Methodology for the determination of the cover and secondary phase correction plots for a Loran-C chain

To fully characterize a Loran-C chain it is necessary not only to predict the likely extent of the cover (both geometry-limited and signal-to-noise-ratio-limited) but also the phase correction plots. The authors describe in detail how these related aspects can be determined for any particular chain. Both types of plot rely on similar computational techniques and data which have been derived from G. Millington's method (1949) to cope with the effects caused by boundary changes at land/land and land/sea interfaces; and the geometric-optics approach of H. Bremmer (1949) which calculated the attenuation and phase variations with distance over a path with known electrical characteristic.<>