Ultra-wideband radar-based accurate motion measuring: human body landmark detection and tracking with biomechanical constraints

The authors propose and investigate a methodology for accurate human motion measuring by detecting and tracking human body landmarks using ultra-wideband (UWB) radars. The proposed method can estimate the markers´ positions and velocities in a two-dimensional space based on range measurements from a single radar given a prior information about the markers´ initial states. The detection of multiple human body landmarks is achieved by moving target indication and a new out-of-band constant false alarm rate detection, and the multiple landmark tracking is accomplished by a novel iterative convex optimisation-based approach with considerations of biomechanical constraints. The data association technique is then applied to validate and relate the detection results to target landmarks for generating range measurements, which are used for a convex optimisation-based sequential estimation algorithm to estimate the accurate marker locations. It is noted that the proposed optimisation-based sequential estimation is able to incorporate biomechanical constraints. In the field experiments, two radio frequency reflectors are attached to the wrist and the elbow of one human arm. It is demonstrated that detection and tracking of the moving trajectories of two markers are successfully achieved, and thus, the human arm motion is accurately measured using one UWB radar.