Abstract
Ultra-Wide-Band (UWB) positioning systems are now a real option to estimate the position of generic agents (e.g., robots) within indoor/GPS-denied environments. However, these environments can comprise metallic structures or other elements which can negatively affect the signal transmission and hence the accuracy of UWB-based position estimations. Regarding this fact, this paper proposes a novel method based on point-to-sphere ICP (Iterative Closest Point) to determine the 3D position of a UWB tag. In order to improve the results in noise-prone environments, our method first selects the anchors’ subset which provides the position estimate with least uncertainty (i.e., largest agreement) in our approach. Furthermore, we propose a previous stage to filter the anchor-tag distances used as input of the ICP stage. We also consider the addition of a final step based on non-linear Kalman Filtering to improve the position estimates. Performance results for several configurations of our approach are reported in the experimental results section, including a comparison with the performance of other position-estimation algorithms based on trilateration. The experimental evaluation under laboratory conditions and inside the cargo hold of a vessel (i.e., a noise-prone scenario) proves the good performance of the ICP-based algorithm, as well as the effects induced by the prior and posterior filtering stages.
Highlights
Position estimation in GPS-denied environments is of great interest in a large variety of applications, including indoor mobile robotics
We have presented a novel method for UWB-based position estimation by means of point-to-sphere ICP
During the development of the proposed method, and the subsequent comparative evaluation, one of our concerns has been the quality of the anchor-tag distance estimations and to establish an adequate anchor selection process
Summary
Position estimation in GPS-denied environments is of great interest in a large variety of applications, including indoor mobile robotics. UWB systems allow high-accuracy positioning, but can be affected by the presence of metallic materials These are only a selection of the considerations to be made; the reader is referred to [2] for a more detailed overview and a comparison of IPSs. In this paper, we focus on UWB positioning systems, with the goal of estimating the position of one or more devices, generally named tags, which are moving through an environment where a set of devices/beacons named anchors have previously been placed. ICP-based method to estimate the UWB tag position; Section 5 overviews the different methods chosen for the comparative assessment, which is performed, where we evaluate the performance of all the configurations considered, both under laboratory conditions and within a real, noise-prone environment; Section 7 draws some conclusions about the new method, as well as about the experimental results reported ICP-based method to estimate the UWB tag position; Section 5 overviews the different methods chosen for the comparative assessment, which is performed in Section 6, where we evaluate the performance of all the configurations considered, both under laboratory conditions and within a real, noise-prone environment; Section 7 draws some conclusions about the new method, as well as about the experimental results reported
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