单向水听器及其在波束形成中的应用

提出常规反向波束形成技术,构建了单向水听器,并探讨其应用于阵列波束形成的可能性。系统地构建单向水听器模型,导出常规反向波束形成技术,证明得到其空间响应单指向性的存在条件,其指向性指数在3~4.8 d B范围内。以单向水听器为基元构建标准线列阵进行常规波束形成,并与全向水听器比较,理论证明了使用单向水听器能够为线列阵提高3~4.8 d B的指向性指数。仿真实验结果验证了单向水听器自身具有心脏形空间响应、3~4.8 d B的指向性指数和空间响应的宽带一致性等三种特性,使用单向水听器能够在主瓣宽度不变的同时降低旁瓣级、提高指向性指数、保持良好的稳健性。因此,提出的常规反向波束形成技术是一种构建单向水听器的有效方法,在阵列波束形成中使用单向水听器是可行的、有利的。

Unidirectional hydrophone and its application in beamforming

A unidirectional hydrophone is constructed by a novel approach named as conventional reverse beamforming （CRBF）, and its possibility of application in array beamforming is discussed further. This paper builds the model of unidirectional hydrophone systematically, and proposes CRBF from the model. The existence condition of the spatial response unidirectionality is achieved by a simple mathematical proof, and the directivity index of unidirectional re-sponse ranges from 3dB to 4.8dB. A standard linear array, which is built up with the unidirectional hydrophones as elements, is compared with omnidirectional hydrophones array by utilizing conventional beamforming. Theoretical analysis proves the added 3~4.8dB directivity index with using unidirectional hydrophones in linear array. Simulation results verify that the unidirectional hydrophone itself has spatial response of cardioid type, its directivity index would be close to 4.8dB conditionally, and it has the broadband consistency of spatial response. Also the simulation results show that unidirectional hydrophones in array can reduce the sidelobe level with almost the same mainlobe width, improve the directivity index of array, and keep a good robustness. Therefore, CRBF is an effective way to construct unidirectional hydrophone. And it is feasible and beneficial to introduce the unidirectional hydrophones into array beamforming.