孔径扩展中相位修正因子估计的改进算法  

A modified method for estimating phase correction factor in passive synthetic aperture

作　　者：王域[1,2] 宫在晓 张仁和[1] WANG Yu;GONG Zaixiao;ZHANG Renhe(State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences Beijing 100190;University of Chinese Academy of Sciences Beijing 100049)

机构地区：[1]中国科学院声学研究所声场声信息国家重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《声学学报》2018年第4期556-564,共9页Acta Acustica

基　　金：国家自然科学基金项目(11434012,41561144006)资助

摘　　要：传统的扩展拖曳阵列尺寸算法（Extended Towed Array Measurement,ETAM）在信噪比不够高、相位修正因子的相位角处于以间断点为中心的＂跳变区间＂时,扩展孔径均有可能失效。针对传统的ETAM算法中互相关相位角的间断点导致的算法不稳定问题,提出了一种相位修正因子估计的改进算法。该算法使用归一化互相关复向量的统计平均值作为相位修正因子的最小二乘估计,消除了互相关相位角的间断点带来的不利影响。数值仿真和实验数据分析结果表明：对于相位稳定甚至相位随机的单目标信号,改进算法均能有效扩展孔径,获得相对于常规波束形成（Conventional Beamforming,CBF）更高的方位分辨率和检测信噪比;相比于传统的ETAM算法,改进算法提高了相位修正因子的估计准确性,从而有效提高了算法的稳定性。The conventional Extended Towed Array Measurement （ETAM） may fail to extend aperture when the Signalto-Noise Ratio （SNR） is not high enough and the phase angle of phase correction factor is close to the discontinuous point. A modified method for estimating phase correction factor is proposed to reduce the instability of the conventional ETAM caused by the discontinuity of cross-correlation phase angle. In this method, the average value of normalized cross-correlation vectors is estimated as the least-square estimation for phase correction factor, which can eliminate the adverse effects caused by discontinuity of the cross-correlation phase angle. Simulation and experimental results show that the proposed method can effectively extend aperture even in the case of a stochastic source, and obtain higher resolution and SNR relative to Conventional Beamforming （CBF）. Compared with conventional ETAM, the proposed method has a wider range of applications because the estimation accuracy of phase correction factor and the stability of the algorithm are improved.

关 键 词：最小二乘估计 改进算法 修正因子 相位角 孔径 归一化互相关 实验数据分析 常规波束形成 

分 类 号：U666.7[交通运输工程—船舶及航道工程]