自适应空域矩阵滤波器设计和目标方位估计

针对在强干扰背景中检测弱目标信号时被动声信号处理技术的性能会严重降低的问题,提出了一种自适应空域矩阵滤波器的设计方法。该方法是在保证滤波器通带响应与期望响应误差和阻带响应低于某设定值的条件下,最小化滤波后基阵的输出功率,使得滤波器能尽量保证让通带扇面的信号无失真通过,同时抑制阻带扇面的干扰和噪声。将滤波器的优化设计问题表达成二阶锥规划的形式,利用已有的内点方求出其数值解。最后将设计的自适应空域矩阵滤波器用于强干扰背景中弱目标信号的方位估计。计算机仿真结果说明,所提方法能在干扰方位形成零陷,有效地抑制阻带区域的强干扰,提高了后续方位估计方法的性能。

Adaptive Spatial Matrix Filter Design with Application to DOA Estimation

The performance of passive acoustic signal processing techniques can become severely degraded when the acoustic source of interest is obscured by strong interferences. An effective approach to the design of adaptive matrix filters was proposed. The idea is to minimize the output power of the transformed data subject to a set of nonlinear inequality constraints imposed on error between the desired response and the designed filter in passband and stopband. These inequality constraints ensure that the stopband attenuation and the passband deviation satisfy the prescribed specifications, thereby, guarantee that signals of interest distortionlessly pass the filter while those of no interest are cancelled effectively. Computationally efficient convex formulations for the adaptive matrix filter design problems are derived using second-order cone programming (SOC), which can be solved by standard interior point method. Computer simulations show that the proposed method can produce nulls in directions of interferences, thus effectively suppresses strong interferences in stopband. As a result, the ability of the DOA estimator in the following procedure is greatly enhanced.