5G and UAV Integrated Three Dimensional Positioning Using Downlink PRS

The integration of unmanned aerial vehicles (UAVs) with 5G systems has revolutionized positioning technology, offering enhanced accuracy and reliability in challenging environments. We investigate the utilization of 5G downlink (DL) positioning reference signals (PRS) in conjunction with UAV assistance for 3-dimensional (3D) localization in urban macro environments. We introduce the generation of PRS and the corresponding frame structure, followed by their mapping for transmission via cyclic prefix orthogonal frequency division multiplexing (CP-OFDM). Subsequently, the user obtains the time difference of arrival (TDOA) by processing the PRS from each g-NodeB (gNB). An innovative UAV-assisted 3D localization method is then proposed, to address situations where the vertical localization accuracy is severely compromised. Finally, numerical results demonstrate that the proposed method enhances the horizontal localization accuracy by 47% and the vertical localization accuracy by 89%. Based on these findings, the optimal deployment of UAVs and gNBs selection strategy is also provided.