低信噪比下PSK信号的载频估计（英）

针对电子侦察中PSK信号的载频估计问题，提出一种低信噪比下载频估计新方法。该方法将PSK信号划分为等长度的交叠区间，提取各个区间内信号频谱的聚集性测度作为特征参数，然后将此特征参数导入网格密度聚类算法，以聚类结果作为载频估计特征类，最后将特征类对应的频谱叠加后提取峰值得出信号载频估计值。该方法避免了传统PSK信号载频估计的非线性运算，显著降低了PSK信号载频估计的信噪比门限，且无需先验知识，适合于电子侦察场合。仿真实验结果证实了该方法在低信噪比下PSK信号载频估计的有效性。

Blind carrier frequency estimation for phase shift keying signals in low signal to noise ratio

In order to solve the problem of carrier frequency blind estimation of PSK signals in electronic reconnaissance, a new estimation method was proposed. The phase shift keying(PSK) signal was divided into several overlapping intervals which had equal length, and the spectrum concentration measures of every interval were extracted by the FFT. And then, using the grid-density clustering, the spectrum concentration measures were classified into two categories: the narrowband spectrum interval and the wideband spectrum interval. The narrowband spectrum interval was regarded as the characteristic class. The spectrums of the characteristic class were accumulated to estimate the carrier frequency of PSK signal. The proposed method had avoided the non-linear operation in the traditional PSK signal carrier frequency estimation algorithm. Thus, the signal to noise ratio (SNR) threshold was remarkably decreased. Moreover, the proposed method did not need the prior knowledge of the signal, which was suitable to the electronic reconnaissance occasion. Experimental results had verified the validity of the proposed estimation method in low SNR.