Evolution of the Medium Frequency R-Mode Receiver

Intelligent transport systems heavily depend on reliable positioning information. Recent events, all over the world, have shown the vulnerability of today's satellite-based solutions to jamming and spoofing. The terrestrial-based navigation backup system, called R-Mode, is a potential countermeasure, beside many other current systems under development. However, a common problem when introducing a new system is the lack of commercially available solutions. To enable research in the intelligent transport system based on R-Mode, we developed a software-defined radio-based receiver for this system, which has passed through various software and hardware iterations in recent years. In particular, the size of the receiver was reduced, by optimizing the front-end components. In this paper, we will present the different steps in the development, from our first temporary setup through to our current receivers, which were constructed to meet the requirements of different projects and stakeholders. As the most crucial component, we are developing a band-pass filter for the front end of the receiver that is an important step into miniaturization.