Busse, ChristianChristianBusseRenner, Bernd-ChristianBernd-ChristianRenner2022-07-212022-07-212022IEEE International Conference on Robotics and Automation (ICRA 2022)http://hdl.handle.net/11420/13258Navigating autonomous underwater vehicles (AUVs) in shallow and harbor waters is challenging and typically has higher accuracy requirements than navigation in the open sea. We investigate enhancements to underwater localization techniques based on Two-Way Ranging (TWR) using acoustic modems, which have great potential to meet localization accuracy requirements at lower cost and complexity than current systems. By modifying the Extended Kalman Filter, we account for dynamic positioning errors that occur during the movement of the localization target, i.e., the underwater vehicle, and the fact that distance measurements with acoustic modems are delayed in time. The method is evaluated numerically and experimentally showing an accuracy improvement of about 20 cm compared to the traditional EKF scheme. In real-world tests at ranges below 30 m, the absolute localization accuracy is assessed using an RTK-GPS reference, showing that a positioning error below 35 cm can be achieved in a quasi-static test, while in a dynamic test the tracking error is mostly below 75 cm.enTechnikConference Paper10.1109/ICRA46639.2022.9811851978-1-7281-9681-7Conference Paper