【作者】 陈争；

【导师】 曾以成；

【作者基本信息】 湘潭大学 ， 物理电子学， 2008， 硕士

【摘要】 混沌信号是由确定性系统产生的具有类随机性的信号。随着对信号检测和混沌动力学越来越深入的研究,发现在很多场合都遇到目标信号湮没在混沌背景信号中的情况。于是,如何检测混沌背景中的目标信号或提取混沌背景中目标信号的特征参数成为目前信号检测与估计领域的研究热点。本论文利用混沌信号的几何特征,在混沌背景中信号提取与信号参数估计等方面开展了以下工作:①研究混沌信号在重构相空间中局部切空间投影方法的特点,在数值实验的基础上研究相空间重构参数选取对局部切空间投影方法提取谐波信号的影响;②将局部切空间投影方法应用于检测混沌背景中的瞬态信号,并通过大量的数值实验充分验证了该方法的有效性;③根据混合信号在混沌流形局部的奇异值分解特点,提出一种混沌背景中信号提取的新方法——最小相对奇异值(MRSV)法。实例仿真表明该方法能够有效地估计出混沌背景中的AR模型的参数和正弦信号的频率。在估计AR模型参数时,较短的数据长度,本方法也能很好地估计出参数;在估计正弦信号的频率时,本方法能有效地将FFT不能分辨的强混沌背景中的正弦信号的频率估计出来。本论文的研究工作对混沌背景中小信号检测有一定理论和应用价值。更多还原

【Abstract】 The chaotic signal is pseudo-random and generated by a deterministic dynamical system. By more and more profound studies of signal detection and chaotic dynamics, it is found that a lot of target signals are embedded in the strong chaotic background. So some researchers that work on the signal detection and estimation field are paying attentions to detection of the target signals or extraction of the target signals’feature parameters in the chaotic background at present.Based on the chaotic signals’geometric features, some studies on extracting the target signals and estimating the signals’parameters in the chaotic background are worked out. The main works are as followings:①After studying the features of the local-tangent space projection method, we do many numerical experiments on the harmonic signal’s extraction from chaotic signal with the method, then analyze the experiments’results to research how the quality of the harmonic signal’s extraction depends on the phase-space reconstruction parameters.②The local-tangent space projection method is used to detect the transient signals in the chaotic background, and many numerical experiments fully verify the validity of the method.③A novel method, named the Minimization of Relative Singular Value(MRSV) ,to extract useful signal in chaotic background is proposed, and the method is based on the mixed-signal’s features of local singular value decomposition(SVD) on chaotic manifold. Simulations show that the method can effectively estimate the AR model’s parameters and sine wave frequencies in chaotic background. The AR model’s parameters can be estimated effectively with the short length of the data. The frequency of the sine signal not being distinguished by FFT can be estimated.The research results of this thesis have certain theoretical and practical value in detection weak signal from chaotic background.更多还原