A GPS/compass based train integrated positioning method for high-speed railways

Accurate and real-time positioning is an important part of train control, which is crucial for safety assurance of high speed railway in China. For GPS based train positioning scheme, the signal unavailability and signal interference could not be completely solved with current configuration mode. In this paper, from the safety requirements of train positioning in high-speed railways, based on the consideration of signal availability and fault-tolerant performance, an integrated train positioning system is formed by integration of GPS and Compass. The structure and function of the integrated system are given, and the nonlinear filter solution for information fusion is presented, which is compared to traditional Kalman filter based strategies. An HTL-based integrity monitoring method is presented to enhance fault tolerant ability. Results from experiments and simulations demonstrate the integrated positioning method could meet the precision requirement with effective integrity characteristics, and keep its potential for efficiency and safety in various environments.