Finding the Right Place: Sensor Placement for UWB Time Difference of Arrival Localization in Cluttered Indoor Environments

Abstract

Ultra-wideband (UWB) time difference of arrival (TDOA)-based localization has\nrecently emerged as a promising indoor positioning solution. However, in\ncluttered environments, both the UWB radio positions and the obstacle-induced\nnon-line-of-sight (NLOS) measurement biases significantly impact the quality of\nthe position estimate. Consequently, the placement of the UWB radios must be\ncarefully designed to provide satisfactory localization accuracy for a region\nof interest. In this work, we propose a novel algorithm that optimizes the UWB\nradio positions for a pre-defined region of interest in the presence of\nobstacles. The mean-squared error (MSE) metric is used to formulate an\noptimization problem that balances the influence of the geometry of the radio\npositions and the NLOS effects. We further apply the proposed algorithm to\ncompute a minimal number of UWB radios required for a desired localization\naccuracy and their corresponding positions. In a real-world cluttered\nenvironment, we show that the designed UWB radio placements provide 47% and 76%\nlocalization root-mean-squared error (RMSE) reduction in 2D and 3D experiments,\nrespectively, when compared against trivial placements.\n