The Study ofASF Prediction Method in Irregular-Terrain

As the potential of Loran-C in land vehicle tracking, and in marine and aeronautical navigation explored, the importance of employing accurate values of additional secondary factors (ASFs) is increasingly being recognized. A computer method that used to generate ASFs for irregular terrain is developed. In order to determine the prediction accuracy of the method in irregular terrain, during the summer of 2005, a series of tests were conducted in the selected area in Jiangxi Province. Using the set of ASF values obtained by the method above, the time delay correction errors of ground-wave propagation are reduced to less than 200 ns in the land.