The invention discloses an estimation method based on time-frequency analysis of frequency gravity jump cycle, including the calculation of ultrashort wave frequency hopping signal through ascending low-pass filter the cosine of the N time-frequency analysis of time-frequency moment K frequency interval analysis of the value of the calculation steps, the N time-frequency analysis center frequency window the steps and calculation of adjacent time-frequency analysis window difference frequency gravity step, the estimated value of the skip cycle steps; the value of time-frequency representation of the window analysis results of the invention to the time-frequency analysis of frequency gravity energy window, and overcomes the traditional time-frequency analysis methods of aggregation and cross contradiction. To achieve optimization of the two, and weakened the influence of spread spectrum frequency hopping signal baseband shaping filter and flat, avoid the maximum energy method for the divergence of the baseband shaping filter estimation of carrier frequency, is gained. Good estimation performance. The method is more practical and accurate for skip frequency estimation of frequency hopping signals, and provides reference and reference for reconnaissance and estimation of frequency hopping signals.
【技术实现步骤摘要】
基于时频分析频率重心的跳周期估计方法
本专利技术属于跳频信号侦察
,具体涉及一种基于时频分析频率重心的跳周期估计方法。
技术介绍
跳频信号属于典型的非平稳信号,国内外学者大多采用时频分析方法得到清晰的时频图后,再估计其跳频参数。但目前的时频分析方法存在聚集性和交叉项的矛盾,当时频聚集性较高时,会产生较多的交叉项;当交叉项较少时,时频聚集性较低;无法达到二者的同时最优。同时,为适应信道传输,跳频信号多经过升余弦等低通成型滤波,基带信号频率波形发生变化。目前针对跳频信号的跳周期估计方法,多采用时频分析窗内的能量最大值所在频率作为该窗载频,对该载频序列进行快速傅里叶(FastFourierTransform,FFT)变换,得到跳周期估计值;这种方法对于经升余弦低通滤波后的跳频信号的跳周期估计性能较差。跳频通信由于其优良的低截获概率和抗干扰性,在军事通信对抗领域得到广泛应用;其中,跳频信号的参数估计,尤其是跳周期估计已成为研究的重点。跳频信号属于典型的非平稳信号,国内外学者大多采用时频分析方法得到清晰的时频图后,再估计其跳频参数。时频分析方法主要包括以短时傅里叶变换(ShortTimeFourierTransform,STFT)、Gabor变换、小波变换和S变换等为代表的线性变换和以魏格纳威尔分布(Wigner-VilleDistribution,WVD)、伪WVD(PseudoWigner-VilleDistribution,PWVD)、平滑伪WVD(SmoothedPseudoWigner-VilleDistribution,SPWVD)及以Cohen类 ...
【技术保护点】
一种基于时频分析频率重心的跳周期估计方法,其特征在于包括如下步骤:(1)计算经升余弦低通滤波后的超短波跳频信号sn(τ)的第n个时频分析时刻第k个频率间隔点的时频分析值STFTn(n,k);
【技术特征摘要】
1.一种基于时频分析频率重心的跳周期估计方法,其特征在于包括如下步骤:(1)计算经升余弦低通滤波后的超短波跳频信号sn(τ)的第n个时频分析时刻第k个频率间隔点的时频分析值STFTn(n,k);在(式1)中,S为跳频信号功率;TH为跳周期;Tr为跳周期的频率转换时间;T0为起跳时刻;fn为跳频瞬时频率;θ为跳频信号相位;ΔT为时间采样间隔;Δf为频率采样间隔;n=1,2,3,…;k=1,2,3,…;g(τ-k(TH-Tr)-T0)为经基带成型滤波之后的等效低通信号,g*(τ-i·ΔT)为g(τ-i·ΔT)的共轭;在(式1)中,若基带成型滤波为升余弦低通成型滤波,则g(τ-k(TH-Tr)-T0)的表达式为那么(式1)则为在(式3)中,B为基带信号带宽,α为升余弦滚降因子;(2)第n个时频分析时刻即为第n个时频分析窗,计算第n个时频分析窗的频率重心:(式4)中,fs为时频采样率;N为时频分析窗长,即STFT...
【专利技术属性】
技术研发人员:刘广凯,全厚德,孙慧贤,崔佩璋,李召瑞,袁丁,袁全盛,王晓晗,
申请(专利权)人:中国人民解放军军械工程学院,
类型:发明
国别省市:河北,13
还没有人留言评论。发表了对其他浏览者有用的留言会获得科技券。