超短基线在低频基阵指向性测量中的应用

Application of USBL in low frequency array directivity measurement

随着水声换能器工作频率的降低,实验室空间很难达到自由场和远场测量的要求。而开阔水域的水下环境复杂,基阵很难实现更深层次的吊放,需要安装价格昂贵的吊装平台来获取标准声源与待测基阵之间的相对位姿,效率低且维护成本高。文章采用超短基线定位技术,信号选用线性调频脉冲信号与伪随机编码脉冲信号,并分别基于脉冲压缩法和复相关算法实现距离和相位测量。比对湖上定位精度试验和基阵指向性标定静态试验的结果显示:角度误差为2.5°以内;-6 dB波束宽度在2~10 kHz频率范围内测量误差在5.38%以内。证明超短基线定位在低频基阵指向性标定的可行性。

As the frequency of the underwater acoustic transducer decreases,the laboratory space is difficult to meet the requirements of free-field and far-field measurement.However,and the underwater environment in open water is relatively complex,so it is difficult to achieve deep lifting of the array.Therefore,it is necessary to equip an expensive lifting platform to obtain the standard sound source and the relative pose of the array to be measured,which has low efficiency and high maintenance cost.In this paper,the ultra-short baseline positioning technology is adopted,and the linear frequency modulated pulse signal and the pseudo random coded pulse signal are selected as the signals.The distance and phase measurement are realized based on the pulse compression method and the complex correlation algorithm respectively.The results of comparison of the positioning accuracy test on the lake and the static test of array directivity calibration show that the angle error is within 2.5°.The measurement error of-6 dB beamwidth is within 5.38%in the frequency range of 2-10 kHz.It proved the feasibility of ultra-short baseline positioning in low frequency array directivity calibration.