Design of Chaotic Waveforms for Application to Active Sonar

In this paper specified codes used to modulate the chaotic signal as waveform of active sonar to improve the covertness of active sonar. The main advantage of this chaotic modulation technique is that modulated signal is noise-like. The issues of the distortions introduced by additive noise and filtered by physical underwater channel are discussed. Echo signals are demodulated by adaptive filter and recovered signals are identified by stored specified codes. It is found that the demodulator based on Lyapunov adaptive filter outperform other adaptive filters. The Lyapunov adaptive filter is also improved in the phase space. The obtained results indicate that proposed demodulator is capable of reducing mean squares error of the received source signals and as an on-line demodulator.