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激光器产生混沌信号时,由于腔长原因使产生的信号具有周期性,若将该信号应用于雷达系统,易被识别与攻破。针对上述问题,文中提出采用随机采样法对原始混沌序列进行不等间隔随机采样,讨论分析了采样前后混沌的自相关和功率谱性能,结果显示采样后混沌信号自相关及功率谱的周期性均明显减弱并逐步消除。搭建基于光生混沌的调频雷达信号模型,理论推导分析了信号的频谱和模糊函数。结果表明,混沌自相关的旁瓣较原始混沌序列明显降低,功率谱也更加平坦,可获得sinc函数频谱和图钉状的模糊函数,该信号可以应用于雷达探测系统。
When a laser generates a chaotic signal, the signal generated by the cavity has a periodicity. If the signal is applied to a radar system, it is easy to be identified and broken. In order to solve the above problems, this paper proposes a random sampling method to random sampling the original chaotic sequences at different intervals. The autocorrelation and power spectral performance of chaos before and after sampling are discussed. The results show that both the autocorrelation and the periodicity of the power spectrum Obviously weakened and gradually eliminated. The signal model of the FM radar based on photo-generated chaos is built, and the spectrum and ambiguity function of the signal are theoretically deduced and analyzed. The results show that the chaotic autocorrelation sidelobe is obviously lower than the original chaotic sequence, and the power spectrum is also more flat. The spectrum of sinc function and the thumbtack-like ambiguity function can be obtained. This signal can be applied to the radar detection system.