High Precision Localisation with Dual-Constellation for Railway Applications

Jan-Jöran Gehrt, Thomas Konrad, Jiaying Lin, Michael Breuer, Dirk Abel, René Zweigel

Peer Reviewed

Abstract:	This publication presents the ongoing developments of a tightly coupled navigation filter especially designed for railway applications, which are part of the joint-research project Galileo Online: GO!. The filter bases on quantities of an inertial measurement unit (IMU) and signals of a Global Navigation Satellite System (GNSS). Challenges are high accuracy, robustness, and availability of train localization even under harsh environmental conditions. This publication introduces and evaluates the filter extensions regarding multi-constellation, which means the parallel use of GPS and Galileo signals for position determination, and the evaluation of two frequencies for each satellite system. Using different satellite systems at the same time enables a higher satellite availability and better geometrical constellation. Furthermore, some GPS and all Galileo satellites provide dual frequency, which enables precise first order ionospheric path delay correction. This paper describes the integration of the time difference compensation between GPS and Galileo system in the tightly coupled filter, which is necessary to synchronize both systems and to achieve high localization accuracy. Furthermore, the algorithm implementation at the used target hardware and results of extensive validation tests are described. First tests were carried out in the proximity of the RWTH Aachen University with a car, and further campaigns were performed within the railway test center Pruef- und Validationscenter Wegberg-Wildenrath (PCW) of the Siemens Company in Germany. The attained accuracy is compared to differential corrected GNSS observables (DGPS) and online capability is verified. Results show that a 2D accuracy of up to 0.6 m is reached using the dual-constellation and that the dual-frequency aided filter is almost as accurate as the filter using DGPS.
Published in:	Proceedings of the 2018 International Technical Meeting of The Institute of Navigation January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia
Pages:	35 - 45
Cite this article:	Gehrt, Jan-Jöran, Konrad, Thomas, Lin, Jiaying, Breuer, Michael, Abel, Dirk, Zweigel, René, "High Precision Localisation with Dual-Constellation for Railway Applications," Proceedings of the 2018 International Technical Meeting of The Institute of Navigation, Reston, Virginia, January 2018, pp. 35-45. https://doi.org/10.33012/2018.15570
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