Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient im...Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.展开更多
针对欺骗干扰环境中的线性调频(linear frequency modulation,LFM)雷达干扰抑制问题,提出了一种动态环境下性能较好的数字射频存储器(digital radio frequency memory,DRFM)假目标干扰抑制方法。该方法通过自适应滤波从时-频解耦后的信...针对欺骗干扰环境中的线性调频(linear frequency modulation,LFM)雷达干扰抑制问题,提出了一种动态环境下性能较好的数字射频存储器(digital radio frequency memory,DRFM)假目标干扰抑制方法。该方法通过自适应滤波从时-频解耦后的信号中估计出干扰信号并对干扰信号进行对消,从而恢复出目标回波信号。该方法无需进行干扰环境下的多分量信号参数估计,运算复杂度低。仿真结果表明,在干扰与目标信号之间的时延差大于0.2μs的情况下,对干扰信号的脉压峰值功率抑制可达50 dB以上,而目标信号脉压峰值功率损失小于1 dB,且算法对干信比不敏感。展开更多
针对现有基于最小均方误差准则的全双工射频域自干扰对消算法存在收敛速度与干扰对消比相互制约的矛盾,提出一种改进时变步长归一化最小均方算法。该算法通过建立最小均方误差步长因子与改进时变sigmod函数的非线性关系,利用实时误差信...针对现有基于最小均方误差准则的全双工射频域自干扰对消算法存在收敛速度与干扰对消比相互制约的矛盾,提出一种改进时变步长归一化最小均方算法。该算法通过建立最小均方误差步长因子与改进时变sigmod函数的非线性关系,利用实时误差信号自相关和时间参量t协同控制步长因子μ(t),较好的兼顾了收敛速度与干扰对消比。分析与仿真表明:在干信比为80 d B、步进间隔Δt=1/32 ms、信噪比Eb/N0=10 d B的2FSK全双工系统模型下,该算法能够实现88 d B的自干扰消除高出同类算法至少1.5 d B且收敛速度和抗突发干扰能力提升显著。展开更多
针对基于射频干扰对消的扰中通系统,本文研究了采用多抽头射频干扰重建技术可获得的自干扰抑制度,给出了抽头数为2的自干扰消除器的解析结构,并分析了干扰消除效果与信号带宽和抽头数的关系。数值分析与计算机仿真结果表明:干扰消除能...针对基于射频干扰对消的扰中通系统,本文研究了采用多抽头射频干扰重建技术可获得的自干扰抑制度,给出了抽头数为2的自干扰消除器的解析结构,并分析了干扰消除效果与信号带宽和抽头数的关系。数值分析与计算机仿真结果表明:干扰消除能力随信号带宽增大而减弱,随抽头数增加而提升,对于100 MHz带宽信号,6抽头射频对消器在S频段可提供约70 d B的自干扰消除能力。展开更多
文摘Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.
文摘针对欺骗干扰环境中的线性调频(linear frequency modulation,LFM)雷达干扰抑制问题,提出了一种动态环境下性能较好的数字射频存储器(digital radio frequency memory,DRFM)假目标干扰抑制方法。该方法通过自适应滤波从时-频解耦后的信号中估计出干扰信号并对干扰信号进行对消,从而恢复出目标回波信号。该方法无需进行干扰环境下的多分量信号参数估计,运算复杂度低。仿真结果表明,在干扰与目标信号之间的时延差大于0.2μs的情况下,对干扰信号的脉压峰值功率抑制可达50 dB以上,而目标信号脉压峰值功率损失小于1 dB,且算法对干信比不敏感。
文摘针对现有基于最小均方误差准则的全双工射频域自干扰对消算法存在收敛速度与干扰对消比相互制约的矛盾,提出一种改进时变步长归一化最小均方算法。该算法通过建立最小均方误差步长因子与改进时变sigmod函数的非线性关系,利用实时误差信号自相关和时间参量t协同控制步长因子μ(t),较好的兼顾了收敛速度与干扰对消比。分析与仿真表明:在干信比为80 d B、步进间隔Δt=1/32 ms、信噪比Eb/N0=10 d B的2FSK全双工系统模型下,该算法能够实现88 d B的自干扰消除高出同类算法至少1.5 d B且收敛速度和抗突发干扰能力提升显著。
文摘针对基于射频干扰对消的扰中通系统,本文研究了采用多抽头射频干扰重建技术可获得的自干扰抑制度,给出了抽头数为2的自干扰消除器的解析结构,并分析了干扰消除效果与信号带宽和抽头数的关系。数值分析与计算机仿真结果表明:干扰消除能力随信号带宽增大而减弱,随抽头数增加而提升,对于100 MHz带宽信号,6抽头射频对消器在S频段可提供约70 d B的自干扰消除能力。
