中心回线航空瞬变电磁探测系统误差与噪声的定量分析  

Quantitative analysis of error and noise in concentric loop airborne TEM detection system

作　　者：尹雄 王中兴[1,2,3] 康利利[1,2,3] 刘志尧 赵冬荣 YIN Xiong;WANG ZhongXing;KANG LiLi;LIU ZhiYao;ZHAO DongRong(CAS Engineering Laboratory for Deep Resources Equipment and Technology,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,CAS,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院深地资源装备技术工程实验室,中国科学院地质与地球物理研究所,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049

出　　处：《地球物理学进展》2022年第2期902-910,共9页Progress in Geophysics

基　　金：北京市科技计划“地球深部探测技术攻关”专项(Z181100005718001);中国科学院科研仪器设备研制项目(ZDZBGCH2018006)联合资助.

摘　　要：航空瞬变电磁法具有探测效率高、地形适应性强等优点,广泛应用于复杂地形条件下的资源勘探.但是,航空瞬变电磁系统位于空中,测量过程一直处于运动状态,极易产生误差和噪声,影响该方法的探测效果.本文通过仿真模拟和量化分析,分别研究了偏心误差、姿态误差和运动噪声对中心回线式航空瞬变电磁系统接收响应的影响.研究结果表明,偏心误差对接收响应的影响最小,带来的误差不会超过0.38%.姿态偏转带来的误差较大,横滚角和俯仰角在0°~20°之间时,姿态误差分布在11%以内,因而需要进行校正.利用姿态角测量可进行姿态误差校正,测量精度为0.3°时,校正误差降至0.2%以下.运动噪声对接收响应影响最大,线圈摆动幅度降至0.1°,频率降至25 Hz时,运动噪声减小到8.0μV,约0.2 ms后,运动噪声将湮没有效信号.通过三分量磁场测量并投影到地磁场方向能有效降低运动噪声,25 Hz、0.1°的摆动下,运动噪声减小到0.013μV,减小615倍,湮没时间推迟至4.8 ms,从而大大拓展了有用信号可用范围.本研究为减小系统误差、削弱噪声,提高航空电磁数据信噪比提供了指导.Airborne Transient Electromagnetic Method(TEM)has the advantages of high detection efficiency and strong terrain adaptability,which is widely used in resource exploration under complex terrain conditions.However,the airborne TEM system works in the air,and the measurement process is always in motion.It is easy to produce error and noise,which affects the detection effect of this method.In this paper,through simulation and quantitative analysis,the effects of eccentricity error,attitude error and motion noise on the receiving response of concentral loop airborne TEM system are studied.The results show that the eccentricity error caused by horizontal eccentricity and vertical eccentricity is very small.When the horizontal eccentricity is 1.5 m,the error is less than 0.1%,and when the vertical eccentricity is 0.1 m,the error is less than 0.28%.The error caused by attitude deflection is relatively large.When the roll angle and the pitch angle are between 0 and 20°,the attitude error is within 11%,so it needs to be corrected.The posture angle measurement can be used to correct the posture error.When the measurement accuracy is 0.3°,the correction error is reduced to less than 0.2%.Motion noise has the greatest impact on the receiving response.When the attitude angle is 0°~1°and the attitude angle change frequency is 0~50 Hz,the amplitude of the motion noise is within 160μV.Therefore,the receiving coil must be damped to suppress noise.When the swing amplitude of the coil drops to 0.1°and the vibration frequency drops to 25 Hz,the motion noise is reduced to 8.0μV.After about 0.2 ms,the motion noise signal will annihilate the invalid signal.The three-component magnetic field measurement and projection to the direction of the geomagnetic field can effectively reduce the motion noise.Under 25 Hz,0.1°swing,the motion noise is reduced to 0.013μV,which is reduced by 615 times,and the annihilation time is delayed to 4.8 ms,which greatly expands the available range of useful signals.This research provides guidance for

关 键 词：中心回线 航空瞬变电磁响应 偏心误差 姿态误差 运动噪声 

分 类 号：P631[天文地球—地质矿产勘探]