宽带恒定束宽盲波束形成算法

Wideband Constant Beamwidth Blind beamforming Algorithm

针对传统盲源分离算法对宽带阵列信号适用性较差的问题,提出一种基于时频分析的宽带恒定束宽盲波束形成算法。该算法首先将接收信号变换到时频域上并提取出单源点。然后,对单源点聚类并求解信号在不同频点上的导向矢量。最后,通过提出一种信号来向未知的空间响应变化约束方法,实现宽带恒定束宽盲波束形成。该算法避免了将宽带盲波束形成转换为卷积混合的盲源分离,因而不存在时域盲源分离算法中系统参数随滤波器阶数急剧增加的问题,也不存在频域算法中排序和幅度模糊的问题。仿真结果表明,算法能够较好地实现宽带信号的盲分离,且输出信干噪比高于时域、频域以及时频域盲源分离算法,实测数据的处理结果验证了该算法的实用性。

Conventional blind source separation algorithms have poor suitability for wideband array signals. To address the problem, a novel wideband constant beamwidth blind beamforming algorithm based on time-frequency analysis is proposed. The received array signals are firstly transformed into time-frequency domain, and the single-source points are extracted. Then, the single-source points are clustered into different classes, which are used to obtain the signal steering vector at dif- ferent frequencies. Finally, the wideband constant beamwidth blind beamforming is achieved by a spatial response variation constraint method without knowledge of the direction of arrival （DOA）. The transformation from wideband blind beamform- ing to the blind separation of convolution mixtures is avoided in the proposed algorithm. Thus, the system parameters of time-domain algorithms will not increase sharply with the length of filter order, and the arbitrary permutation and scaling ambiguity of frequency-domain algorithms are also eliminated. The simulations illustrate that the proposed algorithm can well separate the wideband signals and achieve a higher output signal to interference plus noise ratio （SINR） compared with the time-domain, frequency-domain and time-frequency-domain algorithms. The practicality of the proposed algorithm is demonstrated by the measured data.