Using Adaptive Motion Constraints to Support UWB/IMU Based Navigation: UWB/IMU Nav. with Adaptive Motion Constraints

This study addresses the problem of short UWB (ultra-wide band) outages in a UWB/IMU (inertial measurement unit) integrated navigation system. UWB outages may occur due to non-line-of-sight between the UWB radios. To mitigate the errors during short UWB outages, we consider the special dynamics of the platform by adaptively applying constraints in the navigation filter. The application presented here is the navigation problem of the unexploded ordnances (UXOs) mapping platform. A UXO platform moves straight or performs turns or stops; these are the three dynamic states with pre-defined constraints. Two neural networks are examined to determine the current dynamic state based on IMU data. Tests on open-sky and canopied areas were carried out for the performance assessment. The networks were trained on the open-sky dataset, and then tested on the canopied area. The detected improvement of the proposed solution is 10–30% (10–15 cm) for 5–10 s long outages.