Development and Validation of a Distance Measurement System in Metro Lines

While different location technologies have been used to collect data for trains, the development and validation of new systems remain a challenge. In this paper, a formal approach is presented for the development and verification of a new metro train-to-train distance measurement system. This system is based on the spread-spectrum technology to accomplish distance measurement. Different from existing systems in the air and maritime transport, this system does not require any other localization unit, except for a communication unit. To assist the development of the system, colored Petri nets (CPNs) are used to formalize and evaluate its structure. Based on the CPN model, the system structure is validated. In addition, a procedure is proposed to generate a code architecture from the formal model. The system performance is assessed in terms of the range and accuracy of its detection. Therefore, both mathematical simulation and actual measurements, and model-based estimation validations are implemented. The results indicate that the system is able to carry out distance measurement in metro lines, and the formal approaches are reusable for further development and verification of other systems.