进行子阵加权波束形成的波达方向估计
Weighted beamspace direction-of-arrival estimation based on subarrays
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摘要: 针对水声信道的多径效应以及海底散射信号信噪比低导致方位估计性能较差的问题,提出了一种基于子阵加权波束形成的UESPRIT算法(Weighted Beamspace UESPRIT Based on Subarrays,BS-BUESPRIT)。首先利用密集波束域转换矩阵估计回波信号的方位谱,进而估计同一时刻到达阵列的回波数目;之后将均匀线阵分为多个尺寸相同、相互重叠的子阵,利用加权波束形成对各子阵接收信号做指定方向的空域滤波;最后基于各子阵波束形成后的输出结果,利用UESPRIT算法实现回波方向的估计。仿真和湖试、海试试验结果表明,与UESPRIT算法相比,BS-BUESPRIT算法提高了信号波达方向估计性能,在多径和较低信噪比条件下有着更高的估计精度,应用于高分辨率测深侧扫声呐时有效地提高了声呐的测深性能。Abstract: Performance of Direction-Of-Arrival (DOA) estimation decreases obviously under multipath interference and low Signal to Noise Ratio (SNR) circumstance.Considering this problem,weighted beamspace UESPRIT based on subarrays (BS-BUESPRIT) algorithm is proposed.Firstly,estimate the azimuth spectrum of the signal through dense beamspace conversion matrix,then the estimation of source number can be obtained.Secondly,subdivide the Uniform Linear Array (ULA) into multiple overlapping subarrays,make beamforming for each subarray in specified direction.Finally,based on the outputs of beamforming,estimate the DOA of multiple signals through unitary ESPRIT (UESPRIT) algorithm.Simulations and the processing results based on the lake-trial and sea-trial data show that compared with UESPRIT,BS-BUESPRIT algorithm improves the performance of DOA estimation,and has higher accuracy under multipath interference or low SNR condition.