INS/GNSS/odometer data fusion in railway applications

Integrated navigation systems installed on trains usually make use of data fusion of GNSS data, INS data and wheel velocity data. Since the connection between the carriage body of the wagon and the wheel is not rigid, special considerations need to be taken into account to achieve a mostly optimal behavior of the integrated navigation solution even under pro-longed GNSS outages. In this paper, an approach to deal with this problem is presented and its effectiveness is evaluated with experimental test data from the brand new 57 km Gotthard Base Tunnel (GBT) in Switzerland. Using a navigation-grade RLG based INS of type iNAT-RQT-4003, errors <; 15 m for a complete passage are achieved with the presented approach.