基于分段拟合的非线性组合调制雷达信号设计

摘要

线性调频与伪随机码组合调制的雷达信号可增加信号复杂度,在降低信号被截获概率方面有突出优势,但该组合具有线性调频高旁瓣,且无法克服加窗处理后主瓣宽度增大的缺点.利用驻留相位产生的非线性调频信号能够抑制旁瓣的特点,提出分段拟合的非线性调频与巴克码调制相结合的方法,将其各自的优点加以结合,不仅可以减小距离与速度模糊度,而且可以抑制旁瓣.对该组合信号的显函数模型仿真曲线和模糊函数图进行分析,仿真结果表明,该方法不仅可以降低距离与速度模糊度、降低信号被低截获概率,而且产生了比传统非线性调频更低的旁瓣,说明了该方法用于雷达信号的可行性与优越性.%The combinational modulated radar signal by linear frequency modulation and pseudo random code can increase signal complexity and reduce the probability of signal interception.However,this combination keeps the disadvantage of high sidelobe of linear frequency modulation and cannot overcome the increase of main lobe width caused by adding window function.Using the advantages of nonlinear frequency modulation signal generated by traditional stationary phase principle in suppressing sidelobe,a method which combined piecewise fitting nonlinear frequency modulation with Barker code modulation was proposed,and by using their respective advantages,the proposed method can not only reduce the ambiguity between distance and velocity,but also suppress the sidelobe.Finally,the simulation curve of explicit function model of this signal and ambiguity function were analyzed.The simulation results show that this method not only further reduces the ambiguity between distance and velocity and improves the performance of low probability signal interception,but also produces lower sidelobe than that of traditional nonlinear frequency modulation,which illustrates the feasibility and efficiency of the method used for radar signal.