宽带随机混沌雷达高速目标速度估计与成像

随机混沌具有真随机性、对初值敏感、易于产生和控制等特点，频率步进信号易于工程实现和处理，结合两者的优势，提出了一种载频随机步进的随机混沌信号(RSCFSCS)模型,用于高速目标的速度估计和距离维高分辨成像。首先，通过非周期函数激励非线性系统，产生不可预测的随机混沌信号(SCS)，经频率调制后用作基带子脉冲。同时，将SCS通过映射变换得到跳频编码(FHC)，用来决定调频脉冲串的载频步进。RSCFSCS 速度估计包括粗搜索和精搜索，粗搜索采用固定步长，保证速度偏差小于速度分辨单元，而精搜索采用黄金分割搜索算法可得到精确的速度估计。最后，子脉冲经相干合成形成宽带信号，实现高分辨距离成像。数值仿真表明提出的信号模型和处理算法性能良好。

Velocity estimation and imaging of high-speed targets for wide-band stochastic chaotic radar

A new radar signal,the randomly stepped carrier frequencies stochastic chaotic signal(RSCFSCS),is proposed because of characteristics of stochastic chaos such as true random behavior,sensitivity to initial condition,accessibility for generation and control,and easy realization and processing for the stepped frequency signal. Firstly,excited by an aperiodic function,a nonlinear system generates unpredictable stochastic chaotic signal(SCS) to form baseband subpulse by frequency modulation. Meanwhile,SCS is transformed to frequency-hopping(FH) codes to determine carrier frequencies step. RSCFSCS is used for velocity estimation and high-resolution range imaging of high-speed moving targets. The velocity estimation includes a coarse search and a precise search,where the coarse search is conducted with a fixed step to make the velocity deviation less than the velocity resolution,while the precise search adopts the golden section search(GSS) algorithm to get an accurate estimation of velocity. Then the spectra are coherently synthesized to realize wide bandwidth and high-resolution range imaging. Finally,numerical simulations demonstrate a good performance of the proposed signal model and the processing algorithm.