一种新型海底沉积物声学原位测量系统的研制及应用

为了能够精确地测量海底表层沉积物的声学参数,自主研制了一种新型海底沉积物声学原位测量系统,与国内外传统的声学原位测量系统相比,该系统能够实时显示声波波形,调整测量参数,其工作方式除了站位式测量之外,还实现了拖行式连续测量,极大地提高了工作效率.根据前期海试情况,对海底仪器结构进行了重新设计,使之可以同时测量海底沉积物及海底海水的声学参数,同时建立了双向数字信道,解决了测量过程中系统信号的干扰问题.该系统的结构分为两部分:甲板控制单元和水下测量单元,整套系统通过主机控制程序进行控制,采用GPS定位系统测定仪器的大地坐标.为了检验系统的稳定性及准确性,分别进行了实验室水槽实验和海上试验.利用水声测量设备对测量系统进行实验室水槽标定分析,实验结果表明系统测量值相对误差仅为0.04%,测量结果具有较高的精度.海上试验在青岛胶州湾和东海海域进行,获得了试验区域海底沉积物声速和声衰减系数的测量数据,将测量数据与他人的研究结果进行对比分析,结果表明测量数据与前人研究结果一致,较为准确.该原位测量系统在站位式测量和拖行式测量中都能够快速准确地测量出沉积物声速和声衰减系数,可以作为海底底质声学测量的调查设备.

Development and application of a new type in-situ acoustic measurement system of seafloor sediments

To accurately measure the acoustic parameters of seafloor sediment, we independently developed a new type in-situ acoustic measurement system of seafloor sediment and compared it with the conventional in-situ acoustic measurement system at home and abroad. This system can display acoustic waveforms in real-time and adjust measurement parameters on the computer. In addition to work station measurements, it also carried out a continuous dragging measurement for the first time, which greatly improves the work efficiency. According to preliminary sea trials, the structure of the underwater instrument has been redesigned such that it can measure the acoustic parameters of the seabed water and seabed sediment simultaneously. We also established a two-way digital channel, which solved the signal interference problem during the measurement. The in-situ measurement system consists of two parts: the deck control unit and the underwater measurement unit. The entire system was controlled by the host computer control procedures, and its geodetic coordinate was located by GPS.Laboratory tank experiments and sea trials were conducted to test the stability and accuracy of the system. System calibration was carried out in the laboratory tank using an underwater acoustic measurement device, and the experimental results show that the relative error of system measurement is only 0.04%, indicating high accuracy. Sea trials were conducted in Qingdao Jiaozhou Bay and the East China Sea, and the velocity and attenuation coefficient data were obtained in test areas. The comparison analysis among the measured data and other studies indicates good consistency. The tank experiments and sea trial results showed that the in-situ measurement system is capable of measuring the sound velocity and attenuation coefficient rapidly and accurately for both station measurements and drag measurements, and it can serve as survey equipment for seabed sediment acoustic measurements.