Today, most covert communications systems use a spreadspectrum
approach to ensure that transmissions remain
clandestine. This paper expands beyond traditional spreadspectrum
schemes and into chaos theory in communications
by presenting a novel design for a covert noncoherent
binary communication system that uses chaotic signals.
Three techniques are developed, with varying performance.
Each system uses two chaotic signals with antipodal
attractors as the information carriers.
Although the two chaotic signals used are continuously
generated from random starting values without containing
repetitious patterns, the receiver requires neither those
initial values nor does it require synchronization with the
transmitter. The chaotic signals used are both spreadspectrum
in the frequency domain and undetectable using
matched-filter receivers, thereby achieving a level of
covertness. The signal-to-noise ratio performance is presented
through simulated receiver operating characteristic
(ROC) curves for a comparison to binary phase shift keying.
This system provides a binary communication scheme
which is not detectable by standard matched filtering techniques
and has noise-like spectra, requiring a new receiver
configuration and yielding security.