Methods and systems for covert authentication of resilient navigation

A system for superimposing a navigation message and an authentication message comprising:

• a transmitter comprising:
• a first channel including a first channel encoder for encoding a navigation message;
• a second channel including a second channel encoder for encoding an authentication message;
• and
• a processor;
• and
• a memory storing one or more processor-readable instructions that, when executed by the processor, cause the transmitter to:
• superimpose the authentication message onto the navigation message to generate a superposition coding;
• transmit the superposition coding such that the navigation message and the authentication message are transmitted simultaneously at the same frequency, and
• wherein the navigation message is split into multiple navigation message segments and each navigation message segment is spread using a different spreading code.