Onboard Train Localization Based on Railway Track Irregularity Matching

Train localization is a task of fundamental importance to provide reliable and accurate train positioning information for railway control and operation. Determining the train's position using onboard sensors is a technical trend in this field. In this research, we proposed a train positioning approach by matching a new kind of rail feature, that is, track irregularity. By using an onboard inertial navigation system (INS), continuous and location-dependent track irregularity can be sensed, and then, this signal measurement is matched up to the predefined track irregularity map to locate the train. Train-borne experiments were carried out to validate the feasibility and evaluate the navigation performance of the proposed method. The results show that 0.6-m positioning accuracy with 97.26% confidence can be achieved when using a typical tactical grade inertial measurement unit (IMU), and the accuracy is 0.8 m with 95.39% confidence for a low-cost microelectromechanical system (MEMS) IMU. The proposed method is proven to be able to enhance the robustness and accuracy of the multisensory train positioning system.