主动声纳侦察中的LFM信号参数估计方法

Parameters Estimation Method of LFM Signal in Active Sonar Reconnaissance

针对主动声纳侦察中LFM信号的参数估计问题,提出一种快速有效的LFM信号参数估计方法。该方法依据LFM信号的频谱特征,通过构造频域正负门,有效解决了低信噪比情形下LFM信号中心频率估计问题;通过粗搜索和精搜索,在保证调频斜率估计精度的基础上,大大提高了运算效率;利用高精度的调频斜率估计值构造参考函数,对去载频后的LFM信号进行脉冲压缩,通过测量脉压后信号-4dB处时间宽度并取其倒数,有效解决了低信噪比情形下信号带宽估计问题。仿真结果表明了所提方法的有效性。

In order to resolve the problem of parameters estimation of linear frequency modulation（LFM）signals,an effective parameters estimation method is proposed in this paper.By constructing apositive-negative-gate signal in frequency domain and according to the characteristics of LFM signal frequency spectrum,the proposed method obtains a high quality of center frequency estimated value.By dividing the once search into secondary search in the estimation of chirp rate,referred as to the coarse search and the fine search,the proposed method has a high calculation efficiency and a precise chirp rate estimated value at the same time.In addition,by measuring the-4dB time width of the pulse compressed signal and taking its reciprocal,aprecise signal bandwidth estimated value is obtained.The simulation results show the effectiveness of the proposed method.