Lu, D.; Schnieder, E.:
Real-time Verification of GNSS Receiver Measured Train Location.
CERGAL 2014 - International Symposium on Certification of GNSS Systems & Services, Dresden, Deutschland, Juli 2014.


GNSS receiver measured train locations need to be verified for safety-related applications. To apply GNSS receiver in train localisation, the stringent performance requirements need to be met, thus location performance is assured by verification result. This paper proposes a location verification process using two-step hypothesis testing based on the statistic characteristics of the measurements. The first step is to verify the GNSS receiver measured train location acceptable on the track, then the second step is to verify the train location acceptable as at the appropriate mileage. In order to implement the train location verification process, a satellite-based localisation unit for trains (SaLUT) is built. SaLUT is composed by a GNSS receiver, a Doppler radar sensor, and a validated high accuracy digital track map. GNSS receiver delivers both train location and velocity measurements, Doppler radar delivers train velocity measurements. The verification process is tested using the data collected at the High Tatra Mountains railway track in Slovakia. The performance of the process is studied according to the hypothesis testing detection probabilities. The missed detections and false detections are discussed quantitatively. This provides necessary data for safety cases of SaLUT.