低信噪比下雷达回波谱矩快速估计方法  

A Fast Spectral Moments Estimation Approach of Radar Echoes with Low Signal-to-noise Ratio

作　　者：赵倢 卢晓光[1,2] 李海 张喆[1,2] Zhao Jie;Lu Xiaoguang;Li Hai;Zhang Zhe(Tianjin Key Lab for Advanced Signal Processing, Civil Aviation University of China, Tianjin 300300, China)

机构地区：[1]中国民航大学天津市智能信号与图像处理重点实验室,天津300300 [2]中国民航大学电子信息与自动化学院

出　　处：《信号处理》2020年第5期703-709,共7页Journal of Signal Processing

基　　金：国家自然科学基金民航联合基金(U1633106);工信部民机专项(MJ-2018-S-28);航空基金(20182067008);中央高校基本科研业务费(3122017007);中国民航大学蓝天教学名师培养经费。

摘　　要：针对在低信噪比下机载气象雷达回波多普勒参数(谱矩)估计不准确的问题,本文在气象目标的雷达回波频谱服从高斯分布的基础上,给出了一种利用协方差矩阵分解的快速参数化谱矩估计算法。通过理论分析,推导出雷达回波的协方差矩阵具有范德蒙结构特性,进而将用于谱矩估计的代价函数转化为类傅里叶变换结构,然后进一步通过快速傅里叶变换和高斯加权滑窗计算代价函数,实现快速的谱矩估计。仿真实验结果表明,该方法在信噪比低于5 dB时仍可以有效估计雷达回波的谱矩参数,同时运算复杂度大大降低,而且在谱宽值较大情况下仍能保持较好的估计性能。A fast parameterized spectral moments estimation method is proposed for enhancing the estimation accuracy of the Doppler parameters of airborne weather radar echoes in low SNR scenarios.Covariance matrix decomposition is employed in the estimation,based on the assumption that the spectral of echoes from weather targets is subject to Gaussian distribution.Theoretical analysis suggests that the covariance matrix of the echoes conforms to the Vandermonde structure,thus the cost function for covariance-matrix-based spectral moment estimation can be interpreted by a DFT-type matrix.The cost function for fast spectral moment estimation is then computed by Fast Fourier Transform and Gaussian weighted sliding window.Simulation results demonstrate that the proposed method is capable of estimating spectral parameters of echoes even when the SNR is lower than 5 dB.And there is no compromise of estimation performance under a wide spectral width situation with this reduced computational complexity method.

关 键 词：机载气象雷达 谱矩估计 低信噪比 矩阵分解 

分 类 号：TN959.4[电子电信—信号与信息处理]