基于最小一乘的虚拟阵元波束形成仿真研究

水下多波束成像系统成像质量的关键主要在于波束形成的质量。在信号频率一定时,常规相移波束形成只有通过增加基阵的孔径来得到更窄的波束,但是在有限的应用条件下,这种方法又受到实际工程的限制。因此,提出一种基于最小一乘估计的虚拟阵元波束形成方法。在低信噪比的情况下,利用最小一乘估计的稳健性可以得到更加准确的估计信号,从而在不增加基阵尺寸的情况下获得更窄和抗干扰性更强的波束,提高阵增益和声呐图像的角度分辨率。通过Matlab仿真并与其他方法比较验证,证明了上述方法的优越性。

Simulation of virtual array beamforming based on least absolute deviation

The quality of beamforming is the key to the imaging quality of underwater multi-beam imaging system. When the signal frequency is constant, the conventional phase-shifting beamforming algorithm can only get a narrower beam by increasing the aperture of the array, but this method is restricted by practical conditions in engineering. Therefore, a virtual array beamforming algorithm based on least absolute deviation (LAD) estimation is presented, by which a narrower and more robust beam can be obtained without increasing the array size, moreover the array gain and the angle resolution of sonar image can be increased under low signal to noise ratio (SNR). The superiority of the above method is verified by using Matlab simulation and comparing with other methods.