High-Accuracy Carrier Phase Positioning Technology Based on CSI in UAV-Assisted 5G NR system

Using communication signals for positioning can achieve high-accuracy and wide coverage at a relatively low cost. This is an inevitable trend for the future. Especially, the UAV-Assisted 5G NR (New Radio) system provides great flexibility and controllability, bringing enormous potential for positioning applications. However, the widely used positioning methods based on time delay and angle measurement are limited by bandwidth and device conditions. Due to the lightweight requirements of UAV, low-capacity device makes high- accuracy positioning difficult to achieve. If we can apply the carrier phase positioning technology in Global Navigation Satellite Systems to 5G NR systems, it may be possible to overcome these limitations. However, due to different signal formats, applying carrier phase technology to 5G NR systems faces many challenges. The problems that need to be solved include poor TOA (Time of Arrival) measurement accuracy, methods for measuring carrier phase, resolution of integer ambiguity, and real-time positioning. This paper proposes a TOA and carrier phase estimation method based on channel state information, which can achieve higher resolution. In addition, we designed an extended Kalman filter to integrate TOA estimation and carrier phase estimation to solve integer ambiguity problems while estimating the user's three-dimensional position. The simulation results have verified that this method can significantly improve the positioning accuracy and achieve high-accuracy positioning.