The basic vertical distance map matching algorithms provides the projection of the fusion location on the DTM, then the movement direction is cross-checked with the projected location and DTM topology. This paper will illustrate the benefit of DTM and GNSS fusion location, heading information integration for track occupancy. This paper investigates the DTM topologies with the consideration of section relation in XML definitions, these “frozen” information is applied in map-matching algorithm for movement direction detection and prediction. Then DTM provides sub-meter accuracy of the point-of-interests (POIs), and the connections between POIs are the defined sections. The pre-surveyed DTM is normally generated by precise localization methods as real time kinematic (RTK) and post-processing techniques. LDS provides possibilities for continuous and trustable train location along the train journey, and the auxiliary information provided by IMU and DTM delivers track occupancy identification with ease. The multi-sensor integrated train location determination system (LDS) solution using multi-constellation and multifrequency GNSS and digital track map (DTM) are designed to benefit the advantages of each sensor. In these GNSS performance degraded scenarios, to satisfy safety requirements, the use of compensation sensors becomes necessary. The GNSS performances are degraded and will lead to train location uncertainty and large measurement deviations. Since GNSS itself suffers from the propagation errors, especially for the train movement in railway stations, the buildings near the track bring multipath and signal blockage effects to the GNSS RF signals. When the train moves along the railway track, the train movement is constrained by the railway track which provides certainty of train trajectory and the possibility of environmental scenario perception in advance. Once the performance indicates that the characteristics stated above meet the requirement according to railway safety standards, then GNSS can be applied. In that, GNSS accuracy/continuity/reliability/availability/integrity/safety integrity performance characteristics are vital to the smooth adoption of GNSS. Applying GNSS in signalling system to provide accurate and safe location solely from train-borne sensors, is currently the hot issue in the development of next generation of train control system (NGTC). Railway signalling system is a safety on demand system, requires the transportation system to be safe when failure occurs. Global Navigation Satellite System (GNSS) localization solutions have been applied in various transportation systems the GNSS application proves current GNSS performance meets non-safety relevant requirements at meter level accuracy. Tao Yang, Debiao Lu, Baigen Cai, Jian Wang, Jiang Liu, Philippe Laviron Digital Track Map Aided Track Occupancy Identification Method in Railway Stations
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