Research on Train Integrity Monitoring Using Multi-constellation Measurements

Abstract

Train integrity monitoring is the key to ensure the safe operation of trains. Traditional train integrity monitoring is based on ground equipment. However, with the development of satellite positioning technology, and in order to meet the needs of the next generation train control system (NGTC), the demand for ground equipment should be minimized. The application of satellite positioning technology in train positioning is more and more. Its principle is to calculate the length of the moving-baseline between the head and end antennas of the train by satellite positioning, and monitor the integrity status of the train according to the length change. The multi-constellation positioning has more visible satellites and better geometric distribution of satellites compared with the single constellation system. Especially, the advantages of the multi-constellation system are more prominent in the limited satellite signals scenes. Therefore, this paper proposes a train integrity monitoring method based on multi-constellation moving-baseline solution. The first step is to unify the time and space systems, then make full use of the multi constellation carrier phase measurements, and finally eliminate the propagation path error and satellite clock error by double difference carrier phase. The moving-baseline length between two antennas is calculated in real time by Kalman filter algorithm, and then compared with the actual train length to realize the train integrity monitoring.