# UWB-Based Human-Following System with Obstacle and Crevasse Avoidance for Polar-Exploration Robots
## 7 Conclusions  
This paper proposes an explorer-following system that estimates the position of an explorer carrying a UWB tag by utilizing the relationship between UWB anchors and the tag. The system detects and avoids collisions with obstacles that may occur during the process of following the tag.  
To add explorer-recognition capabilities to robots exploring polar regions such as Antarctica, conventional methods using vision or RGB-D sensors are inadequate due to extreme weather conditions like blizzards and whiteouts, which make image acquisition impossible. Therefore, UWB devices are utilized to recognize the explorer under these conditions.  
First, to estimate the position of the UWB tag, the locations of the UWB anchors and the distance information from the tag were used to implement triangulation through an optimization method, enabling real-time estimation of the UWB tag's position. To move the robot toward the UWB tag, the direction toward the tag is marked as a sub-goal on the local obstacle map, and nearby obstacles that could cause collisions are detected and marked using LiDAR. Finally, a pre-path is generated from the center of the local obstacle map (the robot's position) to the sub-goal. Among the points on this path, the point at the shortest distance that does not result in a collision when connected by a straight line is selected as the final local path to avoid collisions.  
By following the generated local path, it was confirmed through both simulation and real-world experiments that the robot can avoid collisions with surrounding obstacles while following the explorer carrying the UWB tag.  
The explorer-following functionality proposed in this paper allows explorers in extreme environments to focus on their specialized exploration activities without having to pay constant attention to the robot, thereby reducing their burden and increasing their efficiency in exploration tasks. The proposed collision-avoidance explorer-following functionality is planned to be integrated into KAREX and utilized to support explorers in Antarctica.  
Figure 15: Route of robot and target during simulation: (**a**) The proposed local path and LoS in the local obstacle map; (**b**) The proposed local path and LoS in the wavefront cost map.  
**Author Contributions:** Conceptualization, J.-W.K.; Methodology, J.-W.K. and H.L.; Software and Simulation, J.-W.K., H.L., N.-H.L. and J.L.; Validation, J.-W.K. and J.C.K.; Formal analysis, J.-W.K., J.C.K. and T.U.; Investigation, T.U. and Y.-H.C.; Data curation, J.L. and N.-H.L.; Writing--original draft, J.-W.K.; Writing--review and editing, J.-W.K.; Supervision T.U. and Y.-H.C.; Formal analysis, T.U. and Y.-H.C. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was supported by Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Trade, Industry and Energy in 2023 (Project Number 20210630).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflicts of interest.