强干扰下跳频信号的参数估计

针对通信对抗中跳频信号参数估计问题,考虑存在强干扰的情况下,提出了一种基于时频重心的跳频信号跳周期估计和基于跳频部分接收的跳时估计方法。对于跳周期估计,在短时傅里叶变换(STFT)时频变换的基础上提取信号随时间变化的时频重心,再结合小波变换和谱分析估计出跳频周期;对于跳时估计,采用跳频带宽的部分接收避开强干扰,构造含有跳变信息的参考信号,通过参考信号采用最大似然(ML)方法得到跳时的精确估计。仿真实验表明,算法运算复杂度低,跳频定位精度高,在强定频干扰的情况下仍能有效估计出跳频周期和起跳时刻。

Parameter estimation of frequency hopping signals under strong interference

To estimate the parameters of the frequency hopping(FH) signal in communication countermeasures, a hop duration estimation method based on the core of time-frequency and a hop timing estimation method based on partial reception of frequency hopping signal are proposed. For hop duration estimation, on the basis of short time Fourier transform(STFT), the core of time-frequency which varies with time is extracted, then the hop duration estimation is obtained according to wavelet transform and spectral analysis. For hop timing estimation,the partial reception of FH signal is adopted to avoid the strong interference,a reference signal which has the same transition information as the original signal is constructed, then a maximum likelihood estimation method is used to get the hop timing. Simulation shows that this algorithm features low computation complexity and high accuracy in time-frequency plane. The results indicate that this algorithm can estimate the hop duration and hop timing under the strong interference.