渔用声呐利用声波来探测水下鱼群分布和活动，通常采用全向发射或指向性扫描发射的方式实现对鱼群位置的初步探测。针对传统全向发射方式信号指向性较差，指向性扫描发射方式波束覆盖不均匀的问题，根据渔用声呐在实际捕捞场景中的需求，提出了一种基于旋转扇区扫描的改进方法。通过水声学算法仿真分析方法，分别仿真分析了扇区数量、边界角度等影响扫描发射性能的因素并进行了水池测试。仿真结果表明，采用4扇区旋转扇区的指向性扫描发射方式，在实现水平360°全向扫描的同时，提高了信号的指向性和探测区域的均匀性：主瓣强度相较全向发射提高8 dB，单个扇区中的发射波束最大强度差小于1.5 dB，波束宽度差在2°以内。综合现有测试条件，通过实验室水池测试了相邻两扇区发射扫描指向性。测试结果表明，所提出的设计方案在两扇区前方64°范围，指向性比全向发射平均高约8 dB，在提高探测效率和精度方面可行且有效，有助于在更广泛的范围内获得准确的鱼群信息。

 Fishing sonar utilizes sound waves to detect the distribution and activities of underwater fish schools. It typically employs either omni-directional transmission or directional scanning transmission methods for preliminary detection of the position of fish schools. However, there are several limitations with these traditional methods, including poor signal directivity in omni-directional transmission and uneven beam coverage in directional scanning transmission. To address these challenges, this study proposed an improved method based on rotating sector scanning, which aims to optimize the detection performance and meet the specific requirements of fishery sonar in practical fishing scenarios. This study used acoustic simulation methods to systematically analyze the factors that influence the scanning transmission performance, such as the number of sectors and the boundary angles between sectors. The performance of the proposed method was further validated through pool tests conducted under controlled laboratory conditions. The simulation results showed that the use of a four-sector rotating sector scanning transmission method effectively improves the signal directivity while maintaining a full 360° horizontal scan coverage. Specifically, the main lobe intensity was increased by 8 dB when compared to omni-directional transmission, and the maximum intensity difference within a single sector’s transmission beam was reduced to less than 1.5 dB, with the beamwidth difference kept within 2°. These results demonstrated the advantages of the proposed method in enhancing the detection capabilities of the sonar system. To further evaluate the practical performance of the system, laboratory pool tests were carried out to measure the transmission directivity between two adjacent sectors. The results from these tests showed that the proposed method improves the directivity by approximately 8 dB on average over a 64° range in front of the two sectors compared to the omnidirectional transmission. This finding suggests that the proposed design not only enhances the efficiency and accuracy of fish school detection but also helps to obtain accurate fish information in a wider range.