带远参考测量方式的海底大地电磁同步采集技术

THE SYNCHRONIZING ACQUISITION TECHNOLOGY OF REMOTE REFERENCE MAGNETOTELLURIC METHOD

在海底进行带远参考的大地电磁数据采集,需解决的技术问题包括:仪器的硬件电路中需含有高精度的时钟源,该时钟的走时误差仅为微秒级;需将GPS时间信息写入主控计算机中,使得高精度时钟源成为与标准时间一致的时钟;设计同步性能可靠的数据采集电路。在研发过程中,采用温补晶振技术使振荡频率稳定至10-7秒;编写对钟驱动程序使PC104计算机能成功地在海面上实施与GPS对钟;运用同步控制电路芯片组成完善的采集系统。海洋试验证明了上述方案的有效可行性。

In order to realize synchronizing acquisition on the seafloor, some technical problems should be solved. First of all, the hardware of the instrument should has a high-precision clock which has errors at microsecond level; secondly the GPS information should be input into the controlling computer and which make the clock synchronize with the standard time; the third problem is that the acquisition electrocircuit with good synchronizing capability should be designed. In this research, the temperature compensation technology of crystal vibration has been used to make the vibration frequency of the clock stabilize at 10-7 second. The synchronization program had been written, which made the PC 104 synchronize with the GPS on the sea. The system is improved by electrocircuit chips which have good synchronizing capability. The experimentations in the sea had shown that the scheme is valuable and practicable.