Yang Long, Wang Yong, Yang Yixin
School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
J Acoust Soc Am. 2021 Dec;150(6):4256. doi: 10.1121/10.0008900.
When the intersensor spacing of a uniform linear array (ULA) is larger than the half-wavelength of an incident narrowband signal, spatial aliasing is generated. For broadband signals, the broadband spatial spectrum is still affected as a result of the spatial aliasing in each frequency bin. In this paper, an aliasing-free broadband direction-of-arrival (DOA) estimation algorithm for ULAs is proposed. First, an array output is constructed with a given Gaussian random sequence from the direction ϑ. Then, a frequency-difference (FD) operation is conducted, which multiplies the array observation in the frequency bin f by the conjugate form of the constructed array output in the frequency bin f+Δf. Thus, an equivalent array output at a desired frequency Δf is obtained, whose wavelength is equal to twice the intersensor spacing. In this manner, an aliasing-free spatial spectrum in the FD domain is achieved. Scanning the direction ϑ, the DOA of signals is finally estimated based on the difference between the peaks in the aliasing-free spatial spectrum and direction ϑ. The proposed method can achieve a satisfactory estimation even in a strong interference environment. The simulations and experimental results are included to demonstrate the superiority of the proposed method.
当均匀线性阵列（ULA）的阵元间距大于入射窄带信号的半波长时，会产生空间混叠。对于宽带信号，由于每个频率 bin 中的空间混叠，宽带空间谱仍然会受到影响。本文提出了一种用于ULA的无混叠宽带到达方向（DOA）估计算法。首先，从方向ϑ用给定的高斯随机序列构建阵列输出。然后，进行频差（FD）运算，即将频率 bin f 中的阵列观测值与频率 bin f +Δf 中构建的阵列输出的共轭形式相乘。这样，就得到了所需频率Δf 处的等效阵列输出，其波长等于阵元间距的两倍。通过这种方式，在FD域中实现了无混叠空间谱。扫描方向ϑ，最终根据无混叠空间谱中的峰值与方向ϑ之间的差异来估计信号的DOA。所提方法即使在强干扰环境下也能实现令人满意的估计。文中包含了仿真和实验结果以证明所提方法的优越性。
