Low Cost SDR Receiver for Medium FrequencyR-Mode

Abstract

Medium frequency R-Mode is a candidate to pro-viding backup for Positioning Navigation and Timing, in caseof an outage of the Global Navigation Satellite Systems. Itsimplementation and first results have shown good performance inthe R-Mode Baltic Sea test bed. However, to make the technologyavailable to a broad user group, the availability of a cost-effectivereceiver is crucial. In this work, we will compare four differentapproaches of SDR-based receivers for medium frequency R-Mode. More specifically, the performances of a LimeSDR, anRTL, an SDR and the higher priced ETTUS ecosystem will bepresented. We will in addition investigate the possibility of usingan oscilloscope as SDR. The paper will furthermore present aGNUradio-based R-Mode receiver implementation, which is ableto perform real-time positioning for static cases with Hardwarein the loop testing