Precision beidou/GNSS for high-speed rail link initiative : enhancing route accuracy for the proposed Pretoria-Polokwane-Musina corridor in South Africa

Abstract

This paper investigates the integration of an IMU/INS + GNSS (BeiDou) navigation system with Real-Time Kinematic (RTK) technology for the proposed high-speed rail corridor linking Pretoria, Polokwane, and Musina in South Africa. By merging BeiDou/GNSS with RTK and IMU/INS, the system achieves ±2 cm accuracy by correcting ionospheric delays, multipath effects, and noise, ensuring precise train alignment, station positioning, and infrastructure monitoring. Experiments on April 6, 2025, at Beihang University Stadium, using a high-grade IMU (100-200 Hz), RTK GNSS (1-10 Hz), and EKF/UKF fusion, demonstrated sub-10 cm accuracy during 30-second GNSS outages and robust performance in dynamic conditions (50 m/s with 90° turns). Trajectory comparisons show the Integrated system outperforms GNSS-only systems, maintaining precision in challenging environments like tunnels. The study recommends that South African rail authorities adopt this RTK-enhanced INS/GNSS system to ensure world-class accuracy, safety, and efficiency, supporting regional connectivity and economic growth.