基于形态学滤波和时频谱图对消的多跳频信号参数估计

Morphological filtering and time-spectrogram cancellation based parameters estimation algorithm of multi FH signals

针对复杂电磁环境下多跳频信号的参数估计问题,提出一种基于多尺度形态学滤波和时频谱图对消的信号参数盲估计算法。首先根据跳频信号、干扰和噪声的时频特征差异性,采用多尺度形态学滤波消除噪声、突发和扫频信号,并利用谱图对消法剔除定频信号;然后通过八连通域标记获取跳频信号的位置信息,利用改进的K-means聚类算法实现异速跳频信号的分离;最后由各类簇参数估计多跳频信号的周期、跳变时刻和跳频频率。仿真结果表明,与利用形态学滤波并提取时频脊线的方法相比,该算法在低信噪比下具有更高的估计精度,且在定频、跳频信号发生频率碰撞时,仍能准确估计跳频参数。

Aiming at estimating the parameters of multi-frequency hopping signals in complex electromagnetic environment,a blind estimation algorithm of signals parameters based on multi-scale morphological filtering and time-spectrogram cancellation is proposed.Firstly,considering the characteristic differences of frequency hopping signals,interference signals and noise,multi-scale morphological filtering is used to eliminate the noise,frequency sweep signals and burst signals,the time-spectrogram cancellation is used to remove the fixed-frequency signals.Then the position information of the frequency hopping signals is obtained through the eight-connected domain mark,and then the all-speed frequency hopping signals are separated by the improved K-means clustering algorithm.Finally,the period,hopping time and frequency of multiple frequency hopping signals are estimated according to the parameters of each class cluster.The simulation results show that compared with the estimation algorithm that uses morphological filtering and extracts the time-frequency ridge,the proposed algorithm has higher estimation accuracy under low signal-to-noise ratio,and even though the frequency collision between frequency hopping signals and the fixed frequency signals occurs,the frequency hopping parameters can still be estimated accurately.