With the increasing utilization of location information, attempts to improve the safety of absolute positioning coordinates, which have depended on global navigation satellite systems (GNSSs), such as the Global Positioning System (GPS), are underway. Among these, enhanced long range navigation (eLoran) is the most technically developed system. In Korea, related technologies have been developed since 2016, and a testbed for eLoran performance evaluation, which is currently in operation as a pilot service, was completed in 2021. We analyze the position accuracy of the eLoran pilot service to use it as an alternative when GNSS usage is challenging within Korea’s eLoran testbed. We evaluated the accuracy of the absolute position using the eLoran system by sailing up to 160 km away from the Incheon testbed transmitter according to four navigation stages (inland waterway, port approach, coastal, and ocean) classified by the International Maritime Organization (IMO). To validate the eLoran positioning performance in which an additional secondary factor (ASF) map is not provided, we propose a differential GPS (DGPS) position-based ASF estimation technique. Based on this study, Korea’s eLoran system can calculate the absolute position with an accuracy of approximately 15 m with 95% probability at the port-approach stage.

There is an increasing need for an independent terrestrial navigation system, owing to the increasing reliance on global navigation satellite systems (GNSS). The medium-frequency range (MF R-Mode) system is considered a promising alternative; however, the skywave effect caused by ionospheric changes at night can degrade its positioning accuracy. To address this problem, we developed an algorithm to detect and mitigate the skywave effect on MF R-Mode signals. The proposed algorithm was tested using data collected from Continuously Operating Reference Stations (CORS) monitoring the MF R-Mode signals. The skywave detection algorithm is based on the signal-to-noise ratio (SNR) induced by the groundwave and skywave composition, whereas the skywave mitigation algorithm was derived from the I and Q components of the signals obtained through IQ modulation. The results demonstrate a significant improvement in the precision and standard deviation of the range estimation using CW1 and CW2 signals. The standard deviations decreased from 39.01 and 39.28 m to 7.94 and 9.12 m, respectively, while the precision (2-sigma) increased from 92.12 and 79.82 m to 15.62 and 17.84 m, respectively. These findings confirm that the proposed algorithms can enhance the accuracy and reliability of MF R-Mode systems.