超低信噪比下的准周期大带宽多普勒信号高实时性混沌检测方法

The key to achieve excellent performance of fuze-warhead coordination(FWC) is to improve ability of radio fuze on extracting Doppler signal. For the difficult problem of radio fuze to extract weak Doppler signal in complex battlefield electromagnetic environment, the project will carry out a new method based on chaotic oscillator to detect Doppler signal with quasi-periodicity and large-bandwidth frequency in ultra-low signal-to-noise ratio(SNR). In the first place, the chaos detection model of radio fuze Doppler signal will be constructed. The detection efficiency of chaos model will be analyzed to optimize the model parameters. And the applicability of chaotic system on fuze Doppler signal detection will be extended. Secondly, fuze Doppler signal chaos detection criterion based on circular zone percentage will be studied to solve the contradiction of detection precision and observation time. Subsequently, the chaos detection algorithm with low complexity and high performance for fuze Doppler signal will be designed to ensure test accuracy and real-time requirement in wide-bandwidth. At last, the chaotic detection method to fuze Doppler signal will be validated and optimized using an engineering prototype system. And the optimal SNR detection result will be obtained by quantitative analysis of the detection error. The research achievements will give theoretical supports and engineering reserves to extract fuze Doppler signal detection efficiently under ultra-low SNR environment.

无线电引信实现优良引战配合性能的核心在于提高其多普勒信号提取能力。课题针对无线电引信在复杂恶劣的电磁环境下提取多普勒信号难问题，开展超低信噪比下对具有准周期、大带宽、高频率特征的引信多普勒信号进行高实时性混沌检测理论和方法研究。首先，针对引信多普勒信号特征及其变化规律，改进传统的Duffing振子模型并优化模型参数，扩展混沌振子低信噪比下检测微弱信号的适用性，从理论上获取多普勒信号形变与检测效果之间的关系；然后，提出并深化研究基于圆形区域百分比判别法的引信多普勒信号混沌检测判据，解决虚警率和检测精度与观测时间的矛盾；接着，设计低复杂度、高性能的引信多普勒信号混沌检测算法，在大带宽情况下保证检测精度的同时满足实时性要求；最后，对引信多普勒信号混沌检测方法进行验证，定量分析其检测误差，获取最优的引信多普勒信号信噪比检测结果。本项目的研究成果为无线电引信大幅度提升多普勒信号提取能力提供理论支撑。

项目在分析Duffing振子动力学特性及其局限性的基础上，研究了扩展型Duffing振子微弱信号检测机理；提出了基于圆形区域百分比判别法的扩展型Duffing振子系统混沌判据，解决了不同噪声背景下混沌检测系统临界阈值选取困难的问题；为便于对Duffing振子系统混沌态、间歇混沌态和大尺度周期态的参数进行有效判别，提出了基于STFT状态判决参数的扩展型Duffing振子微弱信号检测方法；为解决扩展型Duffing振子检测系统的固有缺陷，构建了Duffing振子可停振动系统检测模型，提出了基于Duffing振子可停振动系统的微弱信号检测方法，理论推导和仿真实验表明，该方法在进一步降低系统输入信噪比检测门限的同时大大扩展了单个Duffing振子的频率检测范围。同时，Duffing振子可停振动系统检测方法不仅可以检测周期信号，对幅值变化的衰减和发散振荡信号以及频率调制信号都具有很好的频率检测效果，扩展了Duffing振子检测对象的类型，为无线电引信目标回波信号检测提供了理论依据。针对超低信噪比下引信多普勒信号瞬时频率检测问题，构建了基于扩展型Duffing振子阵列的多普勒信号频率检测方法，通过圆上相点计数法结合STFT状态判决参数方法，实现了-25dB信噪比条件下的多普勒信号瞬时频率估计；为了降低阵列方法的复杂度和运算量以满足引信实时性要求，提出了基于Duffing振子可停振动系统的多普勒信号频率检测方法，通过计算相空间角余弦函数，在-35dB信噪比条件下获得了高精度的多普勒信号频率检测结果，仿真和实验测试结果证明了该方法的有效性，为无线电引信能够在超低信噪比下高效提取多普勒信号提供理论支撑和技术储备。