动平台下在对多普勒敏感信号回波进行速度搜索匹配滤波处理时，相对速度和舷角的耦合关系会造成混响多普勒扩展，导致难以利用速度信息检测低速目标。为在强混响背景中检测低速运动目标，本文在常规波束形成、自身多普勒补偿和速度搜索匹配滤波的基础上提出一种新方法，将分裂波束形成和速度匹配相结合，通过对各速度通道的左右半波束进行后置相位差判断来抑制非关心方位的回波，达到抑制亮点速度和舷角耦合的效果。通过推导不同信噪比下分裂阵相位差的概率密度分布，给出了相位差区间的选择方法。经海试数据验证表明，该方法与常规方法相比可使多普勒展宽减少50%，更有利于从强混响中辨识低速弱目标。基阵孔径越小，平台速度越大，该方法相比常规方法的优势越明显。
When matched-filter processing with velocity channels is applied to Doppler-sensitive pulse echoes on a moving platform, the coupling relationship between velocity and relative bearing leads to reverberation Doppler spread, making it difficult to detect low-speed targets using velocity information. Based on conventional beamforming, matched-filter processing and own Doppler nullification, a new method that combines split beamforming and velocity matching is presented. The post judgment on phase difference between left and right half-beams in all velocity channels is introduced to suppress echoes from unexpected bearing, reducing the coupling between velocity and relative bearing. A method for selecting the phase difference interval is provided by deducing the probability density distribution of phase difference between split beams under different signal-to-noise ratios. It is verified by sea trial data that Doppler spread obtained by the new approach is reduced by 50% compared with the conventional method and low- speed weak targets are easier to be identified from strong reverberation. The advantage of this method is greater than that of the conventional method when array aperture is smaller and speed of sonar platform is slower.
2024,46(23): 116-121 收稿日期：2024-2-4
DOI：10.3404/j.issn.1672-7649.2024.23.019
分类号：U665；TB566
基金项目：国家自然科学基金资助项目（41976177）
作者简介：王晓彤(1991-),女,博士,工程师,研究方向为水声信号处理与水声对抗
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