低信噪比线性调频信号目标的方位估计

发布时间：2018-01-29 06:08

本文关键词： 方位估计信噪比线性调频信号分数阶背景噪声常规波束形成最佳滤波干扰信息滤波输出信号能量 　出处：《声学学报》2017年04期 　论文类型：期刊论文

【摘要】：线性调频(LFM)信号目标的方位估计是水声探测研究的重要内容,在进行方位估计时,若存在强干扰信号源与强背景噪声,阵元接收信号的信噪比会显著降低,严重影响LFM信号目标方位估计结果的准确性.针对该问题,提出了一种简明分数阶滤波方法,并将其与常规波束形成方法(CBF)相结合来实现低信噪比条件下LFM信号目标的方位估计.简明分数阶傅里叶变换能在正交角度上将LFM信号的能量聚集在特定频点处并形成明显的能量峰,利用该特性,可对阵列各阵元接收的低信噪比LFM信号在简明分数阶域聚集的能量峰进行最佳滤波,以滤除干扰信息及背景噪声.对滤波输出进行逆简明分数阶傅里叶变换可得到增强信干比和信噪比的阵元域信号,进一步用于目标方位估计,就能获得更加准确的目标方位。数值仿真结果和海试实验数据处理结果验证表明,本文所提出的方法可有效抑制干扰和背景噪声,并对低信噪比LFM信号进行准确、稳健的方位估计。
[Abstract]:The azimuth estimation of LFM signal is an important part of underwater acoustic detection. If there is strong interference signal source and strong background noise in azimuth estimation. The signal-to-noise ratio (SNR) of the received signal of array elements will be significantly reduced, which seriously affects the accuracy of the target azimuth estimation results of LFM signal. In order to solve this problem, a simple fractional filtering method is proposed. And the conventional beamforming method CBF). Simple fractional Fourier transform (FRT) can gather the energy of LFM signal at a specific frequency point and form a distinct energy peak at the orthogonal angle in order to realize the azimuth estimation of LFM signal under the condition of low signal-to-noise ratio (SNR). By using this characteristic, the energy peaks of low signal-to-noise ratio (LFM) signals received by array elements in simple fractional order domain can be filtered optimally. In order to filter the interference information and background noise, the inverse simple fractional Fourier transform can be used to obtain the enhanced signal to interference ratio and signal-to-noise ratio signals in array domain, which can be further used to estimate the target azimuth. Numerical simulation results and experimental data processing results show that the proposed method can effectively suppress interference and background noise. And accurate and robust azimuth estimation of low SNR LFM signal is carried out.
【作者单位】：中国科学院声学研究所声场声信息国家重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(61571436)资助
【分类号】：TB566;TN911.23
【正文快照】： 换性质,提出了一种简明分数阶滤波器方法与波束形成方法相结合来实现低信噪比LFM信号目标的91 5 方位估计。首先对各阵元接收信号进行CFRFT变线性调频信号(LFM)是研究最早的一类脉冲压换,搜索LFM信号在CFRFT域中出现能量聚集的缩信号[1_2],通过非线性相位调制具有大的时宽-带

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