LDC messages have been defined that communicate time-of-day,

leap second information, differential corrections and LORAN-C network health and status information to

users [8]. Time-of-day is calculated by propagating a count of LORAN message repetition intervals (MRI)

that have occurred since the LORAN-C epoch (January 1, 1958) and applying the leap second information.

The MRI count and the leap second information are provided in the time message via the LDC.

s. The epoch for steering and time

of coincidence (TOC) for the Loran-C chains had been previously defined to occur at 00hrs

00min 00sees on January 1, 1958[Sl.