UAV-aided localization algorithm with relay for train-mounted mobile terminals

摘要

In some complex environment, the train and the base station (BS) cannot connect directly. And the train-mounted mobile terminals cannot receive global positioning system (GPS) signals because of the shadow of the train shells. To address this issue, an unmanned aerial vehicle (UAV) aided localization algorithm with relay is proposed in this paper, which consists of four steps: coordinates dividing, step-by-step positioning, coupling and results comparison. The proposed method transforms the complex in-train environment into a traditional indoor scene to avoid the influence of non-line-of-sight (NLOS). It locates the absolute position of the train in a wireless sensor network (WSN) unit composed of nodes installed on UAVs. In addition, aiming at reducing the distance-measuring errors caused by velocity difference between the train and the UAV, an error compensation factor is carried out in received signal strength indicator (RSSI). Based on the simulation results, we find that the proposed method is more accurate working in confined space where GPS signals cannot be captured. Compared with traditional methods, it can also correct the velocity difference errors. The positioning system achieves a mean positioning accuracy of 2.13m. (C) 2019 Elsevier B.V. All rights reserved.