基于改进复声强法的非合作跳频信号方位估计

Azimuth estimation of non-cooperative frequency hopping signals based on improved complex sound intensity method

针对由于跳频信号的频率随时间不断跳变,导致传统复声强法对其方向估计性能不佳的问题,提出一种改进复声强测向方法。首先,构建时频分布矩阵,利用跳频信号模糊函数的特点,对时频交叉项进行抑制;然后,利用迭代法滤除分布于整个时频面的高斯白噪声,获得清晰的时频分布图,并利用信号的时频特征对信号分离与提取时频脊线;最后,将脊线所对应的时频点进行时间积分,利用时频信息提升复声强法对跳频信号的测向能力。仿真及水池试验结果表明,在信噪比大于0 dB时,方位估计均方根误差小于1°,提升了复声强方法对跳频信号方位估计的准确性与稳定性。

The frequency of the frequency-hopping(FH)signal is constantly changing with time,which leads to the poor performance of the azimuth estimation of the traditional complex acoustic intensity method.An improved complex acoustic intensity method is proposed.Firstly,the time-frequency distribution matrix is constructed,and the time-frequency cross term is suppressed by using the characteristics of FH signal fuzzy function.Then,the white Gaussian noise distributed in the whole time-frequency surface is filtered by iterative method to obtain a clear time-frequency distribution,and the time-frequency characteristics of the signal are used to separate and extract the time-frequency ridges.Finally,the time-frequency points corresponding to the ridge are integrated in time,and the time-frequency information is used to improve the azimuth estimation ability of the complex acoustic intensity method for FH signals.The simulation and pool test results show that the root mean square error of azimuth estimation is less than 1°when the SNR is greater than 0 dB,which improves the accuracy and stability of azimuth estimation of FH signals by the complex sound intensity method.