GNSS

Simulator uses GNSS to track railway positioning

A recent activity with TDE and Hitachi Rail in Italy, has developed a testbed simulator to see how GNSS can be utilised on a railway.

The Sim4Rail Project developed, verified, validated, installed and commissioned a simulation testbed, suitable for the of GNSS Performance in a Railway Environment, at the ESA/ ESTEC TEC Navigation Laboratory. In the frame of this activity, laboratory software tools have been developed as building blocks for a simulation testbed of positioning technologies in railway signalling applications.

As part of the activity, different versions of feared events had to be well characterised, modelled and simulated; to validate the simulated outputs. With this approach, conditions that are statistically unlikely to be observed in the field can be tested repeatedly in a highly controlled environment.

Five scenarios were tested. The first is a normal scenario where the train ran completely as expected with no obstacles and just one train per track. The second was more similar to an actual rail environment, with three different channels such as urban or rural rail use.

The third scenario involved the most feared events. On a railwaylike simulation the activity included some of the worst situations a train can face, such as a jammed signalling system. The fourth and fifth used different equipment and data sets.

The testbed has been installed and commissioned for use in the ESA/ ESTEC TEC Navigation Laboratory; while no further development is currently envisaged for the testbed itself, potential follow-ons include developing a multipath channel model for the railway environment. www.esa.int

Improving situational awareness of satellite positioning with research expertise

Satellite positioning (GNSS) is used by many critical functions in society, such as the construction sector, rescue services, the finance industry, telecommunications networks and electrical grids. However, GNSS signals are weak and therefore sensitive to interference, which could be caused by, for example, the environment and atmosphere (particularly the ionosphere) or various unintentional equipment malfunctions. Signals can also be deliberately jammed or spoofed.

Currently, the quality of the satellite positioning signal in Finland is monitored by the GNSSFinland service developed by the National Land Survey of Finland and funded by Traficom.

This new project will further develop the GNSS-Finland service. The project will start by identifying what kind of services end-users need and in what format the information should be available. The project will run from 2022 to 2023. It was commissioned by the National Emergency Supply Agency and is being implemented by the Finnish Geospatial Research Institute of the National Land Survey of Finland, which specialises in research, methodology and development. As the competent authority responsible for the monitoring of radio frequencies and keeping them interference-free, Traficom is responsible for providing situational awareness of GNSS.

The Finnish Geospatial Research Institute of the National Land Survey of Finland will bring in a dedicated unit to support the security of supply of satellite positioning. Funded by the National Emergency Supply Agency’s Digital Security 2030 programme, the project will improve national security of supply while promoting scientific research in the field. www.maanmittauslaitos.fi