Multichain-based Loran Performance with Spatial and Directional ASF Correction in Yellow Sea

Abstract

South Korea has established eLoran testbed since 2016 to provide resilient navigation information to the maritime users even though GNSS are not available due to its vulnerability. It is expected that the Korean eLoran testbed compromises 20 m of position accuracy (95%) at the major two ports in Yellow Sea. Additional Secondary Factor (ASF), which dominates the eLoran accuracy, varies over the spatial and temporal environment along the propagation path of Loran signal. Because topography or coastline near the ports is very complicated, ASF would vary dynamically at the area. Therefore, it is essential to compensate ASF appropriately when the user wants to estimates its own position within 20 m of position accuracy. In this paper, we conduct a pilot experiment of the validation of eLoran testbed performance. We set the limited area for an experiment near Pyeongtaek Harbor. Temporary dLoran station is installed to produce temporal correction whichis used to generate ASF map. We also calculates and compensates the directional ASF to get more accurate position. This experiment shows about 16 m of position accuracy and we can expect eLoran testbed’s performance based on HDOP calculation according to the various scenarios.