AUTONOMOUS POSITIONING OF RAIL VEHICLES USING THE GNSS BASED SIPOS-RAIL APPROACH

摘要

To ensure safe train operation the position of all trains on a track has to be known at any time. Today this is ensured by trackside equipment (train detection systems and train integrity supervision). To reduce costs, shorten innovation cycles and optimize utilization of routes a shift of position determination into the train and reducing trackside equipment to a minimum is desired. Therefore, trains shall be able to determine their own position with high accuracy, integrity and reliability. To reach these goals but especially to achieve the required reliability the use of complementary localisation sensors is necessary. Combining a receiver-based autonomous differential GNSS system and integrated inertial navigation the SiPoS-Rail concept aims at enabling GNSS navigation for safety critical rail applications. The system is to be used within a train control system with moving block signalling like ETCS level 3 does. The SiPoS-Rail approach combines augmentation of satellite navigation measurements with multi-sensor data fusion. A SiPoS-Rail based localisation unit works in two different modes, a Rover mode and an extended operation mode In the basic operation mode the train operates as a GNSS rover For the PVT (Position, Velocity, Time) calculation a tightly coupled Kalman filter combines measurements of a satellite receiver and a inertial measurement unit. The complementary characteristics of these sensors result in higher availability of the overall system. The localisation unit can handle the temporary failure of a sensor For example in the case of losing the GNSS signal when driving through a tunnel. When passing a balise the localisation unit in the train switches to an extended operation mode acting as a moving reference station to compute differential GNSS corrections. The train uses the precisely known balise position to perform an error estimation of the measured pseudo-ranges. The error model obtained thereby is used for the differential error correction of the GNSS measurements in basic mode. Additionally the integrity of the position information with high certainty can be detected. Due to the equally distribution of balises in the railway system the error model gets frequent local and temporal updates. Within the last years the SiPoS-Rail approach was evaluated at RV/TH Aachen University by the Institute of Automatic Control (IRT) in collaboration with the Institute for Rail Vehicles and Materials Handling Technology (IFS). The required algorithms were developed during this time and deployed to a rapid control prototyping system. The applicability of the proposed method has been shown by extensive test drives. These test drives took place in the railway Galileo testing environment (railGATE). Results of these test drives are part of this publication.