多级背景均衡在多波束LOFAR处理中的应用

被动声纳检测中背景均衡通常是沿着频率或者方位对噪声进行均值估计。为了提高多波束窄带检测能力,需采用一种新的背景均衡方法来估计噪声的均值。针对水下目标辐射噪声的线谱横跨相邻多个波束,将多级背景均衡应用到被动多波束窄带检测中。它是根据所选择的数据窗,沿着频率和方位对多波束LOFAR图进行两维的背景均衡处理。该方法能够有效地抑制目标方位相邻波束线谱,提高多波束LOFAR图中窄带信号检测能力。海试数据处理结果表明,该方法不仅有效,而且计算量小。

Noise normalization technique in multi-beam LOFAR processing

In passive sonar, the noise normalization is usually implemented along frequency axis or azimuth axis. In order to improve the performance of the multi-beam narrowband detection, a new normalization technique needs to be taken for estimating the mean of noise. Because line frequency spectrum of radiated noise could leak into adjacent beams, a multi-stage normalization method is applied to passive narrowband detection. According to a selected window, noise normalization is implemented along frequency axis and azimuth axis of multi-beam LOFAR pictogram. This method can suppress leakage of line frequency spectrum among the adjacent beams and improve the detection performance of multi-beam LOFAR processing effectively. The results of sea-trial data processing show that the new noise normalization technique is effective.