﻿ 改进的基于本征滤波的时域宽带波束形成
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Improved eigenfilter-based time-domain wideband beamforming
WANG Jianshu, FAN Yangyu , DU Rui, LYU Guoyun
School of Electronics and Information, Northwestern Polytechnical University, Xi'an 710129, China
Abstract: An improved eigenfilter-based wideband beamforming method with frequency invariance and nulls was proposed. Based on the optimization model formed by maximum energy array cost function and linear constraints of array response in main great direction, array spatial response variation was integrated into the cost function to achieve frequency invariance. Two methods, integrating the extended sidelobe energy into cost function and using linear constraints of array response in the direction of inference, were designed to achieve nulls, so that two new constraint optimization models were formed, which could be solved by eigenfilter. Simulation results show that frequency invariance and nulls of beam response are achieved at the specified angle region in the frequency passband, and the gain of the sidelobe is small, the effectiveness and satisfactory performance of the proposed method are proved.
Key words: wideband beamforming     eigenfilter     frequency invariance     nulls     sidelobe

1 时域宽带波束形成模型

 图 1 时域宽带波束形成的结构图Fig. 1 Structure diagram of time-domain wideband beamforming
2 基于本征滤波的宽带波束形成 2.1 最大能量阵列代价函数

2.2 主极大方向阵列响应线性约束

2.3 优化问题求解

3 改进的方法

3.1 频率不变性设计

SRV的值可以用来衡量波束形成器的频率不变性,其定义为

3.2 零陷设计

3.2.1 扩展旁瓣能量法

3.2.2 线性约束法

4 仿真分析

4.1 频率不变性和零陷验证

 图 2 方法1和方法2的二维波束响应图Fig. 2 Two-dimensional array response of method 1 and method 2

4.2 性能分析

 图 3 文献[14]二维波束响应图Fig. 3 Two-dimensional array response of method in Ref.[14]

 评价指标 主瓣SRV值 波束宽度 旁瓣增益/dB 文献[14]方法 5.88×10-7 [-10°,9°] -24.03 方法1 1.47×10-10 [-10°,9°] -28.4 方法2 4.97×10-10 [-10°,9°] -29.54

5 结 论

1) 两种方法均能实现阵列响应在指定角度范围内的频率不变性或零陷.

2) 在获得足够零陷深度和相同波束宽度条件下,两种方法均获得比文献[14]中方法更小的主瓣SRV值和旁瓣增益.

#### 文章信息

WANG Jianshu, FAN Yangyu, DU Rui, LYU Guoyun

Improved eigenfilter-based time-domain wideband beamforming

Journal of Beijing University of Aeronautics and Astronsutics, 2015, 41(10): 1830-1835.
http://dx.doi.org/10.13700/j.bh.1001-5965.2014.0778