改进的相控阵多普勒计程仪波束形成技术

Improved beamforming technology for phased array Doppler log

目前相控阵式多普勒计程仪的基阵体积比活塞式多普勒计程仪已经缩减了很多,该技术只需通过一个收发共用的平面基阵实现信号的发射和接收,可以同时形成4个方向的波束,大大减小了基阵的尺寸,同时还消除了声速变化对测速的影响。但在中深度和大深度多普勒计程仪设备中,换能器基阵的体积仍然限制了其适装的载体种类。以多普勒计程仪小型化思想为核心,分析了密排相控阵多普勒计程仪波束形成技术,对多普勒计程仪进行集成化、小型化设计。针对密排相控阵波束形成技术,比较其发射指向性、声源级、信噪比、系统复杂度与稀疏相控阵的差异。分析表明,在相同频率、相同发射功率以及相同尺寸的条件下,密排相控阵的收发联合响应较稀疏相控阵提高近6 dB。同时在相同测速作用距离的条件下,利用密排相控阵技术可以减少换能器阵元数,从而减小换能器尺寸,达到小型化的目的。

At present,the volume of phased array Doppler log has been reduced a lot compared with the piston type Doppler log.The former can simply transmit and receive signal by a transceiver planar array,and can form multibeams in four directions at the same time,so it can greatly reduce the size of the array and eliminate the influence of sound velocity change on speed measurement.However,the volume of transducer array in medium-depth and large-depth Doppler logging equipment still limits the type of suitable carrier.Taking the miniaturization of Doppler log as the core,in this paper the beamforming technology for the element densely arranged phased array of Doppler log is analyzed,and the integrated and miniaturized Doppler log is developed.The transmitting directivity,sound source level,sensitivity and system complexity of the element densely arranged phased-array are compared with the traditional phased-array.Analyses show that under the same frequency,same transmitting power and same size,the joint response of the transceiver of element densely arranged phased-array is improved by nearly 6 dB compared to the traditional phased array,and in the same range of speed measurement,this technology can reduce the element number of transducer array,so as to decrease the size of the transducer and achieve the purpose of miniaturization.