Prediction and Measurement of Loran-C Additional Secondary Factor (ASF)

摘要

Loran-c can provide excellent repeatable accuracy measured in tens of meters; however, its absolute accuracy is currently dissatisfactory. It is clear that the Additional Secondary Factor (ASF) is the most important factor affecting the accuracy. Research showed that absolute accuracy can be greatly improved by correcting the ASF. There are two ways to correct ASF: theoretic prediction and actual measurement. The two methods were presented in detail in this paper, and the results indicate that the two methods are all available, but further works need to be done in following two aspects: how can we greatly improved the accuracy on the especial complex path, and how to determine reasonable and economical measuring grid density.