强干扰环境水下运动阵列方位估计的新方法

A New Bearing Estimation Method for Underwater Moving Arrays in the Context of Strong Interferences

针对水下存在方位不确定的强干扰源时基于合成孔径技术的多目标方位估计方法失效的问题,提出一种基于稳健卡朋波束形成器(RCB)的波束域处理技术的扩展拖曳阵测量方法(RCB-ETAM).该方法先利用物理线列阵的直线运动特点和水中信号的相干性,通过对不同时段的数据进行相位补偿将物理阵的数据矩阵合成更长孔径的虚拟阵的数据矩阵,然后根据虚拟阵数据和干扰源方位,使用RCB自适应调整虚拟阵元权值在感兴趣的范围内形成若干个波束,每个波束在干扰源方位形成零陷从而减小干扰对波束输出结果的影响,最后将虚拟阵数据转换到波束域,使用常规波束形成方法得到目标方位.仿真结果表明,与ETAM方法相比,RCB-ETAM的抗强干扰能力有了很大提高,在ETAM完全失效的情况下,依然能够给出目标方位的准确估计.

A new method called RCB-ETAM is proposed to solve the problem that the conventional passive aperture-synthesis methods for multi-target bearing estimation generally fail in the context of strong interferences.The method exploits the merits of beamspace processing techniques based on robust Capon beamformer（RCB） and the effective data restructuring ability of ETAM（Extended Towed Array Measurements）.The method consists of following steps： The phases of different data section of the physical array are compensated to synthesize into a data matrix corresponding to a much longer virtual array by using advantage of the array linear movement and coherence of underwater signals;Then according to the virtual array data and directions of interferences,RCB method is used to adaptively adjust the weights for elements of virtual array such that several beams are formed in the scope of interest with each beam having deep nulls in the directions of interferences;Finally the virtual array data is transformed into the beam domain,and the conventional beamforming technique is used to find the target directions.Simulation results show that the proposed RCB-ETAM method has much better anti-interference ability than the conventional ETAM method,and yields quite correct bearing estimations even when ETAM completely fails.