Method and system for reducing navigation error and spatial wave navigation position error when carrying message communication on Loran C navigation signal transmission etc.

摘要

A Loran-C communications technique and system are disclosed involving appropriate encoding of communication messages and logical multiplication and inversion of encoded signals prior to phase modulation of the Loran-C pulses, with novel bit-flip connections for producing complementary plus and minus modulation position shifts in the first and third and second and fourth, etc., of the Loran-C pulse groups, and with perfect balance irrespective of the nature of the raw data and irrespective of skywave interference. Also disclosed is a method of obviating errors in navigation locking caused by sampling reception at the conventional symmetrical pulse modulation time intervals in advance of and in delay from the normal transmission interval, through rendering the pulse modulation asymmetrical to a degree that compensates for different cycle amplitudes at sampling points above and below the desired sixth zero crossing used for navigation position determination.