井下磁力计的研制  

Design of borehole magnetometer

作　　者：胡星星[1] 滕云田[1] 张炼[1] 王晓美[1] 谢凡[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《地球物理学进展》2011年第5期1849-1858,共10页Progress in Geophysics

基　　金："十一五"国家科技支撑子专题项目(2006BAC01B01-02-05)资助

摘　　要：如何提高观测的信噪比,克服在人类社会工业化、城市化、现代化发展中带来的交通、工业等人为高噪音的影响,分辨微小地震和来自地下微弱的地球物理信息,是当代地球物理面临的重要研究内容.开展深井观测是提高观测精度的有效途径.为此中国地震局研制了井下集成综合观测系统,地面主机用RS-422总线与井下各传感器进行实时数据通信.在井下磁力计单元中,研制了高精度的磁通门探头信号调理电路和数字采集系统,提高其检测微弱变化磁场的能力,发挥井下观测的优势;为满足井下仪器高稳定性要求,并适应井下集成综合观测传输要求和实时测试实验以及井下安装定向的需要,磁力计设计有被动发送的协议传输状态和主动发送的实时传输状态两种工作状态;设计了高精度的背景磁场自动/手动补偿方法,使仪器能够实现井下观测的自动化、智能化和远程监控的需要;采用精确到字节检验的命令协议解析方式,使磁力计有很好的抗干扰能力和工作可靠性;设计了人机友好的专用监控软件.通过在天津静海地磁台站为期半个月的拷机性能测试表明,磁力计工作稳定;观测结果准确,记录的地磁信号与DIMARK-FGE等进口高性能地磁仪器完全一致;峰-峰值噪声为0.043 nT,RMS噪声为0.014 nT/√Hz;能够满足井下实际观测的要求.Geosciences are based on observation. It＇s a vital part of geophysics instruments to distinguish minor and weak signals of the earthquake from contaminated signals bring by human~ s modernization activity, such as transportation, industrialization or urbanization. In order to improve the observation accuracy, integrated multidisciplinary observation system of Deep Well is developed by China Earthquake Administration. Real-time data communication between host on the ground and all kinds of borehole sensors is linked by RS-232. For the borehole Magnetometer, a part of deep well sensor, in order to improve the ability of detect weak geomagnetic signals and take advantage of deep well observation, we develop signal process circuit and digital acquisition system of fluxgate probe with higher precision. The magnetometer developed two types of transfer conditions including passive mode of transfer protocol and active one to meet requirements of stability and data communication of real-time test and position adjustment underground. We develop the auto/manual background geomagnetic compensation method to meet the requirement of automatic remote monitor, as well as position adjustment, instrumental test, system calibration. Meanwhile a novel method of protocol analysis with bytes check is developed. Thus the magnetometer has the better anti-jamming capability and more reliability. We develop the monitoring software with user-friendly interface. Thought the half month performance test in Jinhai Geomagnetic Observatory. The magnetometer shows a good performance. It＇s proved that the observational results are accurate, and same as the DIMARK-FGE. Peak to peak noise is 0. 043 nT. RMS noise is 0. 014nT/-./Hz. Therefore the deep well magnetometer can meet the requirement of deep well observation.

关 键 词：井下磁力计 深井地球物理观测 全波整流相敏检波器 背景磁场补偿 ADIS16209 

分 类 号：TH762[机械工程—仪器科学与技术]