Analysis of Chaotic Waveforms for Application to Active Sonar Systems

摘要

This report evaluates the feasibility of using a new class of chaotic waveformsin low-frequency active acoustic scenarios. These waveforms are generated by nonlinear processes and therefore have characteristics that differ from their linear counterparts. There are two principal findings of this evaluation. First, as broadband signals, chaotic waveforms have desirable characteristics such as range resolution, range-rate resolution (Doppler), and-reverberation discrimination against moving targets. Second, unlike pseudo-random noise, chaotic waveforms are amenable to noise reduction techniques that enhance the Signal-to-Noise Ratio (SNR) because they are of low dimensionality. Additionally, because chaotic signals are difficult to recognize, they decrease the potential for recognition by opposition forces. Using a selection of qualitative and quantitative metrics, the Lorenz waveform is identified as suitable for use in active surveillance scenarios. Further, it is demonstrated that, given present acoustic projector technology constraints, waveform generation can be accomplished using straightforward band-shifting techniques Chaos, Underwater acoustics, Nonlinear processes, Signal processing.