八波束相控阵换能器的研制

Development of eight-beam phased array transducer

声学多普勒计程仪(Doppler velocity log,DVL)是一种能为水面或水下载体提供定位和导航信息的重要设备。传统的DVL通常采用Janus配置方式,向海底发射沿载体前后左右方向的4个波束,并利用多普勒频移来计算载体的速度。而对于传统相控阵DVL,阵元布阵间距通常为二分之一波长,同一方向两波束间夹角为60°。该研究在传统相控阵DVL的基础上,提出一种八波束的相控阵DVL,在两个互相垂直的方向上,各形成4个波束,即双Janus配置方式。根据仿真对比分析,确定阵元布阵间距为0.35倍波长,同一方向上4个波束所对应的角度分别是±43.56°和±20.16°,这样,在两个互相垂直的方向上,4个与水平面方向夹角较小的波束,可以提供更大的水平分量,更有利于进行多普勒频移的计算;4个与水平面方向夹角较大的波束,有着更大的垂直分量,使接收的回波信号有较大的信号强度,两种波束优势互补。同时,制作了一个八波束换能器,并进行了水池测试,指向性波束夹角分别为±43.49°和±20.10°,与仿真结果较好吻合,对应发送电压响应分别为170.2 dB和170.6 dB。

Doppler velocity log(DVL)is one of the important devices which can provide positioning and navigation information for surface or underwater vehicle.The traditional DVL usually uses Janus configuration method to launch four beams along the front,rear,left,and right directions of the vehicle to the seabed,and uses Doppler frequency shift to calculate the speed of the carrier.For traditional phased array DVL,the distance between array elements is usually half of the wavelength,and the angle between two beams in the same direction is 60°.Based on the traditional phased array DVL,an eight-beam phased array DVL was proposed,which forms four beams in two mutually perpendicular directions,so is namely double Janus configuration mode.According to the simulation,it was determined that the distance between the array elements is 0.35 of wavelength,and the angles corresponding to the four beams in the same direction are±43.56°and±20.16°respectively.In this way,in two mutually perpendicular directions,the four beams with a smaller angle with the horizontal plane can provide a larger horizontal component,which is more conducive to the calculation of Doppler shift;the four beams with larger angles to the horizontal plane have larger vertical components,so that the received echo signals have larger signal strength,and the advantages of the two types of beams are complementary.At the same time,an eight-beam transducer was made and tested in a pool.The angles of the directional beams are±43.49°and±20.10°,which are in good agreement with the simulation results.The corresponding transmitting voltage response is 170.2 dB and 170.6 dB respectively.