ION GNSS+ 2017 Portland, Oregon USA

Category: News Last Updated: Friday, 10 November 2017

Projected Performance of a Baseline High Integrity GNSS Railway Architecture under Nominal and Faulted Conditions 

This work, born thanks to the collaboration of RadioLabs and University of Stanford, describes a reference RHINOS architecture and examines its performance under nominal and faulted conditions. The performance analysis is conducted through simulation using the Matlab Algorithm Availability Simulation Tool (MAAST). MAAST, which was developed for aviation integrity analyses, was modified to support Protection Level (PL) calculations based on a proposed RHINOS reference architecture. It calculates PLs at representative locations throughout Europe for both nominal and faulted cases. The nominal case assumes that all GNSS range measurements are bounded by fault free error models. Error models derived from accepted Satellite Based Augmentation System (SBAS) and Ground Based Augmentation System (GBAS) models are used. The main exception is multipath, which is known to be more severe for trains than for aircraft. The fault cases examined are those where either ionosphere gradients, satellite (ephemeris or clock) errors, or multipath exceed the nominal models. The integrity monitoring should detect and exclude the fault, if it is sufficiently large or not detected it, in which case it will bound its effect. Finally, sensitivity analysis is conducted to provide insights for designing the system. Different multipath assumptions are tested and different levels of mitigation are examined what level of mitigation and monitoring should be targeted.

Paper ION-GNSS+ 2017.pdf


This project has received funding from the European GNSS Agency under the European Union’s Horizon 2020 research and innovation programme under grant agreement No.687399