncollocated, asynchronous, and heterogeneous sensors.