Development and analysis of a train-centric distance measurement system by means of colored petri nets

Based on the technology trends, the train control system should weaken the proportion of ground facilities, and give trains more individual initiative than in the past. As a result, the safety and flexibility of the train control system can be further improved. In this thesis, an enhanced movement authority system is proposed, which combines advantages of the train-centric communication with current movement authority mechanisms. To obtain the necessary train distance interval data, the onboard equipment and a new train-to-train distance measurement system (TTDMS) are applied as normal and backup strategies, respectively. While different location technologies have been used to collect data for trains, the development and validation of new systems remain challenges. In this thesis, formal approaches are presented for developing and verifying TTDMS. To assist the system development, the Colored Petri nets (CPNs) are used to formalize and evaluate the system structure and its behavior. Based on the CPN model, the system structure is validated. Additionally, a procedure is proposed to generate a Code Architecture from the formal model. The system performance is assessed in detection range and accuracy. Therefore both mathematical simulation and practical measurements validation are implemented. The results indicate that the system is feasible to carry out distance measurements both in metropolitan and railway lines, and the formal approaches are reusable to develop and verify other systems.