eLoran: Resilient Positioning, Navigation, and Timing Infrastructure in Maritime Areas

Abstract

Global navigation satellite system (GNSS) and localization technology have become highly compact and effective. Although GNSS has been proven to be vulnerable to jamming when the signal strength is weak, most vehicles rely on it for navigation. Compared to GNSS, enhanced Loran (eLoran) is more resistant to jamming and is recommended as a realistic alternative to GNSS. Therefore, South Korea embarked on an eLoran testbed development project to provide resilient navigation information for maritime users. The primary goal of this project was to demonstrate that the system can provide a 20-m position accuracy to the maritime user within a 30-km coverage of a differential Loran station. In this paper, we describe the development of the eLoran testbed implementation and the performance of its preliminary experimental results. To confirm the feasibility of the eLoran testbed performance, we installed an eLoran transmitter and two differential Loran stations and subsequently conducted a zero-baseline performance test at the Pyeongtaek differential Loran station with a new eLoran signal. We also conducted a survey to collect conventional Loran signals along the western and southern coastlines of South Korea. Our experimental results show that the eLoran system met the performance requirements of this project, as well as that the signal to noise ratio of the eLoran signals changed over the topographic characteristics of the propagation path.