TDOA-based ASF Map Generation to Increase Loran Positioning Accuracy in Korea

The long-range navigation (Loran) system can be a complement to global navigation satellite systems that are vulnerable to radio frequency interference. To increase the positioning accuracy of Loran in Korea, this study generates a time-difference-of-arrival-based additional secondary factor (ASF) map, which is different from the conventional time-of-arrival-based ASF map that is currently not suitable in Korea because Korean Loran transmitters are not synchronized to the coordinated universal time.