R-Mode receiver development for medium frequency signals

Abstract

Abstract: Signals from Global Navigation Satellite Systems are the primary sources for Position, Navigation and Time (PNT) information on-board any vessel today. Because these signals are prone to interferences, a maritime backup system is needed to provide reliable PNT data. R(anging)-Mode is such a system. It utilizes existing maritime radio beacons or base stations of the Automatic Identification System (AIS) by adding ranging components to the legacy signals. The first modified radio beacons transmit medium frequency (MF) R-Mode signals in the north of Germany. This paper describes the current state of our research and development activities at the receiver-level for MF R-Mode signals. It introduces the receiver platform which is based on off-the-shelf components and explains the implemented algorithms for distance estimation. Furthermore, the results of first ranging measurements are presented which show the general suitability of R-Mode technology as a source for maritime positioning and timing data.